The study included 132 patients treated between 2021 and 2024, all of whom had at least two brain metastases and underwent microsurgical resection of one or more selected lesions. In this population, surgery is rarely curative in the conventional sense. Surgeons operate either to relieve symptoms caused by a mass pressing on critical brain structures, or to obtain tissue for histopathologic diagnosis when the primary cancer or its molecular profile remains uncertain. Because most of the tumor burden remains elsewhere in the brain, the operation is a calculated intervention whose value depends entirely on whether the patient lives long enough, and recovers well enough, to benefit from it.

The headline finding is stark: the ninety-day mortality rate was 28 percent, with 37 of the 132 patients dying within three months of surgery. That figure alone reframes the conversation around surgery for multiple metastases, a field where much of the historical literature has focused on carefully selected single-lesion patients. The median age of the cohort was 63 years, roughly 41 percent were women, and about two-thirds of patients had between two and four metastases while nearly a third had five or more. The median resected tumor volume was 15.4 cubic centimeters, quantified through volumetric assessment of magnetic resonance imaging rather than the crude diameter measurements used in many older studies.

What elevates the work beyond a simple outcome audit is its systematic search for preoperative predictors. Four factors emerged as significantly associated with increased ninety-day mortality: advanced age, a lower preoperative Karnofsky Performance Status, the absence of adjuvant treatment after surgery, and a higher score on the five-item modified frailty index. Each of these captures a different dimension of physiological reserve. Age reflects cumulative biological wear; the Karnofsky score, a scale from 0 to 100 that grades a patient’s functional independence, measures how much the disease has already eroded daily functioning; the frailty index aggregates comorbidities such as diabetes, cardiac disease and functional dependence into a compact vulnerability score; and adjuvant therapy, whether radiotherapy or systemic treatment, addresses the residual disease that surgery cannot touch.

The statistical relationships were strong. Age and lack of adjuvant treatment each reached p-values below 0.001, meaning the probability that these associations arose by chance is vanishingly small. The frailty index was associated with mortality at p = 0.008, and Karnofsky status at p = 0.048. Notably, the sheer number of metastases and the volume of the resected tumor did not predict early death. This is a counterintuitive and clinically important result: it suggests that the decision to operate should hinge less on how many lesions a patient carries, and more on who the patient is physiologically when they arrive in the operating room.

Survival was not the only endpoint. The researchers also examined where patients went after discharge, how long they stayed in the hospital, and whether they were allocated to adjuvant treatment. Here, two variables dominated. Patients with lower preoperative Karnofsky scores and higher frailty index scores were significantly more likely to be discharged to institutional care rather than to their own homes, with both associations reaching p-values below 0.001. For patients and families weighing surgery against symptom-directed care, this is a concrete and often underappreciated consideration: the operation may relieve pressure and clarify diagnosis, but in frail or functionally compromised patients it may also mark the transition from independent living to a nursing facility.

Length of postoperative hospital stay told a similar story through correlation analysis. Stay duration correlated inversely with Karnofsky status, with a Spearman rank correlation coefficient of rs = -0.29 and p = 0.001, meaning weaker patients stayed longer. It correlated positively with the frailty index at rs = 0.26 and p = 0.003. Once again, age, tumor volume and the number of lesions showed no significant relationship with recovery time. The pattern is consistent and mechanistically plausible: functional reserve and frailty govern how quickly a brain recovers from surgery, how well wounds heal, and how quickly complications such as confusion, weakness or infection can be overcome, whereas the anatomical extent of metastatic disease matters less for the perioperative trajectory.

The findings arrive at a moment when the treatment landscape for brain metastases is shifting rapidly. Stereotactic radiosurgery, which delivers precisely focused radiation to multiple lesions in a single session without opening the skull, has become the default for many patients with limited metastatic burden, supported by large prospective studies such as the JLGK0901 trial. Meanwhile, targeted therapies and immunotherapies increasingly penetrate the blood-brain barrier, allowing systemic treatment to control intracranial disease in ways that were unimaginable two decades ago. Surgery has retained a defined but narrower role: large symptomatic lesions threatening herniation or severe neurological deficit, and diagnostic uncertainty that blocks access to molecularly matched treatment. Within that narrowed role, knowing who benefits and who is harmed becomes paramount, which is precisely the gap this study addresses.

The authors are careful about the implications. They do not argue that frail, elderly or functionally impaired patients should be denied surgery outright; rather, they state that resection for symptom relief or tissue diagnosis in patients with multiple metastases may be performed with these precautions in mind. In practice, that means the four risk factors should be part of the preoperative conversation. A 78-year-old with a Karnofsky score of 50, a frailty index of three out of five, and no realistic prospect of adjuvant therapy carries a fundamentally different risk profile from a 58-year-old who is functionally independent, robust, and eligible for radiosurgery or targeted drugs afterward. Quantifying that difference before consent is obtained is the essence of risk stratification, and it converts a vague warning about being a poor candidate into a structured, evidence-based assessment.

There are limits worth keeping in view. The study is retrospective and bicentric, drawing on two academic centers in Germany and Austria, so selection biases in who was offered surgery cannot be fully excluded, and the ninety-day window captures early perioperative harm but not longer-term survival or quality of life. The frailty index, while practical, is a coarse instrument compared with comprehensive geriatric assessment. Still, the message for oncology teams is actionable and timely: in the era of powerful non-surgical options for multiple brain metastases, the bar for operative intervention is set not by the tumor map alone, but by age, frailty, functional status and the availability of subsequent therapy. Patients with multiple brain metastases and their families should expect those four factors to be weighed explicitly, and documented, before anyone is wheeled into the operating theater.

Subject of Research: Risk stratification for surgical outcomes in patients with multiple brain metastases

Article Title: Risk stratification for unfavorable outcome after resection of selected brain metastases in patients with multiple brain metastases

Article References: Eibl, T., Mercea, P. A., Liebert, A., Ritter, L., Rossmann, J., Rezai, A., Moskwa, M., Hurtig, H., Stadler, C., Wunderlich, S., Feldheim, J., Liman, J., Schwartz, C., Griessenauer, C. J., & Schebesch, K.-M. (2026). Risk stratification for unfavorable outcome after resection of selected brain metastases in patients with multiple brain metastases. Journal of Neuro-Oncology, 180(1), Article 9. https://doi.org/10.1007/s11060-026-05819-6

Image Credits: AI Generated

DOI: 10.1007/s11060-026-05819-6

Keywords: brain metastases, neurosurgery, risk stratification, Karnofsky Performance Status, frailty index, 90-day mortality, tumor resection, adjuvant therapy, stereotactic radiosurgery, Journal of Neuro-Oncology, prognostic factors, cancer surgery

The retrospective analysis drew on an institutional database of patients who had received first-time stereotactic radiosurgery for a single brain metastasis and subsequently underwent surgical resection of that same lesion, providing the gold standard of histopathological confirmation for what the imaging had shown. Thirty-six patients met the inclusion criteria. For each patient, the team manually measured tumor volumes before treatment and at three standardized post-treatment intervals: six weeks, three months, and six months. Rather than relying on a single measurement dimension, the investigators segmented three distinct tissue compartments on each scan: the contrast-enhancing volume, the FLAIR hyperintense volume, and the necrotic component. From these they derived two ratios intended to capture the relationship between edema and tumor burden, the FLAIR-to-enhancing ratio and the enhancing-to-necrotic ratio, and then modeled how each parameter evolved over time.

The volumetric data revealed a treatment effect that was real but incomplete. Mean enhancing volume declined by 28.5 percent from baseline at six weeks, 25.8 percent at three months, and 18.9 percent at six months, a pattern consistent with an initial radiosurgical response that partially attenuated over the follow-up window. The FLAIR volume followed a different and more revealing course: it fell by 16.9 percent at six weeks and 22.2 percent at three months, but then rebounded to nearly baseline, changing only 2.4 percent from the pretreatment measurement at six months. This divergence between the enhancing core and the surrounding hyperintensity is precisely why the authors argue that single-compartment assessment, the standard practice in most surveillance protocols, misses a substantial portion of the biological story unfolding after radiation.

Statistical analysis confirmed that the two compartments do not move independently. Percent changes in FLAIR volume and enhancing volume correlated significantly at both the six-week time point, with a p-value of 0.004, and the three-month time point, where the association was even stronger at p less than 0.001. In practical terms, lesions whose enhancing cores were shrinking tended to show shrinking edema as well, at least in the early post-treatment period. But the correlation broke down in the cohort’s most clinically important subgroup: the patients whose lesions ultimately failed treatment and required resection. When the investigators stratified the surgical outcomes by pathology, the FLAIR-to-enhancing ratio trended differently between radiation necrosis and recurrent tumor, and patients who developed radiation necrosis had significantly lower FLAIR volumes at six weeks compared with those whose lesions harbored recurrent tumor.

This finding carries a counterintuitive implication. Clinicians often assume that more edema signals more trouble, and in the context of symptomatic mass effect that intuition holds. But the data suggest the opposite relationship for diagnostic purposes: a lesion that retains relatively little FLAIR hyperintensity six weeks after radiosurgery, despite failing to shrink, is more likely to be radiation necrosis, whereas a non-responding lesion wrapped in substantial and persistent edema raises greater concern for viable, actively growing tumor. The biological rationale is plausible. Radiation necrosis is fundamentally a vascular and inflammatory process driven by endothelial injury, blood-brain barrier disruption, and cytokine-mediated swelling, whereas recurrent tumor generates edema through tumor-cell infiltration, angiogenic signaling, and active secretion of vascular permeability factors. The two processes stamp different volumetric signatures on the surrounding brain, and the early post-treatment window appears to be when those signatures are most distinguishable.

Beyond the diagnostic ratios, the study identified which patient and lesion characteristics shape the edema trajectory itself. Linear mixed-effects models, a statistical framework well suited to repeated measurements nested within individual patients, showed that baseline lesion size, baseline FLAIR volume, and the FLAIR-to-enhancing ratio all influenced FLAIR trajectories with p-values below 0.001. Primary cancer type and sex also emerged as significant factors, each with p-values of 0.02. These results echo a growing body of literature indicating that peritumoral edema after radiosurgery is not a uniform phenomenon but one modulated by tumor histology, systemic therapy exposure, and intrinsic lesion characteristics. Larger lesions and those with greater baseline edema burdens follow different swelling curves than small, dry lesions, which means that any future edema-based diagnostic criterion will likely need to be normalized to baseline values rather than applied as an absolute threshold.

The clinical context makes the stakes of this work concrete. Stereotactic radiosurgery has become a cornerstone of brain metastasis management precisely because it delivers ablative doses of radiation with submillimeter accuracy while sparing surrounding tissue, allowing many patients to avoid whole-brain radiation and its cognitive sequelae. But local failure rates remain nontrivial, and a meaningful fraction of patients with non-responding lesions eventually come to surgery. Prior biopsy series have shown that enlarging lesions after radiosurgery frequently turn out to be radiation necrosis rather than tumor, which means that a substantial number of patients may currently undergo resection, or receive escalating systemic therapy, for a process that was never malignant. Conversely, misattributing recurrent tumor to necrosis delays effective treatment in a population where every month of uncontrolled intracranial disease matters. Any imaging tool that sharpens this fork in the road has immediate utility.

The Yale team’s methodological choices deserve attention because they point toward how such a tool could be deployed at scale. Manual segmentation of FLAIR hyperintensity is labor-intensive and subject to interobserver variability, which has historically limited edema volumetry to research settings. The authors explicitly recommend that automated edema volumetry be incorporated into routine post-SRS surveillance, and their proposal aligns with recent pilot work demonstrating that picture archiving and communication system-integrated volumetric tools can provide peritumoral edema measurements that add information beyond standard response assessment criteria for brain metastases. If FLAIR volume trajectories can be generated automatically at each surveillance scan, the six-week and three-month ratios identified in this study could become practical decision-support metrics, flagging non-responding lesions whose edema behavior suggests recurrent tumor for earlier tissue diagnosis or intensified imaging follow-up with advanced sequences such as perfusion and diffusion MRI.

The study’s limitations are those inherent to its design. Thirty-six patients from a single institution, all of whom underwent surgery and therefore represent the more severe end of the non-response spectrum, is a modest and selected sample. The pathological endpoint was available only for lesions that failed treatment, so the volumetric signatures of well-behaved responding lesions could not be compared against a full spectrum of outcomes. The authors also note that edema trajectories are variable across patients, and the FLAIR-to-enhancing ratio trended, rather than decisively separated, the two pathological groups at all time points, with the significant six-week FLAIR volume difference being the clearest single discriminator. Validation in larger, multi-institutional cohorts, ideally with prospective edema volumetry and standardized imaging protocols, will be essential before these thresholds inform treatment decisions.

Even so, the study adds a deceptively simple idea to the post-radiosurgery toolkit: the brain around the tumor is talking, and clinicians should start listening to it quantitatively. For two decades, surveillance after radiosurgery has centered on the enhancing lesion, with edema assessed qualitatively, if at all. This analysis demonstrates that perilesional FLAIR volume follows measurable, statistically characterizable trajectories that correlate with the enhancing compartment early after treatment and diverge in diagnostically informative ways when treatment fails. As automated segmentation matures and is folded into routine radiology workflows, the humble edema measurement that radiologists have long eyeballed as background noise may become one of the most actionable numbers on the post-radiosurgery scan, helping to spare patients with radiation necrosis from unnecessary surgery while accelerating definitive intervention for those whose tumors have truly returned.

Subject of Research: Volumetric MRI analysis of edema and enhancement changes after stereotactic radiosurgery for non-responding brain metastases

Article Title: Volumetric analysis of radiographic changes after stereotactic radiosurgery for treatment of non-responding brain metastases

Article References: Rajkumar, S., Moy, H., Ji, X., Aboian, M., & Chiang, V. (2026). Volumetric analysis of radiographic changes after stereotactic radiosurgery for treatment of non-responding brain metastases. Journal of Neuro-Oncology, 180(1), Article 7. https://doi.org/10.1007/s11060-026-05824-9

Image Credits: AI Generated

DOI: 10.1007/s11060-026-05824-9

Keywords: stereotactic radiosurgery, brain metastases, radiation necrosis, FLAIR volumetry, perilesional edema, Gamma Knife, MRI surveillance, tumor recurrence, neuro-oncology, volumetric analysis, Journal of Neuro-Oncology, Volumetric

The clinical logic behind the study is straightforward but consequential. Small cell lung cancer is exquisitely radiosensitive, so outside true emergencies patients with this subtype may derive limited benefit from surgical resection of brain metastases. Large tumors from non-small cell lung cancer, by contrast, may warrant surgical removal before radiotherapy to relieve mass effect and improve local control. And a subset of non-small cell lung cancers harboring EGFR driver mutations may allow clinicians to defer upfront radiation entirely while trializing a tyrosine kinase inhibitor with intracranial activity. Three subtypes, three fundamentally different treatment pathways, and a diagnostic pipeline too slow to inform the moment when those pathways are chosen. The researchers therefore set out to build a tool that could estimate subtype using data available on day one.

The study team retrospectively identified 305 patients with metastatic lung cancer diagnosed between 2016 and 2025 at a single institution. In an unusual and methodologically deliberate design choice, the 182 patients who did not have brain metastases at diagnosis formed the training cohort, while the entire 123-patient group presenting with synchronous brain metastases was reserved as a held-out testing cohort. This partitioning preserved the clinically relevant target population for honest evaluation, though it introduced the possibility of distribution shift between the two groups, a concern the investigators addressed with dedicated sensitivity analyses. Patients were classified into three groups: small cell lung cancer, EGFR-mutated NSCLC, and EGFR-wild-type NSCLC. EGFR was singled out for independent categorization because it is among the most prevalent driver mutations and, unlike KRAS, has multiple central-nervous-system-penetrating targeted therapies already approved.

Clinical variables included sex, age, race, smoking history, pack-years, and prior lung disease such as emphysema or interstitial lung disease. The imaging features were extracted from narrative diagnostic chest CT reports using a firewalled institutional large language model, Anthropic Claude Sonnet 4.6, blinded to patient identifiers and tumor subtype. The model determined the presence or absence of fifteen predefined features, including tumor location, pleural attachment, cavitation, lymphangitic spread, fibrosis, miliary pattern, emphysema, mediastinal lymphadenopathy, vessel encasement, superior vena cava involvement, and osseous metastases. To validate this extraction, investigators manually reviewed fifty randomly selected reports as a reference standard, finding 96.8 percent overall agreement and a Cohen’s kappa of 0.918 across 750 individual feature comparisons. Notably, the authors emphasize that the modeling approach itself does not depend on the use of a large language model; the tool simply enabled consistent, high-throughput data extraction.

Two machine-learning approaches were tested: LASSO-regularized logistic regression, which performs feature selection while guarding against overfitting, and random forest, an ensemble method that aggregates many decision trees. Each was trained on clinical variables alone and on the combined clinical-plus-imaging feature set, and performance was evaluated with one-versus-rest AUC analysis in the held-out brain metastasis cohort. The combined LASSO logistic regression model achieved testing AUCs of 0.887 for EGFR-mutated disease, 0.811 for small cell lung cancer, and 0.801 for EGFR-wild-type disease. The random forest reached 0.907, 0.783, and 0.810 respectively. Adding imaging features significantly improved discrimination for EGFR-mutated cancer and small cell histology under logistic regression, and for small cell histology under random forest, while clinical variables alone were largely sufficient for the EGFR-wild-type group. Neither modeling approach demonstrated clear superiority over the other.

The three-way classification analysis offered perhaps the most clinically interpretable results. Both multiclass models showed their highest positive predictive value for EGFR-mutated cancer, exceeding 80 percent, with negative predictive values approaching 90 percent. For small cell lung cancer, the pattern inverted: positive predictive value was low, around 33 to 36 percent, but negative predictive value remained high, above 89 percent. In practical terms, the models are better at ruling out small cell histology than at confirming it, and patients predicted to have EGFR-mutated disease may represent a particularly informative group for early multidisciplinary discussion. An exploratory analysis of misclassified EGFR-wild-type patients revealed that several harbored other driver mutations, including KRAS G12A, ERBB2 mutations, and EML4-ALK fusions, suggesting the EGFR-wild-type category may partly capture a broader oncogenic-driver phenotype rather than a homogeneous entity.

Decision curve analysis added a layer of clinical realism by quantifying net benefit across a range of threshold probabilities, representing the minimum confidence at which a clinician would act on a predicted subtype. For EGFR-mutated cancer, the multiclass random forest outperformed both the flag-all and flag-none reference strategies across the entire examined threshold range from 0.05 to 0.80. At a representative threshold of 0.30, the models corresponded to roughly 12 to 14 additional correct EGFR-positive identifications per 100 patients evaluated without an increase in false positives. For small cell lung cancer, benefit was confined to low thresholds below approximately 0.30 and turned negative at higher thresholds, a limitation the authors attribute largely to the small number of small cell cases, just 19 of 123 testing patients, which constrains attainable positive predictive value and widens confidence intervals.

The feature-level analyses revealed biologically plausible signals. Miliary pulmonary metastases and pleural attachment were associated with EGFR-mutated disease, consistent with previously described imaging phenotypes of this molecular subtype, while smoking history, greater pack-years, superior vena cava involvement, and central thoracic disease distribution were associated with small cell histology. Cavitation and pleural attachment leaned toward EGFR-wild-type tumors. The investigators also confronted their design’s weaknesses directly: the single-institution cohort may overrepresent EGFR-mutated disease, imaging features were drawn from unstructured radiology reports rather than standardized interpretation, and the EGFR-wild-type group is biologically heterogeneous. Covariate reweighting and size-matched sensitivity analyses showed minimal change in model discrimination, but the authors stress that these checks cannot prove the training and testing populations were equivalent.

The bottom line is carefully bounded. The researchers explicitly state that these models should not substitute for histologic or molecular diagnosis, nor serve as a stand-alone basis for treatment decisions, and that generalizability requires validation in independent external cohorts. Yet as a proof of concept, the study demonstrates something genuinely useful: clinical and radiographic information already available at initial presentation can carry meaningful probabilistic information about lung cancer subtype during the diagnostic limbo that follows a devastating synchronous brain metastasis diagnosis. In that window, when neurosurgeons, radiation oncologists, and medical oncologists must weigh surgery, radiosurgery, and targeted therapy against one another, even an imperfect early estimate could sharpen multidisciplinary conversations and help prioritize which patients need expedited molecular confirmation. Prospective implementation studies will determine whether that promise translates into better outcomes, but the study makes a compelling case that the answers clinicians need may already be hiding in the charts and scans they see on day one.

Subject of Research: Machine-learning prediction of lung cancer subtype from clinical and chest CT features to guide early management of synchronous brain metastases

Article Title: Predictive modeling of lung cancer subtype with integration of clinical and thoracic imaging features to guide early brain metastasis management

Article References: Park, J., Buclez, P., Lubisich, J., Hanubal, K., Inda, A., Hui, C., Harris, J., & Simon, A. (2026). Predictive modeling of lung cancer subtype with integration of clinical and thoracic imaging features to guide early brain metastasis management. Journal of Neuro-Oncology, 180(1), Article 5. https://doi.org/10.1007/s11060-026-05812-z

Image Credits: AI Generated

DOI: 10.1007/s11060-026-05812-z

Keywords: lung cancer, brain metastases, EGFR mutation, small cell lung cancer, non-small cell lung cancer, machine learning, chest CT, predictive modeling, LASSO logistic regression, random forest, radiology reports, Journal of Neuro-Oncology

The technique, known as spinal laser interstitial thermal therapy, or sLITT, involves threading thin laser fibers through a small percutaneous channel directly into a tumor, then destroying it from the inside with precisely controlled heat. Real-time magnetic resonance thermography tracks temperature continuously during the procedure, and an Arrhenius damage model estimates tissue destruction on the treatment workstation as a color-coded overlay on anatomical images. Up to six temperature-monitoring points are placed at the interface between the epidural tumor and the dura mater, the protective membrane covering the spinal cord. When the interface approaches a safety threshold of approximately 50 degrees Celsius, the system automatically shuts the laser off, protecting the cord and nerve roots from thermal injury.

One of the most striking technical challenges the team had to solve involves breathing itself. Respiratory motion degrades the reliability of the thermal map, so ablations are delivered in cycles under ventilatory arrest. Patients are preoxygenated to 100 percent oxygen saturation, each ablation cycle is capped at 100 seconds, and ventilation resumes between cycles. If oxygen saturation falls below 94 percent or the dura-interface temperature threshold is reached, the procedure halts immediately. Each laser fiber produces a zone of thermal damage extending roughly 5 millimeters radially, and additional access cannulas are placed in tandem when greater coverage along the spine is needed. It is a delicate choreography of neurosurgery, physics, and anesthesiology performed inside an intraoperative MRI suite.

The new report, led by Sumeeth V. Jonathan and senior author Claudio E. Tatsui, describes the largest clinical experience with sLITT for chordoma to date: four patients treated across five procedures between January 2016 and November 2025. The tumors spanned the full anatomic range of the disease, including metastatic foci from primary sacral, clival, and cervical chordomas, plus one primary thoracic lesion. Four procedures served as salvage therapy after prior surgery, radiotherapy, or systemic treatment had failed, while one patient received sLITT as primary treatment specifically to avoid the morbidity of open surgery. Median time from diagnosis to LITT was 19.1 months, and all patients entered treatment with excellent functional status, with Karnofsky Performance Status scores of 90 to 100.

Procedurally, the team used a median of four laser fibers and 16 ablations per case, delivering power between 12 and 15 watts. Median case duration was 352.5 minutes, and patients went home after a median hospital stay of just two days. Postoperative stereotactic radiosurgery, a highly focused form of radiation, was administered after all but one procedure, at a median of 7.5 days after LITT. Only one complication occurred: a transient episode of proximal arm radiculopathy that resolved completely with a short course of steroids by the one-month follow-up. There was no procedure-related mortality and no other perioperative complications.

The oncologic results were encouraging. Every patient showed volumetric tumor shrinkage on the earliest postoperative MRI, obtained at a median of 4.2 months, with a mean volume reduction of 25.7 percent. More importantly, by the conventional endpoint of freedom from local progression, meaning no radiographic growth and no further intervention at the treated site, no treated lesion progressed or required additional treatment during available follow-up, which extended to a median of 16.8 months and reached 48.1 months in the longest-followed case. Median overall survival from LITT was 23.0 months. Two patients had died by last follow-up, typically from disease progressing elsewhere in the body, while two remained alive.

A systematic review of the literature performed by the authors found only four previously published case reports of LITT for chordoma, three of which described complete thermal ablation with radiographic response. Those reports used remarkably varied approaches, including endoscopic endonasal, percutaneous translaminar, and transcranial catheter placement, reflecting the anatomic diversity of chordoma across the skull base and spine. No major complications were reported in any of them. The new series more than doubles the aggregate published experience and is the first to report volumetric outcomes and local control systematically across multiple patients.

Two biological questions have long shadowed the idea of laser-ablating chordomas. First, the tumor’s characteristic lipid-rich physaliferous cells were hypothesized to conduct heat poorly compared with other ablated tumor types, potentially limiting ablation size. Yet intraoperative thermography in prior work demonstrated spherical ablation zones of 14 to 16 millimeters in axial diameter, comparable to those achieved in other histologies, suggesting the theoretical concern is not clinically significant. Second, because chordomas are notorious for seeding tumor along biopsy and surgical tracts, researchers worried the percutaneous laser trajectory could do the same. That risk was mitigated with an outer access cannula that isolates the tract from direct tumor contact, and no tract seeding has been observed on follow-up imaging.

The authors are careful about what these data can and cannot show. Because radiosurgery followed four of the five procedures, the independent contribution of LITT cannot be separated from that of radiation in this retrospective design. Still, several observations hint that the laser is doing real work: the one procedure not followed by radiosurgery nonetheless showed volumetric reduction, and shrinkage appeared on scans as early as 2.8 months, a timeframe consistent with the immediate ablative effect of heat rather than the slower radiobiological response to radiation. Prior large sLITT series in metastatic disease, including one of 129 patients treated across 144 thoracic segments, found that patients treated with LITT alone achieved one-year local control of 83.4 percent, statistically similar to those who also received radiotherapy.

The researchers position sLITT as a complement to, not a replacement for, established therapies. Repeat resection remains the most definitive local treatment but carries high complication rates in previously irradiated fields, and reirradiation is constrained by cumulative dose to the spinal cord and other organs at risk. The realistic niche for sLITT is narrow but meaningful: local tumor reduction and decompression in patients whose lesions sit in previously treated fields, who need to resume systemic therapy quickly, or for whom open surgery is too risky. Intriguingly, the team also raises a forward-looking hypothesis. Chordoma harbors an immune-excluded microenvironment in which stromal barriers wall off effector immune cells, and LITT-induced hyperthermia has been shown in other tumors to release damage-associated molecular patterns and transiently open the blood-brain barrier, potentially converting immunologically cold tumors into hot ones. Whether laser ablation could help unlock chordoma’s defenses against immunotherapy remains untested, but it offers one more reason this small proof-of-concept study may mark the beginning of a much larger story.

Subject of Research: MRI-guided spinal laser interstitial thermal therapy as a minimally invasive treatment for chordoma

Article Title: Spinal laser interstitial thermal therapy for treatment of chordoma: single-center experience and literature review

Article References: Jonathan, S. V., Chen, J. W., Wu, K., Flores, A. R., Ghia, A. J., Kimchi, G., North, R. Y., Alvarez-Breckenridge, C. A., Rhines, L. D., & Tatsui, C. E. (2026). Spinal laser interstitial thermal therapy for treatment of chordoma: single-center experience and literature review. Journal of Neuro-Oncology, 179(2), Article 59. https://doi.org/10.1007/s11060-026-05764-4

Image Credits: AI Generated

DOI: 10.1007/s11060-026-05764-4

Keywords: chordoma, laser interstitial thermal therapy, LITT, spinal tumor, MRI thermometry, stereotactic radiosurgery, neurosurgery, MD Anderson, salvage therapy, thermal ablation, tumor microenvironment, Journal of Neuro-Oncology

The study, led by Sauradeep Sarkar and colleagues, retrospectively analyzed 60 patients with adamantinomatous craniopharyngioma, the most common histological subtype in children and young adults. Crucially, none of the patients received planned adjuvant radiotherapy after surgery, which allowed the researchers to isolate the effect of surgery itself on tumor control. Using manual segmentation of preoperative and postoperative magnetic resonance imaging scans, the team calculated precise tumor volumes and derived the extent of resection, or EOR, for each patient. With a median follow-up of five years, the dataset provided a robust window into how surgical decisions made in the operating room play out over the years that follow.

The headline finding is sobering: tumor progression or recurrence occurred in 60 percent of patients during follow-up. That figure underscores why the craniopharyngioma debate remains so heated. These tumors have a notorious tendency to regrow, and the surgical community remains split between advocates of aggressive gross-total resection, which maximizes tumor control but risks damage to the hypothalamus, optic pathways, and pituitary stalk, and proponents of conservative surgery followed by radiation, which spares critical structures but exposes patients to the long-term costs of irradiating a developing or aging brain.

On univariable analysis, the researchers found that each 1 percent increase in extent of resection was associated with a modest but statistically significant improvement in progression-free survival, with a hazard ratio of 0.981. In practical terms, the more completely the tumor was removed, the longer patients remained free of recurrence. But the analysis went further than the traditional binary of gross-total versus subtotal resection. Each additional cubic centimeter of residual solid tumor increased the risk of progression by a hazard ratio of 1.178, meaning that even small volumes of leftover solid disease carried measurable consequences. Preoperative tumor volume itself also mattered, with each additional cubic centimeter of starting tumor nudging the hazard ratio upward by 1.006.

Perhaps the most striking result concerned cystic disease. Patients left with residual cystic components after surgery faced more than three and a half times the risk of progression compared with those who did not, with a hazard ratio of 3.600. This finding aligns with a growing body of literature on the biology of adamantinomatous craniopharyngioma, which is characterized by finger-like protrusions of tumor into surrounding brain tissue and by cyst walls that harbor proliferative epithelial cells capable of independent growth. Cysts are not merely fluid-filled spaces to be drained; their walls can be biologically active, and leaving them behind appears to be a potent predictor of future trouble.

Because extent of resection and residual solid tumor volume are mathematically intertwined, the researchers constructed separate multivariable models to avoid the statistical distortion caused by collinearity. In both models, the volumetric variables retained their significance, and residual cystic disease remained a strong independent predictor of progression regardless of which model was used. This methodological care matters. Many prior studies have relied on the surgeon’s operative impression of whether resection was total or subtotal, a subjective judgment that can diverge substantially from what postoperative imaging actually shows. By quantifying residual disease in cubic centimeters, the Bengaluru team converted a binary surgical judgment into a continuous, gradable risk variable.

The predictive power of these volumetric measures was assessed using time-dependent receiver operating characteristic analysis at three years, a technique that evaluates how well a model discriminates between patients who progress and those who remain disease-free at a specific time point. The optimism-corrected area under the curve was 0.777 for the extent-of-resection model and 0.813 for the residual solid tumor volume model. Values above 0.8 are generally considered to indicate good discriminative ability, suggesting that simple measurements from routine postoperative MRI could meaningfully stratify patients into higher- and lower-risk groups without requiring any additional testing.

The clinical implications of this risk stratification are substantial. The current standard of care after incomplete craniopharyngioma resection is often immediate adjuvant radiotherapy, which improves tumor control but carries well-documented long-term risks including hypothalamic dysfunction, vascular injury, cognitive effects, and secondary tumors, particularly in children. Conversely, a surveillance strategy spares patients these risks but requires vigilant imaging and readiness to intervene at the first sign of progression. The Bengaluru group’s own prior work has compared upfront irradiation with postoperative surveillance after incomplete resection, and the new volumetric data provide a quantitative framework for making that choice patient by patient. A patient with a near-complete resection, minimal residual solid disease, and no residual cyst might reasonably be monitored with serial MRI, while a patient with several cubic centimeters of residual solid tumor or a residual cystic component might be steered toward earlier radiotherapy.

The study also resonates with parallel developments in the field. The Response Assessment in Pediatric Neuro-Oncology Working Group has emphasized standardized volumetric response assessment for craniopharyngioma, and proton beam therapy centers have documented the importance of tracking cyst dynamics during treatment. Recent surgical series have explored two-stage strategies for cystic tumors and examined the prognostic significance of the tumor’s microscopic finger-like protrusions, which can extend beyond what is visible on even high-resolution MRI. Together, these strands of evidence point toward a common conclusion: craniopharyngioma management is moving away from one-size-fits-all paradigms and toward precision approaches in which imaging-derived measurements directly inform treatment intensity.

Limitations remain, as they do in any retrospective single-institution analysis. Manual segmentation is labor-intensive and subject to interobserver variability, and the cohort of 60 patients, while carefully followed, cannot capture the full heterogeneity of craniopharyngioma presentations, including the giant tumors that pose distinct surgical challenges. The authors note that the underlying data are sensitive and available only upon reasonable request. Nevertheless, the core message is difficult to ignore: the fate of a patient with craniopharyngioma is written, at least in part, in the cubic centimeters of tumor left behind, and especially in whether any of what remains is cystic. As neurosurgeons continue to balance the competing imperatives of tumor control and quality of life, volumetric analysis offers a common language for that negotiation, one that could transform the postoperative conversation from a matter of surgical philosophy into a matter of measurable risk.

Subject of Research: Volumetric determinants of progression-free survival after craniopharyngioma resection

Article Title: Extent of resection and craniopharyngioma recurrence: a volumetric analysis

Article References: Sarkar, S., Vijayaraghavan, S., Thakar, S., & Aryan, S. (2026). Extent of resection and craniopharyngioma recurrence: a volumetric analysis. Journal of Neuro-Oncology, 179(2), Article 65. https://doi.org/10.1007/s11060-026-05770-6

Image Credits: AI Generated

DOI: 10.1007/s11060-026-05770-6

Keywords: craniopharyngioma, extent of resection, tumor volumetry, progression-free survival, residual cystic disease, neurosurgery, MRI segmentation, Cox regression, adjuvant radiotherapy, adamantinomatous craniopharyngioma, Journal of Neuro-Oncology, risk stratification

The research, led by João Victor Garcia de Souza and Débora Tavares de Resende e Silva of the Federal University of Fronteira Sul in Chapecó, Brazil, enrolled 40 patients undergoing surgical resection at two regional hospitals between June 2023 and December 2024. Of these, 27 tumors were classified as WHO grade 1 and 6 as WHO grade 2, while 7 cases could not be graded because pathology reports were unavailable in the electronic medical record. The cohort was predominantly female, with women making up 85 percent of participants, and the mean age was 52.9 years. Notably, two thirds of the grade 2 tumors occurred in patients aged 65 or older, a statistically significant age association, and systemic arterial hypertension was the most prevalent comorbidity in both groups.

The scientific rationale rests on the purinergic system, a signaling network that regulates cellular homeostasis through the controlled breakdown of extracellular ATP. The enzyme CD39, also known as ENTPD1, hydrolyzes ATP and ADP into AMP, after which CD73, encoded by the NT5E gene, converts AMP into adenosine. Adenosine is a potent immunosuppressive metabolite that can dampen anti-tumor T cell activity, and the CD39-CD73 axis has become a major focus of cancer immunotherapy research in gliomas and other brain tumors. Adenosine deaminase, or ADA, completes the circuit by degrading adenosine to inosine. Until now, however, these pathways had received scant attention in meningiomas, largely because the tumors are usually benign.

Using quantitative reverse transcription PCR on tumor tissue preserved in RNAlater, the researchers measured mRNA levels of ENTPD1/CD39, NT5E/CD73, CD274/PD-L1 and IL1B, normalizing expression to the ACTB reference gene with the 2^-ΔΔCt method. The results revealed a striking grade-associated pattern: NT5E/CD73 mRNA was approximately 2.15-fold higher in WHO grade 2 tumors than in grade 1, a difference that reached statistical significance, while CD274/PD-L1 and IL-1β transcripts were significantly reduced in the higher-grade tumors. CD39 mRNA, by contrast, showed no change between grades. Spearman correlation analysis found no significant relationships among the measured markers, suggesting the alterations vary independently across tumors.

Immunohistochemistry on paraffin-embedded tissue, quantified digitally with QuPath software across five representative fields per sample, validated the transcriptional findings at the protein level. CD73 immunostaining averaged 0.684 in grade 2 tumors compared with just 0.082 in grade 1, while PD-L1 staining averaged 0.211 in grade 1 versus 0.044 in grade 2. The discordance between PD-L1 mRNA and protein in grade 2 tumors, where the transcript was abundant but the protein scarce, points the authors toward post-transcriptional regulatory mechanisms, such as blocked translation or accelerated protein degradation, a phenomenon known in oncology as mRNA-protein discordance.

The team also looked beyond the tumor itself, measuring enzyme activities in peripheral blood lymphocytes isolated by Ficoll-Hypaque density gradient centrifugation. CD39 activity in hydrolyzing ATP was significantly elevated in grade 2 patients compared with healthy age- and sex-matched controls and compared with grade 1 patients, while CD73 activity in hydrolyzing AMP was higher in grade 2 than in grade 1. ADA activity was increased in both patient groups relative to controls, though it did not differ between grades. Plasma concentrations of six cytokines, including IFN-γ, TNF, IL-10, IL-6, IL-4 and IL-2, measured by cytometric bead array, showed non-significant trends toward higher values in grade 2 patients, with TNF coming closest to the significance threshold.

The authors are careful to frame these observations as hypothesis-generating rather than proof of mechanism. Because the study was cross-sectional, relied on small assay-specific subsets, sometimes numbering only four to six patients per group, and did not directly measure extracellular adenosine concentrations, adenosine receptor expression or downstream signaling, the findings cannot demonstrate adenosine-mediated immune evasion or tumor progression. The researchers also note that peripheral lymphocyte enzyme activity and circulating cytokines do not necessarily reflect what happens within the tumor microenvironment, and confounders such as hypertension, corticosteroid use and other medications may have influenced systemic measurements.

The PD-L1 result is particularly provocative because it diverges from earlier work. A 2015 study by Du and colleagues reported increased PD-L1 expression in anaplastic meningiomas, now classified as WHO grade 3, whereas the present cohort found lower PD-L1 in grade 2 tumors. The authors caution that grade 2 and grade 3 meningiomas are biologically distinct categories, and that differences in antibody clones, staining protocols, scoring thresholds and the relative abundance of neoplastic versus immune cells expressing PD-L1 can all shape immunohistochemical results. They argue that standardized, compartment-resolved analyses across larger cohorts are needed before any grade-dependent switch in immune-evasion strategy can be claimed.

The lower PD-L1 expression in higher-grade tumors also raises practical questions about therapy. Checkpoint inhibitor monotherapy relies on tumor-cell PD-L1 as both a target and a predictive biomarker, and the study’s findings suggest that such an approach may be less effective in WHO grade 2 meningiomas, where the ligand is scarce. Conversely, the consistent elevation of CD73 at both mRNA and protein levels in grade 2 tumors identifies it as a candidate grade-associated biomarker and provides a biological rationale for testing whether adenosinergic signaling differs between meningioma grades, though the authors stress that no treatment response, recurrence or survival data were analyzed.

For now, the study stands as an early map of purinergic and immune-related profiles in the most common primary brain tumor, drawn from a region of southern Brazil where agricultural employment was noted in a subset of patients, echoing prior reports linking farming and pesticide exposure to CNS tumor risk. The authors call for larger, longitudinal and mechanistic studies combining cell-type-resolved tissue analysis, direct adenosine measurements, immune phenotyping and clinical outcomes to determine whether CD73 can serve as a prognostic marker or a therapeutic target. Until then, the message is measured: CD73 rises and PD-L1 falls with meningioma grade, and understanding why could reshape how these tumors are monitored and treated.

Subject of Research: Purinergic signaling and immune checkpoint marker expression in WHO grade 1 and grade 2 meningiomas

Article Title: CD73 and PD-L1 expression in WHO grade 1 and grade 2 meningiomas: an exploratory analysis of purinergic and immune-related profiles

Article References: de Souza, J. V. G., Pretto, K. P., da Silva, L. V. G., Oenning, B. A. M., Pin, C., Menegassi, J., Franscescon, F., Chimelo, M. B., da Cunha, M. L. V., & de Resende e Silva, D. T. (2026). CD73 and PD-L1 expression in WHO grade 1 and grade 2 meningiomas: an exploratory analysis of purinergic and immune-related profiles. Journal of Neuro-Oncology, 179(2), Article 82. https://doi.org/10.1007/s11060-026-05786-y

Image Credits: AI Generated

DOI: 10.1007/s11060-026-05786-y

Keywords: meningioma, CD73, PD-L1, purinergic signaling, adenosine, tumor microenvironment, WHO grading, ectonucleotidases, immunotherapy, brain tumor, biomarker, Journal of Neuro-Oncology