The starting point of the review is the physical assault that radiotherapy delivers. Ionizing radiation deposits energy that breaks DNA directly and, indirectly, floods cells with reactive oxygen species that damage proteins, lipids, and genomes alike. The dose, the fractionation schedule, and the type of radiation used all determine the character of this pressure. Cells that survive the initial insult do so by activating their DNA damage response machinery, a coordinated network of sensors, transducers, and effectors that pauses the cell cycle, repairs double-strand breaks through pathways such as non-homologous end joining and homologous recombination, and, when damage is overwhelming, triggers senescence or apoptosis. But the review emphasizes that DNA repair is only the first layer of a much deeper program of tolerance.

That deeper program is cellular plasticity. Rather than dying or fully recovering, a subset of surviving cells appears to enter altered, quasi-stable states that echo phenomena described in drug-treated tumors. The authors catalog several of these: persister-like states in which cells reversibly suspend proliferation; cancer stem cell-like states marked by molecules such as CD44 and aldehyde dehydrogenase, with enhanced self-renewal and repair capacity; senescence-like states, detectable in part by senescence-associated beta-galactosidase, in which cells remain metabolically alive but stop dividing and can secrete inflammatory signals; and hybrid epithelial-mesenchymal transition states that combine adhesive and migratory traits. Crucially, these states are not permanent identities. They are plastic, meaning the same residual cell may drift between them, and that fluidity makes them extraordinarily difficult to eliminate with any single targeted agent.

Alongside chromatin remodeling and transcriptional stress memory, which allow cells to carry a kind of biochemical recollection of the radiation they endured, these plastic states form the tumor-cell-intrinsic half of the radioresistance story. The review is careful to note that this intrinsic component complements rather than replaces classical radiosensitivity, which depends on factors such as oxygenation, cell-cycle phase, and repair capacity. What is new is the recognition that intrinsic tolerance alone cannot explain why recurrences so often emerge in predictable locations and time windows. For that, the authors argue, one must look outward, to the microenvironment that surrounds and stabilizes the surviving cells.

The concept of the tolerant niche is the conceptual heart of the paper. The authors describe several recurring microenvironmental configurations that act as sanctuaries for residual disease. Hypoxic niches are perhaps the best known: low oxygen reduces the radiation-induced free radical chemistry that makes oxygen so potent a radiosensitizer, and hypoxia simultaneously drives stem-like and invasive transcriptional programs. Perivascular niches, the zones around surviving blood vessels, shelter quiescent tumor cells and are rich in protective signaling. Niches dominated by cancer-associated fibroblasts and remodeled extracellular matrix provide both mechanical and biochemical support, secreting growth factors and stiffening tissue architecture in ways that dampen radiation lethality. Metabolic niches, shaped by nutrient scarcity and altered metabolite exchange, and myeloid niches, populated by tumor-associated macrophages, myeloid-derived suppressor cells, and regulatory T cells that suppress antitumor immunity, complete the picture. In each case, the niche does not merely coexist with tolerant cells; it actively maintains their state.

One of the review’s most useful contributions is its insistence that these mechanisms vary substantially among tumor types. The relative weight of hypoxia, stromal shielding, immune suppression, or stem-like plasticity differs between, for example, glioblastoma, pancreatic ductal adenocarcinoma, and lung cancer, and the authors caution against assuming that a strategy validated in one context will transfer to another. This heterogeneity has practical consequences for how the field measures residual disease. The authors assess the tools available and find them strikingly unequal in maturity. Functional imaging, including hypoxia-targeted PET tracers and advanced MRI sequences, and liquid biopsy based on circulating tumor DNA, offer selected clinical readouts that can already be deployed in trials to track residual disease and recurrence risk over time.

Spatial omics technologies, by contrast, which map gene expression and other molecular features across intact tissue sections, currently serve mainly as discovery and validation tools rather than clinical diagnostics. They are indispensable for identifying which cells occupy which niches and how those relationships change after irradiation, but sampling limitations, cost, and analytical complexity keep them out of routine practice. The review is candid about this gap: the field can describe tolerant niches in exquisite detail in resected specimens, yet it largely lacks the longitudinal, minimally invasive measurements needed to watch them form and dissolve in living patients. Bridging that gap, the authors suggest, will require combining serial ctDNA monitoring with imaging and, where feasible, repeat tissue sampling.

On the therapeutic side, the review outlines both evidence-based and investigational strategies for what the authors term niche-informed radiotherapy. Established approaches include hypoxia modification, dose escalation and altered fractionation, and combinations with DNA damage response inhibitors that disable the repair programs tolerant cells rely on. More speculative candidates target the niche itself: agents that reprogram cancer-associated fibroblasts, normalize tumor vasculature, modulate myeloid suppressor cells, or relieve immune suppression so that checkpoint blockade can act on residual disease. Senolytic strategies aimed at clearing senescence-like cells, and agents designed to push plastic persister states out of their protective equilibrium, also feature among the investigational options. The unifying principle is that candidate combinations should be validated against the specific niche dependencies of a given tumor before clinical adaptation, rather than applied indiscriminately.

The authors are equally clear about the obstacles standing between this framework and the clinic. Conceptually, tolerant niches are dynamic and heterogeneous, so static snapshots may mislead. Sampling remains a fundamental problem, since the most informative regions of a treated tumor are often inaccessible. Implementation faces the usual barriers of combination-therapy trials, toxicity management, and the absence of validated biomarkers that identify which patients carry which niche dependencies. None of these limitations, in the authors’ view, undermines the framework; they simply define the work that remains. The review, which was supported by numerous Chinese national and institutional research programs and published open access on 9 October 2026, is intended as a roadmap rather than a final verdict.

If the tolerant niche concept holds up under experimental and clinical scrutiny, its implications for oncology could be considerable. Recurrence after radiotherapy would no longer be viewed as a mysterious resurgence but as the predictable product of a documented sequence: radiation pressure, followed by the emergence of plastic residual states, followed by their stabilization within hypoxic, stromal, metabolic, and immune sanctuaries. Each step in that sequence offers an interception point, a moment when a rationally chosen combination therapy might extinguish the embers before they reignite. Turning that vision into practice will demand the longitudinal monitoring tools and niche-specific combination trials the review calls for, but it reframes one of radiotherapy’s oldest frustrations as a solvable, spatially defined problem in tumor ecology.

Subject of Research: Radioresistance and tumor recurrence through cellular plasticity and radiation-induced tolerant niches in the tumor microenvironment

Article Title: Radioresistance and tumor recurrence: cellular plasticity, tolerant niches, and therapeutic opportunities

Article References: Zhang, Y., Li, H., Lv, S., Peng, L., Meng, W., Guo, J., Lu, Y., Chen, W., Yang, W., & Peng, X. (2026). Radioresistance and tumor recurrence: cellular plasticity, tolerant niches, and therapeutic opportunities. Molecular Cancer. https://doi.org/10.1186/s12943-026-02806-3

Image Credits: AI Generated

DOI: 10.1186/s12943-026-02806-3

Keywords: radioresistance, radiotherapy, tumor recurrence, tolerant niches, cellular plasticity, DNA damage response, tumor microenvironment, cancer stem cells, hypoxia, residual disease, spatial omics, ctDNA

The biological foundation of this progress lies in the ERBB2 oncogene, which encodes the HER2 receptor tyrosine kinase. Amplification of ERBB2 drives constitutive signaling through downstream pathways that promote proliferation, survival and invasion, and it was first linked to aggressive breast cancer behavior and shortened survival in landmark work published in Science in 1987. That discovery created the therapeutic target. Monoclonal antibodies such as trastuzumab and pertuzumab, which bind the extracellular domain of the receptor and block signaling and antibody-dependent cellular cytotoxicity, were followed by small-molecule tyrosine-kinase inhibitors that act intracellularly, and most recently by antibody–drug conjugates (ADCs) that couple a HER2-directed antibody to a cytotoxic payload released selectively at the tumor site.

The most consequential recent arrival is trastuzumab deruxtecan (T-DXd), an ADC with a high drug-to-antibody ratio, a cleavable linker and a membrane-permeable payload that exerts a bystander effect on neighboring tumor cells. Originally demonstrated in heavily pretreated metastatic disease, T-DXd has now been moved rapidly into earlier lines of therapy and even into the curative setting. The review highlights its emerging roles in the first-line metastatic setting — where the DESTINY-Breast09 trial showed that T-DXd plus pertuzumab outperformed the traditional taxane, trastuzumab and pertuzumab regimen — as adjuvant treatment for high-risk residual disease after neoadjuvant chemotherapy, and as a neoadjuvant option in high-risk early breast cancer, as tested in DESTINY-Breast11. Each step forward creates new opportunity but also new uncertainty about optimal sequencing, duration and retreatment.

In early-stage disease, right-sizing cuts in two directions. For patients with low-risk tumors — small, node-negative cancers — the field has successfully de-intensified therapy. The APT trial established that weekly paclitaxel plus trastuzumab delivers excellent long-term outcomes for node-negative disease, and the ATEMPT trial compared the ADC trastuzumab emtansine (T-DM1) with that regimen in stage I disease, showing comparable efficacy with a different toxicity profile. Even more minimalist approaches, such as chemotherapy-free dual HER2 blockade in selected patients, are being explored in trials like DECRESCENDO and WSG-ADAPT, supported by biomarkers such as the HER2-enriched intrinsic subtype and tumor-infiltrating lymphocytes that identify tumors most likely to respond to antibody therapy alone.

For patients with stage II–III disease, the focus has shifted to optimizing the neoadjuvant chemotherapy backbone. Anthracyclines, once standard, have been progressively dropped from many HER2-directed regimens after trials such as TRAIN-2 demonstrated comparable outcomes without them, sparing patients cardiac and secondary-leukemia risks. Carboplatin, too, is being re-evaluated: the randomized phase III neoCARHP trial showed noninferiority of taxane-based dual blockade without carboplatin, and the HELEN-006 trial found that weekly nab-paclitaxel with trastuzumab and pertuzumab matched the classic docetaxel–carboplatin doublet. These de-escalation strategies matter because long-term survival in early HER2-positive disease is now so favorable that late toxicities and quality of life weigh heavily in treatment decisions.

At the other end of the early-disease spectrum sits the patient with residual invasive disease after neoadjuvant therapy, historically the group at highest relapse risk. The KATHERINE trial established adjuvant T-DM1 as the standard for these patients, and the more recent DESTINY-Breast05 program has now pushed T-DXd into this space for high-risk residual disease, following evidence from a phase III trial reported in the New England Journal of Medicine that T-DXd improved invasive disease-free survival in this population. The review emphasizes that residual disease is heterogeneous — varying in size, nodal status, hormone receptor status and residual cancer burden — and that escalation should be risk-based rather than uniform, with genomic tools such as HER2DX and circulating tumor DNA assays under development to refine who truly needs intensification.

In metastatic disease, the algorithm is being rebuilt around two concepts: maintenance therapy and first-line intensification. After induction with a taxane plus trastuzumab and pertuzumab, patients traditionally continued dual antibody therapy alone. New maintenance options are expanding that framework. The HER2CLIMB-05 phase III trial tested tucatinib — a highly selective HER2 tyrosine-kinase inhibitor with central nervous system activity — versus placebo added to trastuzumab and pertuzumab as first-line maintenance, while for hormone receptor-positive disease the addition of the CDK4/6 inhibitor palbociclib to trastuzumab and endocrine therapy has shown benefit in advanced settings. Meanwhile, DESTINY-Breast09 has positioned continuous T-DXd plus pertuzumab as a new first-line standard, raising unresolved questions about how long such intensive therapy should continue, how to sequence subsequent lines, and whether patients with exceptional responses might eventually de-escalate.

Biomarkers are emerging as the connective tissue that could make right-sizing practical at scale. Quantitative HER2 expression measured by tissue and plasma profiling correlates with ADC activity and may predict benefit from T-DXd. The PAM50 intrinsic subtype, particularly the HER2-enriched phenotype, predicts pathological complete response to HER2-directed therapy and underpins the commercially available HER2DX genomic assay, which is now being tested prospectively in the DEFINITIVE trial. Dynamic imaging biomarkers, including FDG-PET response adapted in the PHERGain strategy, allow chemotherapy de-escalation in patients showing early metabolic response, and ultrasensitive circulating tumor DNA tracking can identify minimal residual disease and exceptional responders, informing trials such as HEROES that explore treatment withdrawal in patients with sustained deep response.

The review also confronts persistent evidence gaps and equity concerns. The optimal duration of first-line T-DXd plus pertuzumab remains unknown, as does the value of retreating with T-DXd after prior exposure, an approach being studied in the EN-SEMBLE cohort. Brain metastases remain a dominant site of failure in HER2-positive disease, and the review details how tucatinib-based regimens, T-DXd and modern stereotactic radiation strategies are reshaping central nervous system management, while noting the risk of symptomatic necrosis when ADCs are combined with brain radiotherapy. Globally, access to HER2-targeted therapies remains uneven, and real-world data reveal racial and ethnic disparities in outcomes even among patients receiving ADCs, underscoring that right-sizing must include right of access.

What emerges from this synthesis is a vision of HER2-positive breast cancer care as a continuum of calibrated decisions rather than a fixed sequence of regimens. For the low-risk patient, the goal is a cure with the least toxicity; for the high-risk residual-disease patient, intelligent escalation; for the metastatic patient, durable control with the flexibility to intensify, maintain or step down as biology dictates. The tools — ADCs, kinase inhibitors, CDK4/6 inhibitors, genomic classifiers, ctDNA and molecular imaging — are largely in hand. The task now, the authors conclude, is to deploy them with precision, powered by prospective biomarker-driven trials that convert an era of drug abundance into an era of individually right-sized cures.

Subject of Research: Risk-adapted treatment strategies for HER2-positive breast cancer across early-stage and metastatic settings

Article Title: Right-sizing treatment for HER2-positive breast cancer: evolving algorithms across the disease continuum

Article References: Tarantino, P., Valenza, C., Segui, E., Lin, N. U., Prat, A., Curigliano, G., Waks, A. G., & Tolaney, S. M. (2026). Right-sizing treatment for HER2-positive breast cancer: evolving algorithms across the disease continuum. Nature Reviews Clinical Oncology. https://doi.org/10.1038/s41571-026-01211-5

Image Credits: AI Generated

DOI: 10.1038/s41571-026-01211-5

Keywords: HER2-positive breast cancer, trastuzumab deruxtecan, antibody-drug conjugates, de-escalation, neoadjuvant therapy, residual disease, maintenance therapy, tucatinib, palbociclib, circulating tumor DNA, HER2DX, biomarkers

HER2, a growth factor receptor encoded by the ERBB2 gene, is amplified or overexpressed in roughly 15 to 20 percent of breast cancers. That molecular signature once heralded an aggressive disease course, but the arrival of trastuzumab, pertuzumab, and a growing arsenal of HER2-targeted agents transformed the prognosis. Today, giving these drugs before surgery—neoadjuvant therapy—is standard practice for stage I to III HER2-positive disease, because it can shrink tumors, sometimes eliminating them entirely, and allows oncologists to gauge response in real time. Yet a meaningful fraction of patients still reach the operating table with residual invasive carcinoma in the breast or lymph nodes.

For those patients, the landmark KATHERINE trial established trastuzumab emtansine (T-DM1) as the standard of care, improving invasive disease-free survival and overall survival compared with trastuzumab alone. More recently, the DESTINY-Breast05 trial showed that trastuzumab deruxtecan (T-DXd) outperformed T-DM1 in patients with residual HER2-positive early disease. Critically, however, both frameworks assumed that a tumor classified as HER2-positive before treatment remained HER2-positive afterward. The MD Anderson study directly tested that assumption—and found it wanting.

The research team, led by pathologist Payu Raval and senior author Aysegul Sahin, retrospectively examined 161 patients treated with HER2-targeted neoadjuvant therapy between 2016 and 2025. Sixty-five of them had enough residual invasive tumor for reliable biomarker reassessment. Using the same clinically validated immunohistochemistry protocol applied in routine care, two study pathologists independently scored HER2 expression in the surgical specimens under the 2018 ASCO/CAP guidelines, with a third pathologist resolving any discordant readings. Every equivocal case—those scored IHC 2+—underwent reflex fluorescence in situ hybridization to determine whether the ERBB2 gene remained amplified.

The results were striking. Thirty-seven of the 65 tumors, or 57 percent, showed a change in HER2 status, shifting from overexpression or amplification before treatment to IHC 0, IHC 1+, or IHC 2+ without gene amplification afterward. Only 28 cases, 43 percent, retained clear HER2 positivity. The pattern depended on where tumors started: among the 33 tumors that were strongly HER2 IHC 3+ at baseline, just under half lost HER2, whereas among the 32 tumors classified as IHC 2+/FISH-amplified, more than two-thirds—68.8 percent—did so. Several of the converted tumors even fell into the emerging HER2-ultralow category, expressing barely detectable levels of the protein.

Perhaps the most sobering aspect of the study is what the researchers could not find. When the team compared the HER2-retained and HER2-changed groups across a battery of clinicopathologic variables—age, clinical stage, histologic subtype, Nottingham grade, hormone receptor status, residual cancer burden, and type of surgery—the two groups were essentially indistinguishable. Hormone receptor positivity was common in both, present in 82.1 percent of the retained group and 89.2 percent of the changed group, and the distribution of residual cancer burden categories was nearly identical. In other words, there is no easy clinical flag that tells oncologists in advance which tumors will shed their target.

Why does this happen? The leading explanation is intratumoral heterogeneity: a single tumor can harbor mixed populations of cells with differing levels of HER2 expression and ERBB2 amplification. Potent HER2 blockade wipes out the dependent cells, while subclones with little or no HER2 survive and repopulate the residual disease—a classic case of clonal selection under therapeutic pressure. Supporting this model, a phase II trial of T-DM1 plus pertuzumab found zero pathologic complete responses in tumors with HER2 heterogeneity, compared with 55 percent in homogeneous tumors. Other work has shown that HER2 heterogeneity is far more prevalent in tumors with low-level amplification, which may explain why the IHC 2+/FISH-amplified group in the new study was so vulnerable to status change. Resistant subclones, genomic studies suggest, often exist before treatment even begins.

The clinical stakes are considerable. Current national and international guidelines recommend adjuvant HER2-targeted therapy for residual disease regardless of post-treatment HER2 status, largely because trials like KATHERINE enrolled patients based on their original diagnosis and never required repeat testing. Whether T-DM1 or T-DXd actually benefits tumors that have lost HER2 remains unknown. There are reasons for cautious optimism: antibody-drug conjugates deliver cytotoxic payloads via the HER2 antibody, so even low levels of the protein may suffice for activity, and the DESTINY-Breast04 trial demonstrated survival benefits of T-DXd in HER2-low metastatic disease. Real-world data from China reported remarkably low recurrence rates among patients who continued HER2-directed therapy despite conversion. But preclinical studies complicate the picture, indicating that HER2-low cells may resist ADCs while remaining susceptible to HER2 kinase inhibitors—hinting that combination strategies may ultimately be needed.

Prognostic evidence is equally unsettled. Several meta-analyses have linked HER2 loss after neoadjuvant therapy to worse recurrence-free and overall survival, with hazard ratios approaching 2, and one registry analysis of more than 21,000 Japanese patients found that 21.4 percent of initially HER2-positive tumors became HER2-negative after treatment. Yet other cohorts, including a surgical series from 2021, found no oncologic penalty for losing HER2 positivity, and some even reported better outcomes with reduced expression. These contradictions likely reflect differences in definitions, therapy intensity, and sampling, but they underscore that complete loss and partial reduction of HER2 may carry different prognostic meanings. Intriguingly, one study found that shorter intervals between therapy and tissue sampling were associated with greater HER2 loss, raising the possibility that some of the change is a reversible pharmacodynamic effect rather than permanent clonal elimination.

The MD Anderson authors are careful about their limitations: the study was retrospective, single-institution, and modest in size, excluded residual tumors smaller than 5 millimeters, and lacked outcome data and molecular profiling. Still, their conclusion is pointed. HER2 should be viewed not as a fixed binary label but as a dynamic continuum reshaped by treatment, and routine reassessment of residual disease deserves serious consideration. Prospective randomized phase II and III trials, they argue, are now needed to determine whether patients whose tumors lose HER2 actually benefit from continuing HER2-targeted therapy—or whether, in the era of antibody-drug conjugates, the biopsy taken after neoadjuvant treatment should become the new starting point for every adjuvant decision.

Subject of Research: HER2 biomarker status change in residual breast carcinoma after neoadjuvant HER2-targeted therapy

Article Title: HER2 status change in residual breast carcinoma after neoadjuvant HER2-targeted therapy in patients with HER2-positive breast cancer

Article References: Raval, P., Ding, Q., Singh, P., Alrohaibani, A., Sun, H., Ai, D., Wanis, K. N., Zhao, M., Chen, H., Valero, V., Chavez-MacGregor, M., & Sahin, A. (2026). HER2 status change in residual breast carcinoma after neoadjuvant HER2-targeted therapy in patients with HER2-positive breast cancer. Breast Cancer Research and Treatment, 219(3), Article 25. https://doi.org/10.1007/s10549-026-08088-z

Image Credits: AI Generated

DOI: 10.1007/s10549-026-08088-z

Keywords: HER2-positive breast cancer, neoadjuvant therapy, HER2 status change, biomarker discordance, immunohistochemistry, FISH, trastuzumab, pertuzumab, antibody-drug conjugates, intratumoral heterogeneity, residual disease, adjuvant therapy

Neuroblastoma is a cancer of the sympathetic nervous system that arises most often in the adrenal glands or along the spine, and it accounts for a disproportionate share of childhood cancer deaths. The girl at the center of this report carried one of the worst prognostic markers in the disease: amplification of the MYCN gene, a genetic signature associated with aggressive, treatment-resistant tumors. Her initial treatment followed the standard European induction protocol known as COJEC, a rapid cycle of cisplatin, vincristine, carboplatin, etoposide, and cyclophosphamide, followed by two courses of topotecan, vincristine, and doxorubicin. When doctors re-evaluated her disease, the news was grim. The primary tumor in her abdomen remained large and active, it pressed on critical blood vessels, and scans revealed widespread involvement of her bones and bone marrow, yielding a skeletal disease score of 45 on the SIOPEN scale used across European pediatric oncology centers.

What followed was a relentless escalation of therapy. Second-line chemotherapy with temozolomide and irinotecan, later combined with the anti-GD2 antibody dinutuximab beta, succeeded in clearing the metastatic disease from her bones and marrow. She then underwent consolidation with two rounds of radiometabolic therapy using iodine-131 labeled MIBG—a radioactive form of the same tracer molecule used to image neuroblastoma—each followed by reinfusion of her own stem cells, and finally high-dose chemotherapy with busulfan and melphalan supported by another stem-cell rescue. Yet when the dust settled, one enemy remained entrenched: a residual mass in her retroperitoneum, the space behind the abdominal organs, measuring 13.3 by 9.8 by 6.9 centimeters. The mass continued to light up on MIBG scans, proof that living neuroblastoma cells persisted within it, and it wrapped around the celiac artery and the right renal artery while compressing the inferior vena cava, the largest vein in the body.

This anatomical situation presented surgeons with an impossible calculus. Any attempt at resection risked catastrophic hemorrhage from vessels that the tumor had encased, and there was no guarantee that a complete removal could be achieved even at that price. A biopsy taken through the skin confirmed that the mass contained viable neuroblastoma tissue showing differentiating features, meaning the cells were still alive and capable of regrowth. It was at this impasse that a multidisciplinary tumor board—bringing together pediatric oncologists, surgeons, interventional radiologists, pathologists, and radiation therapists at Bambino Gesù Children’s Hospital in Rome—turned to a technique that had never before been applied to a child with this disease: percutaneous electrochemotherapy.

The principle behind electrochemotherapy is elegantly physical. Cell membranes, though thin, are formidable barriers that normally prevent many chemotherapy drugs from entering cells efficiently. When short, high-voltage electric pulses are applied across a tissue, they transiently reorganize the lipid bilayer of those membranes, opening nanoscale pores in a process called reversible electroporation. The pores allow drug molecules to flood into the cell interior, and because the pulses are calibrated carefully, the membranes reseal afterward and the cells survive—only to be killed by the chemotherapy they have now absorbed in quantities far beyond what ordinary exposure could achieve. The drugs most commonly paired with electroporation are bleomycin and cisplatin, both of which become dramatically more cytotoxic inside electroporated cells. In adults, the technique has earned validated roles against melanoma, sarcoma, and head and neck tumors, but pediatric experience has been almost nonexistent.

The Roman team tailored the procedure to the unique biology of neuroblastoma. Rather than administering cisplatin intravenously, they injected it directly into the tumor, a strategy designed to maximize drug concentration within the lesion while minimizing systemic side effects—a rational choice given that platinum compounds are among the drugs to which neuroblastoma is classically sensitive. Under general anesthesia, with the child positioned prone, three variable-geometry needle electrodes with an active length of three centimeters were inserted intercostally, between the ribs, using computed tomography and ultrasound guidance. The target was the most metabolically active portion of the mass, precisely the region where MIBG single-photon emission imaging had shown the greatest tracer uptake and where the tumor pressed hardest against the inferior vena cava. Once the electrodes bracketed the target, an 18-gauge coaxial biopsy was taken through the field, and four milligrams of cisplatin at a concentration of two milligrams per milliliter were injected through a Chiba needle. The Cliniporator VITAE device then delivered voltage pulses ranging from 900 to 1,700 volts, completing the session.

The technical choreography matters because electroporation is unforgiving of sloppy planning. The electric field must cover the entire tumor volume homogeneously; any region that falls between electrodes may receive sub-lethal exposure and survive as a seed of recurrence. This is why careful pre-treatment planning and meticulous electrode placement are considered the linchpins of the technique, particularly for large or irregularly shaped lesions like the one in this case. Encouragingly, the procedure itself was uneventful. No immediate or delayed complications occurred, post-procedure monitoring revealed nothing concerning, and the child was discharged in stable condition. The team notes that the approach is also repeatable, an important attribute for a disease where residual lesions sometimes require more than one local intervention.

The follow-up imaging tells the story in two snapshots. One month after the procedure, magnetic resonance imaging revealed a necrotic, liquefied area of 20 by 20 millimeters within the treated field—direct evidence that the electroporated cells had died on schedule, consistent with the six-to-eight-week window in which electrochemotherapy’s radiological effects typically become apparent. The child then completed her maintenance phase of treatment with cis-retinoic acid and dinutuximab beta without any complications. Twelve months after the procedure, computed tomography and MIBG imaging delivered the decisive verdict: the mass had shrunk to 9.2 by 8.9 by 9.4 centimeters, and, critically, no residual MIBG uptake could be detected anywhere in the treated area. The metabolically active component that had survived everything modern pediatric oncology could throw at it had been silenced.

Why does the disappearance of MIBG avidity matter so much? MIBG is a norepinephrine analog that is taken up specifically by neuroblastoma cells, so persistent tracer uptake is a molecular signature of living tumor. In neuroblastoma, residual primary disease that remains MIBG-avid after multimodal treatment is a well-established negative prognostic factor, strongly correlated with relapse and poor survival. The ability to selectively target and neutralize these metabolically active foci—without opening the abdomen, without thermal energy that could damage vessels and adjacent organs, and without adding systemic toxicity—addresses one of the most frustrating gaps in current therapy. Thermal ablation techniques such as radiofrequency ablation and cryoablation have been used in selected pediatric tumors, but they are hazardous near major vessels, which act as heat sinks and limit ablation margins, and near structures like the celiac artery that cannot tolerate thermal injury. Electrochemotherapy’s non-thermal mechanism sidesteps that constraint, and the authors note that its effects are applicable across tumor histologies, including tumors resistant to other modalities.

The caveats are as important as the promise. This is a single case, reported by the team of Giulia Cassanelli, Maria Antonietta De Ioris, and Gian Luigi Natali, and pediatric oncology is littered with promising one-patient results that failed to generalize. The authors themselves are careful, framing electrochemotherapy as a feasible local option for selected patients and calling for further evaluation within a multidisciplinary framework rather than declaring a new standard of care. Yet the signals here are hard to dismiss: a first-in-child application performed safely in one of the most anatomically hostile locations imaginable, durable local control of the exact tumor component that predicts relapse, and a treatment that can be repeated if needed. If larger studies confirm these findings, children with refractory neuroblastoma whose tumors are deemed inoperable may one day have an option that today they lack entirely—a minimally invasive, precisely targeted way to finish what chemotherapy, antibodies, and radiation started.

Subject of Research: Electrochemotherapy for residual MIBG-avid disease in refractory pediatric neuroblastoma

Article Title: Electrochemotherapy as a potential local treatment for residual MIBG-avid disease in refractory pediatric neuroblastoma: a case report

Article References: Cassanelli, G., De Ioris, M. A., & Natali, G. L. (2026). Electrochemotherapy as a potential local treatment for residual MIBG-avid disease in refractory pediatric neuroblastoma: a case report. CVIR Oncology, 2(1), Article 3. https://doi.org/10.1007/s44343-026-00032-8

Image Credits: AI Generated

DOI: 10.1007/s44343-026-00032-8

Keywords: neuroblastoma, electrochemotherapy, electroporation, cisplatin, pediatric oncology, interventional radiology, MIBG imaging, tumor ablation, MYCN amplification, residual disease, case report, local therapy