The clinical course began with what appeared to be a subungual hematoma, a collection of blood beneath the toenail of the kind familiar to anyone who has ever dropped a heavy object on a foot. Trephination, a procedure in which a small hole is made in the nail plate to relieve pressure and drain the trapped blood, was performed under the assumption that this was the problem. But two weeks after the procedure, the swelling had not resolved and the dark discoloration beneath the nail persisted. A clinical photograph taken at that point documented marked soft-tissue swelling of the toe along with the stubborn subungual discoloration, findings that prompted the team to look deeper. What the imaging revealed would rewrite the entire diagnostic picture.

A frontal radiograph of the toe demonstrated a destructive, predominantly lytic process replacing the entire distal phalanx, the small bone at the very tip of the great toe, in the region distal to the open physis, the growth plate that in children remains a cartilaginous zone between the bony shaft and the epiphysis. The normal trabecular architecture, the delicate internal lattice of bony struts that gives healthy bone its strength and appearance on X-ray, had been completely lost. In its place the radiologists described a pattern of bone destruction that was permeative to moth-eaten, terms that refer to the way aggressive lesions riddle bone with countless tiny, ill-defined holes rather than producing one clean cavity. Cortical thinning and disruption were also present, meaning the dense outer shell of the bone had been eroded and breached by the growing tumor.

Notably, the physeal contour remained intact. The growth plate, a structure that in growing children acts as a boundary between bone segments, had not yet been visibly breached by the process, even though the bone beyond it had been substantially destroyed. This detail matters because the behavior of tumors relative to the physis can offer clues about their nature and extent, and because preserving the physis has implications for surgical planning in a skeletally immature patient. Even with this anatomical nuance, the overall radiographic appearance was unmistakably aggressive. In pediatric bone radiology, permeative destruction with cortical breakdown is a red flag that demands consideration of malignancy, whatever the clinical history might suggest.

Given the boy’s history of repeated crush injuries, chronic osteomyelitis, a persistent infection of the bone, was the initial suspicion. This was a reasonable hypothesis. Chronic osteomyelitis can follow trauma, can produce lytic bone destruction, and is far more common than a malignant tumor in the distal phalanx of a toe. The distinction, however, could not be made on imaging alone, and biopsy was performed. The tissue diagnosis established Ewing sarcoma, a small round blue cell tumor driven in the vast majority of cases by a characteristic chromosomal translocation that fuses the EWSR1 gene with members of the ETS family of transcription factors, most commonly FLI1. This fusion protein acts as an aberrant transcriptional regulator, driving the uncontrolled proliferation that defines the disease. Definitive diagnosis of Ewing sarcoma typically rests on a combination of histology, immunohistochemistry demonstrating membrane staining for CD99, and molecular confirmation of the pathognomonic fusion.

The rarity of this presentation cannot be overstated. Ewing sarcoma is the second most common primary malignant bone tumor in children and adolescents, yet it has a strong predilection for specific locations: the pelvis, the femur, the tibia, the ribs, and the bones of the chest wall. It typically arises in the diaphysis or metaphysis of long bones, and involvement of the small bones of the hands and feet is exceptionally uncommon. Within those small bones, the distal phalanges are the rarest of sites. The authors of the report note that Ewing sarcoma of the toes is exceptionally rare, with distal phalangeal involvement reported in only a handful of cases worldwide. Every published instance therefore becomes a teaching case, because the accumulated experience of most radiologists and oncologists with tumors at this site is close to zero.

That rarity carries a real clinical cost, and it is the central message of the report: unusual location and clinical resemblance to trauma or infection may delay recognition. In this case, three months elapsed between the onset of symptoms and the establishment of the correct diagnosis, with the interval punctuated by procedures and treatments aimed at conditions the toe did not actually have. Delay in diagnosing Ewing sarcoma is not a trivial matter. The tumor is highly aggressive, with a capacity for local infiltration and early hematogenous metastasis, most commonly to the lungs and to other bones. Modern multimodal therapy, combining intensive multi-agent chemotherapy with local control through surgery, radiation, or both, has transformed five-year survival for localized disease, but outcomes deteriorate sharply once metastatic spread has occurred. Every week of diagnostic delay is a week in which a curable localized tumor has the opportunity to become something far worse.

The case also illustrates a broader principle in radiology and clinical medicine: the history is a guide, not a verdict. A plausible mechanism of injury, a swollen painful digit, and a dark nail can lull clinicians into anchoring on subungual hematoma and its complications, and later on osteomyelitis, without ever questioning whether the underlying process might be neoplastic. The authors urge radiologists to maintain suspicion for malignancy when confronted with aggressive phalangeal bone destruction, even when the clinical history suggests a more common process. In practical terms, this means that when an X-ray of a small bone shows permeative destruction, cortical disruption, and loss of trabecular architecture, the radiology report should explicitly flag the possibility of an aggressive neoplasm and recommend further evaluation, including magnetic resonance imaging to define the soft-tissue extent and marrow involvement, and ultimately biopsy to obtain tissue.

For the wider audience beyond the radiology reading room, the story is a reminder that persistent symptoms that fail to respond to appropriate treatment deserve escalation, not repetition. A crushed toe that keeps hurting and swelling for months, that darkens beneath the nail and does not improve after drainage, is not behaving like a simple injury. Children and adolescents are not immune to malignant bone tumors, and while the odds overwhelmingly favor benign explanations for a sore toe, the consequences of missing the rare alternative are profound. The authors of this report, who obtained informed consent from the patient’s parent for publication of the clinical information and images, have contributed a documented example of exactly this diagnostic trap, complete with the clinical photograph and radiograph that show how deceptive the presentation can be.

Ultimately, the case of the great toe distal phalanx joins a small but important body of literature documenting Ewing sarcoma in the most peripheral bones of the body. It underscores the value of open-access publication in pediatric radiology, allowing a single instructive case to reach clinicians everywhere who might otherwise never encounter this entity in their own practices. It reinforces the technical vocabulary of aggressive bone lesions, permeative and moth-eaten patterns, cortical disruption, and physeal relationships, as more than academic descriptors: they are the visual signatures that separate a tumor from an infection and from a healed crush injury. And above all, it demonstrates that in medicine, as in the imaging itself, what lies beneath the surface can only be known when someone thinks to look, and keeps looking when the first answer does not fit.

Subject of Research: Ewing sarcoma of the great toe distal phalanx in a pediatric patient

Article Title: Ewing sarcoma of the great toe distal phalanx

Article References: Ewing sarcoma of the great toe distal phalanx. (n.d.). https://doi.org/10.1007/s00247-026-06773-1

Image Credits: AI Generated

DOI: 10.1007/s00247-026-06773-1

Keywords: Ewing sarcoma, pediatric radiology, bone tumor, distal phalanx, great toe, lytic bone lesion, osteomyelitis, subungual hematoma, biopsy, radiography, sarcoma, diagnostic delay

NCCN Guidelines occupy a distinctive position in modern oncology. They are compiled by more than 60 expert panels drawing on more than 2,000 interdisciplinary specialists from the network’s 34 member institutions, working alongside patient advocates, and they are updated continuously rather than on a fixed revision schedule. Independent studies have found that care delivered in concordance with these recommendations is associated with longer survival, better outcomes, and lower costs across a range of cancer types. The guidelines function as a roadmap for clinicians making complex treatment decisions, establishing guardrails against both overtreatment, which exposes children to unnecessary toxicity, and undertreatment, which can compromise the chance of cure. For a rare pediatric cancer, where an individual oncologist may encounter only a handful of cases across an entire career, that kind of standardized expert consensus can be transformative.

The clinical picture of Ewing sarcoma helps explain why dedicated pediatric guidance is so important. The disease typically strikes teenagers between the ages of 15 and 19, a developmental window in which patients are forging their identities and their sense of independence. It often announces itself as severe and persistent pain or swelling in the limbs or pelvis, symptoms that overlap substantially with far more benign adolescent complaints such as sports injuries and growing pains. Because of that overlap, x-rays serve as a key first step in the diagnostic process, allowing physicians to identify suspicious bone lesions before proceeding to more definitive imaging and biopsy. The guidelines therefore address not only treatment but the diagnostic pathway that determines how quickly a young patient reaches specialist care.

Survival statistics underscore the stakes. When Ewing sarcoma is diagnosed at an early, localized stage, the five-year survival rate stands at 81 percent, a figure that reflects decades of progress in multimodal therapy combining chemotherapy, surgery, and radiation. When the disease has already spread to distant sites by the time of diagnosis, however, that rate falls to 41 percent. The steep drop-off between localized and metastatic disease illustrates both the progress that has been achieved and the considerable distance that remains. It also highlights the importance of risk stratification, the process of sorting patients by the biological and clinical features of their tumor so that therapy intensity can be matched to the true severity of disease, a topic on which Dr. Leavey noted there have been significant improvements in recent years.

Patrick Leavey, MD, of UT Southwestern Simmons Comprehensive Cancer Center, who chairs the NCCN Guidelines Panel for Pediatric Bone Sarcoma, emphasized the particular vulnerabilities of the adolescent patient population the guidelines are designed to serve. Intensive cancer treatment, he explained, can drain a teenager’s energy and disrupt their developing sense of autonomy at precisely the moment when they are striving for independence. The guidelines, in his view, serve a reassurance function as well as a clinical one, ensuring that young patients know they have a knowledgeable team ready to support them through a regimen that will test them physically and emotionally. That dual purpose, technical precision paired with developmental sensitivity, distinguishes pediatric oncology guidance from its adult counterparts.

The patient advocate perspective on the panel carries equal weight in shaping the document. Paula Head, who served as a caregiver for her own daughter, described the guidelines as clear, accurate medical roadmaps that reduce anxiety and build confidence in the care a child is receiving. Her advocacy was driven by a conviction that pediatric cancers and their treatments differ fundamentally from those of adults, and that families deserve recommendations written specifically for children rather than adapted from adult protocols. Reflecting on the toll the disease takes on young people, she offered a simple measure of its impact: whether the number of children affected is one or 101, whatever that number is, it is too many.

One of the thorniest challenges in advancing care for Ewing sarcoma is its sheer rarity. Clinical trials, the engine of therapeutic progress in oncology, depend on enrolling enough patients to detect meaningful differences between treatment approaches. A cancer this uncommon makes that arithmetic difficult, and Dr. Leavey pointed to clinical trials as essential to overcoming the stagnation that rarity can impose. Cooperative group trials that span multiple countries and institutions have historically been the mechanism by which pediatric sarcoma outcomes have improved, and the new guidelines are expected to reinforce the trial infrastructure by standardizing the baseline care against which experimental approaches are compared. Recent gains in risk stratification, which allow clinicians to identify which patients need the most aggressive therapy and which might be spared its long-term consequences, represent the kind of progress that careful, coordinated data collection makes possible.

The publication of pediatric bone sarcoma guidance completes a deliberate expansion of NCCN’s pediatric portfolio. Children are not simply small adults: their cancers arise from different biological processes, their bodies respond differently to chemotherapy and radiation, and their long-term survivorship needs, spanning decades of growth and development, demand a distinct framework. By issuing disease-specific pediatric guidelines, the network gives community oncologists and pediatricians outside major cancer centers a direct line to the consensus of the most experienced specialists, potentially shortening the time between diagnosis and appropriate referral. For families, the existence of a free, authoritative reference can convert an overwhelming and opaque journey into a navigable one.

Access is a central part of the NCCN model. All of the guidelines are available free of charge for non-commercial use at NCCN.org and through the Virtual Library of NCCN Guidelines App, and most can now be explored digitally through the NCCN Guidelines Navigator, which allows clinicians to search content interactively rather than paging through traditional PDF documents. Free website registration is required to access the clinical content. That open-access philosophy reflects the network’s mission as a not-for-profit alliance of leading cancer centers devoted to patient care, research, and education, and it ensures that the new pediatric bone sarcoma recommendations can reach practitioners anywhere in the world, including regions where specialized sarcoma expertise is scarce.

For the teenagers and families facing Ewing sarcoma, the arrival of dedicated guidelines is unlikely to change the biology of the disease, but it may change the experience of confronting it. Standardized recommendations mean that a child diagnosed in a community hospital can receive care aligned with the same evidence and expert judgment that governs treatment at the most advanced cancer centers. They mean that the questions families ask, about which therapies to pursue, which trials to consider, and what supportive care to expect, can be answered with reference to a shared, transparent document. And they signal to the research community that this rare and formidable cancer now has a formal place in the framework of modern oncology, a foundation on which the next generation of therapeutic advances can be built.

Subject of Research: First NCCN clinical practice guidelines for pediatric Ewing sarcoma and other bone sarcomas in children and adolescents

Article Title: A formidable type of childhood cancer gets added to highly regarded library of treatment recommendations

Article References: A formidable type of childhood cancer gets added to highly regarded library of treatment recommendations. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: Ewing sarcoma, NCCN Guidelines, pediatric oncology, bone sarcoma, clinical practice guidelines, childhood cancer, risk stratification, clinical trials, adolescent health, cancer survival rates, treatment recommendations, rare cancers

The technique at the heart of the study is called time-dependent diffusion MRI, abbreviated T_d-dMRI. Its underlying logic is elegant. In standard diffusion-weighted imaging, water molecules inside tissue diffuse randomly, and their movement is hindered by cell membranes and other obstacles. The apparent diffusion coefficient, or ADC, summarizes this restriction in a single number, but that number conflates many different microstructural influences. Time-dependent diffusion MRI changes the experimental geometry instead. Using pulsed gradient spin-echo sequences, the diffusion-weighting gradients act over relatively long times, allowing water to wander across substantial distances and probe large-scale tissue structure. Oscillating gradient spin-echo sequences, by contrast, reverse the gradient direction rapidly, effectively confining the measurement to very short diffusion times during which water molecules can only explore their immediate cellular neighborhood. By comparing diffusivity measured at long and short diffusion times, the method gains sensitivity to features such as cell size, cell density, and the volume fraction occupied by cells, which conventional ADC cannot disentangle.

To translate these raw measurements into biologically meaningful numbers, the researchers applied a model known as IMPULSED. This analytical framework treats tissue as a collection of impermeable cells embedded in an extracellular space and fits the diffusion signal acquired at multiple frequencies to estimate specific microstructural parameters. Four quantities emerge from the fit: the extracellular diffusivity, which reflects how freely water moves outside cells; the intracellular volume fraction, which captures the proportion of the tissue volume packed inside cell membranes; an estimate of cellularity; and an estimate of mean cell diameter. Each of these parameters has a direct pathological counterpart that a pathologist can measure under the microscope, which is precisely what makes the approach so attractive for radiologic-pathologic correlation.

The experimental system consisted of xenograft tumors grown in nude mice. The team implanted two human-derived cell lines: RD, which produces rhabdomyosarcoma tumors, and A673, which produces extraosseous Ewing sarcoma tumors. Thirty-three rhabdomyosarcoma xenografts and thirty Ewing sarcoma xenografts underwent the time-dependent diffusion protocol. Two independent readers derived the microstructural parameters from whole-tumor volumes, allowing the study to assess measurement reproducibility as well as diagnostic performance. The choice of xenograft models is an important caveat that the authors themselves emphasize: these are controlled, single-cell-line systems, which are ideal for establishing proof of concept but do not capture the heterogeneity of human tumors.

The results revealed striking and statistically robust differences between the two tumor types. Rhabdomyosarcoma xenografts showed significantly lower cellularity than Ewing sarcoma xenografts, with values of 2.88 versus 4.34 per micrometer, and a lower intracellular volume fraction of 0.44 versus 0.58. The rhabdomyosarcoma cells were also larger, with an estimated mean diameter of 18.59 micrometers compared with 16.56 micrometers for the Ewing sarcoma cells, and water diffused more freely in their extracellular space, at 0.82 versus 0.69 square micrometers per millisecond. Perhaps most intriguing was the behavior of the ADC across diffusion times. When the sequence shifted from the long-diffusion-time pulsed gradient to the rapidly oscillating 50-hertz gradient, the relative ADC change was 85.5 percent in rhabdomyosarcoma but 179.8 percent in Ewing sarcoma. All of these differences reached statistical significance at P less than 0.01. In physical terms, the Ewing sarcoma tumors, being more densely packed with smaller cells, restricted water far more severely at short diffusion times, producing a much larger swing in measured diffusivity.

Diagnostic performance was assessed with receiver operating characteristic analysis, which quantifies how well a parameter separates two classes. Time-dependent diffusion MRI-derived cellularity achieved an area under the curve of 0.92, while the ADC measured with the 50-hertz oscillating gradient achieved 0.91. A DeLong test comparing the two curves found no statistically significant difference, with P equal to 0.67, indicating that the model-derived cellularity estimate and the simpler oscillating-gradient ADC performed comparably in this setting. That equivalence is worth noting: the model-free ADC at a single oscillating frequency captured nearly all of the discriminative power, which could simplify clinical implementation if the finding holds in human tissue.

The methodological centerpiece of the study, and what distinguishes it from much of the existing diffusion MRI literature, is the slice-by-slice radiologic-pathologic correlation. Rather than comparing whole-tumor imaging averages with whole-tumor histology scores, the researchers registered hematoxylin and eosin stained sections to the corresponding MRI slices, aligning each microscopic field with its radiologic counterpart. This co-registration allowed the team to test whether the in vivo imaging parameters genuinely tracked microscopic reality at the same anatomical location. The answer was affirmative across the board: all of the time-dependent diffusion MRI parameters showed significant associations with the matched histological features. The strongest relationship linked in vivo MRI-derived cellularity with ex vivo pathological nuclear density, yielding a Spearman correlation coefficient of 0.784 with P less than 0.001. In other words, the scanner was not merely producing numbers that differed between tumor types; it was reproducing, noninvasively, what the pathologist counted under the lens.

Why does this matter beyond the xenograft laboratory? Soft tissue sarcomas encompass dozens of distinct entities with divergent biology, and rhabdomyosarcoma and extraosseous Ewing sarcoma are among the most clinically consequential in young patients. Rhabdomyosarcoma, arising from skeletal muscle lineage, and Ewing sarcoma, driven in most cases by characteristic gene fusions, require different chemotherapy regimens, different local therapy strategies, and different surveillance plans. Current multiparametric MRI, combining T1-weighted, T2-weighted, and conventional diffusion sequences, provides limited traction because the tumors share so many gross features. A validated microstructural imaging biomarker could, in principle, sharpen pre-biopsy differential diagnosis, guide the placement of biopsy needles toward the most diagnostically informative tumor regions, and potentially serve as a noninvasive marker of treatment response, since effective therapy should alter cellularity and cell size in measurable ways.

The authors are careful, appropriately, to frame the study as a proof of concept rather than a clinical result. The findings are model-specific, derived from two xenograft lines in mice, and do not yet establish that the technique can differentiate human rhabdomyosarcoma from human Ewing sarcoma in patients. Human tumors are heterogeneous mosaics of divergent clones, stromal cells, necrotic regions, and edema, and their microstructural signatures will be far messier than those of pure cell-line xenografts. The IMPULSED model also rests on assumptions, such as impermeable cell membranes, that may be violated in aggressive tumors with leaky vasculature and dying cells. Validation across additional biological models and, crucially, human cohorts is required before any clinical translation. The imaging hardware is another consideration: oscillating gradient sequences demand specialized gradient hardware and acquisition protocols, although the involvement of Siemens Healthineers researchers suggests that implementation on clinical scanners is a realistic goal.

Even with those caveats, the study represents a meaningful step toward a long-sought goal in oncologic imaging: turning the MRI scanner into a virtual microscope. The combination of time-dependent diffusion encoding, biophysical modeling, and rigorous slice-matched histologic validation offers a template for how microstructural imaging biomarkers should be developed and tested. If subsequent studies in human patients confirm that cellularity and related parameters can be measured reliably in vivo and correlate with pathology at the level of individual tissue slices, the implications could extend well beyond sarcomas, potentially informing the characterization of brain tumors, breast lesions, and prostate cancer, where microstructural imaging is already under intense investigation. For now, the Shanghai team has demonstrated that the water molecules diffusing through a living tumor carry a readable record of its cellular architecture, and that record can be checked, slice by slice, against the truth that only the pathologist has traditionally been able to see.

Subject of Research: Time-dependent diffusion MRI microstructural characterization of rhabdomyosarcoma and extraosseous Ewing sarcoma xenografts with radiologic-pathologic correlation

Article Title: Time-dependent diffusion MRI for microstructural characterisation of rhabdomyosarcoma and extraosseous Ewing sarcoma xenografts: a proof-of-concept study with slice-by-slice radiologic-pathologic correlation

Article References: Long, H., Liang, H., Hu, X., Yuan, Z., Liu, M., Feiweier, T., Tao, H., Li, X., & Chen, S. (2026). Time-dependent diffusion MRI for microstructural characterisation of rhabdomyosarcoma and extraosseous Ewing sarcoma xenografts: a proof-of-concept study with slice-by-slice radiologic-pathologic correlation. BMC Medical Imaging. https://doi.org/10.1186/s12880-026-02799-x

Image Credits: AI Generated

DOI: 10.1186/s12880-026-02799-x

Keywords: diffusion MRI, rhabdomyosarcoma, Ewing sarcoma, xenograft, cellularity, IMPULSED model, OGSE, PGSE, ADC, radiologic-pathologic correlation, soft tissue sarcoma, cancer imaging

The strategy rests on a molecular tug-of-war that determines whether a macrophage will engulf a tumor cell. Healthy cells display the surface protein CD47, which engages a receptor on macrophages and delivers a ‘don’t eat me’ signal, protecting normal tissue from collateral destruction. The researchers had previously shown that Ewing sarcoma cells exploit this system by upregulating CD47 while simultaneously downregulating cell-surface calreticulin, an ‘eat me’ signal that normally flags stressed or malignant cells for removal. The tumor, in other words, hides its own alarm while waving a shield. The team’s earlier work showed that blocking CD47 with the antibody magrolimab, while using the chemotherapy drug doxorubicin to push calreticulin back onto the tumor cell surface, dramatically enhanced macrophage phagocytosis of Ewing sarcoma cells in laboratory dishes and suppressed tumor growth and metastasis in an orthotopic mouse model.

That earlier combination, however, carried serious liabilities. Doxorubicin is a cornerstone of Ewing sarcoma treatment, but it is notorious for causing cardiotoxicity, a cumulative injury to heart muscle that can surface years after treatment, a particularly troubling prospect for pediatric survivors. Magrolimab, for its part, binds CD47 on red blood cells, triggering their clearance by the spleen and producing anemia, a side effect that has complicated the clinical development of first-generation anti-CD47 antibodies across the field. The new study set out to answer a deceptively simple question: could the therapeutic principle be preserved while swapping out the components responsible for the worst toxicities?

The first step was diagnostic. The researchers performed single-cell RNA sequencing on cells isolated from Ewing sarcoma xenograft tumors that had been treated with a phosphate buffer control, doxorubicin alone, magrolimab alone, or the doxorubicin plus magrolimab combination. Single-cell transcriptomics allows investigators to profile gene expression in individual cells rather than in bulk tissue, revealing how each cell type within the tumor microenvironment responds to therapy. The results were sobering: doxorubicin, whether given alone or with magrolimab, upregulated cellular pathways and functions associated with dilated cardiomyopathy in macrophages. The sequencing data suggested that the very drug used to sensitize the tumor to immune attack was simultaneously driving molecular changes in the tumor-associated immune compartment consistent with heart muscle disease, reinforcing the need for an alternative partner drug.

The team turned to cyclophosphamide, another standard chemotherapy agent for Ewing sarcoma, as a candidate replacement for doxorubicin. In a series of dose-response experiments, cyclophosphamide significantly enhanced cell-surface calreticulin expression on Ewing sarcoma cells in a dose-dependent manner, replicating the key sensitizing effect of doxorubicin without its cardiomyopathy-associated transcriptional signature. This matters because calreticulin exposure is the mechanistic linchpin of the approach: when the ‘eat me’ signal reappears on the tumor surface, CD47 blockade tips the balance decisively toward phagocytosis. The finding established that the dual-targeting logic of the therapy could be maintained with a chemotherapy agent already familiar to pediatric oncologists.

The second substitution addressed the anemia problem. Rather than magrolimab, the researchers tested lemzoparlimab, a next-generation anti-CD47 antibody engineered to spare erythrocytes. First-generation antibodies such as magrolimab bind CD47 indiscriminately, and because red blood cells are among the most CD47-abundant cells in the body, they are cleared en masse, producing the anemia that has limited dosing in clinical trials. Lemzoparlimab was designed with modified binding properties that reduce its interaction with red blood cells while preserving high-affinity blockade of CD47 on tumor cells. In in vitro phagocytosis assays, combining cyclophosphamide with either lemzoparlimab or magrolimab markedly increased macrophage engulfment of Ewing sarcoma cells, confirming that the newer antibody retained full functional potency in the presence of the calreticulin-inducing chemotherapy.

The decisive tests came in living animals. Using orthotopic Ewing sarcoma xenograft mouse models, in which tumors are established in the anatomically relevant site rather than under the skin, the researchers evaluated cyclophosphamide combined with magrolimab or lemzoparlimab in immunodeficient NSG hosts. Both combinations significantly reduced tumor growth and lung metastasis while prolonging animal survival compared with controls. These results demonstrated that swapping doxorubicin for cyclophosphamide did not sacrifice the anti-tumor and anti-metastatic efficacy that had made the original combination so compelling, and that either anti-CD47 antibody could deliver the phagocytic signal when paired with the calreticulin-inducing chemotherapy.

Safety, however, could only be properly assessed in a model with a functioning human hematopoietic system. In humanized NSG mice, mice engrafted with human immune and blood-forming cells, the difference between the two antibodies became stark. The cyclophosphamide plus magrolimab combination induced severe anemia and animal death, mirroring the red blood cell toxicity predicted from the antibody’s mechanism. The cyclophosphamide plus lemzoparlimab combination, by contrast, was well tolerated: treated animals maintained their blood counts, showed significantly reduced tumor burden, and enjoyed extended survival. The side-by-side comparison in humanized hosts provides unusually direct preclinical evidence that the erythrocyte-sparing design of lemzoparlimab translates into a genuine safety advantage in the context of this combination therapy.

The significance of the work extends beyond Ewing sarcoma itself. The CD47-calreticulin axis is exploited by a wide range of malignancies, and the field has struggled to reconcile the potent anti-tumor activity of CD47 blockade with its hematologic toxicity. By demonstrating that a chemotherapy agent can be selected not only for tumor-killing activity but for its ability to induce calreticulin without cardiomyopathy-associated transcriptional changes, and that an erythrocyte-sparing antibody can substitute for a first-generation blocker without loss of efficacy, the study offers a template for rational optimization of innate immunotherapy combinations. The use of single-cell RNA sequencing to monitor off-target pathway activation in the tumor microenvironment also illustrates how transcriptomic surveillance can flag toxic liabilities before they reach patients.

The authors caution that the findings remain preclinical, and the road from humanized mouse models to pediatric clinical trials involves regulatory, dosing and scheduling questions that animal studies cannot fully answer. Still, the combination of cyclophosphamide and lemzoparlimab brings together two agents with existing clinical pedigrees, one a decades-old standard of care in Ewing sarcoma and the other an antibody already advancing through oncology trials, which may ease the path to translation. For a disease in which new options for relapsed and metastatic patients are desperately needed, a safe and effective way to turn macrophages against the tumor represents a meaningful step forward. The research was supported in part by the National Cancer Institute Cancer Moonshot and the Children’s Cancer Fund, and the published data, the authors conclude, position the cyclophosphamide plus lemzoparlimab regimen as a therapeutic strategy with high potential for clinical translation in patients with Ewing sarcoma.

Subject of Research: Combinatorial macrophage-mediated innate immunotherapy with cyclophosphamide and lemzoparlimab for Ewing sarcoma

Article Title: Optimizing combinatorial macrophage induced innate immunotherapy against Ewing sarcoma

Article References: Luo, W., Zhu, H., Cannon, M. V., Gross, A., Rosenblum, J. M., Bellantoni, A. J., Mo, X., Roberts, R., Cripe, T. P., & Cairo, M. S. (2026). Optimizing combinatorial macrophage induced innate immunotherapy against Ewing sarcoma. Journal of Experimental & Clinical Cancer Research. https://doi.org/10.1186/s13046-026-03840-1

Image Credits: AI Generated

DOI: 10.1186/s13046-026-03840-1

Keywords: Ewing sarcoma, macrophages, CD47 blockade, lemzoparlimab, cyclophosphamide, calreticulin, magrolimab, immunotherapy, single-cell RNA sequencing, humanized mouse model, pediatric cancer, anemia

The meeting opens with a high-profile moment on Sunday, September 27, when John D. Halamka, the Dwight and Dian Diercks president of Mayo Clinic Platform, joins the Presidential Symposium in a session titled Data to Dialogue: Communicating Radiotherapy’s Value to Advance Care. His brief panel appearance, scheduled from 9:49 to 9:53 a.m. EDT, addresses a question that has moved from the margins to the mainstream of scientific discourse: how will science and healthcare information be disseminated tomorrow? The session examines the evolving roles of journals, websites, online platforms, and AI-powered content in shaping what both physicians and patients come to know about radiotherapy. It is a fitting opening note for a meeting in which machine intelligence threads through nearly every major Mayo Clinic presentation, from automated contouring to recurrence prediction.

Perhaps the most clinically consequential Mayo Clinic contribution comes in a Sunday afternoon clinical trials session, when Nadia Laack, a radiation oncologist at Mayo Clinic Comprehensive Cancer Center in Rochester, presents results from the Children’s Oncology Group trial AEWS1221. The study investigated stereotactic body radiation therapy, known as SBRT, combined with comprehensive metastasis-directed therapy in patients with metastatic Ewing sarcoma, an aggressive bone and soft-tissue cancer that has long defied conventional treatment when it spreads. The headline finding is remarkable: the researchers report the highest event-free survival recorded to date in cooperative-group trials of metastatic Ewing sarcoma. Equally important, the study establishes the feasibility and safety of delivering precisely targeted, ablative radiation doses to metastatic sites in this young patient population, a strategy that treats each site of spread as a targetable lesion rather than relying solely on systemic chemotherapy.

Artificial intelligence takes a starring role later that afternoon, when Andres Portocarrero Bonifaz, a radiation oncology medical physicist at Mayo Clinic in Florida, presents on AI-driven automation in pelvic radiation therapy during an education session on artificial intelligence, robotics, and emerging technologies in gynecologic radiation oncology. His talk traces the full pipeline of automation, from automated contouring of organs at risk to treatment plan optimization, and then extends into prediction-guided care. The central idea is that artificial intelligence can identify each patient’s individual risk of side effects before treatment begins, giving physicians a quantitative foundation for more personalized decisions about how aggressively to treat and how to protect healthy tissue. In gynecologic cancers, where pelvic targets sit close to bowel, bladder, and reproductive structures, that kind of predictive personalization could translate directly into fewer long-term toxicities.

Monday morning brings a rapid-fire quick pitch from Diego Santos Toesca, a radiation oncologist at Mayo Clinic in Arizona, on one of the most lethal malignancies in medicine: glioblastoma in older adults. His presentation describes patterns of radiographic failure at first progression among older patients treated with hypofractionated proton therapy guided by both MRI and 18F-DOPA PET imaging. The technical significance lies in the fusion of two imaging modalities: standard MRI delineates anatomical abnormality, while 18F-DOPA PET reveals metabolic activity that can expose tumor infiltration invisible to conventional scans. By targeting the combined imaging signature with a shortened course of proton therapy, which spares surrounding brain tissue from excess radiation dose, the team is mapping exactly where and how these tumors recur. Those failure patterns will inform the next generation of target volumes for a disease where every additional week of survival is hard-won.

Also on Monday, Michael Grams, a radiation oncology medical physicist at Mayo Clinic Comprehensive Cancer Center in Rochester, will describe Mayo Clinic’s first-in-human clinical translation of minibeam radiotherapy as part of an education session on spatially fractionated radiation therapy. Minibeam radiotherapy is one of the most conceptually radical ideas in the field: instead of delivering a broad, uniform radiation field, the beam is divided into many narrow, parallel microbeams separated by untouched tissue. The alternating pattern of dose appears to exploit a differential biological response, damaging tumor tissue while allowing normal tissue between the beams to recover and repair. Presenting the clinical workflow and translational insights from the first patients ever treated with this technique is a milestone moment, marking the journey of a physics concept from laboratory benches and animal models into the clinic for difficult-to-treat cancers.

Patient voice enters the scientific program through Minji Lee, a scientist in radiation oncology at Mayo Clinic in Rochester, who presents an oral session comparing the prognostic value of disease-specific patient-reported outcome measures in prostate cancer. Patient-reported outcomes, or PROs, capture symptoms and quality-of-life data directly from patients rather than from clinician assessments, and they have become increasingly influential in oncology. But not all PRO instruments are created equal, and the study systematically compares how well different measures predict overall survival in prostate cancer. The goal is evidence-based selection: identifying which validated instruments genuinely carry prognostic information so that clinicians and trialists can choose the tools that matter most, rather than defaulting to tradition or convenience.

Pediatric hematology-oncology is the focus of Brad Hoppe, a radiation oncologist at Mayo Clinic Comprehensive Cancer Center in Florida, who presents a post hoc safety analysis of the KEYNOTE-667 study during a scientific session on radiation and systemic therapy in hematologic malignancies. The analysis evaluates maintenance pembrolizumab, an immune checkpoint inhibitor, given concurrently with radiotherapy in pediatric patients with classic Hodgkin lymphoma who showed a slow early response to front-line chemotherapy. Combining immunotherapy with radiation raises a critical safety question, because both modalities can inflame the same normal tissues, and checkpoint inhibitors can trigger immune-related adverse events. Establishing that concurrent immunoradiotherapy is tolerable in children could expand the therapeutic arsenal for the subset of Hodgkin lymphoma patients whose disease does not respond quickly to chemotherapy alone.

The afternoon plenary on Monday features one of the most anticipated randomized trials in neuro-oncology. Paul D. Brown, a radiation oncologist at Mayo Clinic Comprehensive Cancer Center in Rochester and principal investigator of the Alliance A071801 phase III trial, will report results comparing postoperative single-fraction stereotactic radiosurgery with fractionated stereotactic radiosurgery for resected brain metastases. When a brain metastasis is surgically removed, radiation to the surgical cavity reduces the risk of local recurrence, but the optimal dosing schedule has remained contested. Single-fraction radiosurgery offers convenience and a single anesthesia session, while fractionated delivery spreads the dose across multiple sessions, potentially improving tumor control at the cavity margin and reducing radionecrosis. A definitive phase III answer will directly guide treatment for the hundreds of thousands of patients who develop brain metastases each year.

The Mayo Clinic program closes with two further presentations on Tuesday, September 29. Scott Lester, a radiation oncologist at Mayo Clinic Comprehensive Cancer Center in Rochester, delivers the first report from the Headlight trials, evaluating postoperative hypofractionated proton therapy for head and neck cancers unrelated to HPV. Shortening the course of proton therapy could reduce treatment burden while proton physics, which deposits dose with no exit radiation, offers a distinct sparing advantage for the salivary glands, swallowing structures, and spinal cord that surround head and neck tumors. Shortly afterward, in a session on the automated clinic, Mariana Borras-Osorio, a research fellow in radiation oncology at Mayo Clinic in Rochester, presents a machine-learning model designed to personalize PSA follow-up after prostate radiation therapy. The model integrates patient-specific clinical data with the kinetics of prostate-specific antigen, the standard blood-based biomarker monitored after treatment, to predict clinically meaningful recurrence. Together, the presentations sketch the field’s trajectory: imaging-guided precision, AI-augmented decision-making, radically novel beam geometries, and rigorously tested treatment schedules, all converging to make radiation therapy simultaneously more powerful and more personal.

Subject of Research: Mayo Clinic radiation oncology research presentations at the ASTRO 2026 Annual Meeting

Article Title: Mayo Clinic experts present radiation oncology research at ASTRO 2026

Article References: Mayo Clinic experts present radiation oncology research at ASTRO 2026. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: radiation oncology, ASTRO 2026, Mayo Clinic, artificial intelligence, SBRT, Ewing sarcoma, glioblastoma, minibeam radiotherapy, proton therapy, brain metastases, Hodgkin lymphoma, prostate cancer

The meeting, led by ASTRO President Neha Vapiwala, MD, FASTRO, is expected to draw roughly 10,000 oncologists, clinicians, physicists, researchers and other health care professionals from around the globe. Its theme this year, “Data to Dialogue: Communicating Radiotherapy’s Value to Advance Care,” signals a deliberate push to translate dense clinical trial results into conversations that patients, policymakers and the broader public can actually use. The program includes keynote addresses from former U.S. Food and Drug Administration Commissioner Scott Gottlieb, MD, and the award-winning oncologist and bioethicist Ezekiel Emanuel, MD, PhD, along with expert panels on two of the most consequential frontiers in cancer medicine today: artificial intelligence and radiopharmaceutical therapy.

One of the most anticipated presentations is a ten-year outcomes report from a phase 3 randomized trial comparing hypofractionated versus conventional fractionated postmastectomy radiotherapy in high-risk breast cancer patients. Fractionation — the practice of dividing a total radiation dose into many smaller daily treatments — has been a cornerstone of radiotherapy for decades, but the standard schedule for patients who have undergone mastectomy has historically been longer than for those who had lumpectomy. Hypofractionation compresses treatment by delivering larger doses per session over fewer visits, and long-term phase 3 data in the postmastectomy setting could reshape how clinicians counsel tens of thousands of women each year about the trade-offs between convenience, toxicity and cancer control.

The breast cancer theme continues with a study that addresses a different kind of gap: not biological, but logistical. The Navigator-Assisted Hypofractionation program, known as NAVAH, examined the impact of patient navigation within a cancer center-community partnership on access to short-course radiation therapy for African-American breast cancer patients. Shorter hypofractionated courses reduce the burden of daily travel, missed work and childcare conflicts — burdens that fall disproportionately on under-resourced patients — yet adoption has lagged in exactly the communities that stand to benefit most. Early results from this program, presented by Afua Ofori-Darko, BS, MPH, offer a test of whether structured navigation and community partnerships can close that gap, an approach that aligns squarely with the meeting’s “Data to Dialogue” theme.

Liver cancer takes center stage in two separate highlight abstracts. The first is the initial results of NRG-GI003, a phase III randomized trial from NRG Oncology comparing protons with photons — that is, proton beam therapy versus conventional X-ray-based radiotherapy — for hepatocellular carcinoma, the most common form of primary liver cancer. Proton therapy has long been promoted on theoretical grounds: protons deposit most of their energy at a precise depth and stop, sparing healthy tissue downstream of the tumor. In the liver, where patients often have compromised organ function and limited reserve, that dosimetric advantage could translate into meaningful clinical differences. Whether those physics advantages hold up as survival and toxicity outcomes in a rigorous randomized comparison is precisely the question NRG-GI003 was designed to answer, with results presented by Theodore Hong, MD.

A second liver cancer study, from a Chinese research group led by Lihong Wang, MD, tackles an earlier stage of disease. In an interim analysis of a prospective, single-center, non-inferiority randomized clinical trial registered as ChiCTR2000039404, researchers compared stereotactic body radiation therapy, or SBRT, against radiofrequency ablation for small hepatocellular carcinomas measuring two centimeters or less. Radiofrequency ablation has been a standard local treatment for small liver tumors, but it has limitations: tumors in difficult locations may be incompletely treated, and the technique’s effectiveness can depend heavily on tumor position and operator skill. SBRT delivers highly focused, ablative doses of radiation in just a few sessions, and a randomized non-inferiority comparison against ablation could establish radiation as an equally valid first-line option for the smallest liver tumors — a potentially practice-changing result if the interim data hold.

Lung cancer features prominently as well, with two distinct studies. The I-SABR trial reported six-year overall survival data for patients with early-stage non-small cell lung cancer who received nivolumab, an immune checkpoint inhibitor, following stereotactic ablative radiotherapy. The rationale behind combining radiation with immunotherapy rests on a compelling biological idea: radiation can kill tumor cells in ways that release tumor antigens and may prime the immune system, potentially turning a localized treatment into a systemic one. Randomized evidence on whether that synergy improves long-term survival in early-stage disease, presented by Joe Chang, MD, PhD, MS, FASTRO, is among the most closely watched data of the meeting.

The second lung cancer study addresses a frustrating clinical scenario. In the phase 2 MDT-Bridge study, patients with resectable or borderline resectable stage IIB–IIIB non-small cell lung cancer who became unresectable during neoadjuvant treatment were treated with chemoradiotherapy followed by consolidation durvalumab. For these patients, the surgical option disappears mid-treatment, and the study — presented as a late-breaking abstract by Andrea Filippi, MD — explores whether a bridge of definitive chemoradiation plus immunotherapy can salvage outcomes when surgery is no longer on the table. The strategy reflects a broader shift in thoracic oncology, where the boundaries between surgery, radiation and drug therapy are increasingly treated as fluid rather than fixed.

Prostate cancer and pediatric oncology round out the highlight list. NRG Oncology GU003 reported five-year results of a phase 3 trial comparing hypofractionated with conventional postprostatectomy radiotherapy, presented by Mark Buyyounouski, MD, MS, FASTRO — another test of whether shorter schedules can match longer ones in the adjuvant setting after surgery. And from the Children’s Oncology Group, Nadia Laack, MD, MS, presented results from AEWS1221 examining stereotactic body radiation therapy and comprehensive metastasis-directed therapy for patients with Ewing sarcoma, an aggressive cancer of bone and soft tissue that primarily strikes children and young adults. Metastasis-directed therapy — using precisely targeted radiation to attack individual sites of spread — represents one of the most conceptually ambitious ideas in modern radiation oncology, and applying it within a cooperative group pediatric trial marks an important step in bringing that approach to younger patients.

Taken together, the highlighted studies sketch a portrait of a field in transition. Shorter, more convenient treatment schedules are being validated across tumor types. Particle therapy is being put to the test in randomized trials rather than relying on dosimetric theory alone. Radiation is being combined with immunotherapy in ways that exploit its biological, not just its physical, effects. And the field is confronting directly who gets access to its advances, and why. ASTRO, the world’s largest professional society dedicated to advancing radiation medicine with 11,000 members, notes that radiation therapy is integral to 40 percent of cancer cures worldwide and that more than one million Americans receive radiation treatment for cancer each year. The data presented in Boston this week — and the conversations they are designed to spark — will help determine what those treatments look like for the next generation of patients.

Subject of Research: Clinical trial highlights in radiation oncology presented at the 2026 ASTRO Annual Meeting

Article Title: Additional research highlights from the 2026 ASTRO Annual Meeting

Article References: Additional research highlights from the 2026 ASTRO Annual Meeting. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: ASTRO 2026, radiation oncology, hypofractionation, proton therapy, hepatocellular carcinoma, SBRT, nivolumab, immunotherapy, Ewing sarcoma, breast cancer, lung cancer, health equity

The study was led by Bruna Almeida dos Santos, with Caroline Brunetto de Farias serving as corresponding author. The researchers focused on tropomyosin receptor kinases, commonly known as Trk receptors. TrkA, TrkB, and TrkC are encoded by the genes NTRK1, NTRK2, and NTRK3, respectively. These receptors normally transmit signals initiated by neurotrophins, proteins involved in neuronal development and maintenance. In cancer, however, abnormal receptor expression or activation can support cell survival and uncontrolled growth. Earlier work from the same research group indicated that TrkA and TrkB are expressed in Ewing sarcoma cells and that blocking these receptors can reduce tumor-cell proliferation.

To test the effect of broader Trk pathway inhibition in living organisms, the researchers used SK-ES-1 cells, a human Ewing sarcoma cell line. The cells were implanted into immunodeficient mice, allowing tumors to develop without being rejected by the animals’ immune systems. Once the tumors reached approximately 80–100 cubic millimeters, the mice received daily intraperitoneal injections of K252a at a dose of 0.5 milligrams per kilogram for 18 days. Control animals received the vehicle solution instead. K252a is not a selective Trk inhibitor; it can interfere with several protein kinases, meaning that its biological effects may involve multiple signaling systems simultaneously.

The treatment produced a measurable but temporary change in tumor growth. During part of the treatment period, particularly between days 9 and 15, tumors in K252a-treated mice grew more slowly than those in the control group. The difference did not persist, however. By day 18, tumor volumes in the treated animals had returned to levels comparable to those observed in the control group. The investigators also reported no significant differences in body weight or in the serum biochemical markers measured during the experiment, although these observations do not establish the compound’s safety for clinical use.

Molecular analysis of the tumor tissue offered clues about the temporary response. Tumors exposed to K252a showed significantly lower levels of total and phosphorylated TrkA and TrkB. Phosphorylation is a chemical modification that often activates signaling proteins, so reduced phosphorylation can indicate diminished receptor signaling. The researchers also observed reductions in total and phosphorylated PI3K, a central component of the PI3K–AKT pathway, which regulates cell survival, metabolism, growth, and resistance to stress. TrkC levels, by contrast, did not change significantly, suggesting that the three Trk receptors may not contribute equally to signaling in this model.

The analysis also revealed changes in the insulin-like growth factor pathway. Both total and phosphorylated insulin-like growth factor 1 receptor, or IGF1R, were reduced in tumors from treated animals. IGF1R is another receptor tyrosine kinase that can stimulate downstream pathways such as PI3K–AKT and promote proliferation and survival in cancer cells. The overlap between Trk and IGF1R signaling is particularly important because cancer cells can use interconnected pathways to compensate when one growth signal is blocked. The findings therefore suggest that K252a may have affected a broader signaling network rather than acting through Trk receptors alone.

The researchers tested this possibility in cultured SK-ES-1 cells by combining K252a with NVP-ADW742, a selective inhibitor of IGF1R. At the concentrations used, each compound alone caused only a relatively small decrease in cell viability. When the two compounds were administered together, the reduction in viability was significantly greater than that produced by either treatment alone. This result is consistent with the idea that simultaneous disruption of Trk-related and IGF1R signaling could make it more difficult for Ewing sarcoma cells to maintain the survival signals they need. The experiment remains an early laboratory observation and does not demonstrate that the combination would be effective or tolerable in patients.

The study also explored whether the expression of NTRK genes was related to overall survival in patients with Ewing sarcoma. The researchers analyzed two independent gene-expression datasets and found that higher NTRK2 expression was associated with shorter overall survival in a Children’s Oncology Group cohort. In a separate EuroEwing cohort, higher NTRK1 expression was associated with longer survival. NTRK3 showed contrasting associations between the patient populations. These relationships remained statistically significant after correction for multiple comparisons, but the cohorts were relatively small. Differences in patient characteristics, treatment, sample collection, and molecular profiling could also influence the results, so the findings should be regarded as exploratory rather than as validated clinical biomarkers.

The authors emphasize that the study’s conclusions are limited by the use of a single cell line-derived xenograft model and by K252a’s broad kinase activity. Because the compound can inhibit several enzymes, the temporary delay in tumor growth cannot be attributed exclusively to Trk inhibition or to any one molecular pathway. Further work will be needed in additional Ewing sarcoma models, including tumors with different genetic and biological features, and with more selective inhibitors capable of separating the contributions of TrkA, TrkB, TrkC, PI3K, and IGF1R. Even with these limitations, the results highlight the signaling dependence of Ewing sarcoma and point toward combination strategies that could be investigated as potential ways to overcome the tumor’s ability to bypass single-pathway treatment.

Subject of Research: Cells

Article Title: Delayed growth of SK-ES-1 Ewing sarcoma tumor xenografts is associated with reduced Trk and IGF1R pathway markers

News Publication Date: August 10, 2026

Web References: https://doi.org/10.18632/oncotarget.28911; https://www.oncotarget.com/archive/v17/

References: dos Santos et al., “Delayed growth of SK-ES-1 Ewing sarcoma tumor xenografts is associated with reduced Trk and IGF1R pathway markers,” Oncotarget, published August 7, 2026. DOI: 10.18632/oncotarget.28911

Image Credits: Copyright © 2026 dos Santos et al., distributed under the Creative Commons Attribution License (CC BY 4.0).

Keywords: Ewing sarcoma, K252a, Trk, NTRK, insulin-like growth factor 1 receptor, IGF1R, PI3K, cancer signaling, xenograft model, oncology