Stereotactic radiosurgery for glioblastoma: retrospective analysis

Efficacy and indications of gamma knife radiosurgery for recurrent low-and high-grade glioma

PURPOSE

To investigate the indications and efficacy of gamma knife radiosurgery (GKRS) as a salvage treatment for recurrent low-and high-grade glioma.

METHODS

This retrospective study of 107 patients with recurrent glioma treated with GKRS between 2009 and 2022, including 68 high-grade glioma (HGG) and 39 low-grade glioma (LGG) cases. The Kaplan-Meier method was used to calculate the overall survival (OS) and progression-free survival (PFS). The log-rank test was used to analyze the multivariate prognosis of the Cox proportional hazards model. Adverse reactions were evaluated according to the Common Terminology Criteria for Adverse Events version 4.03. The prognostic value of main clinical features was estimated, including histopathology, Karnofsky performance status (KPS), recurrence time interval, target location, two or more GKRS, surgery for recurrence, site of recurrence, left or right side of the brain and so on.

RESULTS

The median follow-up time was 74.5 months. The median OS and PFS were 17.0 months and 5.5 months for all patients. The median OS and PFS were 11.0 months and 5.0 months for HGG, respectively. The median OS and PFS were 49.0 months and 12.0 months for LGG, respectively. Multivariate analysis showed that two or more GKRS, left or right side of the brain and brainstem significantly affected PFS. Meanwhile, the KPS index, two or more GKRS, pathological grade, and brainstem significantly affected OS. Stratified analysis showed that surgery for recurrence significantly affected OS and PFS for LGG. KPS significantly affected OS and PFS for HGG. No serious adverse events were noted post-GKRS.

CONCLUSION

GKRS is a safe and effective salvage treatment for recurrent glioma. Moreover, it can be applied after multiple recurrences with tolerable adverse effects.

Reirradiation with radiosurgery or stereotactic fractionated radiotherapy in association with regorafenib in recurrent glioblastoma

PURPOSE

No standard treatment has yet been established for recurrent glioblastoma (GBM). In this context, the aim of the current study was to evaluate safety and efficacy of reirradiation (re-RT) by radiosurgery or fractionated stereotactic radiotherapy (SRS/FSRT) in association with regorafenib.

METHODS

Patients with a histological or radiological diagnosis of recurrent GBM who received re-RT by SRS/FSRT and regorafenib as second-line systemic therapy were included in the analysis.

RESULTS

From January 2020 to December 2022, 21 patients were evaluated. The median time between primary/adjuvant RT and disease recurrence was 8 months (range 5-20). Median re-RT dose was 24 Gy (range 18-36 Gy) for a median number of 5 fractions (range 1-6). Median regorafenib treatment duration was 12 weeks (range 3-26). Re-RT was administered before starting regorafenib or in the week off regorafenib during the course of chemotherapy. The median and the 6‑month overall survival (OS) from recurrence were 8.4 months (95% confidence interval [CI] 6.9-12.7 months) and 75% (95% CI 50.9-89.1%), respectively. The median progression-free survival (PFS) from recurrence was 6 months (95% CI 3.7-8.5 months). The most frequent side effects were asthenia that occurred in 10 patients (8 cases of grade 2 and 2 cases of grade 3), and hand-foot skin reaction (2 patients grade 3, 3 patients grade 2). Adverse events led to permanent regorafenib discontinuation in 2 cases, while in 5/21 cases (23.8%), a dose reduction was administered. One patient experienced dehiscence of the surgical wound after reintervention and during regorafenib treatment, while another patient reported intestinal perforation that required hospitalization.

CONCLUSION

For recurrent GBM, re-RT with SRT/FSRT plus regorafenib is a safe treatment. Prospective trials are necessary.

Stereotactic Radiosurgery for Contrast-Enhancing Satellite Nodules in Recurrent Glioblastoma: A Rare Case Series From a Single Institution

Introduction Glioblastoma (GBM) is the most common malignant adult brain tumor and is invariably fatal. The standard treatment for GBM involves resection where possible, followed by chemoradiation per Stupp's protocol. We frequently use stereotactic radiosurgery (SRS) as a single-fraction treatment for small (volume ≤ 1cc) nodular recurrent GBM to the contrast-enhancing target on T1 MRI scan. In this paper, we aimed to evaluate the safety and efficacy of SRS for patients with contrast-enhancing satellite nodules in recurrent GBM. Methods This retrospective study analyzed the clinical and radiological outcomes of five patients who underwent CyberKnife (Accuray Inc., Sunnyvale, California) SRS at the institute between 2013 and 2022. Results From 96 patients receiving SRS for GBM, five (four males, one female; median age 53) had nine distinct new satellite lesions on MRI, separate from their primary tumor beds. Those nine lesions were treated with a median margin dose of 20 Gy in a single fraction. The three-, six, and 12-month local tumor control rates were 77.8%, 66.7%, and 26.7%, respectively. Median progression-free survival (PFS) was seven months, median overall survival following SRS was 10 months, and median overall survival (OS) was 35 months. Interestingly, the only lesion that did not show radiological progression was separate from the T2-fluid attenuated inversion recovery (FLAIR) signal of the main tumor. Conclusion Our SRS treatment outcomes for recurrent GBM satellite lesions are consistent with existing findings. However, in a unique case, a satellite nodule distinct from the primary tumor's T2-FLAIR signal and treated with an enlarged target volume showed promising control until the patient's demise. This observation suggests potential research avenues, given the limited strategies for 'multicentric' GBM lesions.

Carbon-ion radiotherapy boost with standard dose proton radiation for incomplete-resected high-grade glioma: a phase 1 study

Background

To investigate the maximal tolerated dose (MTD) of a carbon-ion radiotherapy (CIRT) boost prior to standard dose proton radiotherapy (PRT) for newly diagnosed glioblastoma (GBM) and anaplastic astrocytoma (AA) patients with residual lesion after resection.

Methods

In total, 18 patients with high-grade glioma (HGG) (16 with GBM and 2 with AA) were enrolled in a prospective 3×3 design phase 1 trial. We investigated four dose-levels of CIRT boost [9 (starting level), 12, 15, and 18 Gy relative biological effectiveness (RBE)] delivered in three equal fractions prior to the standard dose PRT (60 Gy RBE in 30 fractions). Concurrent temozolomide (TMZ) was not provided during the CIRT boost but was initiated on the first day of PRT. Acute and late toxicities were scored based on the Common Terminology Criteria for Adverse Events (CTCAE, v 4.03). Dose-limiting toxicities (DLTs) were defined as radiation-induced severe toxicities (≥ grade 3).

Results

With a median follow-up of 17.9 months, no severe (≥ grade 3) acute or late toxicities were observed in patients treated with the first three dose levels (CIRT boost doses of 9, 12, 15 Gy RBE). Severe late toxicity (grade 3 radiation necrosis) was observed in the first patient treated with the 18 Gy RBE CIRT boost level. Therefore, this trial was terminated and the MTD of the induction CIRT boost was determined at 15 Gy RBE in 3 fractions. At the time of this analysis, both patients with AA were alive without disease progression. The progression-free survival (PFS) and overall survival (OS) for GBM at 12 months were 50.6% and 78.6%, respectively.

Conclusions

Particle beam radiotherapy consisting of a CIRT boost of 15 Gy RBE (in 3 fractions) following standard dose PRT (60 Gy RBE in 30 fractions), and used in conjunction with TMZ, is safe and potentially effective for patients with HGG.

Radiosurgery and Stereotactic Brain Radiotherapy with Systemic Therapy in Recurrent High-Grade Gliomas: Is It Feasible? Therapeutic Strategies in Recurrent High-Grade Gliomas

Purpose. For recurrent high-grade gliomas (HGG), no standard therapeutic approach has been reported; thus, surgery, chemotherapy, and re-irradiation (re-RT) may all be proposed. The aim of the study was to evaluate safety and efficacy of re-RT by radiosurgery or fractionated stereotactic radiotherapy (SRS/FSRT) in association to chemotherapy in patients with recurrent HGG. Material/Methods: All patients with histological diagnosis of HGG that suffered by recurrent disease diagnosed by magnetic resonance imaging (MRI), according to Response Assessment in Neuro-Oncology (RANO) criteria, after primary/adjuvant chemo-radiotherapy treatment and underwent to re-RT by SRS/FSRT were included in the analysis. Second-line chemotherapy was administered. Outcomes were evaluated by neurological examination and brain MRI performed 1 month after re-RT and then every 2–3 months. Results: From November 2019 to September 2021, 30 patients presenting recurrent HGG underwent re-RT. Median dose was 24 Gy (range 15–36 Gy), and median fractions was 5 (range 1–6). Twenty-one patients (70%) had RPA class ≤ IV. One patient had a histological diagnosis of anaplastic oligodendroglioma, 24 patients (80%) were affected by glioblastoma (GBM) including 3 cases of multifocal form, and 5 patients (17%) by anaplastic astrocytoma. Median time between primary/adjuvant RT and disease recurrence was 8 months. In six cases (20%) re-operation was performed, and in most cases (87%), a second line of systemic therapy was administrated. At a median follow-up time from recurrence of 13 months (range 6–56 months), 10 patients (33%) were alive: 2 patients with partial response disease, 7 patients with stable disease, and 1 patient with out-field progression disease. Of the 20 patients who died (67%), 15 (75%) died for progression disease and 5 (25%) for other causes (3 due to septic event, 1 due to thrombo-embolic event, and 1 due to car accident). Median OS and PFS after recurrence were 12.1 and 11.2 months. Six-month and one-year OS were, respectively, 81% and 51%. No acute or late neurological side effects grade ≥ 2 and no case of radio-necrosis were reported. One patient experienced, after reintervention and during Regorafenib treatment (administered 40 days after surgery), dehiscence of the surgical wound. In three cases, grade 2 distal paresthesia was reported. Grade 3–4 hematologic toxicity occurred in seven cases. Three case of grade 5 toxicities during chemotherapy were reported: three septic events and one thrombo-embolic event. Conclusion. Re-RT with SRT/FSRT in association with second-line systemic therapy is a safe and feasible treatment for patients with HGG recurrence. Validation of these results by prospective studies is needed.

Repeat laser interstitial thermal therapy for recurrent primary and metastatic intracranial tumors

Background:

Repeat craniotomy in patients with primary and metastatic brain tumors carries significant morbidity and can delay adjuvant treatments. Repeat laser interstitial thermal therapy (LITT) for recurrent disease has been described and could benefit patients with limited cytoreductive options. We aim to describe the indications, safety, and efficacy of repeat LITT for recurrent primary and metastatic intracranial tumors.

Methods:

Patients undergoing repeat ablations for the same lesion were included in the study. We retrospectively analyzed 13 patients treated with 29 total LITT ablations.

Results:

Eleven patients were treated for glioblastoma (GBM), while two had brain metastases. Eleven patients had LITT performed only 2 times, while three patients underwent three total iterations of LITT for disease recurrence. Median length of stay after the 1^st ablation was 2 days, while the median length of stay after the 2^nd ablation was 1 day. The median time to resuming adjuvant treatments after the 1^st LITT was 11 days. The median time to resuming adjuvant treatments after the 2^nd LITT was 28 days. Four patients after the 1^st and 2^nd LITT sustained deficits persisting through 30-day follow-up. The median progression-free survival among the GBM patients from the first ablation was 6.0 months, 3.2 months from the 2^nd ablation, and 2.1 months from the 3^rd ablation.

Conclusion:

Recurrent tumors, especially GBM, can be safely treated using repeat LITT when surgery cannot be effectively performed. Our results indicate that patients tolerate the procedure well and have a meaningful survival given the salvage nature of the procedure.

Synchronous glioblastoma and brain metastases: illustrative case

BACKGROUND

Radiosurgical treatment of brain metastases is usually performed without brain tissue confirmation. While it is extremely rare for glioblastoma to develop concurrently in patients with brain metastases, they can look radiographically similar, and recognition is important because it alters management and prognosis. The synchronous presence of brain metastases and glioblastoma has not been published to date in the literature, making this a rare illustrative case.

OBSERVATIONS

A 70-year-old female had lung biopsy-proven metastatic lung adenocarcinoma and multiple brain metastases. Her treatment course included initial carboplatin, pemetrexed, and bevacizumab followed by maintenance nivolumab, and she underwent stereotactic radiosurgery to the multiple brain metastases. During interval radiological surveillance, one lesion in the right temporal lobe was noted to slowly progress associated with development of significant perilesional edema causing midline shift despite repeated stereotactic radiosurgical treatments. Biopsy of this lesion revealed glioblastoma, IDH wildtype.

LESSONS

Glioblastomas and brain metastases have similar radiological features, so the possibility of incorrect diagnosis needs to be considered for all lesions with interval growth poststereotactic radiosurgery. Biopsy and/or resection/laser ablation should be considered prior to reirradiation.

Radiotherapy versus combination radiotherapy-bevacizumab for the treatment of recurrent high-grade glioma: a systematic review

Background

High-grade gliomas (HGG) comprise the most common primary adult brain cancers and universally recur. Combination of re-irradiation therapy (reRT) and bevacizumab (BVZ) therapy for recurrent HGG is common, but its reported efficacy is mixed.

Objective

To assess clinical outcomes after reRT ± BVZ in recurrent HGG patients receiving stereotactic radiosurgery (SRS), hypofractionated radiosurgery (HFSRT), or fully fractionated radiotherapy (FFRT).

Methods

We performed a systematic review of PubMed, Web of Science, Scopus, Embase, and Cochrane databases, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We identified studies reporting outcomes for patients with recurrent HGG treated via reRT ± BVZ. Cohorts were stratified by BVZ treatment status and re-irradiation modality (SRS, HFSRT, and FFRT). Outcome variables were overall survival (OS), progression-free survival (PFS), and radiation necrosis (RN).

Results

Data on 1399 patients was analyzed, with 954 patients receiving reRT alone and 445 patients receiving reRT + BVZ. All patients initially underwent standard-of-care therapy for their primary HGG. In a multivariate analysis that adjusted for median patient age, WHO grade, RT dosing, reRT fractionation regimen, time between primary and re-irradiation, and re-irradiation target volume, BVZ therapy was associated with significantly improved OS (2.51, 95% CI [0.11, 4.92] months, P = .041) but no significant improvement in PFS (1.40, 95% CI [− 0.36, 3.18] months, P = .099). Patients receiving BVZ also had significantly lower rates of RN (2.2% vs 6.5%, P < .001).

Conclusions

Combination of reRT + BVZ may improve OS and reduce RN rates in recurrent HGG, but further controlled studies are needed to confirm these effects.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00701-021-04794-3.

Survival after hypofractionation in glioblastoma: a systematic review and meta-analysis

BACKGROUND

Glioblastoma multiforme (GBM) has a poor prognosis despite a multi modal treatment that includes normofractionated radiotherapy. So, various hypofractionated alternatives to normofractionated RT have been tested to improve such prognosis. There is need of systematic review and meta-analysis to analyse the literature properly and maybe generalised the use of hypofractionation. The aim of this study was first, to perform a meta-analysis of all controlled trials testing the impact of hypofractionation on survival without age restriction and secondly, to analyse data from all non-comparative trials testing the impact of hypofractionation, radiosurgery and hypofractionated stereotactic RT in first line.

MATERIALS/METHODS

We searched Medline, Embase and Cochrane databases to identify all publications testing the impact of hypofractionation in glioblastoma between 1985 and March 2020. Combined hazard ratio from comparative studies was calculated for overall survival. The impact of study design, age and use of adjuvant temozolomide was explored by stratification. Meta-regressions were performed to determine the impact of prognostic factors.

RESULTS

2283 publications were identified. Eleven comparative trials were included. No impact on overall survival was evidenced (HR: 1.07, 95%CI: 0.89-1.28) without age restriction. The analysis of non-comparative literature revealed heterogeneous outcomes with limited quality of reporting. Concurrent chemotherapy, completion of surgery, immobilization device, isodose of prescription, and prescribed dose (depending on tumour volume) were poorly described. However, results on survival are encouraging and were correlated with the percentage of resected patients and with patients age but not with median dose.

CONCLUSIONS

Because few trials were randomized and because the limited quality of reporting, it is difficult to define the place of hypofactionation in glioblastoma. In first line, hypofractionation resulted in comparable survival outcome with the benefit of a shortened duration. The method used to assess hypofractionation needs to be improved.

Patterns of Failure After Stereotactic Radiosurgery for Recurrent High-Grade Glioma: A Single Institution Experience of 10 Years

BACKGROUND

Stereotactic radiosurgery (SRS) is a treatment modality that is frequently used as salvage therapy for small nodular recurrent high-grade gliomas (HGG). Due to the infiltrative nature of HGG, it is unclear if this highly focused technique provides a durable local control benefit.

OBJECTIVE

To determine how demographic or clinical factors influence the pattern of failure following SRS for recurrent high-grade gliomas.

METHODS

We retrospectively reviewed clinical, radiographic, and follow-up information for 47 consecutive patients receiving SRS for recurrent HGG at our institution between June 2006 and July 2016. All patients initially presented with an HGG (WHO grade III and IV). Following SRS for recurrence, all patients experienced treatment failure, and we evaluated patterns of local, regional, and distant failure in relation to the SRS 50% isodose line.

RESULTS

Most patients with recurrent HGG developed "in-field" treatment failure following SRS (n = 40; 85%). Higher SRS doses were associated with longer time to failure (hazards ratio = 0.80 per 1 Gy increase; 95% confidence interval 0.67-0.96; P = .016). There was a statistically significant increase in distant versus in-field failure among older patients (P = .035). This effect was independent of bevacizumab use (odds ratio = 0.54, P = 1.0).

CONCLUSION

Based on our experience, the majority of treatment failures after SRS for recurrent HGG were "in-field." Older patients, however, presented with more distant failures. Our results indicate that higher SRS doses delivered to a larger area as fractioned or unfractioned regimen may prolong time to failure, especially in the older population.

Stereotactic Radiotherapy in Recurrent Glioblastoma: A Valid Salvage Treatment Option

BACKGROUND

Glioblastoma (GBM) is a dismal disease. Recurrence is inevitable despite initial surgery and postoperative temozolomide (TMZ) and radiotherapy. Salvage surgery is the standard treatment in selected patients. Chemotherapy, biological agents, and re-irradiation are other treatment approaches available. Stereotactic radiotherapy (SRT) is nowadays a common treatment as a salvage treatment option.

MATERIALS AND METHODS

We reviewed the files of 132 GBM cases treated between 2010 and 2018. All patients received TMZ and radiotherapy after surgery or biopsy. Among the patients who had recurrence, we identified 42 cases treated with salvage SRT. The CyberKnife robotic system was used to administer SRT.

RESULTS

While the median follow-up time for all patients was 16 months (range 1-123), the median follow-up time for patients treated with SRT after initial diagnosis was 26.5 months (range 9-123). The median follow-up time after SRT was 10 months (range 2-107). SRT was performed in a median of 3 fractions (range 2-5). The median prescription dose was 20 Gy (range 18-30). While the median actuarial survival after initial diagnosis for patients treated with salvage SRT was 30 months (range 9-123), it was only 14 months (range 1-111) for patients who could not be treated with salvage SRT (p = 0.001). The median survival time after SRT was 12 months, and 1- and 2-year survival rates were 48 and 9%, respectively. The time to progression after SRT was 5 months (range 1-62), and 6-month and 1-year progression-free survival rates were 50 and 22%, respectively. Patients with longer time to recurrence >12 months had longer overall survival with respect to the ones having recurrence <12 months (p < 0.001). Salvage surgery had been performed in 7 out of 42 patients before SRT. These reoperated patients had significantly worse survival after SRT when compared to the patients who underwent SRT alone (p = 0.02). SRT was well tolerated and there was no grade III/IV toxicity.

CONCLUSIONS

SRT is a viable salvage treatment option for recurrent GBM. SRT provides acceptable local control and survival benefit for recurrent GBM cases. SRT can be considered especially in patients with long time to recurrence.

Particle radiation therapy in the management of malignant glioma: Early experience at the Shanghai Proton and Heavy Ion Center

Background

The objective of this study was to evaluate the outcomes of patients with high‐grade glioma who received treatment with particle radiotherapy.

Methods

Between June 2015 and October 2018, 50 consecutive and nonselected patients with glioblastoma multiforme (n = 34) or anaplastic glioma (n = 16) were treated at the Shanghai Proton and Heavy Ion Center. Twenty‐four patients received proton radiotherapy (at a dose of 60 gray‐equivalents in 30 daily fractions), and 26 patients received proton radiotherapy plus a carbon‐ion radiotherapy (CIRT) boost in various dose‐escalating schemes. All patients received temozolomide because of their age or their O‐6‐methylguanine‐DNA methyltransferase (MGMT) promoter methylation status. Progression‐free survival (PFS) and overall survival (OS) rates, as well as treatment‐induced toxicities, were analyzed.

Results

At a median follow‐up of 14.3 months (range, 4.8‐39.6 months), the 12‐month and 18‐month OS rates were 87.8% (95% CI, 77.6%‐98.0%) and 72.8% (95% CI, 56.7%‐88.9%), respectively, and the 12‐month and 18‐month PFS rates were 74.2% (95% CI, 60.9%‐87.5%) and 59.8% (95% CI, 43.1%‐76.5%), respectively. Univariate analyses revealed that age (>50 vs ≤50 years), World Health Organization grade (3 vs 4), and Karnofsky performance status (>80 vs ≤80) were significant prognosticators for OS, and IDH mutation and World Health Organization grade were significant for predicting PFS. Furthermore, MGMT promoter methylation, performance status, and age showed a trend toward predicting PFS. No significant predictive factors for PFS or OS were identified in multivariate analyses. Twenty‐nine patients experienced grade 1 treatment‐related acute adverse effects, and 11 developed grade 1 (n = 6) or grade 2 (n = 5) late adverse effect of radiation‐induced brain necrosis. No grade 3, 4, or 5 toxicities were observed.

Conclusions

Particle radiotherapy produced 18‐month OS and PFS rates of 72.8% and 59.8%, respectively, with acceptable adverse effects in patients with high‐grade glioma. Particle radiotherapy at a dose ≥60 gray‐equivalents appears to be safe and potentially effective.

Particle radiotherapy with concurrent temozolomide could potentially produce better outcomes than conventional radiotherapy plus temozolomide. Particle radiotherapy to a dose of ≥60 gray‐equivalents with concurrent temozolomide is safe for patients with high‐grade glioma.

Outcomes and prognostic stratification of patients with recurrent glioblastoma treated with salvage stereotactic radiosurgery

OBJECTIVE

Glioblastoma (GBM) is the most malignant form of astrocytoma. The average survival is 6-10 months in patients with recurrent GBM (rGBM). In this study, the authors evaluated the role of stereotactic radiosurgery (SRS) in patients with rGBMs.

METHODS

The authors performed a retrospective review of their brain tumor database (1997-2016). Overall survival (OS) and progression-free survival (PFS) after salvage SRS were the primary endpoints evaluated. Response to SRS was assessed using volumetric MR images.

RESULTS

Fifty-three patients with rGBM underwent salvage SRS targeting 75 lesions. The median tumor diameter and volume were 2.55 cm and 3.80 cm3, respectively. The median prescription dose was 18 Gy (range 12-24 Gy) and the homogeneity index was 1.90 (range 1.11-2.02). The median OS after salvage SRS was estimated to be 11.0 months (95% CI 7.1-12.2) and the median PFS after salvage SRS was 4.4 months (95% CI 3.7-5.0). A Karnofsky Performance Scale score ≥ 80 was independently associated with longer OS, while small tumor volume (< 15 cm3) and less homogeneous treatment plans (homogeneity index > 1.75) were both independently associated with longer OS (p = 0.007 and 0.03) and PFS (p = 0.01 and 0.002, respectively). Based on these factors, 2 prognostic groups were identified for PFS (5.4 vs 3.2 months), while 3 were identified for OS (median OS of 15.2 vs 10.5 vs 5.2 months).

CONCLUSIONS

SRS is associated with longer OS and/or PFS in patients with good performance status, small-volume tumor recurrences, and heterogeneous treatment plans. The authors propose a prognostic model to identify a cohort of rGBM patients who may benefit from SRS.

Gamma knife radiosurgery for recurrent gliomas

Objective

In recent years, gamma knife radiosurgery (GKRS) has become increasingly more popular as a salvage treatment modality for patients diagnosed with recurrent gliomas. The goal of GKRS for recurrent glioma patients is to improve survival rates with minimal burden for these patients. The emphasis of this report is on local tumor control (TC), clinical outcome and survival analysis.

Methods

We performed a retrospective analysis of prospectively collected data of all patients who underwent GKRS for gliomas at the Gamma Knife Center Tilburg between 23-09-2002 and 21-05-2015. In total, 94 patients with glioma were treated with GKRS. Two patients were excluded because GKRS was used as a first stage treatment. The other 92 patients were included for analysis.

Results

TC was 37% for all tumors (TC was 50% in LGGs and 27% in HGGs). Local progression (LP) was 46% for all tumors (LP was 31% in LGGs and 58% in HGGs). New distant lesions were seen in 18% of all patients (in 5% of LGG patients and 31% of HGG patients). Median progression-free and overall survival (PFS and OS) for all patients were 10.5 and 34.4 months, respectively. Median PFS was 50.1 and 5.7 months for low and high grade tumors, respectively. Median OS was 86.6 and 12.8 months for low and high grade tumors, respectively. No serious adverse events were noted post-GKRS.

Conclusion

GKRS can safely be used as salvage treatment for recurrent glioma and seems to improve survival rates in (high grade) glioma patients with minimal burden.

Indications and Efficacy of Gamma Knife Stereotactic Radiosurgery for Recurrent Glioblastoma: 2 Decades of Institutional Experience

BACKGROUND

The role of stereotactic radiosurgery (SRS) for recurrent glioblastoma and the radionecrosis risk in this setting remain unclear.

OBJECTIVE

To perform a large retrospective study to help inform proper indications, efficacy, and anticipated complications of SRS for recurrent glioblastoma.

METHODS

We retrospectively analyzed patients who underwent Gamma Knife SRS between 1991 and 2013. We used the partitioning deletion/substitution/addition algorithm to identify potential predictor covariate cut points and Kaplan-Meier and proportional hazards modeling to identify factors associated with post-SRS and postdiagnosis survival.

RESULTS

One hundred seventy-four glioblastoma patients (median age, 54.1 years) underwent SRS a median of 8.7 months after initial diagnosis. Seventy-five percent had 1 treatment target (range, 1-6), and median target volume and prescriptions were 7.0 cm 3 (range, 0.3-39.0 cm 3 ) and 16.0 Gy (range, 10-22 Gy), respectively. Median overall survival was 10.6 months after SRS and 19.1 months after diagnosis. Kaplan-Meier and multivariable modeling revealed that younger age at SRS, higher prescription dose, and longer interval between original surgery and SRS are significantly associated with improved post-SRS survival. Forty-six patients (26%) underwent salvage craniotomy after SRS, with 63% showing radionecrosis or mixed tumor/necrosis vs 35% showing purely recurrent tumor. The necrosis/mixed group had lower mean isodose prescription compared with the tumor group (16.2 vs 17.8 Gy; P = .003) and larger mean treatment volume (10.0 vs 5.4 cm 3 ; P = .009).

CONCLUSION

Gamma Knife may benefit a subset of focally recurrent patients, particularly those who are younger with smaller recurrences. Higher prescriptions are associated with improved post-SRS survival and do not seem to have greater risk of symptomatic treatment effect.

Stereotactic Laser Interstitial Thermal Therapy for Recurrent High-Grade Gliomas

BACKGROUND

The value of maximal safe cytoreductive surgery in recurrent high-grade gliomas (HGGs) is gaining wider acceptance. However, patients may harbor recurrent tumors that may be difficult to access with open surgery. Laser interstitial thermal therapy (LITT) is emerging as a technique for treating a variety of brain pathologies, including primary and metastatic tumors, radiation necrosis, and epilepsy.

OBJECTIVE

To review the role of LITT in the treatment of recurrent HGGs, for which current treatments have limited efficacy, and to discuss the possible role of LITT in the disruption of the blood-brain barrier to increase delivery of chemotherapy locoregionally.

METHODS

A MEDLINE search was performed to identify 17 articles potentially appropriate for review. Of these 17, 6 reported currently commercially available systems and as well as magnetic resonance thermometry to monitor the ablation and, thus, were thought to be most appropriate for this review. These studies were then reviewed for complications associated with LITT. Ablation volume, tumor coverage, and treatment times were also reviewed.

RESULTS

Sixty-four lesions in 63 patients with recurrent HGGs were treated with LITT. Frontal (n = 34), temporal (n = 14), and parietal (n = 16) were the most common locations. Permanent neurological deficits were seen in 7 patients (12%), vascular injuries occurred in 2 patients (3%), and wound infection was observed in 1 patient (2%). Ablation coverage of the lesions ranged from 78% to 100%.

CONCLUSION

Although experience using LITT for recurrent HGGs is growing, current evidence is insufficient to offer a recommendation about its role in the treatment paradigm for recurrent HGGs.

ABBREVIATIONS

BBB, blood-brain barrierFDA, US Food and Drug AdministrationGBM, glioblastoma multiformeHGG, high-grade gliomaLITT, laser interstitial thermal therapy.

Re-irradiation after gross total resection of recurrent glioblastoma : Spatial pattern of recurrence and a review of the literature as a basis for target volume definition

BACKGROUND

Currently, patients with gross total resection (GTR) of recurrent glioblastoma (rGBM) undergo adjuvant chemotherapy or are followed up until progression. Re-irradiation, as one of the most effective treatments in macroscopic rGBM, is withheld in this situation, as uncertainties about the pattern of re-recurrence, the target volume, and also the efficacy of early re-irradiation after GTR exist.

METHODS

Imaging and clinical data from 26 consecutive patients with GTR of rGBM were analyzed. The spatial pattern of recurrences was analyzed according to the RANO-HGG criteria ("response assessment in neuro-oncology criteria for high-grade gliomas"). Progression-free (PFS) and overall survival (OS) were analyzed by the Kaplan-Meier method. Furthermore, a systematic review was performed in PubMed.

RESULTS

All but 4 patients underwent adjuvant chemotherapy after GTR. Progression was diagnosed in 20 of 26 patients and 70% of recurrent tumors occurred adjacent to the resection cavity. The median extension beyond the edge of the resection cavity was 20 mm. Median PFS was 6 months; OS was 12.8 months. We propose a target volume containing the resection cavity and every contrast enhancing lesion as the gross tumor volume (GTV), a spherical margin of 5-10 mm to generate the clinical target volume (CTV), and a margin of 1-3 mm to generate the planning target volume (PTV). Re-irradiation of this volume is deemed to be safe and likely to prolong PFS.

CONCLUSION

Re-irradiation is worth considering also after GTR, as the volumes that need to be treated are limited and re-irradiation has already proven to be a safe treatment option in general. The strategy of early re-irradiation is currently being tested within the GlioCave/NOA 17/Aro 2016/03 trial.

Management of glioblastoma after recurrence: A changing paradigm

Glioblastoma remains the most common primary brain tumor after the age of 40years. Maximal safe surgery followed by adjuvant chemoradiotherapy has remained the standard treatment for glioblastoma (GBM). But recurrence is an inevitable event in the natural history of GBM with most patients experiencing it after 6-9months of primary treatment. Recurrent GBM poses great challenge to manage with no well-defined management protocols. The challenge starts from differentiating radiation necrosis from true local progression. A fine balance needs to be maintained on improving survival and assuring a better quality of life. Treatment options are limited and ranges from re-excision, re-irradiation, systemic chemotherapy or a combination of these. Re-excision and re-irradiation must be attempted in selected patients and has been shown to improve survival outcomes. To facilitate the management of GBM recurrences, a treatment algorithm is proposed.

Can advanced new radiation therapy technologies improve outcome of high grade glioma (HGG) patients? analysis of 3D-conformal radiotherapy (3DCRT) versus volumetric-modulated arc therapy (VMAT) in patients treated with surgery, concomitant and adjuvant chemo-radiotherapy

BACKGROUND

To assess the impact of volumetric-modulated arc therapy (VMAT) compared with 3D-conformal radiotherapy (3DCRT) in patients with newly diagnosed high grade glioma in terms of toxicity, progression free survival (PFS) and overall survival (OS).

METHODS

From March 2004 to October 2014, 341 patients underwent surgery followed by concomitant and adjuvant chemo-radiotherapy. From 2003 to 2010, 167 patients were treated using 3DCRT; starting from 2011, 174 patients underwent VMAT. The quantitative evaluation of the treatment plans was performed by means of standard dose volume histogram analysis. Response was recorded using the Response Assessment in Neuro-Oncology (RANO) criteria and toxicities graded according to Common Terminology Criteria for Adverse Event version 4.0.

RESULTS

Both techniques achieved an adequate dose conformity to the target. The median follow up time was 1.3 years; at the last observation 76 patients (23.4 %) were alive and 249 (76.6 %) dead (16 patients were lot to follow-up). For patients who underwent 3DCRT, the median PFS was 0.99 ± 0.07 years (CI95: 0.9-1.1 years); the 1 and 3 years PFS were, 49.6 ± 4 and 19.1 ± 3.1 %. This shall be compared, respectively, to 1.29 ± 0.13 years (CI95: 1.01-1.5 years), 60.8 ± 3.8, and 29.7 ± 4.6 % for patients who underwent VMAT (p = 0.02). The median OS for 3DCRT patients was 1.21 ± 0.09 years (CI95:1.03-1.3 years); 1 and 5 year OS was, 63.3 ± 3.8 and 21.5 ± 3.3 %. The corresponding results for 3DRCT patients were 1.56 ± 0.09 years (CI95:1.37-1.74 years), 73.4 ± 3.5, 30 ± 4.6 % respectively (p < 0.01). In both groups, prognostic factors conditioning PFS and OS were age, gender, KPS, histology and extent of resection (EOR).

CONCLUSIONS

VMAT resulted superior to 3DCRT in terms of dosimetric findings and clinical results.

Survival of Patients with Primary Brain Tumors: Comparison of Two Statistical Approaches

Purpose

We reviewed the survival time for patients with primary brain tumors undergoing treatment with stereotactic radiation methods at the Masaryk Memorial Cancer Institute Brno. We also identified risk factors and characteristics, and described their influence on survival time.

Methods

In summarizing survival data, there are two functions of principal interest, namely, the survival function and the hazard function. In practice, both of them can depend on some characteristics. We focused on nonparametric methods, propose a method based on kernel smoothing, and compared our estimates with the results of the Cox regression model. The hazard function is conditional to age and gross tumor volume and visualized as a color-coded surface. A multivariate Cox model was also designed.

Results

There were 88 patients with primary brain cancer, treated with stereotactic radiation. The median survival of our patient cohort was 47.8 months. The estimate of the hazard function has two peaks (about 10 months and about 40 months). The survival time of patients was significantly different for various diagnoses (p≪0.001), KI (p = 0.047) and stereotactic methods (p = 0.033). Patients with a greater GTV had higher risk of death. The suitable threshold for GTV is 20 cm³. Younger patients with a survival time of about 50 months had a higher risk of death. In the multivariate Cox regression model, the selected variables were age, GTV, sex, diagnosis, KI, location, and some of their interactions.

Conclusion

Kernel methods give us the possibility to evaluate continuous risk variables and based on the results offer risk-prone patients a different treatment, and can be useful for verifying assumptions of the Cox model or for finding thresholds of continuous variables.

The evolving roles and controversies of radiotherapy in the treatment of glioblastoma

Numerous randomised controlled trials have demonstrated the benefit of radiation therapy in patients with newly diagnosed glioblastoma and it has been the cornerstone of treatment for decades. The aims of this review are to (1) Briefly outline the historical studies which resulted in radiation being the current standard of care as used in the Stupp et al. trial (2) Discuss the evolving role of radiation therapy in the management of elderly patients (3) Review the current evidence and ongoing studies of radiation use in the recurrent/salvage setting and (4) Discuss the continuing controversies of volume delineation in the planning of radiation delivery.

Multimodality therapy approaches, local and systemic treatment, compared with chemotherapy alone in recurrent glioblastoma

BACKGROUND

Long-term local control in Glioblastoma is rarely achieved and nearly all patients relapse. In this study we evaluated the clinical effect of different treatment approaches in recurrent patients.

METHODS

Forty-three patients, with median age of 51 years were evaluated for salvage treatment: re-resection and/or re-irradiation plus chemotherapy or chemotherapy alone. Response was recorded using the Response Assessment in Neuro-Oncology criteria. Hematologic and non-hematologic toxicities were graded according to Common Terminology Criteria for Adverse Events 4.0. Twenty-one patients underwent chemotherapy combined with local treatment, surgery and/or radiation therapy, and 22 underwent chemotherapy only.

RESULTS

The median follow up was 7 months (range 3-28 months). The 1 and 2-years Progression Free Survival was 65 and 10 % for combined treatment and 22 and 0 % for chemotherapy alone (p < 0.01). The 1 and 2-years overall survival was 69 and 29 % for combined and 26 and 0 % for chemotherapy alone (p < 0.01). No toxicity greater than grade 2 was recorded.

CONCLUSION

These data showed that in glioblastoma recurrence the combination of several approaches in a limited group of patients is more effective than a single treatment alone. This stress the importance of multimodality treatment whenever clinically feasible.

Recurrent malignant gliomas

In almost all patients, malignant glioma recurs following initial treatment with maximal safe resection, conformal radiotherapy, and temozolomide. This review describes the many options for treatment of recurrent malignant gliomas, including reoperation, alternating electric field therapy, chemotherapy, stereotactic radiotherapy or radiosurgery, or some combination of these modalities, presenting the evidence for each approach. No standard of care has been established, though the antiangiogenic agent, bevacizumab; stereotactic radiotherapy or radiosurgery; and, perhaps, combined treatment with these 2 modalities appear to offer modest benefits over other approaches. Clearly, randomized trials of these options would be advantageous, and novel, more efficacious approaches are urgently needed.

Radiosurgery reirradiation for high-grade glioma recurrence: a retrospective analysis

Despite various treatment strategies being available, recurrent high-grade gliomas (r-HGG) are difficult to manage. To obtain local control, radiosurgery (SRS) reirradiation has been considered as potential treatment. In the present study, a retrospective analysis was performed on r-HGG patients treated with salvage single- (s-SRS) or multi-fraction SRS (m-SRS). The aim of this study was to evaluate the effectiveness of salvage SRS in terms of overall survival (OS); toxicity was analyzed as well. Between 2004 May and 2011 December, 128 r-HGG patients (161 lesions) treated with CyberKnife(®) SRS reirradiation were retrospectively analyzed. Toxicity was graded according to Radiation Therapy Oncology Group and by Common Terminology Criteria for Adverse Events v.3 criteria. OS from the diagnosis date and OS from reirradiation were estimated using the Kaplan-Meier method. Median follow-up was 9 months (range 15 days-82 months). All patients completed SRS without high-grade toxicity. Radiation necrosis was observed in seven patients (6 %) with large volume lesions. The median survival from initial diagnosis was 32 months. The 1-, 2-, and 3-years survival rates from diagnosis were 95, 62, and 45 % respectively. Median survival following SRS was 11.5 months. The 1-, 2-, and 3-years survival rate following SRS was 48, 20, and 17 % respectively. On multivariate analysis, age <40 years, salvage surgery before SRS, and other post-SRS therapies (second-line chemotherapy and/or surgery) were found to significantly improve survival (p = 0.03). SRS represents a safe and feasible option to treat r-HGG patients with low complication rates and potential survival benefit.

Hypofractionated Stereotactic Radiation Therapy in Recurrent High-Grade Glioma: A New Challenge

Purpose

The aim of this study was to evaluate outcomes of hypofractionated stereotactic radiation therapy (HSRT) in patients re-treated for recurrent high-grade glioma.

Materials and Methods

From January 2006 to September 2013, 25 patients were treated. Six patients underwent radiation therapy alone, while 19 underwent combined treatment with surgery and/or chemotherapy. Only patients with Karnofsky Performance Status (KPS) > 70 and time from previous radiotherapy greater than 6 months were re-irradiated. The mean recurrent tumor volume was 35 cm³ (range, 2.46 to 116.7 cm³), and most of the patients (84%) were treated with a total dose of 25 Gy in five fractions (range, 20 to 50 Gy in 5-10 fractions).

Results

The median follow-up was 18 months (range, 4 to 36 months). The progression-free survival (PFS) at 1 and 2 years was 72% and 34% and the overall survival (OS) 76% and 50%, respectively. No severe toxicity was recorded. In univariate and multivariate analysis extent of resection at diagnosis significantly influenced PFS and OS (p < 0.01). Patients with smaller recurren tumor volume treated had better local control and survival. Indeed, the 2-year PFS was 40% (≤ 50 cm³) versus 11% (p=0.1) and the 2-year OS 56% versus 33% (> 50 cm³), respectively (p=0.26).

Conclusion

In our experience, HSRT could be a safe and feasible therapeutic option for recurrent high grade glioma even in patients with larger tumors. We believe that a multidisciplinary evaluation is mandatory to assure the best treatment for selected patients. Local treatment should also be considered as part of an integrated approach.

Outcome of salvage treatment for recurrent glioblastoma

Most glioblastoma (GBM) cases recur within a year and almost all cases recur at some point. Standard treatment for recurrent GBM has not yet been established. We investigated the outcome of various salvage treatments for recurrent GBM. Retrospective analysis was undertaken in 144 patients who received salvage treatment at the time of first progression after maximum debulking surgery followed by concomitant chemoradiotherapy and adjuvant temozolomide (TMZ) chemotherapy. The median follow-up period was 18.2 months. We grouped these patients into five groups according to the salvage modalities: Gamma Knife radiosurgery (GKS) group (n=29), TMZ group (n=31), GKS+TMZ group (n=28), reoperation group (n=38) and "other treatment" group (n=18). The median time to first progression from initial diagnosis was 8.8 months. The median overall survival (OS) of the five different treatment groups; GKS, TMZ, GKS+TMZ, reoperation, and "other treatment", was 9.2, 5.6, 15.5, 13.2, and 8.0 months, respectively. Median progression-free survival (PFS) was 3.6, 2.3, 6.0, 4.3, and 2.6 months, respectively. Pairwise comparison of OS of the GKS+TMZ group with the other groups showed that the OS of the GKS+TMZ group was significantly better than all others except the reoperation group. Statistically significant prolongation of PFS was observed in the GKS+TMZ group compared with the TMZ group and the "other treatment" group. GKS followed by TMZ salvage treatment was a good prognostic factor for both PFS and OS in multivariate analysis. Retrospectively, GKS+TMZ as a salvage treatment, tended to provide a superior survival benefit at the time of recurrence.

Increased survival using delayed gamma knife radiosurgery for recurrent high-grade glioma: a feasibility study

OBJECTIVE

The current study retrospectively assessed delayed gamma knife radiosurgery (GKRS) in the management of high-grade glioma recurrences.

METHODS

A total of 55 consecutive patients with high-grade glioma comprising 68 World Health Organization (WHO) III and WHO IV were treated with GKRS for local recurrences between 2001 and 2007. All patients had undergone microsurgery and radiochemotherapy, considered as standard therapy for high-grade glioma. Complete follow-up was available in all patients; median follow-up was 17.2 months (2.5-114.2 months). Median tumor volume was 5.2 mL, prescription dose was 20 Gy (14-22 Gy), and median max dose was 45 Gy (30-77.3 Gy).

RESULTS

The patients with WHO III tumors showed a median survival of 49.6 months with and a 2-year survival of 90%. After GKRS of the recurrences, these patients showed a median survival of 24.2 months and a 2-year survival of 50%. The patients with WHO IV tumors had a median survival of 24.5 months with a 2-year survival of 51.4%. After the recurrence was treated with GKRS, the median survival was 11.3 months and a 2-year survival: 22.9% for the WHO IV patients.

CONCLUSION

The current study shows a survival benefit for high-grade glioma recurrences when GKRS was administered after standard therapy. This is a relevant improvement compared with earlier studies that had had not been able to provide a beneficial effect timing radiosurgery in close vicinity to EBRT.

Salvage radiosurgery for selected patients with recurrent malignant gliomas

Purpose. To analyse the survival after salvage radiosurgery and to identify prognostic factors. Methods. We retrospectively reviewed 87 consecutive patients, with recurrent high-grade glioma, that underwent stereotactic radiosurgery between 1997 and 2010. We evaluated the survival after initial diagnosis and after reirradiation. The prognostic factors were analysed by bivariate and multivariate Cox regression model. Results. The median age was 48 years old. The primary histology included anaplastic astrocytoma (47%) and glioblastoma (53%). A margin dose of 18 Gy was administered in the majority of cases (74%). The median survival after initial diagnosis was 21 months (39 months for anaplastic astrocytoma and 18.5 months for glioblastoma) and after reirradiation it was 10 months (17 months for anaplastic astrocytoma and 7.5 months for glioblastoma). In the bivariate analyses, the prognostic factors significantly associated with survival after reirradiation were age, tumour and treatment volume at recurrence, recursive partitioning analyses classification, Karnofsky performance score, histology, and margin to the planning target volume. Only the last four showed significant association in the multivariate analyses. Conclusion. stereotactic radiosurgery is a safe and may be an effective treatment option for selected patients diagnosed with recurrent high-grade glioma. The identified prognostic factors could help individualise the treatment.

Analysis of equivalent uniform dose (EUD) and conventional radiation treatment parameters after primary and re-irradiation of malignant glioma

BACKGROUND

Re-irradiation is a reasonable second treatment option for patients with recurrent malignant glioma (MG) after previous radio(chemo)therapy. However, only limited data is available allowing for a precise selection of patients suitable for re-treatment in regard to safety and efficacy.

METHODS

Using the department database, 58 patients with two courses of percutaneous radiation were identified. Besides classical dose-volume histogram (DVH) parameters equivalent uniform dose (EUD) values were calculated for the tumor and organs at risk (OARs), retrospectively analyzed and correlated to survival outcome parameters. Cumulative EUD values were also calculated in all cases where previous OAR DVHs were available.

RESULTS

Median follow-up was 265 days and no relevant toxicity was observed after re-irradiation in our patient cohort during follow-up. Time interval between first and second irradiation was regularly above 6 months. As a conservative estimation of the cumulative EUD to the OARs, the EUDs of first and second irradiation were added. Median cumulative EUD to the optic chiasm was 48.8 Gy (range, 2.5-76.5 Gy), 57.4 Gy (range, 2.7-75.3 Gy) to the brainstem, 20.9/22.1 Gy (range, 0.0-68.3 Gy) to the right/left optic nerve and 73.8 Gy (range, 64.9-77.3 Gy) to the brain. No correlation between treated volume and survival was seen.

CONCLUSIONS

This study provides retrospective estimates on cumulative doses at the OARs. EUD values are derived and may serve as reference for further studies, including planning studies where specific constraints are needed.

Dosimetry in brain tumor phantom at 15 MV 3D conformal radiation therapy

Glioblastoma multiforme (GBM) is the most common, aggressive, highly malignant and infiltrative of all brain tumors with low rate of control. The main goal of this work was to evaluate the spatial dose distribution into a GBM simulator inside a head phantom exposed to a 15 MV 3D conformal radiation therapy in order to validate internal doses. A head and neck phantom developed by the Ionizing Radiation Research Group (NRI) was used on the experiments. Such phantom holds the following synthetic structures: brain and spinal cord, skull, cervical and thoracic vertebrae, jaw, hyoid bone, laryngeal cartilages, head and neck muscles and skin. Computer tomography (CT) of the simulator was taken, capturing a set of contrasted references. Therapy Radiation planning (TPS) was performed based on those CT images, satisfying a 200 cGy prescribed dose split in three irradiation fields. The TPS assumed 97% of prescribed dose cover the prescribed treatment volume (PTV). Radiochromic films in a solid water phantom provided dose response as a function of optical density. Spatial dosimetric distribution was generated by radiochromic film samples at coronal, sagittal-anterior and sagittal-posterior positions, inserted into tumor simulator and brain. The spatial dose profiles held 70 to 120% of the prescribed dose. In spite of the stratified profile, as opposed to the smooth dose profile from TPS, the tumor internal doses were within a 5% deviation from 214.4 cGy evaluated by TPS. 83.2% of the points with a gamma value of less than 1 (3%/3mm) for TPS and experimental values, respectively. At the tumor, measured at coronal section, a few dark spots in the film caused the appearance of outlier points in 13-15% of dose deviation percentage. And, as final conclusion, such dosimeter choice and the physical anthropomorphic and anthropometric phantom provided an efficient method for validating radiotherapy protocols.

Efficacy and limitations of stereotactic radiosurgery in the treatment of glioblastoma

Treatment of recurrent glioblastoma is still challenging. Stereotactic radiosurgery has been accepted as a treatment option for recurrent glioblastoma after standard chemotherapy and irradiation. However, the efficacy of stereotactic radiosurgery at recurrence has been limited, mainly due to the highly infiltrative nature of the tumor which makes the lesion difficult to define as the target. To enhance the efficacy of stereotactic radiosurgery, several methods of targeting based on neuroimaging technology such as positron emission tomography and magnetic resonance imaging have been adopted to irradiate as many of the viable tumor cells as possible and showed some enhanced efficacy. In a trial of intensified treatment by extending the irradiation field, improvement of local control did not result in longer survival. Radiation-induced adverse event is another problem after stereotactic radiosurgery for recurrent glioblastoma because almost all patients underwent irradiation as a part of the initial treatment. To overcome the side effects associated with re-irradiation, use of bevacizumab, a humanized monoclonal antibody to vascular endothelial growth factor, has shown some efficacy. Advances in irradiation technology, neuroimaging, and adjuvant treatment are needed to enhance the efficacy of stereotactic radiosurgery for recurrent glioblastoma and reduce the morbidity associated with irradiation.

MRI tumor response and clinical outcomes after LINAC radiosurgery on 50 patients with recurrent malignant gliomas

BACKGROUND

The place of radiosurgery (RS) as an option in the treatment of recurrent malignant glioma is still debated on in the absence of prospective randomized trials.

OBJECTIVE

To assess the clinical outcome and MRI response after radiosurgery of recurrent malignant glioma.

METHODS

We evaluated 50 consecutive patients treated in a single institution. Between 2001 and 2008, 34 glioblastoma (GBM) and 16 anaplastic oligodendroglioma (AO) patients were treated with linear accelerator (Linac) RS for recurrence.

RESULTS

The median marginal dose was 15 Gy and the median gross tumor volume (GTV) was 6.64 ml. No patient had acute (< 3 months) neurological morbidity after RS. Ten patients (20%) were reoperated on after RS, histopathological findings included necrosis alone in 3 cases (6%). The median overall survival was 21.5 months for GBM and 57.9 months for AO. The median survival after RS was 9.5 months for GBM and 32.9 months for AO. The median progression-free survival after RS was 6.7 months for GBM and 18 months for AO. MRI volume modifications after RS showed a transitory reduction or stabilization of disease linked to significantly improved survival in 58.8% of patients with GBM, 81.1% of patients with AO. Pathological subtype (AO versus GBM), MRI response, KPS >70, marginal dose > 13 Gy, largest diameter of GTV < 25 mm and GTV < 7 ml were the main prognostic factors, associated with improved survival or PFS from RS.

CONCLUSION

The magnitude of the survival increase compared to historical RPA classes may not be due to selection bias alone. Linac RS in selected patients with recurrent malignant glioma was well tolerated, effective and can be considered as one of several re-treatment options.

Hypofractionated Radiotherapy and Stereotactic Boost with Concurrent and Adjuvant Temozolamide for Glioblastoma in Good Performance Status Elderly Patients - Early Results of a Phase II Trial

Glioblastoma Multiforme (GBM) is an aggressive primary brain neoplasm with dismal prognosis. Based on successful phase III trials, 60 Gy involved-field radiotherapy in 30 fractions over 6 weeks [Standard radiation therapy (RT)] with concurrent and adjuvant temozolomide is currently the standard of care. In this disease, age and Karnofsky Performance Status (KPS) are the most important prognostic factors. For elderly patients, clinical trials comparing standard RT with radiotherapy abbreviated to 40 Gy in 15 fractions over 3 weeks demonstrated similar outcomes, indicating shortened radiotherapy may be an appropriate option for elderly patients. However, these trials did not include temozolomide chemotherapy, and included patients with poor KPS, possibly obscuring benefits of more aggressive treatment for some elderly patients. We conducted a prospective Phase II trial to examine the efficacy of a hypofractionated radiation course followed by a stereotactic boost with concurrent and adjuvant temozolomide chemotherapy in elderly patients with good performance status. In this study, patients 65 years and older with a KPS > 70 and histologically confirmed GBM received 40 Gy in 15 fractions with 3D conformal technique followed by a 1–3 fraction stereotactic boost to the enhancing tumor. All patients also received concurrent and adjuvant temozolomide. Patients were evaluated 1 month post-treatment and every 2 months thereafter. Between 2007 and 2010, 20 patients (9 males and 11 females) were enrolled in this study. The median age was 75.4 years (range 65–87 years). At a median follow-up of 11 months (range 7–32 months), 12 patients progressed and 5 are alive. The median progression free survival was 11 months and the median overall survival was 13 months. There was no additional toxicity. These results indicate that elderly patients with good KPS can achieve outcomes comparable to the current standard of care using an abbreviated radiotherapy course, radiosurgery boost, and temozolomide.

Radiosurgery for high-grade glioma

Background:

For patients with newly diagnosed high-grade gliomas (HGG), the current standard-of-care treatment involves surgical resection, followed by concomitant temozolomide (TMZ) and external beam radiation therapy (XRT), and subsequent TMZ chemotherapy. For patients with recurrent HGG, there is no standard of care. Stereotactic radiosurgery (SRS) is used to deliver focused, relatively large doses of radiation to a small, precisely defined target. Treatment is usually delivered in a single fraction, but may be delivered in up to five fractions. The role of SRS in the management of patients with HGG is not well established.

Methods:

The PubMed database was searched with combinations of relevant MESH headings and limits. Case reports and/or small case series were excluded. Attention was focused on overall median survival as an objective measure, and data were examined separately for newly diagnosed and recurrent HGG.

Results:

With respect to newly diagnosed HGG, there is strong evidence that addition of an SRS boost prior to standard XRT provides no survival benefit. However, recent retrospective evidence suggests a possible survival benefit when SRS is performed after XRT. With respect to recurrent HGG, there is suggestion that SRS may confer a survival benefit but with potentially higher complication rates. Newer studies are investigating the combination of SRS with targeted molecular agents. Controlled prospective clinical trials using advanced imaging techniques are necessary for a complete assessment.

Conclusions:

SRS has the potential to provide a survival benefit for patients with HGG. Further research is clearly warranted to define its role in the management of newly diagnosed and recurrent HGG.

External beam radiotherapy of recurrent glioma: radiation tolerance of the human brain

Malignant gliomas relapse in close proximity to the resection site, which is the postoperatively irradiated volume. Studies on re-irradiation of glioma were examined regarding radiation-induced late adverse effects (i.e., brain tissue necrosis), to obtain information on the tolerance dose and treatment volume of normal human brain tissue. The studies were analyzed using the linear-quadratic model to express the re-irradiation tolerance in cumulative equivalent total doses when applied in 2 Gy fractions (EQD2_cumulative). Analysis shows that the EQD2_cumulative increases from conventional re-irradiation series to fractionated stereotactic radiotherapy (FSRT) to LINAC-based stereotactic radiosurgery (SRS). The mean time interval between primary radiotherapy and the re-irradiation course was shortened from 30 months for conventional re-irradiation to 17 and 10 months for FSRT and SRS, respectively. Following conventional re-irradiation, radiation-induced normal brain tissue necrosis occurred beyond an EQD2_cumulative around 100 Gy. With increasing conformality of therapy, the smaller the treatment volume is, the higher the radiation dose that can be tolerated. Despite the dose escalation, no increase in late normal tissue toxicity was reported. On basis of our analysis, the use of particle therapy in the treatment of recurrent gliomas, because of the optimized physical dose distribution in the tumour and surrounding healthy brain tissue, should be considered for future clinical trials.

Brain tumour and infiltrations dosimetry of boron neutron capture therapy combined with 252Cf brachytherapy

This article presents a dosimetric investigation of boron neutron capture therapy (BNCT) combined with (252)Cf brachytherapy for brain tumour control. The study was conducted through computational simulation in MCNP5 code, using a precise and discrete voxel model of a human head, in which a hypothetical brain tumour was incorporated. A boron concentration ratio of 1:5 for healthy-tissue: tumour was considered. Absorbed and biologically weighted dose rates and neutron fluency in the voxel model were evaluated. The absorbed dose rate results were exported to SISCODES software, which generates the isodose surfaces on the brain. Analyses were performed to clarify the relevance of boron concentrations in occult infiltrations far from the target tumour, with boron concentration ratios of 1:1 up to 1:50 for healthy-tissue:infiltrations and healthy-tissue:tumour. The average biologically weighted dose rates at tumour area exceed up to 40 times the surrounding healthy tissue dose rates. In addition, the biologically weighted dose rates from boron have the main contribution at the infiltrations, especially far from primary tumour. In conclusion, BNCT combined with (252)Cf brachytherapy is an alternative technique for brain tumour treatment because it intensifies dose deposition at the tumour and at infiltrations, sparing healthy brain tissue.

Radiation therapy for the treatment of recurrent glioblastoma: an overview

Despite the therapeutic advances in neuro-oncology, most patients with glioblastoma ultimately experience local progression/relapse. Re-irradiation has been poorly viewed in the past, mainly due to the overestimated risk of side effects using conventional radiotherapy. To date, thanks to the improvement of several delivery techniques, together with improved imaging capabilities, re-irradiation is a viable salvage treatment option to manage such clinical scenario. A literature overview on the feasibility and efficacy of the different irradiation modalities for recurrent glioblastoma along with considerations on areas of improvement are provided.

Tumor-Cut: segmentation of brain tumors on contrast enhanced MR images for radiosurgery applications

In this paper, we present a fast and robust practical tool for segmentation of solid tumors with minimal user interaction to assist clinicians and researchers in radiosurgery planning and assessment of the response to the therapy. Particularly, a cellular automata (CA) based seeded tumor segmentation method on contrast enhanced T1 weighted magnetic resonance (MR) images, which standardizes the volume of interest (VOI) and seed selection, is proposed. First, we establish the connection of the CA-based segmentation to the graph-theoretic methods to show that the iterative CA framework solves the shortest path problem. In that regard, we modify the state transition function of the CA to calculate the exact shortest path solution. Furthermore, a sensitivity parameter is introduced to adapt to the heterogeneous tumor segmentation problem, and an implicit level set surface is evolved on a tumor probability map constructed from CA states to impose spatial smoothness. Sufficient information to initialize the algorithm is gathered from the user simply by a line drawn on the maximum diameter of the tumor, in line with the clinical practice. Furthermore, an algorithm based on CA is presented to differentiate necrotic and enhancing tumor tissue content, which gains importance for a detailed assessment of radiation therapy response. Validation studies on both clinical and synthetic brain tumor datasets demonstrate 80%-90% overlap performance of the proposed algorithm with an emphasis on less sensitivity to seed initialization, robustness with respect to different and heterogeneous tumor types, and its efficiency in terms of computation time.

Novel therapies in glioblastoma

Conventional treatment of glioblastoma has advanced only incrementally in the last 30 years and still yields poor outcomes. The current strategy of surgery, radiation, and chemotherapy has increased median survival to approximately 15 months. With the advent of molecular biology and consequent improved understanding of basic tumor biology, targeted therapies have become cornerstones for cancer treatment. Many pathways (RTKs, PI3K/AKT/mTOR, angiogenesis, etc.) have been identified in GBM as playing major roles in tumorigenesis, treatment resistance, or natural history of disease. Despite the growing understanding of the complex networks regulating GBM tumors, many targeted therapies have fallen short of expectations. In this paper, we will discuss novel therapies and the successes and failures that have occurred. One clear message is that monotherapies yield minor results, likely due to functionally redundant pathways. A better understanding of underlying tumor biology may yield insights into optimal targeting strategies which could improve the overall therapeutic ratio of conventional treatments.

Radiation treatment parameters for re-irradiation of malignant glioma

BACKGROUND AND PURPOSE

Most patients with malignant glioma ultimately fail locally or loco-regionally after the first treatment, with re-irradiation being a reasonable treatment option. However, only limited data are presently available allowing for a precise selection of patients suitable for re-treatment with regard to safety and efficacy.

MATERIAL AND METHODS

Using the department database, 39 patients with a second course of radiation were identified. Doses to gross tumor volume (GTV), planning target volume (PTV), and relevant organs at risk (OARs; brainstem, optic chiasm, optic nerves, brain) were retrospectively analyzed and correlated to outcome parameters. Relevant treatment parameters including D(max), D(min), D(mean), and volume (ml) were obtained. Equivalent uniform dose (EUD) values were calculated for the tumor and OARs. To address the issue of radiation necrosis/leukoencephalopathy posttherapeutic MRI images were routinely examined every 3 months.

RESULTS

Median follow-up was 147 days. The time interval between first and second irradiation was regularly greater than 6 months. Median EUDs to the OARs were 11.9 Gy (range 0.7-27.4 Gy) to the optic chiasm, 17.6 Gy (range 0.7-43.0 Gy) to the brainstem, 4.9/2.1 Gy (range 0.3-24.5 Gy) to the right/left optic nerve, and 29.4 Gy (range 25.2-32.5 Gy) to the brain. No correlation between treated volume and survival was observed. Cold spots and dose did not correlate with survival. Re-irradiated volumes were treated with on average lower doses if they were larger and vice versa.

CONCLUSION

In general, re-irradiation is a safe and feasible re-treatment option. No relevant toxicity was observed after re-irradiation in our patient cohort during follow-up. In this regard, this analysis provides baseline data for the selection of putative patients. EUD values are derived and may serve as reference for further studies, including intensity-modulated radiotherapy (IMRT) protocols.

Spinal radiosurgery--efficacy and safety after prior conventional radiotherapy

Background

Conventional external beam radiotherapy is a standard procedure for treatment of spinal metastases. In case of progression spinal cord tolerance limits further radiotherapy in pre-irradiated areas. Spinal stereotactic radiotherapy is a non-invasive option to re-treat pre-irradiated patients. Nevertheless, spinal radiosurgery results in relevant dose deposition within the myelon with potential toxicity. Aim of the study was to retrospectively analyse the efficacy and feasibility for salvage radiosurgery of spinal metastases.

Methods

During a period of 4 years (2005-2009) 70 lesions in 54 patients were treated in 60 radiosurgery sessions and retrospectively analysed. Clinical (pain, sensory and motor deficit) and radiological (CT/MRI) follow-up data were collected prospectively after radiosurgery. Pain - as main symptom - was classified by the Visual Analogue Scale (VAS) score. Every patient received single session radiosurgery after having been treated first-line with conventionally fractionated radiotherapy. Kaplan-Meier method and life tables were used to analyse freedom from local failure and overall survival.

Results

At a median follow-up of 14.5 months the actuarial rates of freedom from local failure at 6/12/18 months were 93%, 88% and 85%, respectively. The median radiosurgery dose was 1 × 18 Gy (range 10-28 Gy) to the median 70% isodose. The VAS score of patients with pain (median 6) dropped significantly (median 4, p = 0.002). In 6 out of 7 patients worse sensory or motor deficit after SRS was caused by local or distant failures (diagnosed by CT/MRI). One patient with metastatic renal cell carcinoma developed a progressive complete paraparesis one year after the last treatment at lumbar level L3. Due to multiple surgery and radiosurgery treatments at the lumbar region and further local progression, the exact reason remained unclear. Apart from that, no CTC grade III or higher toxicity has been observed.

Conclusions

By applying spinal radiosurgery relevant radiation doses can be limited to small parts of the myelon. This prevents myelopathic side effects and makes it an effective and safe treatment option for well-suited patients. Especially for previously irradiated patients with local failure or pain salvage SRS represents a valuable treatment option with high local control rates, low toxicity and significant pain reduction.

MiRNA expression patterns predict survival in glioblastoma

Background

In order to define new prognostic subgroups in patients with glioblastoma a miRNA screen (> 1000 miRNAs) from paraffin tissues followed by a bio-mathematical analysis was performed.

Methods

35 glioblastoma patients treated between 7/2005 - 8/2008 at a single institution with surgery and postoperative radio(chemo)therapy were included in this retrospective analysis. For microarray analysis the febit biochip "Geniom^® Biochip MPEA homo-sapiens" was used. Total RNA was isolated from FFPE tissue sections and 1100 different miRNAs were analyzed.

Results

It was possible to define a distinct miRNA expression pattern allowing for a separation of distinct prognostic subgroups. The defined miRNA pattern was significantly associated with early death versus long-term survival (split at 450 days) (p = 0.01). The pattern and the prognostic power were both independent of the MGMT status.

Conclusions

At present, this is the first dataset defining a prognostic role of miRNA expression patterns in patients with glioblastoma. Having defined such a pattern, a prospective validation of this observation is required.

A Review of the Role of Re-Irradiation in Recurrent High-Grade Glioma (HGG)

Despite the use of more effective multimodal treatments in high-grade glioma (HGG), the outcome of patients affected by this disease is still dismal and recurrence is a very common event. Many therapeutic approaches, alone or combined (surgery, drugs, targeted agents, immunotherapy, radiotherapy, supportive therapy), are available in the clinical armamentarium so far. The attitude of physicians is increasingly interventionist, but recurrent HGG still remains a very difficult scenario to be treated. Radiotherapy with different re-irradiation techniques is increasingly proposed as a therapeutic option with interesting results, even though the resulting duration of response is usually quite short. Most lesions re-recur locally, with inadequate identification and targeting of viable tumor being the most important cause of failure. Prognosis is affected by many patient-, tumor-, and treatment-associated prognostic factors. Radiotherapy is delivered with many advanced modalities: 3D-CRT, intensity-modulated radiation therapy, stereotactic fractionated radiotherapy, radiosurgery, and brachitherapy with or without chemotherapy administration. In order to evaluate the feasibility and efficacy of re-irradiation in this setting, we reviewed the PubMed and MEDLINE databases restricting the search to original reports published from January 1990 to June 2011. The search resulted in a total of 155 reports: 78 of them covering 2,688 patients treated with different irradiation modalities overall fulfilled the entry criteria. Radiation therapy demonstrated to be an acceptable option in recurrent HGG with good response rates and acceptable toxicity.