Salvage re-irradiation for recurrent high-grade glioma and comparison to bevacizumab alone

Preferred Imaging for Target Volume Delineation for Radiotherapy of Recurrent Glioblastoma: A Literature Review of the Available Evidence

BACKGROUND

Recurrence in glioblastoma lacks a standardized treatment, prompting an exploration of re-irradiation's efficacy.

METHODS

A comprehensive systematic review from January 2005 to May 2023 assessed the role of MRI sequences in recurrent glioblastoma re-irradiation. The search criteria, employing MeSH terms, targeted English-language, peer-reviewed articles. The inclusion criteria comprised both retrospective and prospective studies, excluding certain types and populations for specificity. The PICO methodology guided data extraction, and the statistical analysis employed Chi-squared tests via MedCalc v22.009.

RESULTS

Out of the 355 identified studies, 81 met the criteria, involving 3280 patients across 65 retrospective and 16 prospective studies. The key findings indicate diverse treatment modalities, with linac-based photons predominating. The median age at re-irradiation was 54 years, and the median time interval between radiation courses was 15.5 months. Contrast-enhanced T1-weighted sequences were favored for target delineation, with PET-imaging used in fewer studies. Re-irradiation was generally well tolerated (median G3 adverse events: 3.5%). The clinical outcomes varied, with a median 1-year local control rate of 61% and a median overall survival of 11 months. No significant differences were noted in the G3 toxicity and clinical outcomes based on the MRI sequence preference or PET-based delineation.

CONCLUSIONS

In the setting of recurrent glioblastoma, contrast-enhanced T1-weighted sequences were preferred for target delineation, allowing clinicians to deliver a safe and effective therapeutic option; amino acid PET imaging may represent a useful device to discriminate radionecrosis from recurrent disease. Future investigations, including the ongoing GLIAA, NOA-10, ARO 2013/1 trial, will aim to refine approaches and standardize methodologies for improved outcomes in recurrent glioblastoma re-irradiation.

Phase I study of a novel glioblastoma radiation therapy schedule exploiting cell-state plasticity

BACKGROUND

Glioblastomas comprise heterogeneous cell populations with dynamic, bidirectional plasticity between treatment-resistant stem-like and treatment-sensitive differentiated states, with treatment influencing this process. However, current treatment protocols do not account for this plasticity. Previously, we generated a mathematical model based on preclinical experiments to describe this process and optimize a radiation therapy fractionation schedule that substantially increased survival relative to standard fractionation in a murine glioblastoma model.

METHODS

We developed statistical models to predict the survival benefit of interventions to glioblastoma patients based on the corresponding survival benefit in the mouse model used in our preclinical study. We applied our mathematical model of glioblastoma radiation response to optimize a radiation therapy fractionation schedule for patients undergoing re-irradiation for glioblastoma and developed a first-in-human trial (NCT03557372) to assess the feasibility and safety of administering our schedule.

RESULTS

Our statistical modeling predicted that the hazard ratio when comparing our novel radiation schedule with a standard schedule would be 0.74. Our mathematical modeling suggested that a practical, near-optimal schedule for re-irradiation of recurrent glioblastoma patients was 3.96 Gy × 7 (1 fraction/day) followed by 1.0 Gy × 9 (3 fractions/day). Our optimized schedule was successfully administered to 14/14 (100%) patients.

CONCLUSIONS

A novel radiation therapy schedule based on mathematical modeling of cell-state plasticity is feasible and safe to administer to glioblastoma patients.

Survival analysis in high-grade glioma: The role of salvage surgery

OBJECTIVES

This study addresses the survival of consecutive patients with high-grade gliomas (HGG) treated at the same institution over a period of 10 years. We analyse the importance of associated factors and the role of salvage surgery at the time of progression.

METHODS

We retrospectively analysed a series of patients with World Health Organization (WHO) grade III/IV gliomas treated between 2008 and 2017 at Hospital Gregorio Marañón (Madrid, Spain). Clinical, radiological, and anatomical pathology data were obtained from patient clinical histories.

RESULTS

Follow-up was completed in 233 patients with HGG. Mean age was 62.2 years. The median survival time was 15.4 months. Of 133 patients (59.6%) who had undergone surgery at the time of diagnosis, 43 (32.3%) underwent salvage surgery at the time of progression. This subgroup presented longer overall survival and survival after progression. Higher Karnofsky Performance Status score at diagnosis, a greater extent of surgical resection, and initial diagnosis of WHO grade III glioma were also associated with longer survival.

CONCLUSIONS

About one-third of patients with HGG may be eligible for salvage surgery at the time of progression. Salvage surgery in this subgroup of patients was significantly associated with longer survival.

Analyzing the role of reoperation in recurrent glioblastoma: a 15-year retrospective study in a single institution

BACKGROUND

Multiple treatment options at glioblastoma progression exist, including reintervention, reirradiation, additional systemic therapy, and novel strategies. No alternative has been proven to be superior in terms of postprogression survival (PPS). A second surgery has shown conflicting evidence in the literature regarding its prognostic impact, possibly affected by selection bias, and might benefit a sparse subset of patients with recurrent glioblastoma. The present study aims to determine the prognostic influence of salvage procedures in a cohort of patients treated in the same institution over 15 years.

METHODS

Three hundred and fifty patients with confirmed primary glioblastoma diagnosed and treated between 2005 and 2019 were selected. To examine the role of reoperation, we intended to create comparable groups, previously excluding all diagnostic biopsies and patients who were not actively treated after the first surgery or at disease progression. Uni- and multivariate Cox proportional hazards regression models were employed, considering reintervention as a time-fixed or time-dependent covariate. The endpoints of the study were overall survival (OS) and PPS.

RESULTS

At progression, 33 patients received a second surgery and 84 were treated with chemotherapy only. Clinical variables were similar among groups. OS, but not PPS, was superior in the reintervention group. Treatment modality had no impact in our multivariate Cox regression models considering OS or PPS as the endpoint.

CONCLUSIONS

The association of reoperation with improved prognosis in recurrent glioblastoma is unclear and may be influenced by selection bias. Regardless of our selective indications and high gross total resection rates in second procedures, we could not observe a survival advantage.

Whole Blood Transcriptional Fingerprints of High-Grade Glioma and Longitudinal Tumor Evolution under Carbon Ion Radiotherapy

Simple Summary

Particle therapy with carbon ions is a promising novel option for the treatment of recurrent high-grade glioma (rHGG). Lack of initial and sequential biopsies limits the investigation of rHGG evolution under therapy. We hypothesized that peripheral blood transcriptome derived from liquid biopsies (lbx) as a minimal invasive method may provide a useful decision support for identification of glioma grade and provide novel means for longitudinal molecular monitoring of tumor evolution under carbon ion irradiation (CIR). We demonstrate feasibility and report patient, tumor and treatment fingerprints in whole blood transcriptomes of rHGG patients with pre-CIR and three post-CIR time points.

Abstract

Purpose: To assess the value of whole blood transcriptome data from liquid biopsy (lbx) in recurrent high-grade glioma (rHGG) patients for longitudinal molecular monitoring of tumor evolution under carbon ion irradiation (CIR). Methods: Whole blood transcriptome (WBT) analysis (Illumina HumanHT-12 Expression BeadChips) was performed in 14 patients with rHGG pre re-irradiation (reRT) with CIR and 3, 6 and 9 weeks post-CIR (reRT grade III:5, 36%, IV:9, 64%). Patients were irradiated with 30, 33, 36 GyRBE (n = 5, 6, 3) in 3GyRBE per fraction. Results: WTB analysis showed stable correlation with treatment characteristics and patients tumor grade, indicating a preserved tumor origin specific as well as dynamic transcriptional fingerprints of peripheral blood cells. Initial histopathologic tumor grade was indirectly associated with TMEM173 (STING), DNA-repair (ATM, POLD4) and hypoxia related genes. DNA-repair, chromatin remodeling (LIG1, SMARCD1) and immune response (FLT3LG) pathways were affected post-CIR. Longitudinal WTB fingerprints identified two distinct trajectories of rHGG evolution, characterized by differential and prognostic CRISPLD2 expression pre-CIR. Conclusions: Lbx based WTB analysis holds the potential for molecular stratification of rHGG patients and therapy monitoring. We demonstrate the feasibility of the peripheral blood transcriptome as a sentinel organ for identification of patient, tumor characteristics and CIR specific fingerprints in rHGG.

A multi-center prospective study of re-irradiation with bevacizumab and temozolomide in patients with bevacizumab refractory recurrent high-grade gliomas

PURPOSE

Survival is dismal for bevacizumab refractory high-grade glioma patients. We prospectively investigated the efficacy of re-irradiation, bevacizumab, and temozolomide in bevacizumab-naïve and bevacizumab-exposed recurrent high-grade glioma, without volume limitations, in a single arm trial.

METHODS

Recurrent high-grade glioma patients were stratified based on WHO grade (4 vs. < 4) and prior exposure to bevacizumab (yes vs. no). Eligible patients received radiation using a simultaneous integrated boost technique (55 Gy to enhancing disease, 45 Gy to non-enhancing disease in 25 fractions) with bevacizumab 10 mg/kg every 2 weeks IV and temozolomide 75 mg/m² daily followed by maintenance bevacizumab 10 mg/kg every 2 weeks and temozolomide 50 mg/m² daily for 6 weeks then a 2 week holiday until progression. Primary endpoint was overall survival. Quality of life was studied using FACT-Br and FACT-fatigue scales.

RESULTS

Fifty-four patients were enrolled. The majority (n = 36, 67%) were bevacizumab pre-exposed GBM. Median OS for all patients was 8.5 months and 7.9 months for the bevacizumab pre-exposed GBM group. Patients ≥ 36 months from initial radiation had a median OS of 13.3 months compared to 7.5 months for those irradiated < 36 months earlier (p < 0.01). FACT-Br and FACT-Fatigue scores initially declined during radiation but returned to pretreatment baseline. Treatment was well tolerated with 5 patients experiencing > grade 3 lymphopenia and 2 with > grade 3 thrombocytopenia. No radiographic or clinical radiation necrosis occurred.

CONCLUSIONS

Re-irradiation with bevacizumab and temozolomide is a safe and feasible salvage treatment for patients with large volume bevacizumab-refractory high-grade glioma. Patients further from their initial radiotherapy may derive greater benefit with this regimen.

High-dose salvage re-irradiation for recurrent/progressive adult diffuse glioma: healing or hurting?

PURPOSE

To report survival outcomes and identify prognostic factors of salvage re-irradiation (re-RT) in recurrent/progressive glioma.

METHODS

Medical records of patients treated with high-dose re-RT as part of multi-modality salvage therapy for recurrence/progression of adult diffuse glioma from 2010 to 2019 were analyzed retrospectively.

RESULTS

A total of 111 patients developing recurrent/progressive high-grade glioma after adequate upfront treatment at initial diagnosis were included. The first course of radiotherapy (RT) had been delivered to a median dose of 59.4 Gy with an inter-quartile range (IQR) of 54-60 Gy. Median time to recurrence/progression was 4.3 years (IQR = 2.3-7.4 years) while the median time to re-RT was 4.8 years (IQR = 3.6-7.9 years). Re-RT was delivered with intensity-modulated radiation therapy (IMRT) using 1.8 Gy/fraction to a median dose of 54 Gy (IQR = 50.4-55.8 Gy) for a cumulative median equivalent dose in 2-Gy fractions (EQD2) of 104.3 Gy (IQR = 102.6-109.4 Gy). At a median follow-up of 14 months after re-RT, the 1-year Kaplan-Meier estimates of post-re-RT progression-free survival (PFS) and overall survival (OS) were 42.8 and 61.8%, respectively. Univariate analysis identified histological grade at recurrence/progression; histological subtype; disease-free interval (DFI) and time interval between both courses of RT; performance status at re-RT; dose at re-RT and cumulative EQD2; isocitrate dehydrogenase (IDH) mutation; and O⁶-methyl-guanine DNA methyl transferase (MGMT) gene promoter methylation as significant prognostic factors. Preserved performance status, longer DFI, prolonged time interval between both courses of RT, and presence of IDH mutation were associated with significantly improved PFS on multi-variate analysis. However, only performance status retained independent prognostic significance for OS on multi-variate analysis. Post-treatment changes were seen in 33 (30%) patients on follow-up imaging, with higher cumulative dose (EQD2 ≥ 104.3 Gy) being associated with increased risk of post-re-RT pseudo-progression.

CONCLUSION

This clinical audit reports encouraging survival outcomes and identifies key prognostic factors associated with high-dose salvage re-RT in recurrent/progressive glioma.

Survival analysis in high-grade glioma: the role of salvage surgery

OBJECTIVES

This study addresses the survival of consecutive patients with high-grade gliomas treated at the same institution over a period of 10 years. We analyse the importance of associated factors and the role of salvage surgery at the time of progression.

METHODS

We retrospectively analysed a series of patients with World Health Organization (WHO) grade III/IV gliomas treated between 2008 and 2017 at Hospital Gregorio Marañón (Madrid, Spain). Clinical, radiological, and anatomical pathology data were obtained from patient clinical histories.

RESULTS

Follow-up was completed in 233 patients with HGG. Mean age was 62.2 years. The median survival time was 15.4 months. Of 133 patients (59.6%) who had undergone surgery at the time of diagnosis, 43 (32.3%) underwent salvage surgery at the time of progression. This subgroup presented longer overall survival and survival after progression. Higher Karnofsky Performance Status score at diagnosis, a greater extent of surgical resection, and initial diagnosis of WHO grade III glioma were also associated with longer survival.

CONCLUSIONS

About one-third of patients with HGG may be eligible for salvage surgery at the time of progression. Salvage surgery in this subgroup of patients was significantly associated with longer survival.

Carbon Ion Beam Reirradiation in Recurrent High-Grade Glioma

Background

Patients with recurrent glioma after prior radiotherapy have a poor prognosis. Carbon ion beam radiotherapy offers highly conformal dose distributions and more complex biological radiation effects eventually resulting in optimized normal tissue sparing and improved outcome. The aim of this study was to analyze toxicity, local control and overall survival after reirradiation of recurrent high-grade glioma with carbon ion radiotherapy.

Methods

Between 10/2015 and 12/2018, 30 patients (median age: 59 years) with recurrent high-grade glioma were reirradiated with carbon ion beams and retrospectively analyzed. Diagnosis of recurrent glioma was based on magnetic resonance imaging. Thirteen patients had repeated resection prior to reirradiation and 24 patients underwent additional chemotherapy. The median initial radiation dose was 60 Gy and the median time interval between the initial and repeated radiotherapy was 10 months. The reirradiation dose was 45 Gy (relative biological effectiveness) applied in 15 fractions. All patients received regular follow-up imaging after reirradiation. Kaplan-Meier estimation, log rank test and Cox regression analysis were used for statistical assessment.

Results

Applying common toxicity criteria, there were no grade 5 or 4 adverse events, while 8 patients showed grade 3 adverse events. The median follow-up after reirradiation was 11 months and the median overall survival after diagnosis of recurrent high-grade glioma was 13 months. The 6-, 12- and 24-month overall survival rates after diagnosis of recurrent high-grade glioma were 76%, 50% and 19%, respectively. Upon multivariate Cox regression analysis, a Ki67 score of the initial tumor histology of less than 20% was prognostic. Repeated resection or chemotherapy for the recurrent disease did not result in significantly prolonged survival.

Conclusion

Carbon ion reirradiation in recurrent high-grade glioma is safe and feasible. No radiation-associated grade 4 toxicities were documented and treatment was tolerated well.

Digital biomarkers: Importance of patient stratification for re-irradiation of glioma patients - Review of latest developments regarding scoring assessment

PURPOSE

To review scoring assessments in re-irradiation of high-grade glioma (HGG) patients and how to use scoring for patient stratification. The next aim was to investigate the different approaches employed by the scoring systems and the way they can be applied to build homogeneous patient groups for a reliable prognosis.

METHODS

We searched the Medline/Pubmed and Web of science databases for relevant articles regarding scores for re-irradiation of recurrent HGG. All references were divided into the following groups: novel score establishment (n = 5), score validation (n = 6), not relevant to this evaluation (n = 26).

RESULTS

We identified five scoring systems. Two are modifications of an already existing score. Calculations differ immensely from easy point addition to a more complex formula with including three up to 10 individual parameters. Six validation articles were found for three of the scores; one was validated four times. Two scores were never validated.

CONCLUSION

For recurrent HGG, the clinical situation remains demanding. Due to the heterogeneity of data at re-irradiation, patient stratification is important. Several scoring systems have been developed to predict prognosis. As a digital biomarker, scores are of high value regarding quick patient assessment and therapy decision making. For the next generation of digital biomarkers, easy calculation, and inclusion of easily available parameters are crucial.

Repeat irradiation for children with supratentorial high-grade glioma

BACKGROUND

There are very few studies about the role of repeat irradiation (RT2) for children with recurrent supratentorial high-grade glioma (HGG). It was the aim of this study to assess the effectiveness and safety of RT2 in this population.

PROCEDURE

This was a retrospective cohort study of 40 children age 18 years and under with recurrent supratentorial HGG who had received at least one course of RT. In-field reirradiation volumes included focal or whole brain RT, with doses ranging from 30 to 54 Gy. The primary endpoint was overall survival (OS) from the first day of RT2.

RESULTS

Fourteen patients underwent RT2. The median survival of these patients was 6.5 months. Patients with ≥12 months elapsed time between RT1 and RT2 experienced longer OS than patients who had < 12 months (P = 0.009). There was no difference in OS between patients with or without germline mutations (e.g., Lynch, Li-Fraumeni, or constitutional mismatch-repair deficiency, P = 0.20). Ten patients received RT2 that overlapped with RT1 volumes for locally recurrent disease. Of this group, 80% experienced clinical benefit from in-field RT2, defined as clinical/radiologic response or stable disease. Ninety-three percent completed the prescribed course of RT2, with one patient developing grade 3 radiation necrosis four months after RT2. When compared with 26 patients who were not offered reirradiation, those selected for RT2 had improved median survival from the time of first disease progression (9.4 vs 3.8 months, P = 0.005).

CONCLUSIONS

Reirradiation for children with recurrent supratentorial HGG is a safe, effective treatment that provides short-term disease control.

Reduction of intratumoral brain perfusion by noninvasive transcranial electrical stimulation

Malignant brain neoplasms have a poor prognosis despite aggressive treatments. Animal models and evidence from human bodily tumors reveal that sustained reduction in tumor perfusion via electrical stimulation promotes tumor necrosis, therefore possibly representing a therapeutic option for patients with brain tumors. Here, we demonstrate that transcranial electrical stimulation (tES) allows to safely and noninvasively reduce intratumoral perfusion in humans. Selected patients with glioblastoma or metastasis underwent tES, while perfusion was assessed using magnetic resonance imaging. Multichannel tES was applied according to personalized biophysical modeling, to maximize the induced electrical field over the solid tumor mass. All patients completed the study and tolerated the procedure without adverse effects, with tES selectively reducing the perfusion of the solid tumor. Results potentially open the door to noninvasive therapeutic interventions in brain tumors based on stand-alone tES or its combination with other available therapies.

A Second Course of Radiotherapy in Patients with Recurrent Malignant Gliomas: Clinical Data on Re-irradiation, Prognostic Factors, and Usefulness of Digital Biomarkers

OPINION STATEMENT

The treatment of malignant gliomas has undergone a significant intensification during the past decade, and the interdisciplinary treatment team has learned that all treatment opportunities, including surgery and radiotherapy (RT), also have a central role in recurrent gliomas. Throughout the decades, re-irradiation (re-RT) has achieved a prominent place in the treatment of recurrent gliomas. A solid body of evidence supports the safety and efficacy of re-RT, especially when modern techniques are used, and justifies the early use of this regimen, especially in the case when macroscopic disease is present. Additionally, a second adjuvant re-RT to the resection cavity is currently being investigated by several investigators and seems to offer promising results. Although advanced RT technologies, such as stereotactic radiosurgery (SRS), fractionated stereotactic radiotherapy (FSRT), intensity-modulated radiotherapy (IMRT), and image-guided radiotherapy (IGRT) have become available in many centers, re-RT should continue to be kept in experienced hands so that they can select the optimal regimen, the ideal treatment volume, and the appropriate techniques from their tool-boxes. Concomitant or adjuvant use of systemic treatment options should also strongly be taken into consideration, especially because temozolomide (TMZ), cyclohexyl-nitroso-urea (CCNU), and bevacizumab have shown a good safety profile; they should be considered, if available. Nonetheless, the selection of patients for re-RT remains crucial. Single factors, such as patient age or the progression-free interval (PFI), fall too short. Therefore, powerful prognostic scores have been generated and validated, and these scores should be used for patient selection and counseling.

Reirradiation of recurrent high-grade glioma and development of prognostic scores for progression and survival

Background

Optimal techniques and patient selection for salvage reirradiation of high-grade glioma (HGG) are unclear. In this study, we identify prognostic factors for freedom from progression (FFP) and overall survival (OS) after reirradiation, risk factors for high-grade toxicity, and validate clinical prognostic scores.

Methods

A total of 116 patients evaluated between 2000 and 2018 received reirradiation for HGG (99 WHO grade IV, 17 WHO grade III). Median time to first progression after initial therapy was 10.6 months. Salvage therapies before reirradiation included surgery (31%) and systemic therapy (41%). Sixty-five patients (56%) received single-fraction stereotactic radiosurgery (SRS) as reirradiation. The median biologically effective dose (BED) was 47.25 Gy, and the median planning target volume (PTV) was 4.8 cc for SRS and 95.0 cc for non-SRS treatments. Systemic therapy was given concurrently to 52% and adjuvantly to 74% of patients.

Results

Median FFP was 4.9 months, and median OS was 11.0 months. Significant multivariable prognostic factors for FFP were performance status, time to initial progression, and BED; for OS they were age, time to initial progression, and PTV volume at recurrence. High-grade toxicity was correlated to PTV size at recurrence. Three-level prognostic scores were generated for FFP and OS, with cross-validated receiver operating characteristic area under the curve (AUC) of 0.640 and 0.687, respectively.

Conclusions

Clinical variables at the time of reirradiation for HGG can be used to prognosticate FFP and OS.

Patterns of re-irradiation for recurrent gliomas and validation of a prognostic score

PURPOSE OR OBJECTIVE

Re-irradiation is a generally accepted method for salvage treatment in patients with recurrent glioma. However, no standard radiation regimen has been defined. This study aims to compare the efficacy and safety of different treatment regimens and to independently externally validate a recently published reirradiation risk score.

MATERIAL AND METHODS

We retrospectively analyzed a cohort of patients with recurrent malignant glioma treated with salvage conventionally fractionated (CFRT), hypofractionated (HFRT) or stereotactic radiotherapy (SRT) between 2007 and 2017 at the University Medical Centers in Utrecht and Groningen.

RESULTS

Of the 121 patients included, 60 patients (50%) underwent CFRT, 22 (18%) HFRT and 39 (32%) SRT. The primary tumor was grade II-III in 52 patients and grade IV in 69 patients with median Overall Survival (mOS) since first surgery of 113 [Interquartile range: 53.2-137] and 39.7 [24.6-64.9] months respectively (p < 0.01). Overall, mOS from the first day of re-irradiation was 9.7 months [6.5-14.6]. No significant difference in mOS was found between the treatment groups. In multivariate analysis, the Karnofsky performance scale ≥70% (p < 0.01), re-irradiation for first recurrence (p = 0.02), longer time interval between RT start dates (p < 0.01) and smaller planning target volume (p < 0.05) were significant favorable prognostic factors. The reirradiation risk score was validated.

CONCLUSION

In our series, mOS after reirradiation was sufficient to justify use of this modality. Until a reliable treatment decision tool is developed based on larger retrospective research, the decision for re-irradiation schedule should remain personalized and based on a multidisciplinary evaluation of each patient.

Treatment outcomes of radiotherapy for primary spinal cord glioma

PURPOSE

Spinal cord gliomas are rare, and there is no consensus on the optimal radiotherapy (RT) regimen. Herein, we investigated therapeutic outcomes in spinal cord gliomas to obtain clues for the optimal RT regimen.

METHODS

We assessed 45 patients who received RT for primary spinal cord non-ependymoma gliomas between 2005 and 2017: 37 (82%) received postoperative RT, 6 (13%) underwent definitive RT without surgery, and 2 (5%) received salvage RT for recurrent tumors. Craniospinal irradiation (CSI; median, 40 Gy) was administered in 4 patients with seeding at diagnosis; all other patients received local RT only (median, 50.4 Gy).

RESULTS

In all 23 failures occurred (20 in patients without initial seeding +3 in patients with initial seeding and CSI; median follow-up, 33 months). The 2‑year overall survival and progression-free survival rates were 74 and 54%, respectively. Overall, 13 (32%) new seeding events outside the local RT field developed either first or subsequently. Tumor grade was significantly associated with survival endpoints (p = 0.009, 0.028) and overall seeding rates (p = 0.042). In grade II tumors, seeding developed in 23%, with a dismal prognosis (median, 10 months after RT). In grade III tumors, seeding developed in 45% with diverse prognosis. In grade IV tumors, seeding developed in 45%. The survival of patients with newly developed seeding was significantly worse than the others (2-year 50%, p < 0.001).

CONCLUSION

To encompass a considerable rate of progressive disease seeding, aggressive treatment such as pre-emptive application of CSI needs to be considered for high-grade spinal cord gliomas with adverse features. Prophylactic CSI could be an option for survival prolongation and requires prospective validation.