Background:Despite intensified frontline therapy for medulloblastoma, 20-30% of patients still experience disease failure. Outcomes for recurrent disease remain poor, largely due to the lack of standardized salvage strategies. This study evaluated treatment patterns and outcomes of salvage therapy in recurrent or progressive medulloblastoma. Methods:Patients aged ≤ 21 years with histologically confirmed medulloblastoma diagnosed between 2000 and 2020 were analyzed. Inclusion criteria required prior surgery or biopsy followed by postoperative radiotherapy and completion of initial therapy. Disease recurrence or progression was confirmed by MRI and clinical assessment. Local control treatment (LCT) was defined as salvage radiotherapy or surgery. Primary endpoints were progression-free survival (PFS) and overall survival (OS) from initial recurrence. Results:Seventy-six patients from five centers were included. The median time to first failure was 23.9 months (IQR, 14.9-36.2). Salvage treatments included chemotherapy alone (n = 26), LCT alone (n = 11), and combined LCT and chemotherapy (n = 30); 9 patients received best supportive care. The 1- and 3-year PFS rates were 47.4% and 7.2%, while OS rates were 81.1% and 42.8%, respectively. In univariate analysis, MYCN non-amplification, chemotherapy, and LCT were associated with improved PFS. In multivariate analysis, both chemotherapy (HR, 0.39; p = 0.003) and LCT (HR, 0.51; p = 0.013) remained significant prognostic factors for PFS. For OS, focal relapse and chemotherapy were associated with improved survival. Conclusions:Outcomes for recurrent medulloblastoma remain unfavorable. However, LCT was associated with improved PFS, while chemotherapy was associated with both improved PFS and OS.

Definitive radiotherapy (RT) doses ≥ 30 Gy are traditionally applied for Helicobacter pylori-independent stage IE gastric mucosa-associated lymphoid tissue (MALT) lymphoma, achieving excellent control. Although 24 Gy may offer comparable efficacy with reduced toxicity, high-quality comparative data are limited. This study aimed to compare the efficacy, toxicity, and long-term outcomes of 24 and 30 Gy RT. We retrospectively analyzed 202 patients treated with RT for stage IE gastric MALT lymphoma between 2009 and 2023 (24 Gy, n = 74; 30 Gy, n = 128) at a single tertiary institution. Outcomes included complete remission (CR), freedom from treatment failure (FFTF), overall survival (OS), and grade 2 acute toxicity. Statistical methods included Fisher’s exact test, logistic regression, and Kaplan–Meier estimation, with additional technique-adjusted subgroup analyses to account for temporal changes in RT practice. Median follow-up was 55 months (24 Gy, 36 months; 30 Gy, 69 months; p < 0.001). All patients achieved CR, with 94.1

BACKGROUND:Patients with glioblastoma (GBM) often have disease progression after standard temozolomide-based chemoradiation. The benefits and optimal use of re-irradiation (re-RT) following re-operation (re-OP) in recurrent GBM (rGBM) remain uncertain. In this study, we assessed the efficacy and safety of post-operative re-RT in patients with isocitrate dehydrogenase-wild-type rGBM, aiming to identify survival benefits and determine clinicogenetic criteria for patient selection. PATIENTS AND METHODS:Data from the Korean Radiation Oncology Group 21-02 retrospective study were evaluated, including 531 patients with rGBM from 2013 to 2019. A subset of 164 patients undergoing re-OP were analyzed for survival and benefits of post-operative re-RT. Additionally, 206 patients receiving re-RT, irrespective of re-OP, were evaluated for risks of radiation necrosis. The overall survival (OS) after re-OP was the primary endpoint. Statistical analyses included the Kaplan-Meier method and log-rank test for OS, Cox proportional hazards regression model for univariate and multivariate analyses, and the Fine-Gray competing risk model for assessing the risk of brain necrosis. RESULTS:The median OS after re-OP was 13.4 months. Kaplan-Meier analysis revealed significantly better OS for those who received re-RT (17.6 months) than for those who did not (11.0 months; P = 0.002). Factors associated with improved OS included higher Karnofsky performance status scores, post-operative re-RT, and additional systemic therapy after re-OP. Factors associated with adverse outcomes included recurrence outside the initial RT field and homozygous deletion of CDKN2A/B. The incidence of grade 2 or higher RT necrosis was 5.8% among those undergoing both re-OP and post-operative re-RT. CONCLUSION:Post-operative re-RT appears to be associated with enhanced survival and minimal toxicity in patients with rGBM following temozolomide chemoradiation. Our study suggests a novel clinicogenetic criterion for re-RT after re-OP in rGBM, which requires further validation.

PURPOSE:Craniospinal irradiation (CSI) is a standard treatment for pediatric brain tumors and is increasingly used for leptomeningeal metastases. Although effective, CSI often causes radiation-induced severe lymphopenia (RISL), which is associated with poor outcomes across various cancer types. We developed and validated a novel platform for personalized dosimetry of circulating blood cells (CBCs) and assessed its predictive value for RISL. METHODS AND MATERIALS:We combined a prospective pediatric CSI registry (initiated April 2018; n = 48) and retrospectively collected patients (January 2010-November 2024; n = 168). RISL was defined as grade 4 lymphopenia (<200/µL) during or within 1 week after CSI. The platform integrated deep learning-based whole-body segmentation, individualized blood volume modeling (HEDOS), patient-specific hemodynamics (cardiac output), and treatment delivery parameters to estimate CBC dose-volume histograms, which quantify the cumulative radiation dose distribution to circulating blood during CSI. CBC dose metrics were analyzed using LASSO, Random Forest, and XGBoost models, with and without cross-validation and Synthetic Minority Over-sampling Technique, to identify RISL predictors. RESULTS:Among 216 patients (median age 12 years; range, 2-68), proton beam therapy was used in 163 (75.5%). RISL occurred in 92 patients (42.6%). Among various CBC dosimetric parameters, CBC D5% consistently emerged as the most important predictor of RISL across all machine learning models. Stratification by CBC D5% with 3.0 GyE effectively differentiated overall survival and event-free survival outcomes (all P < .05). CONCLUSIONS:The current deep learning-based personalized blood dosimetry platform enables personalized CBC dosimetry during CSI. CBC D5% is associated with the development of RISL and survival outcomes. Personalized blood dosimetry may serve as a potential tool to identify patients at high risk for RISL, which may inform future efforts to optimize CSI planning.

The benefit of external beam radiotherapy (EBRT) over Gamma Knife surgery (GKS) for central neurocytoma (CN) remains unclear. The aim of this retrospective, multicenter study was to investigate the role of adjuvant radiotherapy (ART) after surgical removal of CN and compare the outcomes of these modalities. We included 128 patients with CN who underwent surgery during 2000–2020. Patients were categorized according to the extent of resection, Ki-67 labeling index, and ART modality. Progression-free survival (PFS) was assessed using Kaplan–Meier analysis and Cox proportional-hazards modeling. The median tumor size and follow-up duration were 5 cm and 66 months, respectively. ART was independently associated with an improved PFS (p = 0.005). Five-year PFS rates were higher among patients who received EBRT (n = 20, 95.0

PURPOSE:This study investigated the association between pancreatic irradiation dose and hemoglobin A1c (HbA1c) elevation in patients with indolent gastroduodenal lymphomas treated with radiotherapy (RT). MATERIALS AND METHODS:We retrospectively reviewed 103 patients treated at Samsung Medical Center between 2010 and 2023, with or without RT. Patients were stratified by mean pancreas dose (< 2,300 cGy vs. ≥ 2,300 cGy). The primary outcome was the 2-year HbA1c elevation, with additional time-to-event analyses for HbA1c elevation ≥ 0.5% and diabetes mellitus (DM) development. RESULTS:RT was administered to 62 (60.2%) patients, while 41 (39.8%) did not receive RT. There was no significant difference in baseline characteristics except for cancer type. Patients with a mean pancreas dose ≥ 2,300 cGy had a significantly greater 2-year HbA1c increase than those receiving < 2,300 cGy (p=0.003) or no RT (p < 0.001). No significant difference was found between patients receiving < 2,300 cGy and those without RT (p=0.120). In multivariate time-to-event analysis, a mean pancreas dose ≥ 2,300 cGy was the sole significant risk factor for an HbA1c increase ≥ 0.5% (p < 0.001), while mean pancreas dose < 2,300 cGy did not show a significant effect (p=0.851). Furthermore, a mean pancreas dose ≥ 2,300 cGy (p=0.017) and baseline prediabetes (HbA1c ≥ 5.7%) (p=0.023) were independent predictors of DM development. CONCLUSION:A mean pancreas dose ≥ 2,300 cGy was associated with HbA1c elevation, whereas doses < 2,300 cGy had minimal effect. Given the established link between higher HbA1c level and increased risk of DM and cardiovascular events, pancreatic dose reduction should be considered in RT planning for patients with an expected good prognosis.

To survey the real-world effectiveness and cost of optic nerve sheath meningioma (ONSM) treating with Gamma Knife Radiosurgery (GKRS), and compare with the external beam radiation therapy (EBRT). Retrospective, comparative study that included patients with primary ONSM treated with either GKRS or EBRT in Samsung Medical Center, Korea. The treatment response, and treatment costs were compared between GKRS and EBRT groups. There were 34 adult patients with primary ONSM treated with either GKRS (n = 25) or EBRT (n = 9) (follow-up period: 6–207 months). The local tumor control rates (GKRS: 92

PURPOSE:We aimed to identify the transcriptomic signatures of soft tissue sarcoma (STS) related to radioresistance and establish a model to predict radioresistance. MATERIALS AND METHODS:Nine STS cell lines were cultured. Adenosine triphosphate-based viability was determined 5 days after irradiation with 8 Gy of X-rays in a single fraction. Radiosensitive and radioresistant groups were stratified according to the survival rates. Whole transcriptomic sequencing analysis was performed and differentially expressed genes (DEGs) were identified between the radiosensitive and radioresistant groups. For model generation, a cohort of 59 patients with sarcomas from The Cancer Genome Atlas (TCGA) was used. DEGs of the responder and non-responder groups according to the radiotherapy-best response were identified. The overlapping DEGs between those from TCGA data and the STS cell line were subjected to linear regression to develop a formula, namely the STS-specific radioresistance index (STS-RRI), and its performance was compared with that of the previously established radiosensitivity index (RSI). RESULTS:We selected thirteen overlapping DEGs and established STS-RRI using seven of them: STS-RRI = 1.5185 × MYO16-0.01575 × MYH11 + 3.900375 × KCTD16 + 0.105375 × SYNPO2-0.777375 × MYPN-0.849875 × PCSK6-0.700125 × LTK + 39.4635. Delong's test revealed that the STS-RRI performed better at stratifying responder and non-responder in TCGA cohort than the RSI (p = .002). The progression-free survival curves of the TCGA cohort were significantly discriminated by STS-RRI (p = .013) but not by RSI (p = .241). CONCLUSION:We developed the STS-RRI to predict the radioresistance of patients with STS in the TCGA dataset, showing a higher performance than RSI.

PURPOSE:Radiotherapy (RT) is a cornerstone in GBM management, but the optimal RT regimen for elderly patients remains controversial. To compare survival outcomes of hypofractionated radiotherapy (HFRT) and conventional fractionated radiotherapy (CFRT) in elderly glioblastoma (GBM) patients through a systematic review and meta-analysis. METHODS:A comprehensive search was conducted with Embase, Ovid-Medline, and Cochrane library databases. The hazard ratios (HRs) for overall survival (OS) were pooled using a random-effects model. Subgroup analyses were performed based on treatment modalities, prognostic factors, and age cut-offs. RESULTS:Nine studies, including 2 prospective randomized trial, comprising 1,441 patients were included. The pooled analysis indicated no statistically significant difference in OS between HFRT and CFRT (HR 0.80; 95% confidence interval [CI]: 0.62-1.04). Subgroup analyses revealed that CFRT demonstrated a survival advantage in patients receiving concurrent chemoradiotherapy with temozolomide (TMZ) (HR 0.68; 95% CI: 0.49-0.93). Regardless of the age cut-off of 65 or 70 years, no significant differences were observed between two regimens. CONCLUSIONS:HFRT and CFRT provide comparable survival outcomes, but CFRT may offer significant survival benefits in specific subgroups, when combined with TMZ or adjusted for prognostic factors. HFRT remains a practical alternative for elderly or frail patients, highlighting the need for individualized RT strategies.

PURPOSE:This study aimed to estimate the 30-day mortality (30D_M) and compare models for 30D_M prediction in patients undergoing palliative radiation therapy (RT). MATERIALS AND METHODS:Data from 3,756 patients who underwent palliative RT between 2018 and 2020 at two institutions were retrospectively reviewed. From one institution, 3,315 patients were randomly assigned to the training (N = 2,652) and internal validation (N = 663) cohorts. The remaining 441 patients from the other institution constituted the external validation cohort. Nineteen features, including seven blood test features, were extracted from medical records. For 30D_M prediction, 4 models were constructed: logistic regression comprising all features (LRM-A) and 7 blood test features (LRM-B) and gradient boosting using all features (GBM-A) and 7 blood test features (GBM-B). RESULTS:The 30D_M rates were 10.6 %, 11.2 %, and 17.5 % in the training, internal validation, and external validation cohorts, respectively. GBM-B demonstrated a good value for the area under the receiver operating characteristic curve (AUC) (0.830-0.863). Among the four models, GBM-A exhibited the highest AUC values, although GBM-B still generally outperformed LRM-A and LRM-B. The 30D_M rates significantly differed across the four prognostic groups according to the quantile values of predictive probability of GBM-B: 0-0.8 % (1st quantile), 1.2-3.4 % (2nd quantile), 8.7-12.9 % (3rd quantile), and 31.1-36.6 % (4th quantile), respectively. CONCLUSIONS:The 30D_M rates were successfully stratified into distinct prognostic groups by using the GBM-B model. The model could serve as a straightforward and objective tool for predicting mortality in patients undergoing palliative RT.

Patients with glioblastoma (GBM) often have disease progression after standard temozolomide-based chemoradiation. The benefits and optimal use of re-irradiation (re-RT) following re-operation (re-OP) in recurrent glioblastoma (rGBM) remain uncertain. In this study, we assessed the efficacy and safety of postoperative re-RT in patients with isocitrate dehydrogenase-wild-type rGBM, aiming to identify survival benefits and determine clinicogenetic criteria for patient selection. Data from the Korean Radiation Oncology Group 21-02 retrospective study were evaluated, including 531 patients with rGBM from 2013 to 2019. A subset of 164 patients undergoing re-OP was analyzed for survival and benefits of postoperative re-RT. Additionally, 206 patients receiving re-RT, irrespective of re-OP, were evaluated for risks of radiation necrosis. The overall survival (OS) after re-OP was the primary endpoint. Statistical analyses included the Kaplan–Meier method and log-rank test for OS, Cox proportional hazards regression model for univariate and multivariate analyses, and the Fine–Gray competing risk model for assessing the risk of brain necrosis. The median OS after re-OP was 13.4 months. Kaplan–Meier analysis revealed significantly better OS for those receiving re-RT (17.6 months) than for those who did not (11.0 months; p=0.002). Factors associated with improved OS included higher Karnofsky Performance Status scores, postoperative re-RT, and additional systemic therapy post-re-OP. Factors associated with adverse outcomes included recurrence outside the initial RT field and homozygous deletion of CDKN2A/B. The incidence of grade 2 or higher RT necrosis was 5.8% among those undergoing both re-OP and postoperative re-RT. Postoperative re-RT appears to be associated with enhanced survival and minimal toxicity in patients with rGBM following temozolomide chemoradiation. Our study suggests a novel clinicogenetic criterion for re-RT after re-OP in rGBM, which requires further validation.

For high-grade glioma (HGG) patients with old age or poor performance status, hypofractionated radiotherapy (hypoRT) in 10–15 fractions is recommended. Also, limited data exist on the impact of salvage treatment after progression in frail patients. We retrospectively analyzed the outcomes of dose-escalated hypoRT in 40 frail HGG patients who were treated with hypoRT between 2013 and 2021. With a median biologically effective dose of 71.7 Gy, a total dose of 56 Gy in 20 fractions was the most frequently used regimen (53.7%). The median age and Karnofsky Performance Status of patients were 74 years and 70, respectively. Most patients (n = 31, 77.5%) were diagnosed with glioblastoma, IDH-wildtype, CNS WHO grade 4. Only 10 (25.0%) patients underwent surgical resection, and 28 (70.0%) patients received concurrent temozolomide during hypoRT. With a median follow-up of 9.7 months, the median overall survival (OS) was 12.2 months. Of the 30 (75.0%) patients with disease progression, only 12 patients received salvage treatment. The OS after progression differed significantly depending on salvage treatment (median OS, 9.6 vs. 4.6 months, p = 0.032). Dose-escalated hypoRT in 20 fractions produced survival outcomes outperforming historical data for frail patients.

To enhance the efficiency of treatment planning and beam delivery in line-scanning proton beam therapy, we conducted a comparative analysis of various strategies for arranging the Bragg peak within the optimization of treatment plans. In RayStation, we had the flexibility to manipulate optimization parameters, specifically energy layer and line spacing, to control the Bragg peak’s location. To assess the impact of these parameters, we created a virtual spherical target and generated treatment plans employing both single and dual beams with diverse arrangement strategies. We then evaluated the target volume coverage using the homogeneity index. Furthermore, we selected 15 line-scanning plans. For each line-scanning plan, we generated nine comparative plans, employing distinct Bragg peak arrangement strategies. These strategies involved variations in energy layer and line spacing settings. We optimized these plans and compared their quality to the default setting. In addition, treatment planning and beam delivery efficiency were estimated. Our analysis indicated that smaller energy layer and line spacing generally resulted in improved homogeneity indices. Notably, reducing line spacing proved to be more efficient than decreasing energy layer spacing, a trend that remained consistent in the line-scanning plans. For line-scanning plans, adjustments in line spacing produced more efficient improvements in the conformity index and D 1cc . Based on our findings, adjusting line spacing is a more effective strategy for optimizing Bragg peak placement in RayStation. This adjustment not only enhances treatment planning but also improves beam delivery efficiency by reducing the time required for energy layer switching.

Purpose/Objective(s) To evaluate the role of reirradiation (re-RT) in patients with IDH wildtype recurrent glioblastoma (rGBM) after standard temozolomide-based chemoradiation. Materials/Methods Among 531 patients with IDH wildtype rGBM enrolled in the [BLINDED] study, 286 patients who underwent re-operation (re-OP, n = 166) or re-RT (n = 206) or both were analyzed for their overall survival. A comprehensive analysis was done incorporating clinical factors as well as genetic biomarkers. Results Median OS was 13.4 months in the re-OP group and 10.9 in the re-RT group. In the re-OP group, higher Karnofsky Performance Status (KPS), gross total resection (GTR), and postoperative re-RT improved survival, while out-field recurrence and homozygous deletion of CDKN2A/B were poor prognostic factors. Subgroup analysis showed that in patients undergoing re-OP, those with homozygous CDKN2A/B deletion, TERT promoter mutation, KPS ≥80, or recurrence-free interval ≥12 months benefited the most with re-RT. Stratification based on these factors into re-RT favorable (2-4 factors) and unfavorable groups (0-1 factors) showed re-RT significantly improved median OS in the favorable group (23.3 vs. 13.4 months, P = 0.003), but did not in the unfavorable group. Predictors of better survival in all patients who received re-RT were KPS ≥80, age ≤60, and gross total resection, while EGFR gene amplification and TP53 gene mutation were negative indicators (all P<0.05). Risk factors of grade 2 or higher radiation necrosis after re-RT were infield/marginal recurrence and no prior re-OP. Conclusion The addition of re-RT significantly improved overall survival in rGBM patients undergoing re-OP, highlighting the importance of personalized treatment strategies. This study identifies specific patient subgroups that would benefit most from re-OP and re-RT, emphasizing the need for tailored therapeutic approaches in these patients.

Abstract Background To evaluate the effects of local radiotherapy (RT) on growth, we evaluated the chronological growth profiles and vertebral features of children with high-risk neuroblastoma. Methods Thirty-eight children who received local photon or proton beam therapy to the abdomen or retroperitoneum between January 2014 and September 2019 were included. Simple radiography of the thoracolumbar spine was performed before and every year after RT. The height and vertical length of the irradiated vertebral bodies (VBs) compared with the unirradiated VBs (vertebral body ratio, VBR) were analyzed using the linear mixed model. Shape feature analysis was performed to compare the irradiated and unirradiated vertebrae. Results The follow-up was a median of 53.5 months (range, 21–81 months) after RT. A decline in height z-scores was mainly found in the early phase after treatment. In the linear mixed model with height, the initial height (fixed, p < 0.001), sex (time interaction, p = 0.008), endocrine dysfunction (time interaction, 0.019), and age at diagnosis (fixed and time interaction, both p = 0.002) were significant. Unlike the trend in height, the change in VBR (ΔVBR) decreased gradually (p < 0.001). The ΔVBR in the group that received more than 30 Gy decreased more than in the group that received smaller doses. In the shape feature analysis, the irradiated VBs changed to a more irregular surface that were neither round nor rectangular. Conclusion The irradiated VBs in children were gradually restricted compared to the unirradiated VBs in long-term follow-up, and higher RT doses were significantly affected. Radiation-induced irregular features of VBs were observed.

BACKGROUND:Tandem high-dose chemotherapy and autologous stem cell transplantation (HDCT/auto-SCT) and incorporation of 131I-metaiodobenzylguanidine (131I-MIBG) treatment have shown positive outcomes in high-risk neuroblastoma. However, more optimized treatment strategies are still needed. PROCEDURE:The NB-2014 study was a nonrandomized, prospective trial that examined survival outcomes in metastatic high-risk neuroblastoma patients using response-adapted consolidation therapy. We used post-induction residual 123I-MIBG status at metastatic sites as a treatment response marker. Patients achieving complete resolution of MIBG uptake at metastatic sites underwent a reduced first HDCT/auto-SCT with a 20% dose reduction in HDCT. After the first HDCT/auto-SCT, patients with remaining MIBG uptake received dose-escalated (18 mCi/kg) 131I-MIBG treatment. In contrast, those with complete resolution of MIBG at metastatic sites received a standard dose (12 mCi/kg) of 131I-MIBG. We compared survival and toxicity outcomes with a historical control group from the NB-2009. RESULTS:Of 65 patients treated, 63% achieved complete resolution of MIBG uptake at metastatic sites following induction chemotherapy, while 29% of patients still had MIBG uptake at metastatic sites after the first HDCT/auto-SCT. The 3-year event-free survival (EFS) and overall survival (OS) rates were 68.2% ± 6.0% and 86.5% ± 4.5%, respectively. Compared to NB-2009, EFS was similar (p = .855); however, NB-2014 had a higher OS (p = .031), a lower cumulative incidence of treatment-related mortality (p = .036), and fewer acute and late toxicities. CONCLUSIONS:Our results suggest that response-adaptive consolidation therapy based on chemotherapy response at metastatic sites facilitates better treatment tailoring, and appears promising for patients with metastatic high-risk neuroblastoma.

PurposeSevere lymphopenia (SLP) has emerged as a significant prognostic factor in glioblastoma. Intensity-modulated radiation therapy (IMRT)-based radiation therapy (RT) is suggested to minimize the risk of SLP. This study aimed to evaluate SLP incidence based on multi-institutional database in patients with GBM treated with IMRT and develop a predictive nomogram.Patients and methodsThis retrospective study reviewed data from 348 patients treated with IMRT-based concurrent chemoradiation therapy (CCRT) at two major hospitals from 2016 to 2021. After multivariate regression analysis, a nomogram was developed and internally validated to predict SLP risk.ResultsDuring treatment course, 21.0% of patients developed SLP and SLP was associated with poor overall survival outcomes in patients with GBM. A newly developed nomogram, incorporating gender, pre-CCRT absolute lymphocyte count, and brain mean dose, demonstrated fair predictive accuracy (AUC 0.723).ConclusionsThis study provides the first nomogram for predicting SLP in patients with GBM treated with IMRT-based CCRT, with acceptable predictive accuracy. The findings underscore the need for dose optimization and radiation planning to minimize SLP risk. Further external validation is crucial for adopting this nomogram in clinical practice.

BACKGROUND AND OBJECTIVES:Few studies have used real-world patient data to compare overall treatment patterns and survival outcomes for recurrent glioblastoma (rGBM). This study aimed to evaluate postprogression survival (PPS) according to the treatment strategy for rGBM by incorporating biomarker analysis. METHODS:We assessed 468 adult patients with rGBM who underwent standard temozolomide-based chemoradiation. The impact of predictors on PPS was evaluated in patients with isocitrate dehydrogenase wild-type rGBM (n = 439) using survival probability analysis. We identified patients who would benefit from reirradiation (re-RT) during the first progression. RESULTS:Median PPS was 3.4, 13.8, 6.6, and 10.0 months in the best supportive care (n = 82), surgery (with/without adjuvant therapy, n = 112), chemotherapy alone (n = 170), and re-RT (with/without chemotherapy, n = 75) groups, respectively. After propensity score matching analysis of the cohort, both the surgery and re-RT groups had a significantly better PPS than the chemotherapy-only group; however, no significant difference was observed in PPS between the surgery and re-RT groups. In the surgery subgroup, surgery with chemotherapy ( P = .024) and surgery with radio(chemo)therapy ( P = .039) showed significantly improved PPS compared with surgery alone. In the no-surgery subgroup, radio(chemo)therapy showed significantly improved PPS compared with chemotherapy alone ( P = .047). Homozygous deletion of cyclin-dependent kinase inhibitor 2A/B, along with other clinical factors (performance score and progression-free interval), was significantly associated with the re-RT survival benefit. CONCLUSION:Surgery combined with radio(chemo)therapy resulted in the best survival outcomes for rGBM. re-RT should also be considered for patients with rGBM at first recurrence. Furthermore, this study identified a specific genetic biomarker and clinical factors that may enhance the survival benefit of re-RT.

BACKGROUND:During the coronavirus disease 2019 (COVID-19) pandemic, the need for appropriate treatment guidelines for patients with brain tumors was indispensable due to the lack and limitations of medical resources. Thus, the Korean Society for Neuro-Oncology (KSNO), a multidisciplinary academic society, has undertaken efforts to develop a guideline that is tailored to the domestic situation and that can be used in similar crisis situations in the future. METHODS:The KSNO Guideline Working Group was composed of 22 multidisciplinary experts on neuro-oncology in Korea. In order to reach consensus among the experts, the Delphi method was used to build up the final recommendations. RESULTS:All participating experts completed the series of surveys, and the results of final survey were used to draft the current consensus recommendations. Priority levels of surgery and radiotherapy during crises were proposed using appropriate time window-based criteria for management outcome. The highest priority for surgery is assigned to patients who are life-threatening or have a risk of significant impact on a patient's prognosis unless immediate intervention is given within 24-48 hours. As for the radiotherapy, patients who are at risk of compromising their overall survival or neurological status within 4-6 weeks are assigned to the highest priority. Curative-intent chemotherapy has the highest priority, followed by neoadjuvant/adjuvant and palliative chemotherapy during a crisis period. Telemedicine should be actively considered as a management tool for brain tumor patients during the mass infection crises such as the COVID-19 pandemic. CONCLUSION:It is crucial that adequate medical care for patients with brain tumors is maintained and provided, even during times of crisis. This guideline will serve as a valuable resource, assisting in the delivery of treatment to brain tumor patients in the event of any future crisis.