Postoperative hypofractionated radiotherapy versus conventionally fractionated radiotherapy in malignant gliomas. A preliminary report on a randomized trial

Novel Radiation Approaches

The standard of care treatment for glioblastoma is surgical resection followed by radiotherapy to 60 Gy with concurrent and adjuvant temozolomide with or without tumor-treating fields. Advanced imaging techniques are under evaluation to better guide radiotherapy target volume delineation and allow for dose escalation. Particle therapy, in the form of protons, carbon ions, and boron neutron capture therapy, are being assessed as strategies to improve the radiotherapeutic ratio. Stereotactic, hypofractionated, pulsed-reduced dose-rate, and particle radiotherapy are re-irradiation techniques each uniquely suited for different clinical scenarios. Novel radiotherapy approaches, such as FLASH, represent promising advancements in radiotherapy for glioblastoma.

Treating Glioblastoma Multiforme (GBM) with super hyperfractionated radiation therapy: Implication of temporal dose fractionation optimization including cancer stem cell dynamics

PURPOSE

A previously developed ordinary differential equation (ODE) that models the dynamic interaction and distinct radiosensitivity between cancer stem cells (CSC) and differentiated cancer cells (DCC) was used to explain the definitive treatment failure in Glioblastoma Multiforme (GBM) for conventionally and hypo-fractionated treatments. In this study, optimization of temporal dose modulation based on the ODE equation is performed to explore the feasibility of improving GBM treatment outcome.

METHODS

A non-convex optimization problem with the objective of minimizing the total cancer cell number while maintaining the normal tissue biological effective dose (BEDnormal) at 100 Gy, equivalent to the conventional 2 Gy × 30 dosing scheme was formulated. With specified total number of dose fractions and treatment duration, the optimization was performed using a paired simulated annealing algorithm with fractional doses delivered to the CSC and DCC compartments and time intervals between fractions as variables. The recurrence time, defined as the time point at which the total tumor cell number regrows to 2.8×109 cells, was used to evaluate optimization outcome. Optimization was performed for conventional treatment time frames equivalent to currently and historically utilized fractionation schemes, in which limited improvement in recurrence time delay was observed. The efficacy of a super hyperfractionated approach with a prolonged treatment duration of one year was therefore tested, with both fixed regular and optimized variable time intervals between dose fractions corresponding to total number of fractions equivalent to weekly, bi-weekly, and monthly deliveries (n = 53, 27, 13). Optimization corresponding to BEDnormal of 150 Gy was also obtained to evaluate the possibility in further recurrence delay with dose escalation.

RESULTS

For the super hyperfractionated schedules with dose fraction number equivalent to weekly, bi-weekly, and monthly deliveries, the recurrence time points were found to be 430.5, 423.9, and 413.3 days, respectively, significantly delayed compared with the recurrence time of 250.3 days from conventional fractionation. Results show that optimal outcome was achieved by first delivering infrequent fractions followed by dense once per day fractions in the middle and end of the treatment course, with sparse and low dose treatments in the between. The dose to the CSC compartment was held relatively constant throughout while larger dose fractions to the DCC compartment were observed in the beginning and final fractions that preceded large time intervals. Dose escalation to BEDnormal of 150 Gy was shown capable of further delaying recurrence time to 452 days.

CONCLUSION

The development and utilization of a temporal dose fractionation optimization framework in the context of CSC dynamics have demonstrated that substantial delay in GBM local tumor recurrence could be achieved with a super hyperfractionated treatment approach. Preclinical and clinical studies are needed to validate the efficacy of this novel treatment delivery method.

External beam radiation dose escalation for high grade glioma

BACKGROUND

This is an updated version of the original Cochrane Review published in Issue 8, 2016. High grade glioma (HGG) is a rapidly growing brain tumour in the supporting cells of the nervous system, with several subtypes such as glioblastoma (grade IV astrocytoma), anaplastic (grade III) astrocytoma and anaplastic (grade III) oligodendroglioma. Studies have investigated the best strategy to give radiation to people with HGG. Conventional fractionated radiotherapy involves giving a daily radiation dose (called a fraction) of 180 cGy to 200 cGy. Hypofractionated radiotherapy uses higher daily doses, which reduces the overall number of fractions and treatment time. Hyperfractionated radiotherapy which uses a lower daily dose with a greater number of fractions and multiple fractions per day to deliver a total dose at least equivalent to external beam daily conventionally fractionated radiotherapy in the same time frame. The aim is to reduce the potential for late toxicity. Accelerated radiotherapy (dose escalation) refers to the delivery of multiple fractions per day using daily doses of radiation consistent with external beam daily conventionally fractionated radiotherapy doses. The aim is to reduce the overall treatment time; typically, two or three fractions per day may be delivered with a six to eight hour gap between fractions.

OBJECTIVES

To assess the effects of postoperative external beam radiation dose escalation in adults with HGG.

SEARCH METHODS

We searched CENTRAL, MEDLINE Ovid and Embase Ovid to August 2019 for relevant randomised phase III trials.

SELECTION CRITERIA

We included adults with a pathological diagnosis of HGG randomised to the following external beam radiation regimens: daily conventionally fractionated radiotherapy versus no radiotherapy; hypofractionated radiotherapy versus daily conventionally fractionated radiotherapy; hyperfractionated radiotherapy versus daily conventionally fractionated radiotherapy or accelerated radiotherapy versus daily conventionally fractionated radiotherapy.

DATA COLLECTION AND ANALYSIS

The primary outcomes were overall survival and adverse effects. The secondary outcomes were progression free survival and quality of life. We used the standard methodological procedures expected by Cochrane. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

Since the last version of this review, we identified no new relevant trials for inclusion. We included 11 randomised controlled trials (RCTs) with 2062 participants and 1537 in the relevant arms for this review. There was an overall survival benefit for people with HGG receiving postoperative radiotherapy compared to the participants receiving postoperative supportive care. For the four pooled RCTs (397 participants), the overall hazard ratio (HR) for survival was 2.01 favouring postoperative radiotherapy (95% confidence interval (CI) 1.58 to 2.55; P < 0.00001; moderate-certainty evidence). Although these trials may not have completely reported adverse effects, they did not note any significant toxicity attributable to radiation. Progression free survival and quality of life could not be pooled due to lack of data. Overall survival was similar between hypofractionated and conventional radiotherapy in five trials (943 participants), where the HR was 0.95 (95% CI 0.78 to 1.17; P = 0.63; very low-certainty evidence. The trials reported that hypofractionated and conventional radiotherapy were well tolerated with mild acute adverse effects. These trials only reported one participant in the hypofractionated arm developing symptomatic radiation necrosis that required surgery. Progression free survival and quality of life could not be pooled due to the lack of data. Overall survival was similar between hypofractionated and conventional radiotherapy in the subset of two trials (293 participants) which included participants aged 60 years and older with glioblastoma. For this category, the HR was 1.16 (95% CI 0.92 to 1.46; P = 0.21; high-certainty evidence). There were two trials which compared hyperfractionated radiotherapy versus conventional radiation and one trial which compared accelerated radiotherapy versus conventional radiation. However, the results could not be pooled. The conventionally fractionated radiotherapy regimens were 4500 cGy to 6000 cGy given in 180 cGy to 200 cGy daily fractions, over five to six weeks. All trials generally included participants with World Health Organization (WHO) performance status from 0 to 2 and Karnofsky performance status of 50 and higher. The risk of selection bias was generally low among these RCTs. The number of participants lost to follow-up for the outcome of overall survival was low. Attrition, performance, detection and reporting bias for the outcome of overall survival was low. There was unclear attrition, performance, detection and reporting bias relating to the outcomes of adverse effects, progression free survival and quality of life.

AUTHORS' CONCLUSIONS

Postoperative conventional daily radiotherapy probably improves survival for adults with good performance status and HGG compared to no postoperative radiotherapy. Hypofractionated radiotherapy has similar efficacy for survival compared to conventional radiotherapy, particularly for individuals aged 60 years and older with glioblastoma. There are insufficient data regarding hyperfractionation versus conventionally fractionated radiation (without chemotherapy) and for accelerated radiation versus conventionally fractionated radiation (without chemotherapy). There are HGG subsets who have poor prognosis even with treatment (e.g. glioblastoma histology, older age and poor performance status). These HGG individuals with poor prognosis have generally been excluded from randomised trials based on poor performance status. No randomised trial has compared comfort measures or best supportive care with an active intervention using radiotherapy or chemotherapy in these people with poor prognosis. Since the last version of this review, we found no new relevant studies. The search identified three new trials, but all were excluded as none had a conventionally fractionated radiotherapy arm.

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.

Radiation and Immunotherapy in High-grade Gliomas: Where Do We Stand?

High-grade glioma is the most common primary brain tumor, with glioblastoma multiforme (GBM) accounting for 52% of all brain tumors. The current standard of care (SOC) of GBM involves surgery followed by adjuvant fractionated radiotherapy and chemotherapy. However, little progress has been made in extending overall survival, progression-free survival, and quality of life. Attempts to characterize and customize treatment of GBM have led to mitigating the deleterious effects of radiotherapy using hypofractionated radiotherapy, as well as various immunotherapies as a promising strategy for the incurable disease. A combination of radiotherapy and immunotherapy may prove to be even more effective than either alone, and preclinical evidence suggests that hypofractionated radiotherapy can actually prime the immune system to make immunotherapy more effective. This review addresses the complications of the current radiotherapy regimen, various methods of immunotherapy, and preclinical and clinical data from combined radioimmunotherapy trials.

Clinical Results of Unconventional Fractionation Radiotherapy in Central Nervous System Tumors

Malignant brain tumors (primary and metastatic) are apparently resistant to most therapeutic efforts. Several randomized trials have provided evidence supporting the efficacy of radiation therapy. Attempts at improving the results of external beam radiotherapy include altered fractionation, radiation sensitizers and concomitant chemotherapy. In low-grade gliomas, all clinical studies with radiotherapy have employed conventional dose fractionation regimens. In high-grade gliomas, hypofractionation schedules represent effective palliative regimens in poor prognosis subsets of patients; short-term survival in these patients has not allowed to evaluate late toxicity. In tumors arising within the central nervous system, hyperfractionated irradiation exploits the differences in repair capacity between tumour and late responding normal tissues. It may allow for higher total dose and may result in increased tumor cell kill. Accelerated radiotherapy may reduce the repopulation of tumor cells between fractions. It may potentially improve tumor control for a given dose level, provided that there is no increase in late normal tissue injury. In supratentorial malignant gliomas, superiority of accelerated hyperfractionated over conventionally fractionated schedules was observed in a randomized trial; however, the gain in survival was less than 6 months. At present no other randomized trial supports the preferential choice for altered fractionation irradiation. Also in pediatric brainstem tumors there are no data to confirm the routine use of hyperfractionated irradiation, and significant late sequelae have been reported in the few long-term survivors. Shorter treatment courses with accelerated hyperfractionated radiotherapy may represent a useful alternative to conventional irradiation for the palliation of brain metastases. Different considerations have been proposed to explain this gap between theory and clinical data. Patients included in dose/effect studies are not stratified by prognostic factors and other treatment-related parameters. This observation precludes any definite conclusion about the relative role of conventional and of altered fractionation. New approaches are currently in progress. More prolonged radiation treatments, up to higher total doses, could delay time to tumor progression and improve survival in good prognosis subsets of patients; altered fractionation may be an effective therapeutic tool to achieve this goal.

External beam radiation dose escalation for high grade glioma

BACKGROUND

The incidence of high grade glioma (HGG) is approximately 5 per 100,000 person-years in Europe and North America.

OBJECTIVES

To assess the effects of postoperative external beam radiation dose escalation in adults with HGG.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (2015, Issue 9), MEDLINE (1977 to October 2015) and Embase (1980 to end October 2015) for relevant randomised phase III trials.

SELECTION CRITERIA

We included adults with a pathological diagnosis of HGG randomised to the following external beam radiation regimens.1. Daily conventionally fractionated radiation therapy versus no radiation therapy.2. Hypofractionated radiation therapy versus daily conventionally fractionated radiation therapy.3. Hyperfractionated radiation therapy versus daily conventionally fractionated radiation therapy.4. Accelerated radiation therapy versus daily conventionally fractionated radiation therapy.

DATA COLLECTION AND ANALYSIS

The primary outcomes were overall survival and adverse effects. The secondary outcomes were progression-free survival and quality of life. We used the standard methodological procedures expected by Cochrane. We used the GRADE approach, as outlined by Cochrane, to interpret the overall quality of the evidence from included studies.

MAIN RESULTS

We included 11 randomised controlled trials (RCTs) with a total of 2062 participants and 1537 in the relevant arms for this review. There was an overall survival benefit for HGG participants receiving postoperative radiotherapy compared to the participants receiving postoperative supportive care. For the four pooled RCTs (397 participants), the overall hazard ratio (HR) for survival was 2.01 (95% confidence interval (CI) 1.58 to 2.55, P < 0.00001), moderate GRADE quality evidence favouring postoperative radiotherapy. Although these trials may not have completely reported adverse effects, they did not note any significant toxicity attributable to radiation. Progression free survival and quality of life could not be pooled due to lack of data.Overall survival was similar between hypofractionated versus conventional radiotherapy in five trials (943 participants), where the HR was 0.95 (95% CI 0.78 to 1.17, P = 0.63), very low GRADE quality evidence. The trials reported that hypofractionated and conventional radiotherapy were well tolerated with mild acute adverse effects. These trials only reported one patient in the hypofractionated arm developing symptomatic radiation necrosis that required surgery. Progression free survival and quality of life could not be pooled due to the lack of data.Overall survival was also similar between hypofractionated versus conventional radiotherapy in the subset of two trials (293 participants) which included 60 years and older participants with glioblastoma. For this category, the HR was 1.16 (95% CI 0.92 to 1.46, P = 0.21), high GRADE quality evidence.There were two trials which compared hyperfractionated radiation therapy versus conventional radiation and one trial which compared accelerated radiation therapy versus conventional radiation. However, the results could not be pooled.The conventionally fractionated radiation therapy regimens were 4500 to 6000 cGy given in 180 to 200 cGy daily fractions, over 5 to 6 weeks.All these trials generally included participants with World Health Organization (WHO) performance status from 0 to 2 and Karnofsky performance status of 50 and higher.The risk of selection bias was generally low among these randomized trials. The number of participants lost to follow-up for the outcome of overall survival was low. Attrition, performance, detection and reporting bias for the outcome of overall survival was low. There was unclear attrition, performance, detection and reporting bias relating to the outcomes of adverse effects, progression free survival and quality of life.

AUTHORS' CONCLUSIONS

Postoperative conventional daily radiotherapy improves survival for adults with good performance status and HGG as compared to no postoperative radiotherapy.Hypofractionated radiation therapy has similar efficacy for survival as compared to conventional radiotherapy, particularly for individuals aged 60 and older with glioblastoma.There is insufficient data regarding hyperfractionation versus conventionally fractionated radiation (without chemotherapy) and for accelerated radiation versus conventionally fractionated radiation (without chemotherapy).There are HGG subsets who have poor prognosis even with treatment (e.g. glioblastoma histology, older age and poor performance status). These poor prognosis HGG individuals have generally been excluded from the randomised trials based on poor performance status. No randomised trial has compared comfort measures or best supportive care with an active intervention using radiotherapy or chemotherapy in these poor prognosis patients.

Radiation and concomitant chemotherapy for patients with glioblastoma multiforme

Postoperative external beam radiotherapy was considered the standard adjuvant treatment for patients with glioblastoma multiforme until the advent of using the drug temozolomide (TMZ) in addition to radiotherapy. High-dose volume should be focal, minimizing whole brain irradiation. Modern imaging, using several magnetic resonance sequences, has improved the planning target volume definition. The total dose delivered should be in the range of 60 Gy in fraction sizes of 1.8-2.0 Gy. Currently, TMZ concomitant and adjuvant to radiotherapy has become the standard of care for glioblastoma multiforme patients. Radiotherapy dose-intensification and radiosensitizer approaches have not improved the outcome. In spite of the lack of high quality evidence, stereotactic radiotherapy can be considered for a selected group of patients. For elderly patients, data suggest that the same survival benefit can be achieved with similar morbidity using a shorter course of radiotherapy (hypofractionation). Elderly patients with tumors that exhibit methylation of the O-6-methylguanine-DNA methyltransferase promoter can benefit from TMZ alone.

Hypo-fractionated IMRT for patients with newly diagnosed glioblastoma multiforme: a 6 year single institutional experience

OBJECTIVES

Glioblastoma (GBM) is the most common malignant primary brain tumour in adults. Surgery and radiotherapy constitute the cornerstones for the therapeutic management of GBM. The standard treatment today is maximal surgical resection followed by concomitant chemo-radiation therapy followed by adjuvant TMZ according to Stupp protocol. Despite the progress in neurosurgery, radiotherapy and oncology, the prognosis still results poor. In order to reduce the long time of standard treatment, maintaining or improving the clinical results, in our institute we have investigated the effects of hypo-fractionated radiation therapy for patients with GBM.

PATIENTS AND METHODS

Sixty-seven patients affected by GBM who had previously undergone surgical resection (total, subtotal or biopsy) were enrolled between October 2005 and December 2011 in a single institutional study of hypo-fractionated intensity modulated radiation therapy (IMRT) followed or not by adjuvant chemotherapy with TMZ (6-12 cycles). The most important eligibility criteria were: biopsy-proven GBM, KPS ≥ 60, age ≥ 18 years, no previous brain irradiation, informed consensus. Hypo-fractionated IMRT was delivered to a total dose of 25 Gy in 5 fractions prescribed to 70% isodose. Response to treatment, OS, PFS, toxicity and patterns of recurrence were evaluated, and sex, age, type of surgery, Karnofsky performance status, Recursive Partitioning Analysis (RPA) classification, time between surgery and initiation of radiotherapy were evaluated as potential prognostic factors for survival.

RESULTS

All patients have completed the treatment protocol. Median age was 64.5 years (range 41-82 years) with 31 females (46%) and 36 males (54%). Median KPS at time of treatment was 80. The surgery was gross total in 38 patients and subtotal in 14 patients; 15 patients underwent only biopsy. No grade 3-4 acute or late neurotoxicity was observed. With median follow-up of 14.9 months, the median OS and PFS were 13.4 and 7.9 months, respectively.

CONCLUSIONS

The hypo-fractionated radiation therapy can be used for patients with GBM, resulting in favourable overall survival, low rates of toxicity and satisfying QoL. Future investigations are needed to determine the optimal fractionation for GBM.

The role of radiotherapy and chemotherapy in the treatment of primary adult high grade gliomas: assessment of patients for these treatment approaches and the common immediate side effects

Gliomas are the commonest primary brain tumours in adults. They are usually classified and graded according to the criteria by the World Health Organisation. High-grade gliomas are the most malignant primary brain tumours. Conventional therapies include surgery, radiotherapy, and chemotherapy. The tumours often demonstrate high levels of resistance to these conventional therapies, and in spite of treatment advances the prognosis remains poor.

Hypofractionated radiotherapy for glioblastoma: strategy for poor-risk patients or hope for the future?

The prognosis of patients with glioblastoma (GBM) remains poor, and the use of hyperfractionation or dose escalation beyond 60 Gy has not conferred any survival benefit. More recently, hypofractionated radiotherapy (HFRT) has been employed as a novel approach for achieving dose escalation, with interesting results. We present here a systematic overview of the role and development of HFRT as a possible therapeutic strategy in patients with GBM. We searched the PubMed database for studies published since 1990 that reported on the tolerance, safety and survival outcomes after HFRT. These studies reported on the paradox of improved survival in patients developing central radionecrosis within the high-dose volume. Most series reported no significant increase in early or late toxicity, except for one study that reported visual loss in one patient at 7 months after treatment. More recently, studies of HFRT combined with concurrent temozolomide (TMZ) reported a trend towards improved survival compared with historical controls, with a few studies reporting a median survival of approximately 20 months. The interpretation of data from the above studies is limited by the heterogeneities of patient population and the significant variation in the range of employed dose schedules. However, high-dose HFRT using intensity-modulated radiotherapy appears to be a safe and feasible therapeutic option. There is a suggestion of improved outcomes on combining HFRT with TMZ, which warrants further investigation in a randomised trial.

Hypofractionated conformal irradiation of patients with malignant glioma

PURPOSE

The aim of the study is to evaluate the effect of a conformal irradiation in short fractionation scheme of 49.5Gy in 15 fractions in an overall time of 3 weeks, in terms of overall survival (OAS) and progression free survival (PFS) rates in brain glioma patients.

PATIENTS AND METHODS

A prospective study was conducted on 54 brain glioma patients and was carried out in the Radiation Oncology Department, South Egypt Cancer Institute, Assiut University during the period from April 2006 till June 2009. Patients were treated by hypofractionated conformal irradiation (49.5 Gy/15 fractions/3 weeks).

RESULTS

The median follow up was 23 months (range: 9-39 months). Two-year OAS and PFS rates were 68% and 60%, respectively. In univariate analysis, age >50 years, poor performance status [Karnofasky score of ≥40-≤70%], poor neuroperformance status of score III, high-grade tumor [glioblastoma multiforme], and biopsy were all associated with statistically significant reduction in OAS and PFS rates. Multivariate analysis, showed that age >50 years and glioblastoma pathology were the only independent prognostic factors that were associated with poor OAS (p=0.003 and p=0.004, respectively), and PFS (p=0.027 and p=0.011, respectively).

CONCLUSION

Hypofractionated conformal radiotherapy was as effective as the conventional radiotherapy, with time sparing for patients, and for radiation oncology centers. Hypofractionated radiotherapy may be considered the radiotherapy regimen of choice in clinical practice for patients with gliomas.

The treatment of elderly patients with high-grade gliomas

Elderly patients with cancer are frequently excluded from cancer therapy trials, treated suboptimally, or not treated at all because of the widely held belief that elderly patients do not tolerate chemotherapy and/or radiotherapy (RT) as well as younger patients. Excluding elderly patients from conventional treatment, chemotherapy in particular, is often based on ad hoc decisions rather than on sound scientific data. Malignant gliomas are the most common primary brain tumors in adults, and the age-adjusted incidence of high-grade gliomas has increased over recent years, especially in the elderly. However, few investigators focus on the treatment of high-grade gliomas in the elderly. Data from retrospective studies and meta-analyses suggest that elderly patients with high-grade gliomas have a poorer outcome than younger patients, possibly because of the presence of comorbidity, resistance to cancer therapy, genetic aberrations, different histology, neurodegeneration, or age discrimination. The optimal treatment of elderly patients with high-grade gliomas has not been determined. Surgical debulking and postoperative RT are associated with a significant increase in survival among elderly patients who are in good clinical condition. A recent report has shown that treatment with temozolomide (Temodar [US], Temodal [international]; Schering-Plough Corporation, Kenilworth, NJ) plus RT provides a significant survival benefit compared with RT alone and a significantly improved time to progression compared with RT plus standard chemotherapy (lomustine, procarbazine, and vincristine). Further, temozolomide was well tolerated in the elderly patient population and was less toxic than standard chemotherapy. Therefore, it could be recommended that a full course of RT be followed by adjuvant temozolomide in elderly patients with good prognostic factors. Further, temozolomide alone could be considered as a treatment option for elderly patients with glioblastoma with poorer performance status and for patients who cannot tolerate RT. Results from larger prospective trials will determine the optimal role of chemotherapy, particularly temozolomide, in elderly patients with malignant gliomas.

Hypofractionated intensity-modulated radiotherapy for primary glioblastoma multiforme

PURPOSE

A pilot study was designed to evaluate the safety and efficacy of a novel regimen of hypofractionated intensity-modulated radiotherapy (RT) in the adjuvant treatment of primary glioblastoma multiforme (GBM). The rationale of the study was to combine the potential radiobiologic advantage of hypofractionation to GBM with a highly conformal radiotherapeutic technique. The study was designed to measure the acute and chronic morbidity of patients treated with this regimen, response of GBM to the treatment, overall survival, and time to disease progression after therapy completion.

METHODS AND MATERIALS

Twenty eligible patients were accrued between February 1999 and May 2000 for the study. All patients had Karnofsky performance scores of >/=70. All patients were treated with intensity-modulated RT using the NOMOS Peacock system. A dose of 50 Gy was delivered in 5-Gy daily fractions within 2 weeks to enhancing primary disease, residual tumor, or surgical cavity. Simultaneously, 30 Gy was prescribed in 3-Gy daily fractions to surrounding edema. The time to progression was measured with serial neurologic examinations and MRI or CT scans after RT completion. Acute and late toxicity was graded using Radiation Therapy Oncology Group neurotoxicity scores.

RESULTS

Of the 20 patients, 18 were evaluated for outcome. The median time to disease progression was 6 months after RT completion. The median overall survival was 7 months after treatment completion. All recurrences were within 2 cm of the operative bed. Neurotoxicity during therapy was minimal, with all patients experiencing Grade 0 or 1 toxicity. Late toxicity included 10 patients with Grade 0, 2 patients with Grade 2, and 3 patients with Grade 4 toxicity, manifesting as brain necrosis requiring surgical reexcision. The survival of the 3 patients with brain necrosis was 23, 20, and 9 months. Mortality in all cases was the result of tumor recurrence, with no mortality resulting from brain necrosis.

CONCLUSION

This regimen of hypofractionated intensity-modulated RT did not improve the time to disease progression or overall survival compared with historical experience using conventional fractionation. However, the treatment duration was reduced from 6 weeks to 2 weeks, which may be of palliative benefit in certain subsets of patients. This treatment regimen demonstrated a greater incidence of brain necrosis requiring surgical intervention; however, the 3 patients experiencing this toxicity had longer survival times. Future investigation may be useful to determine which fraction size may be optimal for GBM when highly conformal RT is used in the adjuvant setting.

Poor-prognosis high-grade gliomas: evolving an evidence-based standard of care

Patients with high-grade glioma (HGG) can be classified as having a favourable prognosis (younger or with good performance status) or a poor prognosis (older or with poor performance status) with median survival of 12-24 months and 6-9 months, respectively. The standard management for the favourable subgroup is maximum safe resection followed by adjuvant conventionally fractionated radio therapy, with or without chemotherapy. However, most patients with HGG have a poor prognosis and their optimum management has yet to be defined. In the poor-prognosis HGG subgroup, short-course radiotherapy is equivalent to conventional radiotherapy in terms of survival and palliation (level II evidence), but chemotherapy is not recommend ed (level II evidence). The problems with the existing systems of prognosis are discussed and a pragmatic system proposed. Owing to lack of any level I evidence, the need to conduct prospective randomised trials with quality of life and palliative effect as primary endpoints is emphasised. Until such time, maximum safe resection followed by a short course of focal radiotherapy is recommended as the standard of care in poor prognosis HGG.

Radiotherapy for newly diagnosed malignant glioma in adults: a systematic review

PURPOSE

A systematic review was conducted to develop guidelines for radiotherapy in adult patients with newly diagnosed malignant glioma.

METHODS

MEDLINE, CANCERLIT, the Cochrane Library, and relevant conference proceedings were searched to identify randomized trials and meta-analyses.

RESULTS

Pooling of six randomized trials detected a significant survival benefit favouring post-operative radiotherapy compared with no radiotherapy (risk ratio, 0.81; 95% confidence interval, 0.74 to 0.88, P<0.00001). Two randomized trials demonstrated no significant difference in survival rates for whole brain radiation versus more local fields that encompass the enhancing primary plus a 2 cm margin. A randomized trial detected a small improvement in survival with 60 Gy in 30 fractions over 45 Gy in 20 fractions. Radiation dose intensification and radiation sensitizer approaches have not demonstrated superior survival rates compared with conventionally fractionated doses of 50-60 Gy.

CONCLUSIONS

Post-operative external beam radiotherapy is recommended as standard therapy for patients with malignant glioma. The high-dose volume should incorporate the enhancing tumour plus a limited margin (e.g. 2 cm) for the planning target volume, and the total dose delivered should be in the range of 50-60 Gy in fraction sizes of 1.8-2.0 Gy. Radiation dose intensification and radiation sensitizer approaches are not recommended as standard care. For patients older than age 70, preliminary data suggest that the same survival benefit can be achieved with less morbidity using a shorter course of radiotherapy. Supportive care alone is a reasonable therapeutic option in patients older than age 70 with a poor performance status.

Altered therapy schedules in postoperative treatment of patients with malignant gliomas. Twenty year experience of the Maria Skłodowska-Curie Memorial Center in Kraków, 1973-1993

Results of altered therapy schedules obtained in postoperative treatment of 294 patients with malignant gliomas over last 20 years are presented. During this period 135 patients received Conventional Irradiation and Chemotherapy (CICH), 61 patients received Conventional Irradiation (CI), 59 patients received Split Course High Fractional Dose Irradiation (SCHFDI), and 39 patients received Twice a Day Accelerated Irradiation (TDAI). Actuarial survival rates at 2, 3 and 5 years were 19%, 7%, 0% respectively for patients treated with CICH, and they were 21%, 10%, 0% for CI group, 24%, 12%, 0% for SCHFDI option and 15%, 8%, 0% for TDAI schedule. According to the Cox proportional hazard model, only age was significant factor in prognosis.

[Radiotherapy of glioblastoma]

Glioblastoma cells appear to be inherently radioresistant and to present a significant fraction of hypoxic cells. The most significant prognostic factors to compare results achieved in several series of patients are the age, performance status and quality of surgical resection. Several randomized trials have provided evidence supporting the efficacy of radiation therapy in the treatment of glioblastoma. Prescription of a 60-Gy dose delivered according to a conventional dose-fractionation scheme (single daily fractions of 1.7 to 2 Gy five times per week) in a target volume with a 2-3 cm margin of tissue surrounding the perimeter of the contrast enhancing lesion on computerized tomography and magnetic resonance imaging is derived from observations made in several retrospective and prospective studies. Evidence of improvement in survival was observed neither in patients receiving hyperfractioned and accelerated radiotherapy, nor in patients for whom radiation sensitizers such as nitroimidazole compounds or halogenated pyrimidine analogs were associated to radiation therapy. The addition of nitrosourea to radiotherapy increases the 2-year survival rate by about 10%. Combination of full-dose external beam radiotherapy and brachytherapy or radiosurgery boost in selected patients with glioblastoma leads to an increase in the median survival, while external beam radiation alone in patients with similar prognosis does not.

Improving cancer radiotherapy with 2-deoxy-D-glucose: phase I/II clinical trials on human cerebral gliomas

PURPOSE

Evaluation of tolerance, toxicity, and feasibility of combining large fraction (5 Gy) radiotherapy with 2-deoxy-D-glucose (2DG), an inhibitor of glucose transport and glycolysis, which has been shown to differentially inhibit repair of radiation damage in cancer cells.

METHODS AND MATERIALS

Twenty patients with supratentorial glioma (Grade 3/4), following surgery were treated with four weekly fractions of oral 2DG (200 mg/kg body weight) followed by whole brain irradiation (5 Gy). Two weeks later, supplement focal radiation to the tumor (14 Gy/7 fractions) was given. Routine clinical evaluation, x-ray computerized tomography (CT), and magnetic resonance (MR) imaging were carried out to study the acute and late radiation effects.

RESULTS

All the 20 patients completed the treatment without any interruption. The vital parameters were within normal limits during the treatment. None reported headache during the treatment. Mild to moderate nausea and vomiting were observed during the days of combined therapy (2DG + RT) in 10 patients. No significant deterioration of the neurological status was observed during the treatment period. Seven patients were alive at 63, 43, 36, 28, 27, 19, and 18 months of follow-up. In these patients, the clinical and MR imaging studies did not reveal any late radiation effects.

CONCLUSIONS

Feasibility of administering the treatment (2DG + 5 Gy) is demonstrated by the excellent tolerance observed in all 20 patients. Further, the clinical and MR studies also show the absence of any brain parenchymal damage.