A pilot study of glioblastoma multiforme in elderly patients: treatments, O-6-methylguanine-DNA methyltransferase (MGMT) methylation status and survival

Influence of MMR, MGMT Promotor Methylation and Protein Expression on Overall and Progression-Free Survival in Primary Glioblastoma Patients Treated with Temozolomide

Glioblastoma is the most common malignant brain tumor in adults. Standard treatment includes tumor resection, radio-chemotherapy and adjuvant chemotherapy with temozolomide (TMZ). TMZ methylates DNA, whereas O6-methylguanine DNA methyltransferase (MGMT) counteracts TMZ effects by removing the intended proteasomal degradation signal. Non-functional MGMT mediates the mismatch repair (MMR) system, leading to apoptosis after futile repair attempts. This study investigated the associations between MGMT promoter methylation, MGMT and MMR protein expression, and their effect on overall survival (OS) and progression-free survival (PFS) in patients with glioblastoma. MGMT promoter methylation was assessed in 42 treatment-naïve patients with glioblastoma WHO grade IV by pyrosequencing. MGMT and MMR protein expression was analyzed using immunohistochemistry. MGMT promoter methylation was present in 52%, whereas patients <70 years of age revealed a significantly longer OS using a log-rank test and a significance threshold of p ≤ 0.05. MGMT protein expression and methylation status showed no correlation. MMR protein expression was present in all patients independent of MGMT status and did not influence OS and PFS. Overall, MGMT promoter methylation implicates an improved OS in patients with glioblastoma aged <70 years. In the elderly, the extent of surgery has an impact on OS rather than the MGMT promoter methylation or protein expression.

MGMT Promoter Methylation as a Prognostic Factor in Primary Glioblastoma: A Single-Institution Observational Study

Glioblastoma is the most malignant central nervous system tumor, which represents 50% of all glial tumors. The understanding of glioma genesis, prognostic evaluation, and treatment planning has been significantly enhanced by the discovery of molecular genetic biomarkers. This study aimed to evaluate survival in patients with primary glioblastoma concerning O6-methylguanine–DNA methyltransferase (MGMT) promoter methylation and other clinical factors. The study included 41 newly diagnosed glioblastoma patients treated from 2011 to 2014 in the 10th Military Research Hospital and Polyclinic, Poland. All patients underwent surgical resection followed by radiation and chemotherapy with alkylating agents. The MGMT promoter methylation was evaluated in all patients, and 43% were found to be methylated. In 26 and 15 cases, gross total resection and subtotal resection were conducted, respectively. Patients with a methylated MGMT promoter had a median survival of 504 days, while those without methylation had a median survival of 329 days. The group that was examined had a median age of 53. In a patient group younger than 53 years, those with methylation had significantly longer overall survival (639 days), compared to 433.5 days for patients without methylation. The most prolonged survival (551 days) was in patients with MGMT promoter methylation after gross total resection. The value of MGMT promoter methylation as a predictive biomarker is widely acknowledged. However, its prognostic significance remains unclear. Our findings proved that MGMT promoter methylation is also an essential positive prognostic biomarker.

Surgical strategies for older patients with glioblastoma

Objective

While adjuvant treatment regimens have been modified for older patients with glioblastoma (GBM), surgical strategies have not been tailored.

Methods

Clinical data of 48 consecutive patients aged 70 years or older, who underwent surgical resection for GBM with intraoperative ultrasonography (IoUS) alone or combination with intraoperative MRI (IoMRI) at Yale New Haven Hospital were retrospectively reviewed. Variables were analyzed, and comparative analyses were performed.

Results

The addition of IoMRI was not superior to IoUS alone in terms of overall survival (OS) (P = 0.306), Karnofsky Performance Score (KPS) at postoperative 6 weeks (P = 0.704) or extent of resection (P = 0.263). Length of surgery (LOSx), however, was significantly longer (P = 0.0002) in the IoMRI group. LOSx (P = 0.015) and hospital stay (P = 0.025) were predictors of postoperative complications. Increased EOR (GTR or NTR) (P = 0.030), postoperative adjuvant treatment (P < 0.0001) and postoperative complications (P = 0.006) were predictive for OS. Patients with relatively lower preoperative KPS scores (<70) showed significant improvement at postoperative 6 weeks (P<0.0001). Patients with complications (P = 0.038) were more likely to have lower KPS at postoperative 6 weeks.

Conclusions

Aggressive management with surgical resection should be considered in older patients with GBM, even those with relatively poor KPS. The use of ioMRI in this population does not appear to confer any measurable benefit over ioUS in experienced hands, but prolongs the length of surgery significantly, which is a preventable prognostic factor for impeding care.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11060-021-03862-z.

Evaluation of MGMT gene methylation in neuroendocrine neoplasms

Unresectable neuroendocrine neoplasms (NENs) often poorly respond to standard therapeutic approaches. Alkylating agents, in particular temozolomide, commonly used to treat high-grade brain tumors including glioblastomas, have recently been tested in advanced or metastatic NENs, where they showed promising response rates. In glioblastomas, prediction of response to temozolomide is based on the assessment of the methylation status of the MGMT gene, as its product, O-6-methylguanine-DNA methyltransferase, may counteract the damaging effects of the alkylating agent. However, in NENs, such a biomarker has not been validated yet. Thus, we have investigated MGMT methylation in 42 NENs of different grades and from various sites of origin by two different approaches: in contrast to methylation-specific PCR (MSP), which is commonly used in glioblastoma management, amplicon bisulfite sequencing (ABS) is based on high resolution next-generation sequencing and interrogates several additional CpG sites compared to those covered by MSP. Overall, we found MGMT methylation in 74% (31/42) of the NENs investigated. A higher methylation degree was observed in well-differentiated tumors and in tumors originating in the gastrointestinal tract. Comparing MSP and ABS results, we demonstrate that the region analyzed by the MSP test is sufficiently informative of the MGMT methylation status in NENs, suggesting that this predictive parameter could routinely be interrogated also in NENs.

Prognostic value of test(s) for O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation for predicting overall survival in people with glioblastoma treated with temozolomide

BACKGROUND

Glioblastoma is an aggressive form of brain cancer. Approximately five in 100 people with glioblastoma survive for five years past diagnosis. Glioblastomas that have a particular modification to their DNA (called methylation) in a particular region (the O6-methylguanine-DNA methyltransferase (MGMT) promoter) respond better to treatment with chemotherapy using a drug called temozolomide.

OBJECTIVES

To determine which method for assessing MGMT methylation status best predicts overall survival in people diagnosed with glioblastoma who are treated with temozolomide.

SEARCH METHODS

We searched MEDLINE, Embase, BIOSIS, Web of Science Conference Proceedings Citation Index to December 2018, and examined reference lists. For economic evaluation studies, we additionally searched NHS Economic Evaluation Database (EED) up to December 2014.

SELECTION CRITERIA

Eligible studies were longitudinal (cohort) studies of adults with diagnosed glioblastoma treated with temozolomide with/without radiotherapy/surgery. Studies had to have related MGMT status in tumour tissue (assessed by one or more method) with overall survival and presented results as hazard ratios or with sufficient information (e.g. Kaplan-Meier curves) for us to estimate hazard ratios. We focused mainly on studies comparing two or more methods, and listed brief details of articles that examined a single method of measuring MGMT promoter methylation. We also sought economic evaluations conducted alongside trials, modelling studies and cost analysis.

DATA COLLECTION AND ANALYSIS

Two review authors independently undertook all steps of the identification and data extraction process for multiple-method studies. We assessed risk of bias and applicability using our own modified and extended version of the QUality In Prognosis Studies (QUIPS) tool. We compared different techniques, exact promoter regions (5'-cytosine-phosphate-guanine-3' (CpG) sites) and thresholds for interpretation within studies by examining hazard ratios. We performed meta-analyses for comparisons of the three most commonly examined methods (immunohistochemistry (IHC), methylation-specific polymerase chain reaction (MSP) and pyrosequencing (PSQ)), with ratios of hazard ratios (RHR), using an imputed value of the correlation between results based on the same individuals.

MAIN RESULTS

We included 32 independent cohorts involving 3474 people that compared two or more methods. We found evidence that MSP (CpG sites 76 to 80 and 84 to 87) is more prognostic than IHC for MGMT protein at varying thresholds (RHR 1.31, 95% confidence interval (CI) 1.01 to 1.71). We also found evidence that PSQ is more prognostic than IHC for MGMT protein at various thresholds (RHR 1.36, 95% CI 1.01 to 1.84). The data suggest that PSQ (mainly at CpG sites 74 to 78, using various thresholds) is slightly more prognostic than MSP at sites 76 to 80 and 84 to 87 (RHR 1.14, 95% CI 0.87 to 1.48). Many variants of PSQ have been compared, although we did not see any strong and consistent messages from the results. Targeting multiple CpG sites is likely to be more prognostic than targeting just one. In addition, we identified and summarised 190 articles describing a single method for measuring MGMT promoter methylation status.

AUTHORS' CONCLUSIONS

PSQ and MSP appear more prognostic for overall survival than IHC. Strong evidence is not available to draw conclusions with confidence about the best CpG sites or thresholds for quantitative methods. MSP has been studied mainly for CpG sites 76 to 80 and 84 to 87 and PSQ at CpG sites ranging from 72 to 95. A threshold of 9% for CpG sites 74 to 78 performed better than higher thresholds of 28% or 29% in two of three good-quality studies making such comparisons.

Management of elderly patients with glioblastoma-multiforme-a systematic review

The management of elderly patients with glioblastoma-multiforme (GBM) remains poorly defined with many experts in the past advocating best supportive care, in view of limited evidence on efficacy of more aggressive treatment protocols. There is randomised evidence (NORDIC and NA-O8 studies) to support the use of surgery followed by adjuvant monotherapy with either radiotherapy (RT) using hypofractionated regimes (e.g. 36 Gy in 6 fractions OR 40 Gy in 15 fractions) or chemotherapy with temozolomide (TMZ) in patients expressing methylation of promoter for O⁶-methylguanine-DNA methyltransferase enzyme. However, the role of combined-modality therapy involving the use of combined RT and TMZ protocols has remained controversial with data from the EORTC (European Organisation for Research and Treatment of Cancer)-NCIC (National Cancer Institute of Canada) studies indicating that patients more than 65 years of age may not benefit significantly from combining standard RT fractionation using 60 Gy in 30 fractions with concurrent and adjuvant TMZ. More recently, randomised data has emerged on combining hypofractionated RT with concurrent and adjuvant TMZ. We provide a comprehensive review of literature with the aim of defining an evidence-based algorithm for management of elderly glioblastoma-multiforme population.

NDRG4 hypermethylation is a potential biomarker for diagnosis and prognosis of gastric cancer in Chinese population

In order to assess whether N-Myc downstream regulated gene 4 (NDRG4) methylation was associated with the diagnosis and prognosis of gastric cancer, we measured the methylation of NDRG4 promoter and gene body regions among 110 gastric cancer patients using quantitative methods (MethyLight and pyrosequencing). Both NDRG4 promoter and gene body methylation levels were increased in tumor tissues than paired adjacent normal tissues (P < 0.001). NDRG4 gene body methylation was found to be significantly associated with age and tumor differentiation. NDRG4 promoter hypermethylation was proved to be a predictor of poor overall survival. However, opposite result was observed among The Cancer Genome Atlas (TCGA) cohort. The findings from gastric cell lines and public databases have suggested that NDRG4 methylation level was inversely associated with NDRG4 transcription level. Subsequent luciferase reporter gene assay showed that promoter CpG island but not gene body CpG island was able to upregulate gene expression. Collectively, NDRG4 promoter hypermethylation contributed to the risk of gastric cancer and predicted a poor prognosis in Chinese gastric cancer patients. Moreover, the combined methylation levels of NDRG4 promoter and gene body served as diagnostic biomarkers in gastric cancer.

Is the prognostic significance of O6-methylguanine- DNA methyltransferase promoter methylation equally important in glioblastomas of patients from different continents? A systematic review with meta-analysis

BACKGROUND

O6-methylguanine-DNA methyltransferase (MGMT) is an independent predictor of therapeutic response and potential prognosis in patients with glioblastoma multiforme (GBM). However, its significance of clinical prognosis in different continents still needs to be explored.

PATIENTS AND METHODS

To explore the effects of MGMT promoter methylation on both progression-free survival (PFS) and overall survival (OS) among GBM patients from different continents, a systematic review of published studies was conducted.

RESULTS

A total of 5103 patients from 53 studies were involved in the systematic review and the total percentage of MGMT promoter methylation was 45.53%. Of these studies, 16 studies performed univariate analyses and 17 performed multivariate analyses of MGMT promoter methylation on PFS. The pooled hazard ratio (HR) estimated for PFS was 0.55 (95% CI 0.50, 0.60) by univariate analysis and 0.43 (95% CI 0.38, 0.48) by multivariate analysis. The effect of MGMT promoter methylation on OS was explored in 30 studies by univariate analysis and in 30 studies by multivariate analysis. The combined HR was 0.48 (95% CI 0.44, 0.52) and 0.42 (95% CI 0.38, 0.45), respectively.

CONCLUSION

In each subgroup divided by areas, the prognostic significance still remained highly significant. The proportion of methylation in each group was in inverse proportion to the corresponding HR in the univariate and multivariate analyses of PFS. However, from the perspective of OS, compared with data from Europe and the US, higher methylation rates in Asia did not bring better returns.

Correlations of MGMT genetic polymorphisms with temozolomide resistance and prognosis of patients with malignant gliomas: a population-based study in China

This study aims to investigate the associations of O⁶-methylguanine-DNA methyltransferase (MGMT) genetic polymorphisms (Leu84Phe and Ile143Val) with temozolomide (TMZ) resistance and prognosis of patients with malignant gliomas. A total of 212 patients diagnosed with malignant gliomas were enrolled in this study as the case group. All of these patients took oral TMZ and were assigned into the TMZ-sensitive (complete response+partial response) and the TMZ-resistant (stable disease+progressive disease) groups based on the clinical response after chemotherapy. The polymerase chain reaction-restriction fragment length polymorphism was used to identify the gene polymorphism of Leu84Phe and Ile143Val. The survival time and survival outcomes of all the patients were obtained by follow-up. There were significant differences in the genotype and allele of Leu84Phe between the TMZ-sensitive and the TMZ-resistant groups. The CT, TT and CT+TT genotypes and the T allele of MGMT gene Leu84Phe may be associated with increasing TMZ resistance in patients with malignant gliomas. Logistic regression analysis showed that Leu84Phe of MGMT gene and pathological grade were independent risk factors for the increase of TMZ resistance in patients with malignant gliomas. Kaplan-Meier survival curve revealed that the average survival time of patients with the CT+TT and CC genotypes of Leu84Phe in the two groups was statistically significant. COX regression analysis showed that Leu84Phe, degree of resection and pathological grade were independent prognostic factors for patients with malignant gliomas. Our study demonstrates that Leu84Phe of MGMT gene might be a risk factor of TMZ resistance and poor prognosis of patients with malignant gliomas.

Glioblastoma in the elderly: Therapeutic dilemmas

Background:

Glioblastoma (GBM) is commonly diagnosed in patients older than 60 years, but the treatment protocols are mostly based on trials in patients aged up to 70 years. These lead to little consensus and to an absence of protocols regarding the standard treatments. The objective of this study is to analyze the prognostic factors, treatment efficacy, and adverse events in a cohort of elderly patients.

Methods:

A retrospective observational study of all patients aged ≥65 with histologically confirmed GBM followed at Centro Hospitalar S. João between 2005 and 2013. Demographic, clinical, radiographic, treatment, and outcome data were evaluated. Univariate and multivariate analyses were performed.

Results:

A total of 126 patients were reviewed. Median progression-free survival was 5 months (95% confidence interval [CI], 4.138 to 5.862 months). Median overall survival (OS) was 8 months (95% CI, 5.950 to 10.050 months). Univariate analysis showed the statistically significant associations between the higher OS and age <70 (P = 0.046), Karnofsky performance status ≥70 (P = 0.001), single lesions (P = 0.007), lesions affecting one lobe (P = 0.007), total resection (P = 0.048), and Charlson age-comorbidity index ≤5. Multivariate analysis identified the completion of 60 Gy radiotherapy and completion of 6 or more cycles of temozolomide chemotherapy as independent prognostic factors positively correlated with increased survival.

Conclusions:

Maximal resection and radiochemotherapy treatment completion are associated with longer OS, and age alone should not preclude elderly patients from receiving surgery and adjuvant treatment. However, only a few patients were able to finish the proposed treatments. Poor performance and high comorbidity index status might compromise the benefit of treatment aggressiveness and must be considered in therapeutic decision.

Predictors of survival and effect of short (40 Gy) or standard-course (60 Gy) irradiation plus concomitant temozolomide in elderly patients with glioblastoma: a multicenter retrospective study of AINO (Italian Association of Neuro-Oncology)

The efficacy of temozolomide (TMZ) plus radiation therapy (RT) in elderly patients with glioblastoma is unclear. We performed a large multicenter retrospective study to analyze prognostic factors and clinical outcome in these patients. Inclusion criteria were age ≥65 years, newly histologically confirmed glioblastoma, ECOG PS 0-2, adjuvant treatment with RT plus TMZ. We enrolled 237 patients; the average age was 71 and ECOG PS was 0-1 in 196 patients; gross total resection was performed in 174 cases. MGMT was analyzed in 151 persons and was methylated in 56 %. IDH1 was assessed in 100 patients and was mutated in 6 %. Seventy-one patients were treated with RT 40 Gy and 166 with RT 60 Gy. Progression-free survival and overall survival (OS) were 11.3 and 17.3 months, respectively. Overall survival was 19.4 vs 13.8 months for patients treated with RT 60 Gy and 40 Gy (p = 0.02); OS was 17.7 versus 16.1 months for patients treated with gross total resection vs partial surgery (p = 0.02); OS was 21.2 versus 13.6 months for methylated and unmethylated MGMT (p < 0.001). On multivariate analysis, gross total resection, RT 60 Gy, methylated MGMT and ECOG PS 0-1 were independent predictors of longer survival. Twenty-five patients (10 %) had grade 3-4 haematological toxicity during the concomitant treatment. We showed that, in elderly patients in good clinical condition treated with concomitant treatment, standard-course irradiation might be more effective than short-course irradiation. Methylated MGMT remains the most important prognostic factor.

Impact on prognosis of the regional distribution of MGMT methylation with respect to the CpG island methylator phenotype and age in glioma patients

Clinical and molecular prognostic factors in gliomas include age, IDH mutation, the glioma CpG island methylator phenotype (G-CIMP+) and promoter methylation of the O(6)-methylguanine DNA-methyltransferase (MGMT) gene. Among these markers, a predictive value was reported in glioblastomas (GBM) for MGMT promoter methylation, in particular in elderly GBM patients. In this study, methylation data from 46 glioma samples with the Illumina 450K platform were obtained and extended using external data to include a total of 247 glioma samples. Methylation analysis of the whole MGMT gene with this platform revealed two strongly survival-associated CpG regions within the promoter and the gene body, which were confirmed in a reported dataset of high grade-gliomas. Methylation at the promoter (CpG 25, cg12981137 and the prognostic model MGMT-STP27) and at the gene body CpG 165 (cg07933035), were significantly associated with better overall survival, and strongly correlated with G-CIMP+ status. In this series, the prognostic value of MGMT methylation at the promoter was not observed in G-CIMP- cases, although around 50 % of them were MGMT-methylated. These results were also obtained in an homogeneously-treated series of chemoradiated G-CIMP- GBMs analyzed by MSP and qMSP, and confirmed in a reported pyrosequencing-analyzed series of gliomas. Interestingly, in contrast to the MGMT promoter, gene body methylation was of prognostic value in G-CIMP-patients older than 65 years. Our study highlights the relevance of the prognostic value of the different regions of methylation throughout the MGMT gene that could be affected by specific G-CIMP profiles and age groups.

The prognosis of MGMT promoter methylation in glioblastoma patients of different race: a meta-analysis

O(6)-Methylguanine-DNA methyltransferase (MGMT) is a DNA repair gene. Epigenetic silencing of the MGMT promoter methylation compromises DNA repair and has been associated with longer survival in patients with glioblastoma (GBM) who receive alkylating agents. But the prognostic of MGMT promoter methylation in GBM patients of different race is still ambiguous. Based on an univariate or multivariate analysis between different race (Caucasian and Asian), a meta-analysis of the effects of MGMT promoter methylation on both progression-free survival (PFS) and overall survival (OS) among GBM patients was conducted. A total of 6,309 patients from 50 studies were involved in the analysis. Random effect models were applied to estimate the pooled hazard ratio (HR) with 95 % confidence intervals (CIs) for GBM patients of different race prognosis, the Chi square-based Q test was used to test heterogeneity. Begg's (funnel plot method) and Egger's linear regression tests were adopted to check publication bias (a bias with regard to what is likely to be published, among what is available to be published). The HR value estimated for OS was 0.524 (95 % CI 0.428-0.640) by univariate analysis and 0.427 (95 % CI 0.355-0.513) by multivariate analysis in Caucasian. The HR value estimated for OS was 0.892 (95 % CI 0.469-1.698) by univariate analysis and 0.562 (95 % CI 0.394-0.804) by multivariate analysis in Asian. The HR value estimated for PFS was 0.526 (95 % CI 0.372-0.743) by univariate analysis and 0.437 (95 % CI 0.356-0.537) by multivariate analysis in Caucasian. The HR value estimated for PFS was 0.132 (95 % CI 0.006-3.027) by multivariate analysis in Asian. This data revealed that GBM patients with MGMT promoter methylation had longer OS and PFS by univariate or multivariate analysis in Caucasian regardless of therapeutic intervention. However, GBM patients with MGMT promoter methylation only had longer OS by multivariate analysis in Asian.

Treatment of glioblastoma in elderly patients

Although glioblastoma occurs mostly in elderly patients, there is a paucity of trials addressing patients older than 70 years of age. Age, by itself, constitutes an unfavorable prognostic factor, which is probably due to unpropitious genetic features, but also due to iatrogenic defeatism. However, many retrospective studies report a survival benefit achieved by aggressive surgical resection seeking gross total removal of contrast-enhancing tumor according to preoperative MRI. Combined radiochemotherapy with concomitant and adjuvant temozolomide has not been investigated in prospective trials. Numerous retrospective studies and a meta-analysis suggest benefit from combined treatment. Prospective randomized trials only evaluated either temozolomide or radiotherapy. Single-treatment hypofractionated radiotherapy performed superior to conventional fractionation. In patients with methylated MGMT promoter, first-line dose-dense temozolomide facilitates prolonged survival. However, there is no comparison with combined radiochemotherapy as the standard-of-care in adult patients. Comorbidity is more frequent in elderly patients, but does not correlate with preterm termination of temozolomide treatment. This review article compiles data proposing a straightforward glioblastoma treatment, irrespective of age.

The predictive but not prognostic value of MGMT promoter methylation status in elderly glioblastoma patients: a meta-analysis

Background

The clinical implication of O6-methylguanine-DNA methyltransferase (MGMT) promoter status is ill-defined in elderly glioblastoma patients. Here we report a meta-analysis to seek valid evidence for its clinical relevance in this subpopulation.

Methods

Literature were searched and reviewed in a systematic manner using the PubMed, EMBASE and Cochrane databases. Studies investigating the association between MGMT promoter status and survival data of elderly patients (≥65 years) were eligible for inclusion.

Results

Totally 16 studies were identified, with 13 studies included in the final analyses. The aggregate proportion of MGMT promoter methylation in elderly patients was 47% (95% confidence interval [CI]: 42–52%), which was similar to the value for younger patients. The analyses showed differential effects of MGMT status on overall survival (OS) of elderly patients according to assigned treatments: methylated vs. unmethylated: (1) temozolomide (TMZ)-containing therapies: hazard ratio [HR] 0.49, 95% CI 0.41–0.58; (2) TMZ-free therapies: HR 0.97, 95% CI 0.77–1.21. More importantly, a useful predictive value was observed by an interaction analysis: TMZ-containing therapies vs. RT alone: (1) methylated tumors: HR 0.48, 95% CI 0.36–0.65; (2) unmethylated tumors: HR 1.14; 95% CI 0.90–1.44.

Conclusion

The meta-analysis reports an age-independent presence of MGMT promoter methylation. More importantly, the study encouraged routine testing of MGMT promoter status especially in elderly glioblastoma patients by indicating a direct linkage between biomarker test and individual treatment decision. Future studies are needed to justify the mandatory testing in younger patients.

Radiotherapy plus concurrent or sequential temozolomide for glioblastoma in the elderly: a meta-analysis

BACKGROUND

Many physicians are reluctant to treat elderly glioblastoma (GBM) patients as aggressively as younger patients, which is not evidence based due to the absence of validated data from primary studies. We conducted a meta-analysis to provide valid evidence for the use of the aggressive combination of radiotherapy (RT) and temozolomide (TMZ) in elderly GBM patients.

METHODS

A systematic literature search was conducted using the PubMed, EMBASE and Cochrane databases. Studies comparing combined RT/TMZ with RT alone in elderly patients (≥65 years) with newly diagnosed GBM were eligible for inclusion.

RESULTS

No eligible randomized trials were identified. Alternatively, a meta-analysis of nonrandomized studies (NRSs) was performed, with 16 studies eligible for overall survival (OS) analysis and nine for progression-free survival (PFS) analysis. Combined RT/TMZ was shown to reduce the risk of death and progression in elderly GBM patients compared with RT alone (OS hazard ratio [HR] 0.59, 95% confidence interval [CI] 0.48-0.72; PFS: HR 0.58, 95% CI 0.41-0.84). Evaluable patients were reported to tolerate combined treatment but certain toxicities, and especially hematological toxicities, were more frequently observed. Limited data on O6-methylguanine-DNA methyltransferase (MGMT) promoter status and quality of life were reported.

CONCLUSION

The meta-analysis of NRSs provided level 2a evidence (Oxford Centre for Evidence-Based Medicine) that combined RT/TMZ conferred a clear survival benefit on a selection of elderly GBM patients who had a favorable prognosis (e.g., extensive resection, favorable KPS). Toxicities were more frequent but acceptable. Future randomized trials are warranted to justify a definitive conclusion.

Concomitant and adjuvant temozolomide of newly diagnosed glioblastoma in elderly patients

OBJECTIVE

The effect of concomitant and adjuvant temozolomide in glioblastoma patients above the age of 65 years lacks evidence. However, after combined treatment became standard at our center all patients were considered for combined therapy. We retrospectively analyzed the effect of temozolomide focused on elderly patients.

METHODS

293 patients with newly diagnosed glioblastoma treated single-centered between 1998 and 2010, by radiation alone or concomitant and adjuvant radiochemotherapy, were included. Treatment groups were analyzed by multi- and univariate analysis. Matched pairs for age, by a 5-year-caliper, extent of resection and general state was generated for all patients and elderly subgroups.

RESULTS

103 patients received radiation only and 190 combined treatment. Multivariate and matched pair analysis revealed a benefit due to combined temozolomide (HR 1.895 and 1.752, respectively). For patients older than 65 years median survival was 3.6 (95% CI 3.2-4.7) and 8.7 months (6.3-11.8) for radiotherapy only and combined treatment (HR 3.097, p<0.0001, n=90). Over the age of 70 and 75 years median survival was 3.2 (2.3-4.2) vs. 7.5 (5.1-10.9, HR 4.453, p<0.0001, n=62) and 3.2 (1.4-3.9) vs. 9.2 months (4.7-13.5; HR 9.037, p<0.0001, n=24), respectively. In 8/56 (14%) patients over the age of 70 years temozolomide was terminated due to toxicity.

CONCLUSION

Retrospective matched pair analysis gives class 2b evidence for prolonged survival due to concomitant and adjuvant temozolomide in elderly glioblastoma patients. Until prospective data for combined radiochemotherapy in elderly patients will be available concomitant and adjuvant temozolomide therapy should not be withheld.