Final report of a phase I/II trial of hyperfractionated and accelerated hyperfractionated radiation therapy with carmustine for adults with supratentorial malignant gliomas. Radiation Therapy Oncology Group Study 83-02

Dosimetric feasibility analysis and presentation of an isotoxic dose-escalated radiation therapy concept for glioblastoma used in the PRIDE trial (NOA-28; ARO-2022-12)

Background and purpose

The PRIDE trial (NOA-28; ARO-2022-12; NCT05871021) is scheduled to start recruitment in October 2023. Its primary objective is to enhance median overall survival (OS), compared to historical median OS rates, in patients with methylguanine methlyltransferase (MGMT) promotor unmethylated glioblastoma by incorporating isotoxic dose escalation to 75 Gy in 30 fractions. To achieve isotoxicity and counteract the elevated risk of radiation necrosis (RN) associated with dose-escalated regimens, the addition of protective concurrent bevacizumab (BEV) serves as an innovative approach. The current study aims to assess the dosimetric feasibility of the proposed concept.

Materials and methods

A total of ten patients diagnosed with glioblastoma were included in this dosimetric analysis. Delineation of target volumes for the reference plans adhered to the ESTRO-EANO 2023 guideline. The experimental plans included an additional volume for the integrated boost. Additionally, the 60 Gy-volume was reduced by using a margin of 1.0 cm instead of 1.5 cm. To assess the risk of symptomatic RN, the Normal Tissue Complication Probability (NTCP) was calculated and compared between the reference and experimental plans.

Results

Median NTCP of the reference plan (NTCPref) and of the experimental plan (NTCPex) were 0.24 (range 0.11-0.29) and 0.42 (range 0.18-0.54), respectively. NTCPex was a median of 1.77 (range 1.60-1.99) times as high as the NTXPref. In a logarithmic comparison, the risk of RN is enhanced by a factor of median 2.00 (range 1.66-2.35). The defined constraints for the organs at risk were feasible.

Conclusion

When considering the potential protective effect of BEV, which we hypothesized might reduce the risk of RN by approximately two-fold, achieving isotoxicity with the proposed dose-escalated experimental plan for the PRIDE trial seems feasible.

Promising outcome of patients with recurrent glioblastoma after Gamma Knife-based hypofractionated radiotherapy

BACKGROUND

The role of Gamma Knife radiosurgery (GKRS) in recurrent glioblastoma remains unclear. The purpose of this study is to evaluate the effects of GKRS in a group of patients with recurrent glioblastoma, focusing on survival and safety.

METHODS

Patients undergoing GKRS for recurrent glioblastoma between September 2014 and April 2019 were included in this study. Relevant clinical and radiosurgical data, including GKRS-related complications, were recorded and analyzed. Overall survival (OS), local progression free survival (LPFS) and prognostic factors for outcome were thoroughly evaluated.

RESULTS

Fifty-three patients were analyzed (24 female, 29 male). The median age was 50 years (range, 19-78 years). The median GKRS treatment volume was 35.01 cm3 (range, 2.38-115.57 cm3). Twenty patients (38%) were treated with single fraction GKRS, while 33 (62%) were treated with GKRS-based hypofractionated stereotactic radiotherapy (HSRT). The median prescription dose for single fraction GKRS, 3-fractions HSRT and 5-fractions HSRT were 16 Gy (range, 10-20 Gy), 27 Gy (range, 18-33 Gy) and 25 Gy (range, 25-30 Gy), respectively. The median LPFS and OS times were 8.1 months and 11.4 months after GKRS, respectively. HSRT and Bevacizumab were associated with improved LPFS, while HSRT alone was associated with longer OS.

CONCLUSION

Our findings suggested that HRST would likely improve LPFS and OS in definite settings; the addition of Bevacizumab to GKRS was associated with increased rates of local control. No major complications were reported. Further prospective studies are warranted to confirm our findings.

Accelerated hyper-versus normofractionated radiochemotherapy with temozolomide in patients with glioblastoma: a multicenter retrospective analysis

Background and purpose

The standard treatment of glioblastoma patients consists of surgery followed by normofractionated radiotherapy (NFRT) with concomitant and adjuvant temozolomide chemotherapy. Whether accelerated hyperfractionated radiotherapy (HFRT) yields comparable results to NFRT in combination with temozolomide has only sparsely been investigated. The objective of this study was to compare NFRT with HFRT in a multicenter analysis.

Materials and methods

A total of 484 glioblastoma patients from four centers were retrospectively pooled and analyzed. Three-hundred-ten and 174 patients had been treated with NFRT (30 × 1.8 Gy or 30 × 2 Gy) and HFRT (37 × 1.6 Gy or 30 × 1.8 Gy twice/day), respectively. The primary outcome of interest was overall survival (OS) which was correlated with patient-, tumor- and treatment-related variables via univariable and multivariable Cox frailty models. For multivariable modeling, missing covariates were imputed using multiple imputation by chained equations, and a sensitivity analysis was performed on the complete-cases-only dataset.

Results

After a median follow-up of 15.7 months (range 0.8–88.6 months), median OS was 16.9 months (15.0–18.7 months) in the NFRT group and 14.9 months (13.2–17.3 months) in the HFRT group (p = 0.26). In multivariable frailty regression, better performance status, gross-total versus not gross-total resection, MGMT hypermethylation, IDH mutation, smaller planning target volume and salvage therapy were significantly associated with longer OS (all p < 0.01). Treatment differences (HFRT versus NFRT) had no significant effect on OS in either univariable or multivariable analysis.

Conclusions

Since HFRT with temozolomide was not associated with worse OS, we assume HFRT to be a potential option for patients wishing to shorten their treatment time.

Ultra-hyper-fractionated radiotherapy for high-grade gliomas

High-grade gliomas (HGGs; WHO grades III and IV) are invariably lethal brain tumors. Low-dose hyper-radiosensitivity (HRS) of HGG is a well-established phenomenon in vitro. However, possibly linked to the unavailability of accurate animal models of the diseases, this therapeutic effect could not be consistently translated to the animal setting, thus impairing its subsequent clinical development. The purpose of this study was to develop radiotherapeutic (RT) schedules permitting to significantly improve the overall survival of faithful animal models of HGG that have been recently made available. We used primary glioma initiating cell (GIC)-driven orthotopic animal models that accurately recapitulate the heterogeneity and growth patterns of the patients' tumors, to investigate the therapeutic effects of low radiation doses toward HGG. With the same total dose, RT fractions ≤0.5 Gy twice per week [ultra-hyper-fractionation (ultra-hyper-FRT)] started at early stages of tumor progression (a condition that in the clinical setting often occurs at the end of the guidelines treatment) improved the effectiveness of RT and the animal survival in comparison to standard fractions. For the same cumulative dose, the use of fractions ≤0.5 Gy may permit to escape one or more tumor resistance mechanisms thus increasing the effectiveness of RT and the overall animal survival. These findings suggest investigating in the clinical setting the therapeutic effect of an ultra-hyper-FRT schedule promptly extending the conventional RT component of the current guideline ("Stupp") therapeutic protocol.

The impact of anatomical changes during photon or proton based radiation treatment on tumor dose in glioblastoma dose escalation trials

PURPOSE/OBJECTIVE

Most dose-escalation trials in glioblastoma patients integrate the escalated dose throughout the standard course by targeting a specific subvolume. We hypothesize that anatomical changes during irradiation may affect the dose coverage of this subvolume for both proton- and photon-based radiotherapy.

MATERIAL AND METHODS

For 24 glioblastoma patients a photon- and proton-based dose escalation treatment plan (of 75 Gy/30 fr) was simulated on the dedicated radiotherapy planning MRI obtained before treatment. The escalated dose was planned to cover the resection cavity and/or contrast enhancing lesion on the T1w post-gadolinium MRI sequence. To analyze the effect of anatomical changes during treatment, we evaluated on an additional MRI that was obtained during treatment the changes of the dose distribution on this specific high dose region.

RESULTS

The median time between the planning MRI and additional MRI was 26 days (range 16-37 days). The median time between the planning MRI and start of radiotherapy was relatively short (7 days, range 3-11 days). In 3 patients (12.5%) changes were observed which resulted in a substantial deterioration of both the photon and proton treatment plans. All these patients underwent a subtotal resection, and a decrease in dose coverage of more than 5% and 10% was observed for the photon- and proton-based treatment plans, respectively.

CONCLUSION

Our study showed that only for a limited number of patients anatomical changes during photon or proton based radiotherapy resulted in a potentially clinically relevant underdosage in the subvolume. Therefore, volume changes during treatment are unlikely to be responsible for the negative outcome of dose-escalation studies.

Treatment of newly diagnosed glioblastoma in the elderly: a network meta-analysis

BACKGROUND

A glioblastoma is a fatal type of brain tumour for which the standard of care is maximum surgical resection followed by chemoradiotherapy, when possible. Age is an important consideration in this disease, as older age is associated with shorter survival and a higher risk of treatment-related toxicity.

OBJECTIVES

To determine the most effective and best-tolerated approaches for the treatment of elderly people with newly diagnosed glioblastoma. To summarise current evidence for the incremental resource use, utilities, costs and cost-effectiveness associated with these approaches.

SEARCH METHODS

We searched electronic databases including the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and Embase to 3 April 2019, and the NHS Economic Evaluation Database (EED) up to database closure. We handsearched clinical trial registries and selected neuro-oncology society conference proceedings from the past five years.

SELECTION CRITERIA

Randomised trials (RCTs) of treatments for glioblastoma in elderly people. We defined 'elderly' as 70+ years but included studies defining 'elderly' as over 65+ years if so reported.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods for study selection and data extraction. Where sufficient data were available, treatment options were compared in a network meta-analysis (NMA) using Stata software (version 15.1). For outcomes with insufficient data for NMA, pairwise meta-analysis were conducted in RevMan. The GRADE approach was used to grade the evidence.

MAIN RESULTS

We included 12 RCTs involving approximately 1818 participants. Six were conducted exclusively among elderly people (either defined as 65 years or older or 70 years or older) with newly diagnosed glioblastoma, the other six reported data for an elderly subgroup among a broader age range of participants. Most participants were capable of self-care. Study quality was commonly undermined by lack of outcome assessor blinding and attrition. NMA was only possible for overall survival; other analyses were pair-wise meta-analyses or narrative syntheses. Seven trials contributed to the NMA for overall survival, with interventions including supportive care only (one trial arm); hypofractionated radiotherapy (RT40; four trial arms); standard radiotherapy (RT60; five trial arms); temozolomide (TMZ; three trial arms); chemoradiotherapy (CRT; three trial arms); bevacizumab with chemoradiotherapy (BEV_CRT; one trial arm); and bevacizumab with radiotherapy (BEV_RT). Compared with supportive care only, NMA evidence suggested that all treatments apart from BEV_RT prolonged survival to some extent. Overall survival High-certainty evidence shows that CRT prolongs overall survival (OS) compared with RT40 (hazard ratio (HR) 0.67, 95% confidence interval (CI) 0.56 to 0.80) and low-certainty evidence suggests that CRT may prolong overall survival compared with TMZ (TMZ versus CRT: HR 1.42, 95% CI 1.01 to 1.98). Low-certainty evidence also suggests that adding BEV to CRT may make little or no difference (BEV_CRT versus CRT: HR 0.83, 95% CrI 0.48 to 1.44). We could not compare the survival effects of CRT with different radiotherapy fractionation schedules (60 Gy/30 fractions and 40 Gy/15 fractions) due to a lack of data. When treatments were ranked according to their effects on OS, CRT ranked higher than TMZ, RT and supportive care only, with the latter ranked last. BEV plus RT was the only treatment for which there was no clear benefit in OS over supportive care only.   One trial comparing tumour treating fields (TTF) plus adjuvant chemotherapy (TTF_AC) with adjuvant chemotherapy alone could not be included in the NMA as participants were randomised after receiving concomitant chemoradiotherapy, not before. Findings from the trial suggest that the intervention probably improves overall survival in this selected patient population. We were unable to perform NMA for other outcomes due to insufficient data. Pairwise analyses were conducted for the following. Quality of life Moderate-certainty narrative evidence suggests that overall, there may be little difference in QoL between TMZ and RT, except for discomfort from communication deficits, which are probably more common with RT (1 study, 306 participants, P = 0.002). Data on QoL for other comparisons were sparse, partly due to high dropout rates, and the certainty of the evidence tended to be low or very low. Progression-free survival High-certainty evidence shows that CRT increases time to disease progression compared with RT40 (HR 0.50, 95% CI 0.41 to 0.61); moderate-certainty evidence suggests that RT60 probably increases time to disease progression compared with supportive care only (HR 0.28, 95% CI 0.17 to 0.46), and that BEV_RT probably increases time to disease progression compared with RT40 alone (HR 0.46, 95% CI 0.27 to 0.78). Evidence for other treatment comparisons was of low- or very low-certainty. Severe adverse events Moderate-certainty evidence suggests that TMZ probably increases the risk of grade 3+ thromboembolic events compared with RT60 (risk ratio (RR) 2.74, 95% CI 1.26 to 5.94; participants = 373; studies = 1) and also the risk of grade 3+ neutropenia, lymphopenia, and thrombocytopenia. Moderate-certainty evidence also suggests that CRT probably increases the risk of grade 3+ neutropenia, leucopenia and thrombocytopenia compared with hypofractionated RT alone. Adding BEV to CRT probably increases the risk of thromboembolism (RR 16.63, 95% CI 1.00 to 275.42; moderate-certainty evidence). Economic evidence There is a paucity of economic evidence regarding the management of newly diagnosed glioblastoma in the elderly. Only one economic evaluation on two short course radiotherapy regimen (25 Gy versus 40 Gy) was identified and its findings were considered unreliable.

AUTHORS' CONCLUSIONS

For elderly people with glioblastoma who are self-caring, evidence suggests that CRT prolongs survival compared with RT and may prolong overall survival compared with TMZ alone. For those undergoing RT or TMZ therapy, there is probably little difference in QoL overall. Systemic anti-cancer treatments TMZ and BEV carry a higher risk of severe haematological and thromboembolic events and CRT is probably associated with a higher risk of these events. Current evidence provides little justification for using BEV in elderly patients outside a clinical trial setting. Whilst the novel TTF device appears promising, evidence on QoL and tolerability is needed in an elderly population. QoL and economic assessments of CRT versus TMZ and RT are needed. More high-quality economic evaluations are needed, in which a broader scope of costs (both direct and indirect) and outcomes should be included.

Accelerated hyperfractionated radiochemotherapy with temozolomide is equivalent to normofractionated radiochemotherapy in a retrospective analysis of patients with glioblastoma

Background

Current standard of treatment for newly diagnosed patients with glioblastoma (GBM) is surgical resection with adjuvant normofractionated radiotherapy (NFRT) combined with temozolomide (TMZ) chemotherapy. Hyperfractionated accelerated radiotherapy (HFRT) which was known as an option from randomized controlled trials before the temozolomide era has not been compared to the standard therapy in a randomized setting combined with TMZ.

Methods

Data of 152 patients with newly diagnosed GBM treated from 10/2004 until 7/2018 at a single tertiary care institution were extracted from a clinical database and retrospectively analyzed. Thirty-eight patients treated with NFRT of 60 Gy in 30 fractions (34 with simultaneous and 2 with sequential TMZ) were compared to 114 patients treated with HFRT of 54.0 Gy in 30 fraction of 1.8 Gy twice daily (109 with simultaneous and 3 with sequential TMZ). The association between treatment protocol and other variables with overall survival (OS) was assessed using univariable and multivariable Cox regression analysis; the latter was performed using variables selected by the LASSO method.

Results

Median overall survival (OS) was 20.3 month for the entire cohort. For patients treated with NFRT median OS was 24.4 months compared to 18.5 months in patients treated with HFRT (p = 0.131). In univariable regression analysis the use of dexamethasone during radiotherapy had a significant negative impact on OS in both patient groups, HR 2.21 (95% CI 1.47–3.31, p = 0.0001). In multivariable analysis adjusted for O6-methylguanine-DNA methyl-transferase (MGMT) promotor methylation status, salvage treatment and secondary GBM, the use of dexamethasone was still a negative prognostic factor, HR 1.95 (95% CI 1.21–3.13, p = 0.006). Positive MGMT-methylation status and salvage treatment were highly significant positive prognostic factors. There was no strong association between treatment protocol and OS (p = 0.504).

Conclusions

Our retrospective analysis supports the hypothesis of equivalence between HFRT and the standard protocol of treatment for GBM. For those patients who are willing to obtain the benefit of shortening the course of radiochemotherapy, HFRT may be an alternative with comparable efficacy although it was not yet tested in a large prospective randomized study against the current standard. The positive influence of salvage therapy and negative impact of concomitant use of corticosteroids should be addressed in future prospective trials. To confirm our results, we plan to perform a pooled analysis with other tertiary clinics in order to achieve better statistical reliability.

Locally dose-escalated radiotherapy may improve intracranial local control and overall survival among patients with glioblastoma

Background

The dismal overall survival (OS) prognosis of glioblastoma, even after trimodal therapy, can be attributed mainly to the frequent incidence of intracranial relapse (ICR), which tends to present as an in-field recurrence after a radiation dose of 60 Gray (Gy). In this study, molecular marker-based prognostic indices were used to compare the outcomes of radiation with a standard dose versus a moderate dose escalation.

Methods

This retrospective analysis included 156 patients treated between 2009 and 2016. All patients were medically fit for postoperative chemoradiotherapy. In the dose-escalation cohort a simultaneous integrated boost of up to 66 Gy (66 Gy RT) within small high-risk volumes was applied. All other patients received daily radiation to a total dose of 60 Gy or twice daily to a total dose of 59.2 Gy (60 Gy RT).

Results

A total of 133 patients received standard 60 Gy RT, while 23 received 66 Gy RT. Patients in the 66 Gy RT group were younger (p <  0.001), whereas concomitant temozolomide use was more frequent in the 60 Gy RT group (p <  0.001). Other intergroup differences in known prognostic factors were not observed. Notably, the median time to ICR was significantly prolonged in the 66 Gy RT arm versus the 60 Gy RT arm (12.2 versus 7.6 months, p = 0.011), and this translated to an improved OS (18.8 versus 15.3 months, p = 0.012). A multivariate analysis revealed a strong association of 66 Gy RT with a prolonged time to ICR (hazard ratio = 0.498, p = 0.01) and OS (hazard ratio = 0.451, p = 0.01). These differences remained significant after implementing molecular marker-based prognostic scores (ICR p = 0.008, OS p = 0.007) and propensity-scored matched pairing (ICR p = 0.099, OS p = 0.023).

Conclusion

Radiation dose escalation was found to correlate with an improved time to ICR and OS in this cohort of glioblastoma patients. However, further prospective validation of these results is warranted.

Electronic supplementary material

The online version of this article (10.1186/s13014-018-1194-8) contains supplementary material, which is available to authorized users.

Human Glioma Migration and Infiltration Properties as a Target for Personalized Radiation Medicine

Gliomas are primary brain tumors that present the majority of malignant adult brain tumors. Gliomas are subdivided into low- and high-grade tumors. Despite extensive research in recent years, the prognosis of malignant glioma patients remains poor. This is caused by naturally highly infiltrative capacities as well as high levels of radio- and chemoresistance. Additionally, it was shown that low linear energy transfer (LET) irradiation enhances migration and invasion of several glioma entities which might counteract today’s treatment concepts. However, this finding is discussed controversially. In the era of personalized medicine, this controversial data might be attributed to the patient-specific heterogeneity that ultimately could be used for treatment. Thus, current developments in glioma therapy should be seen in the context of intrinsic and radiation-enhanced migration and invasion. Due to the natural heterogeneity of glioma cells and different radiation responses, a personalized radiation treatment concept is suggested and alternative radiation concepts are discussed.

Predicting patterns of failure in temporal lobe GBMs: possible implications on radiotherapy treatment portals

Background

Characterise patterns of failure of Temporal Lobe (TL) Glioblastoma (GBM) following treatment with relation to normal temporal lobe anatomy and neural pathways.

Methods

335 GBM patients received radiotherapy between 03/2007 and 07/2014, 100 were located in TL. Site of initial tumour and subsequent relapse were subdivided into 5 local TL sites (anterior, lateral, medial, posterior and superior); 5 adjacent regional sites (occipital lobe, inferior frontal lobe, caudate/thalamus/internal/external capsules, fornix/ventricular trigone), and 5 distant failure sites (ventricles, contralateral hemisphere, brainstem, leptomeninges and spine). Extension along major neuroanatomical pathways at initial presentation and at first documented Magnetic Resonance Imaging (MRI) failure were categorised into anterior, superior, medial and posterior pathways.

Results

Of the 100 patients, 86 had radiological progress with a median survival of 17.3 months.

At initial diagnosis, 74% of tumours were linked to one TL site and 94% were confined to the TL. 19% had neural pathway disease at initial pre-treatment MRI. At first recurrence locoregional site failure was 74%. 26% failed within distant sites and 53% patients were noted to have neural pathway involvement.

Initial tumour location predicted for local site recurrence (p < 0.0001), regional site recurrence (p = 0.004) and neural pathway recurrence pattern (p = 0.005), but not for distant sites (p = 0.081).

Conclusion

Most GBMs fail at local or adjacent regional sites. Many of the recurrences occurred in a predictable pattern within a local or regional site, unique to initial TL site with more than half involving neural pathways. Knowledge of tumour infiltration and failure may improve target definition and radiotherapy.

Radiotherapy of Glioblastoma 15 Years after the Landmark Stupp's Trial: More Controversies than Standards?

Background

The current standard of care of glioblastoma, the most common primary brain tumor in adults, has remained unchanged for over a decade. Nevertheless, some improvements in patient outcomes have occurred as a consequence of modern surgery, improved radiotherapy and up-to-date management of toxicity. Patients from control arms (receiving standard concurrent chemoradiotherapy and adjuvant chemotherapy with temozolomide) of recent clinical trials achieve better outcomes compared to the median survival of 14.6 months reported in Stupp’s landmark clinical trial in 2005. The approach to radiotherapy that emerged from Stupp’s trial, which continues to be a basis for the current standard of care, is no longer applicable and there is a need to develop updated guidelines for radiotherapy within the daily clinical practice that address or at least acknowledge existing controversies in the planning of radiotherapy.

The goal of this review is to provoke critical thinking about potentially controversial aspects in the radiotherapy of glioblastoma, including among others the issue of target definitions, simultaneously integrated boost technique, and hippocampal sparing.

Conclusions

In conjunction with new treatment approaches such as tumor-treating fields (TTF) and immunotherapy, the role of adjuvant radiotherapy will be further defined. The personalized approach in daily radiotherapy practice is enabled with modern radiotherapy systems.

NRG oncology RTOG 9006: a phase III randomized trial of hyperfractionated radiotherapy (RT) and BCNU versus standard RT and BCNU for malignant glioma patients

From 1990 to 1994, patients with newly diagnosed malignant gliomas were enrolled and randomized between hyperfractionated radiation (HFX) of 72.0 Gy in 60 fractions given twice daily and 60.0 Gy in 30 fractions given once daily. All patients received 80 mg/m² of 1,3 bis(2 chloroethyl)-1 nitrosourea on days 1-3 q8 weeks for 1 year. Patients were stratified by age, KPS, and histology. The primary endpoint was overall survival (OS), with secondary endpoints including progression-free survival (PFS) and toxicity. Out of the 712 patients accrued, 694 (97.5%) were analyzable cases (350 HFX, 344 standard arm). There was no significant difference between the arms on overall acute or late treatment-related toxicity. No statistically significant effect for HFX, as compared to standard therapy, was found on either OS, with a median survival time (MST) of 11.3 versus 13.1 months (p = 0.20) or PFS, with a median PFS time of 5.7 versus 6.9 months (p = 0.18). The treatment effect on OS remained insignificant based on the multivariate analysis (hazard ratio 1.16; p = 0.0682). When OS was analyzed by histology subgroup there was also no significant difference between the two arms for patients with glioblastoma multiforme (MST: 10.3 vs. 11.2 months; p = 0.34), anaplastic astrocytoma (MST: 69.8 vs. 50.0 months; p = 0.91) or anaplastic oligodendroglioma (MST: 92.1 vs. 66.5 months; p = 0.33). Though this trial provided many invaluable secondary analyses, there was no trend or indication of a benefit to HFX radiation to 72.0 Gy in any subset of malignant glioma patients.

Long-Term Outcome of Postoperative Irradiation in Patients with Newly Diagnosed WHO Grade III Anaplastic Gliomas

Purpose

Patients with anaplastic gliomas have a more favorable overall survival than patients with glioblastomas. In most analyses, WHO grade III and IV tumors are not analyzed separately. The present analysis reports outcome after postoperative radiotherapy in patients with WHO grade III gliomas.

Patients and methods

Between January 1988 and January 2007, 127 patients with WHO grade III tumors were treated with radiotherapy; the histological classification was pure astrocytoma in 104 patients, oligoastrocytoma in 12 and pure oligodendroglioma in 11 patients. Median age was 48 years. After the primary diagnosis, a biopsy had been performed in 72 patients; subtotal and total resections were performed in 37 and 18 patients, respectively. In all patients radiotherapy was applied with a median dose of 60 Gy in conventional fractionation. The median follow-up time was 18 months.

Results

Median overall survival was 17 months. Overall survival was significantly influenced by the extent of surgery. Median overall survival was 32 months after complete resection, 36 months after subtotal resection, and 12 months after biopsy. Median overall survival was 7 months for patients with anaplastic astrocytomas, 44 months for patients with mixed tumors, and 47 months for those with pure oligodendrogliomas. Age significantly influenced overall survival. Median progression-free survival was 9 months; the extent of neurosurgical resection significantly influenced progression-free survival.

Conclusion

Patients with WHO grade III anaplastic astrocytomas, oligodendrogliomas and oligoastrocytomas show favorable overall survival after postoperative radiotherapy compared with glioblastoma patients and should therefore be analyzed separately. Radiochemotherapy might further improve outcome.

Hypofractionated intensity-modulated radiotherapy using simultaneous integrated boost technique with concurrent and adjuvant temozolomide for glioblastoma

Aims and background

We assessed the therapeutic efficacy of combined hypofractionated intensity-modulated radiotherapy with temozolomide in patients with primary glioblastoma.

Methods and study design

Thirty-nine patients with histologically confirmed glioblastoma were accrued. Using the simultaneous integrated boost technique, a dose of 50 Gy in 5-Gy fractions was applied to the gross tumor volume, together with 40 Gy in 4-Gy fractions and 30 Gy in 3-Gy fractions to the 1- and 2-cm margins from the gross tumor volume, respectively. Patients were also treated with concurrent temozolomide during intensity-modulated radiotherapy, followed by six cycles of adjuvant temozolomide.

Results

Median follow-up was 16.8 months (range, 4.3–54.3). Tumor progression was observed in 28 patients (71.8%), and the median time to progression was 6.8 months. Median survival was 16.8 months, and it was affected significantly by the extent of surgery. During adjuvant temozolomide treatment, 3 patients (9.7%) developed grade 3–4 hematologic or hepatic toxicity. Radiation necrosis developed in 7 patients (17.9%) and massive necrosis, requiring emergency surgery, in 1 patient (2.6%).

Conclusions

The regimen of hypofractionated intensity-modulated radiotherapy with temozolomide showed a relatively good outcome in patients with glioblastoma. Further studies are required to define the optimal fraction size for glioblastoma using this highly sophisticated radiation technique.

Prognostic Implication of Clinical and Pathologic Features in Patients with Glioblastoma Multiforme Treated with Concomitant Radiation plus Temozolomide

Aims and background

Glioblastoma multiforme is the most common and most malignant primary brain tumor in adults. The current standard of care for glioblastoma is surgical resection to the extent feasible, followed by adjuvant radiotherapy plus temozolomide, given concomitantly with and after radiotherapy. This report is a prospective observational study of 43 cases treated in the Department of Radiotherapy, University of Rome La Sapienza, Italy. We examine the relationship between pathologic features and objective response rate in adult patients treated with concomitant radiation plus temozolomide to identify clinical, neuroradiologic, pathologic, and molecular factors with prognostic significance.

Methods

Forty-three consecutive patients (24 males and 19 females), ages 15-77 years (median, 57) with newly diagnosed glioblastoma multiforme, were included in this trial between 2002 and 2004 at our department. All patients were treated with surgery (complete resection in 81%, incomplete in 19%) followed by concurrent temozolomide (75 mg/m2/day) and radiotherapy (median tumor dose, 60 Gy), followed by temozolomide, 200 mg/m2/day for 5 consecutive days every 28 days. Neurologic evaluations were performed monthly and cranial magnetic resonance bimonthly. We analyzed age, clinical manifestations at diagnosis, seizures, Karnofsky performance score, tumor location, extent of resection, proliferation index (Ki-67 expression), p53, platelet-derived growth factor and epidermal growth factor receptor immunohistochemical expression as prognostic factors in the patients. The Kaplan-Meier statistical method and logrank test were used to assess correlation with survival.

Results

Fourteen patients (32%) manifested clinical and neuroradiographic evidence of tumor progression within 6 months of surgery. In contrast, 5 patients (12%) showed no disease progression for 18 months from the beginning of treatment. Median overall survival was 19 months. Multivariate analysis revealed that an age of 60 years or older (P <0.03), a postoperative performance score ≤70 (P = 0.04), the nontotal tumor resection (P = 0.03), tumor size >4 cm (P = 0.01) and proliferation index overexpression (P = 0.001) were associated with the worst prognosis. p53, PDGF and EGFR overexpression were not significant prognostic factors associated with survival.

Conclusions

The results suggest that analysis of prognostic markers in glioblastoma multiforme is complex. In addition to previously recognized prognostic variables such as age and Karnofsky performance score, tumor size, total resection and proliferation index overexpression were identified as predictors of survival in a series of patients with glioblastoma multiforme.

Radiotherapy using IMRT boosts after hyperbaric oxygen therapy with chemotherapy for glioblastoma

The purpose of this study was to evaluate the feasibility and efficacy of radiotherapy (RT) using intensity-modulated radiotherapy (IMRT) boosts after hyperbaric oxygen (HBO) therapy with chemotherapy in patients with glioblastoma. Twenty-four patients with glioblastoma were treated with the combined therapy, which was RT using IMRT boosts after HBO with chemotherapy, and were retrospectively analyzed. The RT protocol was as follows: first, 3D conformal RT [40 Gy/20 fractions (fr)] was delivered to the gross tumor volume (GTV) and the surrounding edema, including an additional 1.5-2.0 cm. The IMRT boost doses were then continuously delivered to the GTV plus 5 mm (28 Gy/8 fr) and the surrounding edema (16 Gy/8 fr). Each IMRT boost session was performed immediately after HBO to achieve radiosensitization. The planned RT dose was completed in all patients, while HBO therapy was terminated in one patient (4%) due to Grade 2 aural pain. The toxicities were mild, no non-hematological toxicity of Grade 3-5 was observed. The 2-year overall survival (OS) and progression-free survival rates in all patients were 46.5% and 35.4%, respectively. The median OS time was 22.1 months. In conclusion, the combined therapy of RT using IMRT boosts after HBO with chemotherapy was a feasible and promising treatment modality for patients with glioblastoma. The results justify further evaluation to clarify the benefits of this therapy.

Getting into the brain: liposome-based strategies for effective drug delivery across the blood-brain barrier

This review summarizes articles that have been reported in literature on liposome-based strategies for effective drug delivery across the blood–brain barrier. Due to their unique physicochemical characteristics, liposomes have been widely investigated for their application in drug delivery and in vivo bioimaging for the treatment and/or diagnosis of neurological diseases, such as Alzheimer’s, Parkinson’s, stroke, and glioma. Several strategies have been used to deliver drug and/or imaging agents to the brain. Covalent ligation of such macromolecules as peptides, antibodies, and RNA aptamers is an effective method for receptor-targeting liposomes, which allows their blood–brain barrier penetration and/or the delivery of their therapeutic molecule specifically to the disease site. Additionally, methods have been employed for the development of liposomes that can respond to external stimuli. It can be concluded that the development of liposomes for brain delivery is still in its infancy, although these systems have the potential to revolutionize the ways in which medicine is administered.

Accelerated hyperfractionation plus temozolomide in glioblastoma

Introduction

Hyperfractionated (HFRT) or accelerated hyperfractionated radiotherapy (AHFRT) have been discussed as a potential treatment for glioblastoma based on a hypothesized reduction of late radiation injury and prevention of repopulation. HFRT and AHFRT have been examined extensively in the pre-Temozolomide era with inconclusive results. In this study we examined the role of accelerated hyperfractionation in the Temozolomide era.

Materials and methods

Sixty-four patients who underwent AHFRT (62 of which received Temozolomide) were compared to 67 patients who underwent normofractionated radiotherapy (NFRT) (64 of which received TMZ) between 02/2009 and 10/2014. Follow-up data were analyzed until 01/2015.

Results

Median progression-free survival (PFS) was 6 months for the entire cohort. For patients treated with NFRT median PFS was 7 months, for patients treated with AHFRT median PFS was 6 months. Median overall survival (OS) was 13 months for all patients. For patients treated with NFRT median OS was 15 months, for patients treated with AHFRT median OS was 10 months. The fractionation regimen was not a predictor of PFS or OS in univariable- or multivariable analysis. There was no difference in acute toxicity profiles between the two treatment groups.

Conclusions

Univariable and multivariable analysis did not show significant differences between NFRT and AHFRT fractionation regimens in terms of PFS or OS. The benefits are immanent: the regimen does significantly shorten hospitalization time in a patient collective with highly impaired life expectancy. We propose that the role of AHFRT + TMZ should be further examined in future prospective trials.

Concurrent chemoradiotherapy versus radiotherapy alone for "biopsy-only" glioblastoma multiforme

BACKGROUND

Combined temozolomide and radiotherapy (RT) is the standard postoperative therapy for glioblastoma multiforme (GBM). However, the clearest benefit of concurrent chemoradiotherapy (CRT) observed in clinical trials has been among patients who undergo surgical resection. Whether the improved survival with CRT extends to patients who undergo "biopsy only" is less certain. The authors compared overall survival (OS) in a national cohort of patients with GBM who underwent biopsy and received either RT alone or CRT during the temozolomide era.

METHODS

The US National Cancer Data Base was used to identify patients with histologically confirmed, biopsy-only GBM who received either RT alone or CRT from 2006 through 2011. Demographic and clinicopathologic predictors of treatment were analyzed using the chi-square test, the t test, and multivariable logistic regression. OS was evaluated using the log-rank test, multivariable Cox proportional hazard regression, and propensity score-matched analysis.

RESULTS

In total, 1479 patients with biopsy-only GBM were included, among whom 154 (10.4%) received RT alone and 1325 (89.6%) received CRT. The median age at diagnosis was 61 years. CRT was associated with a significant OS benefit compared with RT alone (median, 9.2 vs 5.6 months; hazard ratio [HR], 0.64; 95% confidence interval [CI], 0.54-0.76; P < .001). CRT was independently associated with improved OS compared with RT alone on multivariable analysis (HR, 0.71; 95% CI, 0.60-0.85; P < .001). A significant OS benefit for CRT persisted in a propensity score-matched analysis (HR, 0.72; 95% CI, 0.56-0.93; P = .009).

CONCLUSIONS

The current data suggest that CRT significantly improves OS in patients with GBM who undergo biopsy only compared with RT alone and should remain the standard of care for patients who can tolerate therapy. Cancer 2016;122:2364-2370. © 2016 American Cancer Society.

Radioresistance of Brain Tumors

Radiation therapy (RT) is frequently used as part of the standard of care treatment of the majority of brain tumors. The efficacy of RT is limited by radioresistance and by normal tissue radiation tolerance. This is highlighted in pediatric brain tumors where the use of radiation is limited by the excessive toxicity to the developing brain. For these reasons, radiosensitization of tumor cells would be beneficial. In this review, we focus on radioresistance mechanisms intrinsic to tumor cells. We also evaluate existing approaches to induce radiosensitization and explore future avenues of investigation.

Principles of radiation therapy

Although resection remains the mainstay in the treatment of gliomas, microscopically complete resection of most central nervous system tumors remains challenging, and is, in fact, rarely accomplished. Considering their invasive nature, gross total resections to clearly negative margins often do or would require removal or transection of functional brain, with likely serious neurologic deficits. Consequently, radiotherapy has emerged as an indispensable component of therapy. It is delivered primarily by external-beam radiotherapy or brachytherapy techniques. Herein, we present the biologic principles, techniques, and applications of radiotherapy in glioma treatment today.

Stereotactic radiosurgery (SRS) in high-grade glioma: judicious selection of small target volumes improves results

We present a retrospective review of 55 Stereotactic Radiosurgery (SRS) procedures performed in 47 consecutive patients with high-grade glioma (HGG). Thirty-three (70.2%) patients were diagnosed with glioblastoma and 14 (29.8%) with grade III glioma. The indications for SRS were small (up to 30 mm in diameter) locally progressing lesions in 32/47 (68%) or new distant lesions in 15/47 (32%) patients. The median target volume was 2.2 cc (0.2-9.5 cc) and the median prescription dose was 18 Gy (14-24 Gy). Three patients (5.5% incidence in 55 treatments) developed radiation necrosis. In eight cases (17%) patients received a second salvage SRS treatment to nine new lesions detected during follow-up. In 22/55 SRS treatments (40.0%) patients received concurrent chemo- or biological therapy, including temozolamide (TMZ) (15 patients), bevacizumab (BVZ) (6 patients) and carboplatin in one patient. Median time to progression after SRS was 5.0 months (1.0-96.4). Median survival time after SRS was 15.9 months (2.3-109.3) overall median survival (since diagnosis) was 37.4 months (9.6-193.6 months). Long-lasting responses (>12 months) after SRS were observed in 25/46 (54.3%) patients. We compared a matched (histology, age, KPS) cohort of patients with recurrent HGG treated with BVZ alone with the current study group. Median survival was significantly longer for SRS treated patients compared to the BVZ only cohort (12.6 vs. 7.3 months, p = 0.0102). SRS may be considered an effective salvage procedure for selected patients with small volume, recurrent high-grade gliomas. Long-term radiological control was observed in more than 50% of the patients.

Update on Brain Tumors: New Developments in Neuro-oncologic Diagnosis and Treatment, and Impact on Rehabilitation Strategies

Brain tumors can be a source of functional impairment to patients due to neurologic sequelae associated with the tumor itself as well as treatment side effects. As a result, many of these patients may require rehabilitation services. Surgery, chemotherapy, and radiation therapy have been longstanding, primary treatment modalities in the management of brain tumors, though these treatments continue to evolve given new developments in research and technology. A better understanding of the diagnostic workup and current treatment standards helps the physiatrist and rehabilitation team identify rehabilitation services needed, recognize potential side-effects from anticipated or concurrent treatments, and coordinate care with referral sources. The purpose of this article is to review these new advances in diagnosis and treatment of patients with brain tumors, as well as discuss the rehabilitation implications for this population, including factors such as rehabilitation approach, timing of concomitant treatment, cost management, and coordination of care.

Altered fractionation schedules in radiation treatment: a review

Conventionally fractionated radiotherapy is delivered in 1.8- to 2.0-Gy fractions. With increases in understanding of radiation and tumor biology, various alterations of radiotherapy schedules have been tested in clinical trials and are now regarded by some as standard treatment options. Hyperfractionation is delivered through a greater number of smaller treatment doses. Accelerated fractionation decreases the amount of time over which radiotherapy is delivered typically by increasing the number of treatments per day. Hypofractionation decreases the number of fractions delivered by increasing daily treatment doses. Furthermore, many of these schedules have been tested with concurrent chemotherapy regimens. In this review, we summarize the major clinical studies that have been conducted on altered fractionation in various disease sites.

Rhenium-186 liposomes as convection-enhanced nanoparticle brachytherapy for treatment of glioblastoma

Although external beam radiation is an essential component to the current standard treatment of primary brain tumors, its application is limited by toxicity at doses more than 80 Gy. Recent studies have suggested that brachytherapy with liposomally encapsulated radionuclides may be of benefit, and we have reported methods to markedly increase the specific activity of rhenium-186 ((186)Re)-liposomes. To better characterize the potential delivery, toxicity, and efficacy of the highly specific activity of (186)Re-liposomes, we evaluated their intracranial application by convection-enhanced delivery in an orthotopic U87 glioma rat model. After establishing an optimal volume of 25 µL, we observed focal activity confined to the site of injection over a 96-hour period. Doses of up to 1850 Gy were administered without overt clinical or microscopic evidence of toxicity. Animals treated with (186)Re-liposomes had a median survival of 126 days (95% confidence interval [CI], 78.4-173 days), compared with 49 days (95% CI, 44-53 days) for controls. Log-rank analysis between these 2 groups was highly significant (P = .0013) and was even higher when 100 Gy was used as a cutoff (P < .0001). Noninvasive luciferase imaging as a surrogate for tumor volume showed a statistically significant separation in bioluminescence by 11 days after 100 Gy or less treatment between the experimental group and the control animals (χ(2)[1, N= 19] = 4.8; P = .029). MRI also supported this difference in tumor size. Duplication of tumor volume differences and survival benefit was possible in a more invasive U251 orthotopic model, with clear separation in bioluminescence at 6 days after treatment (χ(2)[1, N= 9] = 4.7; P = .029); median survival in treated animals was not reached at 120 days because lack of mortality, and log-rank analysis of survival was highly significant (P = .0057). Analysis of tumors by histology revealed minimal areas of necrosis and gliosis. These results support the potential efficacy of the highly specific activity of brachytherapy by (186)Re-liposomes convection-enhanced delivery in glioma.

The impact of recent data on the optimization of standards of care in newly diagnosed glioblastoma

Glioblastoma is an aggressive form of brain cancer with a poor long-term prognosis. Treatment regimens for newly diagnosed disease range from surgical resection alone to surgery followed by radiotherapy with concurrent and adjuvant chemotherapy. Ongoing investigations are focused on optimization of chemotherapy by improving dosing and duration schedules and utilization of biomarkers for patient selection. Our understanding of glioblastoma tumor biology, the role of molecular signaling pathways, cellular repair mechanisms, and angiogenesis has increased greatly over the past few years, leading to the investigation of a variety of targeted therapies. In addition, advances in radiographic assessment have significantly impacted not only improvement in diagnosis, but interpretation of response to therapy. In order to effectively evaluate the clinical utility of new agents, as well as incorporate advances in radiographic assessment, changes to current clinical trial design need to be considered. This article reviews the care for newly diagnosed glioblastoma, as well as how recent findings might be incorporated into patient care.

Low-dose fractionated radiotherapy and concomitant chemotherapy in glioblastoma multiforme with poor prognosis: a feasibility study

We explored the feasibility of concurrent palliative chemotherapy and low-dose fractionated radiotherapy (LD-FRT) in glioblastoma multiforme (GBM). Patients with recurrent/progressive GBM at least 3 months after the end of primary radiotherapy received 0.3 Gy twice daily with cisplatin and fotemustine if progressing on temozolomide, or 0.4 Gy twice daily with temozolomide if recurrent 4-6 months later (retreatment group). Newly diagnosed GBM with gross residual mass received 30 Gy with concomitant and adjuvant temozolomide and 0.4 Gy twice daily from the second adjuvant cycle (naive group) for 2-4 cycles. Twenty-six patients were enrolled. In the retreatment group (n = 17; median LD-FRT total dose 7.2 Gy [range 2.4-11.6]), grade 3 or 4 hematological toxicity was observed in 5.9% of patients. Median follow-up time was 20 months (range 4-35). Median progression-free survival (PFS) and overall survival (OS) from the time of recurrence or progression were 4 and 8 months, respectively (OS at 6 months, 69%; at 12 months, 16.7%). In the naive group (n = 9; median LD-FRT total dose 8 Gy [range 3.2-16]), grade 3 or 4 hematological toxicity was observed in 11.1% of patients. Median follow-up time was 17 months (range 8-20)-median PFS was 9 months, with PFS at 6 months and at 1 year of 66.7% and 26.7%, respectively; and median OS was 12 months, with OS at 6 months and at 1 year of 77.8% and 34.6%, respectively. LD-FRT with concurrent chemotherapy was well tolerated.

A phase I dose escalation study of hypofractionated IMRT field-in-field boost for newly diagnosed glioblastoma multiforme

OBJECTIVES

To describe the results of a Phase I dose escalation trial for newly diagnosed glioblastoma multiforme (GBM) using a hypofractionated concurrent intensity-modulated radiotherapy (IMRT) boost.

METHODS

Twenty-one patients were enrolled between April 1999 and August 2003. Radiotherapy consisted of daily fractions of 1.8 Gy with a concurrent boost of 0.7 Gy (total 2.5 Gy daily) to a total dose of 70, 75, or 80 Gy. Concurrent chemotherapy was not permitted. Seven patients were enrolled at each dose and dose limiting toxicities were defined as irreversible Grade 3 or any Grade 4-5 acute neurotoxicity attributable to radiotherapy.

RESULTS

All patients experienced Grade 1 or 2 acute toxicities. Acutely, 8 patients experienced Grade 3 and 1 patient experienced Grade 3 and 4 toxicities. Of these, only two reversible cases of otitis media were attributable to radiotherapy. No dose-limiting toxicities were encountered. Only 2 patients experienced Grade 3 delayed toxicity and there was no delayed Grade 4 toxicity. Eleven patients requiring repeat resection or biopsy were found to have viable tumor and radiation changes with no cases of radionecrosis alone. Median overall and progression-free survival for this cohort were 13.6 and 6.5 months, respectively. One- and 2-year survival rates were 57% and 19%. At recurrence, 15 patients received chemotherapy, 9 underwent resection, and 5 received radiotherapy.

CONCLUSIONS

Using a hypofractionated concurrent IMRT boost, we were able to safely treat patients to 80 Gy without any dose-limiting toxicity. Given that local failure still remains the predominant pattern for GBM patients, a trial of dose escalation with IMRT and temozolomide is warranted.

Validation and simplification of the Radiation Therapy Oncology Group recursive partitioning analysis classification for glioblastoma

PURPOSE

Previous recursive partitioning analysis (RPA) of patients with malignant glioma (glioblastoma multiforme [GBM] and anaplastic astrocytoma [AA]) produced six prognostic groups (I-VI) classified by six factors. We sought here to determine whether the classification for GBM could be improved by using an updated Radiation Therapy Oncology Group (RTOG) GBM database excluding AA and by considering additional baseline variables.

METHODS AND MATERIALS

The new analysis considered 42 baseline variables and 1,672 GBM patients from the expanded RTOG glioma database. Patients receiving radiation only were excluded such that all patients received radiation+carmustine. "Radiation dose received" was replaced with "radiation dose assigned." The new RPA models were compared with the original model by applying them to a test dataset comprising 488 patients from six other RTOG trials. Fitness of the original and new models was evaluated using explained variation.

RESULTS

The original RPA model explained more variations in survival in the test dataset than did the new models (20% vs. 15%) and was therefore chosen for further analysis. It was reduced by combining Classes V and VI to produce three prognostic classes (Classes III, IV, and V+VI), as Classes V and VI had indistinguishable survival in the test dataset. The simplified model did not further improve performance (explained variation 18% vs. 20%) but is easier to apply because it involves only four variables: age, performance status, extent of resection, and neurologic function. Applying this simplified model to the updated GBM database resulted in three distinct classes with median survival times of 17.1, 11.2, and 7.5 months for Classes III, IV, and V+VI, respectively.

CONCLUSIONS

The final model, the simplified original RPA model combining Classes V and VI, resulted in three distinct prognostic groups defined by age, performance status, extent of resection, and neurologic function. This classification will be used in future RTOG GBM trials.

A Phase II study of anti-epidermal growth factor receptor radioimmunotherapy in the treatment of glioblastoma multiforme

OBJECT

This single-institution Phase II study tests the efficacy of adjuvant radioimmunotherapy with (125)I-labeled anti-epidermal growth factor receptor 425 murine monoclonal antibody ((125)I-mAb 425) in patients with newly diagnosed glioblastoma multiforme (GBM).

METHODS

A total of 192 patients with GBM were treated with (125)I-mAb 425 over a course of 3 weekly intravenous injections of 1.8 GBq following surgery and radiation therapy. The primary end point was overall survival, and the secondary end point was toxicity. Additional subgroup analyses were performed comparing treatment with (125)I-mAb 425 (RIT, 132 patients), (125)I-mAb 425 and temozolomide (TMZ+RIT, 60 patients), and a historical control group (CTL, 81 patients).

RESULTS

The median age was 53 years (range 19-78 years), and the median Karnofsky Performance Scale score was 80 (range 60-100). The percentage of patients who underwent debulking surgery was 77.6% and that of those receiving temozolomide was 31.3%. The overall median survival was 15.7 months (95% CI 13.6-17.8 months). The 1- and 2-year survivals were 62.5 and 25.5%, respectively. For subgroups RIT and TMZ+RIT, the median survivals were 14.5 and 20.2 months, respectively. No Grade 3 or 4 toxicity was seen with the administration of (125)I-mAb 425. The CTL patients lacked Karnofsky Performance Scale scores, had poorer survival, were older, and were less likely to receive radiation therapy. On multivariate analysis, the hazard ratios for RIT versus CTL, TMZ+RIT versus CTL, and TMZ+RIT versus RIT were 0.49 (p < 0.001), 0.30 (p < 0.001), and 0.62 (p = 0.008), respectively.

CONCLUSIONS

In this large Phase II study of 192 patients with GBM treated with anti-epidermal growth factor receptor (125)I-mAb 425 radioimmunotherapy, survival was 15.7 months, and treatment was safe and well tolerated.

Radiation oncology in brain tumors: current approaches and clinical trials in progress

Radiation therapy remains a critical therapeutic modality in the treatment of adult brain tumors. However, its use continues to evolve depending on the histologic findings of the brain tumor. In high-grade gliomas, current trials focus on the addition of systemic agents and optimization of target delineation to improve the therapeutic ratio of radiotherapy. In low-grade gliomas, the life expectancy is much greater, and the possibility of late effects of radiotherapy have shaped contemporary trials to attempt to identify groups that benefit from radiotherapy versus the ones that may defer radiotherapy until tumor progression. With primary central nervous system lymphoma, the advent of high-dose methotrexate-based chemotherapy and the risk of severe early neurocognitive toxicity have brought the role of radiotherapy into question. With meningioma, the use of normal tissue-sparing techniques such as radiosurgery has allowed for the successful treatment of patients who are eminently curable and with a life expectancy that is generally no different than that of the general population. Particular attention in this review is paid to current approaches, contemporary trials, and modern therapeutic dilemmas.

A systematic methodology review of phase I radiation dose escalation trials

BACKGROUND AND PURPOSE

The purpose of this review is to evaluate the methodology used in published phase I radiotherapy (RT) dose escalation trials. A specific emphasis was placed on the frequency of reporting late complications as endpoint.

MATERIALS AND METHODS

We performed a systematic literature review using a predefined search strategy to identify all phase I trials reporting on external radiotherapy dose escalation in cancer patients.

RESULTS

Fifty-three trials (phase I: n = 36, phase I-II: n = 17) fulfilled the inclusion criteria. Of these, 20 used a modified Fibonacci design for the RT dose escalation, but 32 did not specify a design. Late toxicity was variously defined as > 3 months (n = 43) or > 6 months (n = 3) after RT, or not defined (n = 7). In only nine studies the maximum tolerated dose (MTD) was related to late toxicity, while only half the studies reported the minimum follow-up period for dose escalation (n = 26).

CONCLUSION

In phase I RT trials, late complications are often not taken into account and there is currently no consensus on the methodology used for radiation dose escalation studies. We therefore propose a decision-tree algorithm which depends on the endpoint selected and whether a validated early surrogate endpoint is available, in order to choose the most appropriate study design.

Irradiation of pediatric high-grade spinal cord tumors

PURPOSE

To report the outcome using radiation therapy (RT) for pediatric patients with high-grade spinal cord tumors.

METHODS AND MATERIALS

A retrospective chart review was conducted that included 17 children with high-grade spinal cord tumors treated with RT at St. Jude Children's Research Hospital between 1981 and 2007. Three patients had gross total resection, 11 had subtotal resection, and 3 underwent biopsy. The tumor diagnosis was glioblastoma multiforme (n = 7), anaplastic astrocytoma (n = 8), or anaplastic oligodendroglioma (n = 2). Seven patients received craniospinal irradiation (34.2-48.6 Gy). The median dose to the primary site was 52.2 Gy (range, 38-66 Gy).

RESULTS

The median progression-free and overall survivals were 10.8 and 13.8 months, respectively. Local tumor progression at 12 months (79% vs. 30%, p = 0.02) and median survival (13.1 vs. 27.2 months, p = 0.09) were worse for patients with glioblastoma multiforme compared with anaplastic astrocytoma or oligodendroglioma. The median overall survival was shorter for patients when failure included neuraxis dissemination (n = 8) compared with local failure alone (n = 5), 9.6 vs. 13.8 months, p = 0.08. Three long-term survivors with World Health Organization Grade III tumors were alive with follow-up, ranging from 88-239 months.

CONCLUSIONS

High-grade spinal cord primary tumors in children have a poor prognosis. The propensity for neuraxis metastases as a component of progression after RT suggests the need for more aggressive therapy.

Prolonged survival for patients with newly diagnosed, inoperable glioblastoma with 3-times daily ultrafractionated radiation therapy

Ultrafractionation of radiation therapy is a novel regimen consisting of irradiating tumors several times daily, delivering low doses (<0.75 Gy) at which hyperradiosensitivity occurs. We recently demonstrated the high efficiency of ultrafractionated radiotherapy (RT) on glioma xenografts and report here on a phase II clinical trial to determine the safety, tolerability, and efficacy of an ultrafractionation regimen in patients with newly and inoperable glioblastoma (GBM). Thirty-one patients with histologically proven, newly diagnosed, and unresectable supratentorial GBM (WHO grade IV) were enrolled. Three daily doses of 0.75 Gy were delivered at least 4 hours apart, 5 days per week over 6-7 consecutive weeks (90 fractions for a total of 67.5 Gy). Conformal irradiation included the tumor bulk with a margin of 2.5 cm. The primary end points were safety, toxicity, and tolerability, and the secondary end points were overall survival (OS) and progression-free survival (PFS). Multivariate analysis was used to compare the OS and PFS with the EORTC-NCIC trial 26981-22981/CE.3 of RT alone vs radiation therapy and temozolomide (TMZ). The ultrafractionation radiation regimen was safe and well tolerated. No acute Grade III and/or IV CNS toxicity was observed. Median PFS and OS from initial diagnosis were 5.1 and 9.5 months, respectively. When comparing with the EORTC/NCIC trial, in both PFS and OS multivariate analysis, ultrafractionation showed superiority over RT alone, but not over RT and TMZ. The ultrafractionation regimen is safe and may prolong the survival of patients with GBM. Further investigation is warranted and a trial associating ultra-fractionation and TMZ is ongoing.

Intralesional lymphokine-activated killer cells as adjuvant therapy for primary glioblastoma

Despite recent advances, median survival for patients with resectable glioblastoma multiforme (GBM) is only 12 to 15 months. We previously observed minimal toxicity and a 9.0-month median survival after treatment with intralesional autologous lymphokine-activated killer (LAK) cells in 40 patients with recurrent GBM. In this study, GBM patients were treated with adjuvant intralesional LAK cells. Eligible patients had completed primary therapy for GBM without disease progression. LAK cells were produced by incubating autologous peripheral blood mononuclear cells with interleukin-2 for 3 to 7 days and then placed into the surgically exposed tumor cavity by a neurosurgeon. The 19 men and 14 women had a median age of 57 years. Prior therapy included surgical resection (97%), partial brain irradiation (97%), gamma knife radiosurgery (97%), and temozolomide chemotherapy (70%). Median time from diagnosis to LAK cell therapy was 5.3 months (range: 3.0 to 11.1 mo). LAK cell treatment was well tolerated; average length of hospitalization was 3 days. At the time of this analysis, 27 patients have died; the median survival from the date of original diagnosis is 20.5 months with a 1-year survival rate of 75%. In subset analyses, superior survival was observed for patients who received higher numbers of CD3+/CD16+/CD56+ (T-LAK) cells in the cell products, which was associated with not taking corticosteroids in the month before leukopheresis. Intralesional LAK cell therapy is safe and the survival sufficiently encouraging to warrant further evaluation in a randomized phase 2 trial of intralesional therapies with LAK or carmustine-impregnated wafers.

Introduction of hypermatrix and operator notation into a discrete mathematics simulation model of malignant tumour response to therapeutic schemes in vivo. Some operator properties

The tremendous rate of accumulation of experimental and clinical knowledge pertaining to cancer dictates the development of a theoretical framework for the meaningful integration of such knowledge at all levels of biocomplexity. In this context our research group has developed and partly validated a number of spatiotemporal simulation models of in vivo tumour growth and in particular tumour response to several therapeutic schemes. Most of the modeling modules have been based on discrete mathematics and therefore have been formulated in terms of rather complex algorithms (e.g. in pseudocode and actual computer code). However, such lengthy algorithmic descriptions, although sufficient from the mathematical point of view, may render it difficult for an interested reader to readily identify the sequence of the very basic simulation operations that lie at the heart of the entire model. In order to both alleviate this problem and at the same time provide a bridge to symbolic mathematics, we propose the introduction of the notion of hypermatrix in conjunction with that of a discrete operator into the already developed models. Using a radiotherapy response simulation example we demonstrate how the entire model can be considered as the sequential application of a number of discrete operators to a hypermatrix corresponding to the dynamics of the anatomic area of interest. Subsequently, we investigate the operators’ commutativity and outline the “summarize and jump” strategy aiming at efficiently and realistically address multilevel biological problems such as cancer. In order to clarify the actual effect of the composite discrete operator we present further simulation results which are in agreement with the outcome of the clinical study RTOG 83–02, thus strengthening the reliability of the model developed.

Stereotactic radiosurgery for glioblastoma: retrospective analysis

Purpose

This retrospective study was done to better understand the conditions for which stereotactic radiosurgery (SRS) for glioblastoma may be efficacious.

Methods

Between 2000 and 2007, 33 patients with a pathological diagnosis of glioblastoma received SRS with the Novalis^® Shaped Beam Radiosurgery system. Eighteen patients (54%) underwent salvage SRS for recurrence while 15 (45%) patients received upfront SRS following standard fractionated RT for newly diagnosed glioblastoma.

Results

There were no RTOG grade >2 acute side effects. The median survival after SRS was 6.7 months (range 1.4 – 74.7). There was no significant difference in overall survival (from the time of initial diagnosis) with respect to the timing of SRS (p = 0.2). There was significantly better progression free survival in patients treated with SRS as consolidation versus at the time of recurrence (p = 0.04). The majority of patients failed within or at the margin of the SRS treatment volume (21/26 evaluable for recurrence).

Conclusion

SRS is well tolerated in the treatment of glioblastoma. As there was no difference in survival whether SRS is delivered upfront or at recurrence, the treatment for each patient should be individualized. Future studies are needed to identify patients most likely to respond to SRS.

Short delay in initiation of radiotherapy may not affect outcome of patients with glioblastoma: a secondary analysis from the radiation therapy oncology group database

PURPOSE

To analyze the Radiation Therapy Oncology Group (RTOG) database of patients with glioblastoma and appraise whether outcome was influenced by time to initiation of radiation therapy (RT).

PATIENTS AND METHODS

From 1974 through 2003, adult patients with histologically confirmed supratentorial glioblastoma were enrolled onto 16 RTOG studies. Of 3,052 enrolled patients, 197 patients (6%) were either initially rendered ineligible or had insufficient chronologic data, leaving a cohort of 2,855 patients for the present analysis. We selected four patient groups based on the interval from surgery to the start of RT: <or= 2 weeks, 2 to 3 weeks, 3 to 4 weeks, more than 4 weeks to the protocol eligibility limit of 6 weeks. Survival times were estimated by the Kaplan-Meier method. Multivariate analysis incorporated variables of time interval, recursive partitioning analysis (RPA) class, and treatment regimen.

RESULTS

No decrement in survival could be identified with increasing time to initiation of RT. Among our four temporal groupings, median survival time was unexpectedly and significantly greater in the group with the longest interval (> 4 weeks) than in those with the shortest delay (<or= 2 weeks): respectively, 12.5 months versus 9.2 months (P < .0001). On multivariate analysis, with overall survival as the end point, time interval more than 4 weeks and lower RPA class were both significant predictors of improved outcome. Treatment regimen was not a significant factor.

CONCLUSION

There is no evident reduction in survival by delaying initiation of RT within the relatively narrow constraint of 6 weeks. An unanticipated yet significantly superior outcome was identified for patients for whom RT was delayed beyond 4 weeks from surgery.

[(18)F]Fluoroethyltyrosine- positron emission tomography-guided radiotherapy for high-grade glioma

Background

To compare morphological gross tumor volumes (GTVs), defined as pre- and postoperative gadolinium enhancement on T₁-weighted magnetic resonance imaging to biological tumor volumes (BTVs), defined by the uptake of ¹⁸F fluoroethyltyrosine (FET) for the radiotherapy planning of high-grade glioma, using a dedicated positron emission tomography (PET)-CT scanner equipped with three triangulation lasers for patient positioning.

Methods

Nineteen patients with malignant glioma were included into a prospective protocol using FET PET-CT for radiotherapy planning. To be eligible, patients had to present with residual disease after surgery. Planning was performed using the clinical target volume (CTV = GTV ∪ BTV) and planning target volume (PTV = CTV + 20 mm). First, the interrater reliability for BTV delineation was assessed among three observers. Second, the BTV and GTV were quantified and compared. Finally, the geometrical relationships between GTV and BTV were assessed.

Results

Interrater agreement for BTV delineation was excellent (intraclass correlation coefficient 0.9). Although, BTVs and GTVs were not significantly different (p = 0.9), CTVs (mean 57.8 ± 30.4 cm³) were significantly larger than BTVs (mean 42.1 ± 24.4 cm³; p < 0.01) or GTVs (mean 38.7 ± 25.7 cm³; p < 0.01). In 13 (68%) and 6 (32%) of 19 patients, FET uptake extended ≥ 10 and 20 mm from the margin of the gadolinium enhancement.

Conclusion

Using FET, the interrater reliability had excellent agreement for BTV delineation. With FET PET-CT planning, the size and geometrical location of GTVs and BTVs differed in a majority of patients.

Modeling the effects of resection, radiation and chemotherapy in glioblastoma

The standard treatment for newly diagnosed glioblastoma multiforme is surgical resection followed by radiotherapy and chemotherapy. Most studies on these treatments are retrospective clinical data analysis. To integrate these studies, a mathematical model is developed. The model predicts the survival time of patients who undergo resection, radiation, and chemotherapy with different protocols.

Phase I three-dimensional conformal radiation dose escalation study in newly diagnosed glioblastoma: Radiation Therapy Oncology Group Trial 98-03

PURPOSE

To evaluate in a Phase I trial the feasibility and toxicity of dose-escalated three-dimensional conformal radiotherapy (3D-CRT) concurrent with chemotherapy in patients with primary supratentorial glioblastoma (GBM).

METHODS AND MATERIALS

A total of 209 patients were enrolled. All received 46 Gy in 2-Gy fractions to the first planning target volume (PTV(1)), defined as the gross tumor volume (GTV) plus 1.8 cm. A subsequent boost was given to PTV(2), defined as GTV plus 0.3 cm. Patients were stratified into two groups (Group 1: PTV(2) <75 cm(3); Group 2: PTV(2) >or=75 cm(3)). Four RT dose levels were evaluated: 66, 72, 78, and 84 Gy. Carmustine 80 mg/m(2) was given during RT, then every 8 weeks for 6 cycles. Pretreatment characteristics were well balanced.

RESULTS

Acute and late Grade 3/4 RT-related toxicities were no more frequent at higher RT dose or with larger tumors. There were no dose-limiting toxicities (acute Grade >or=3 irreversible central nervous system toxicities) observed on any dose level in either group. On the basis of the absence of dose-limiting toxicities, dose was escalated to 84 Gy in both groups. Late RT necrosis was noted at 66 Gy (1 patient), 72 Gy (2 patients), 78 Gy (2 patients), and 84 Gy (3 patients) in Group 1. In Group 2, late RT necrosis was noted at 78 Gy (1 patient) and 84 Gy (2 patients). Median time to RT necrosis was 8.8 months (range, 5.1-12.5 months). Median survival in Group 1 was 11.6-19.3 months. Median survival in Group 2 was 8.2-13.9 months.

CONCLUSIONS

Our study shows the feasibility of delivering higher than standard (60 Gy) RT dose with concurrent chemotherapy for primary GBM, with an acceptable risk of late central nervous system toxicity.