Correlation between O<Superscript>6</Superscript>-methylguanine-DNA methyltransferase and survival in elderly patients with glioblastoma treated with radiotherapy plus concomitant and adjuvant temozolomide

Epigenetic silencing of the O⁶-methylguanine-DNA-methyltransferase (MGMT) gene by promoter methylation is correlated with improved progression-free survival (PFS) and overall survival (OS) in adult patients with newly diagnosed glioblastoma multiforme (GBM) who receive alkylating agents. The aim of this study is to determine the correlation between MGMT and survival in elderly patients with GBM treated with radiotherapy (RT) and temozolomide (TMZ). Eighty-three patients aged 70 years or older with histologically confirmed GBM treated with RT plus TMZ between February 2005 and September 2009 were investigated in this study. The methylation status of the MGMT promoter was determined by polymerase chain reaction analysis. Median PFS and OS were 7.5 and 12.8 months, respectively. The MGMT promoter was methylated in 42 patients (50.6%) and unmethylated in 41 patients (49.4%). Median OS was 15.3 months in methylated patients and 10.2 months in unmethylated patients (P = 0.0001). Median PFS was 10.5 months in methylated tumors and 5.5 months in unmethylated tumors (P = 0.0001). On multivariate analysis MGMT methylation status emerged as the strongest independent prognostic factor for OS and PFS (P = 0.004 and P = 0.005, respectively). The results of the present study suggest that MGMT methylation status might be an important prognostic factor associated with better OS and PFS in elderly patients with GBM treated with RT and TMZ.     

Salvage reirradiation for recurrent glioblastoma with radiosurgery: radiographic response and improved survival

Purpose To determine the radiographic and clinical efficacy of stereotactic single dose radiosurgery (SRS) and fractionated stereotactic radiotherapy (FSRT) as salvage therapy for glioblastoma (GBM) at recurrence. Methods Thirty-six patients with pathologically proven recurrent GBM were treated with salvage reirradiation by either SRS or FSRT between March of 2001 and August of 2006. Thirty-one patients had an initial diagnosis of GBM. Five patients had a malignant transformation. All patients had received radiotherapy with a dose of 50–60 Gy, a median 13.6 months prior to reirradiation (range: 0.8–119 months). At the time of recurrence, 26 patients were treated with SRS with a median dose of 18 Gy (range: 12–20 Gy). FSRT was performed in ten patients with a dose of 36 Gy in six fractions, twice weekly. Follow-up included MRI and clinical examination every 2 months. Results Median survival time after SRS was 8.5 months, compared to 7.4 months after FSRT (P = 0.81). Of 26 patients treated with SRS, radiographic tumor response or stable disease was observed in eight (35%) patients and tumor progression was seen in 18 (65%) patients. Of 10 patients treated by FSRT, radiographic tumor response or stable disease was observed in four (40%) patients and tumor progression was observed in four (40%) patients (two lost to follow-up). Patients who responded to treatment had statistically improved survival compared to non-responders, with median survival of 15.8 vs. 7.3 months (P < 0.05). Conclusion Salvage reirradiation with SRS or FSRT for recurrent GBM results in radiographic response in a proportion of patients. Survival was significantly improved among patients who either responded or had stable disease after salvage reirradiation, compared to non-responders. Further study is warranted to investigate the method and time of reirradiation for recurrent GBM.     

Hypofractionated stereotactic radiotherapy and continuous low-dose temozolomide in patients with recurrent or progressive malignant gliomas

To evaluate the efficacy of reirradiation and systemic chemotherapy as salvage treatment in patients with recurrent malignant glioma. Between May 2006 and December 2011, 54 patients with recurrent malignant glioma received hypofractionated stereotactic radiotherapy (HSRT) plus systemic therapy at University of Rome Sapienza, Sant’ Andrea Hospital. All patients had Karnofsky performance score ≥60 and were previously treated with standard conformal RT (60 Gy) with concomitant and adjuvant temozolomide (TMZ) up to 12 cycles. Thirty-eight patients had a GBM and 16 patients had a grade 3 glioma. The median time interval between primary RT and reirradiation was 15.5 months. At the time of recurrence all patients received HSRT (30 Gy in 6-Gy fractions) plus concomitant TMZ (75 mg/m²/day) followed by continuous TMZ at 50 mg/m² everyday up to 1 year or until progression. Median overall survival after HSRT was 12.4 months, and the 12- and 24-month survival rates were 53 and 16 %, respectively. The median progression-free survival (PFS) was 6 months, and the 12- and 24-month PFS rates were 24 and 10 %, respectively. KPS >70 (P = 0.04) and grade 3 glioma were independent favourable prognostic factors for survival. In general chemoradiation regimen was well tolerated with relatively low treatment-related toxicity. HSRT plus concomitant TMZ followed by continuous dose-intense TMZ is a feasible treatment option associated with survival benefits and low risk of complications in selected patients with recurrent malignant glioma. The potential advantages of combined chemoradiation schedules in patients with recurrent malignant gliomas need to be explored in future studies.     

Evaluation of MGMT promoter methylation status and correlation with temozolomide response in orthotopic glioblastoma xenograft model

CpG methylation within the O6-methylguanine-DNA-methyltransferase (MGMT) promoter is associated with enhanced survival of glioblastoma multiforme (GBM) patients treated with temozolomide (TMZ). Although MGMT promoter is methylated in ~50% of GBM, several studies have reported a lack of correlation between MGMT methylation and protein expression levels and consequently inaccurate discrimination of TMZ sensitive and resistant patients. To understand the limitations of currently used assays, TMZ responsiveness of 13 GBM xenograft lines was correlated with MGMT protein expression and MGMT promoter methylation determined by (1) standard methylation-specific polymerase chain reaction (MS–PCR), (2) quantitative MS–PCR (qMS–PCR), and (3) bisulfite sequencing. For each xenograft line, mice with established intracranial xenografts were treated with vehicle control or TMZ (66 mg/kg × 5 days), and TMZ response was defined as relative prolongation in median survival for TMZ-treated versus control-treated mice. The relative survival benefit with TMZ was inversely related to MGMT protein expression (r = −0.75; P = 0.003) and directly correlated with qMS–PCR (r = 0.72; P = 0.006). There was a direct correlation between MGMT methylation signal by qMS–PCR and the number of methylated CpG sites within the region amplified by MS–PCR (r = 0.78, P = 0.002). However, bisulfite sequencing revealed heterogeneity in the extent of CpG methylation in those tumors with a robust qMS–PCR signal. Three of the 4 GBM lines with a qMS–PCR signal greater than 10% had at least 1 unmethylated CpG site, while only one line was fully methylated at all 12 CpG sites. These data highlight one potential limitation of the evaluation of MGMT methylation by MS–PCR assay and suggest that more detailed evaluation of methylation at individual CpG sites relative to TMZ response may be worth pursuing. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

O<Superscript>6</Superscript>-Methylguanine DNA methyltransferase expression in tumor cells predicts outcome of radiotherapy plus concomitant and adjuvant temozolomide therapy in patients with primary glioblastoma

Expression of the O⁶-methylguanine-DNA methyltransferase (MGMT) gene has been shown to correlate with clinical outcomes in patients with glioblastoma multiforme treated with alkylating agents. We evaluated MGMT protein expression in 53 primary glioblastomas by the immunohistochemistry (IHC) and analyzed the correlation between results of immunostaining and patient outcomes. There were 28 MGMT-immunopositive and 25 negative glioblastomas. Patients with MGMT-immunonegative glioblastomas showed significantly longer progression-free survival (PFS) (P = 0.0032), but no statistically significant benefits on overall survival (OS) (P = 0.0825) were shown. In 41 glioblastomas treated with temozolomide (TMZ) therapy (MGMT-immunopositive: n = 22, negative: n = 19), both PFS and OS were significantly better in MGMT-immunonegative glioblastomas. (PFS: P = 0.0015, OS: P = 0.0384). We conclude that MGMT expression on immunohistochemistry (IHC) correlates with outcomes in patients with primary glioblastoma receiving TMZ and suggest the use of MGMT-IHC as a surrogate marker for predicting tumor chemosensitivity.     

Hypofractionated radiotherapy with or without concurrent temozolomide in elderly patients with glioblastoma multiforme: a review of ten-year single institutional experience

The landmark Stupp study demonstrated a survival advantage with concomitant and adjuvant temozolomide (TMZ) with standard radiotherapy (RT) in glioblastoma multiforme (GBM) patients but excluded those older than 70 years. The prospective Roa study of older GBM patients treated with hypofractionated 3-week course RT demonstrated equivalence to standard 6-week course RT. Taken together, these trials suggest hypofractionated RT with TMZ may be a reasonable treatment option for elderly GBM patients. We conducted a retrospective review of GBM patients (age ≥60 years) treated with hypofractionated RT and temozolomide at our institution between 2000 and 2010. We identified 112 patients who received hypofractionated RT, with 57 receiving concurrent and adjuvant TMZ and 55 without concurrent chemotherapy. Of the 55 patients who received hypofractionated RT alone initially, 24 subsequently received TMZ as salvage treatment at time of progression. Among the concurrent RT + TMZ patients, mean age was 70 years (range 60–86), median KPS was 80 (range 30–100) and 24/57 (42%) received prior debulking surgery. Median overall survival (OS) among the RT + TMZ patients was 6.9 months (95% CI, 4.5–8.6). Patients without concurrent chemotherapy were similar in demographics (age, sex, corticosteroid use, KPS) except 34/55 (62%) were debulked (P-value 0.045.) Median OS was 9.3 months (95% CI, 5.9–11.8) (P-value 0.351). Sub-group analysis revealed patients treated with initial hypofractionated radiation with salvage TMZ had increased median OS of 13.3 months (95% CI, 9.9–19.3) (P-value 0.012). Our results suggest concurrent and adjuvant TMZ does not confer a survival benefit in elderly GBM patients. A sequential approach may be a more effective and efficient strategy by selecting responding patients who may benefit most from subsequent salvage chemotherapy.     

Clinical correlation of MGMT protein expression and promoter methylation in Chinese glioblastoma patients

Promoter methylation of O6-methylguanine-DNA methyltransferase (MGMT) gene has been considered as a prognostic maker and increasingly emphasized in the treatment of glioblastoma multiforme (GBM). Contrastingly, the correlation of MGMT with clinical outcomes in Chinese glioblastoma patients has not been elucidated systematically. In the present study, tumor tissues from 172 GBM patients were analyzed for MGMT protein expression by immunohistochemistry. Of these, 79 were also subjected to pyrosequencing for MGMT promoter methylation analysis. MGMT protein overexpression was found in 109/172 (63.4%) GBM samples. And no significant survival difference was observed between the patients with MGMT overexpression and low expression in terms of progression-free survival or overall survival (P = 0.605 and P = 0.565, respectively). Meanwhile, MGMT promoter methylation was detected in 26/79 cases (32.9%), whereas 53/79 (67.1%) samples were unmethylated. Further survival analysis also revealed that MGMT promoter methylation status cannot predict patients progression-free survival and overall survival (P = 0.906 and P = 0.548, respectively). The integrated analysis showed that there was significant negative correlation between MGMT protein expression and promoter methylation (P = 0.004). These results underscore that, in Chinese GBM patients, (a) MGMT protein expression level was not a prognostic factor, (b) overall survival but not progression-free survival showed a trend toward increase in patients with MGMT promoter methylation, although the difference was not significant statistically and this observation has to be validated in larger patients cohort, (c) there was a significant correlation between MGMT protein expression in immunohistochemistry and MGMT promoter methylation by pyrosequencing.     

Prognostic impact of O6‐methylguanine‐DNA methyltransferase silencing in patients with recurrent glioblastoma multiforme who undergo surgery and carmustine wafer implantation

BACKGROUND:

O⁶‐methylguanine‐DNA methyltransferase (MGMT) is a key enzyme in the DNA repair process after alkylating agent action. Epigenetic silencing of the MGMT gene by promoter methylation has been associated with longer survival in patients with newly diagnosed glioblastoma multiforme (GBM) who receive alkylating agents. In this study, the authors evaluated the prognostic value of different biomarkers in recurrent GBM and analyzed the changes in MGMT status between primary tumors and recurrent tumors.

METHODS:

Twenty‐two patients who had recurrent GBM and who underwent surgery with carmustine wafer implantation were enrolled prospectively between 2005 and 2007. The authors investigated the correlation between MGMT silencing in the tumor at recurrence and survival taking into account other clinically recognized prognostic factors. MGMT status was determined by using methylation‐specific polymerase chain reaction analysis, a high‐throughput quantitative methylation assay, and immunohistochemistry. In addition, expression analyses of human mutL homolog 1, human mutS homolog 2, and tumor necrosis factor α‐induced protein 3 at recurrence were conducted with regard to their prognostic impact.

RESULTS:

The median progression‐free survival (PFS) and overall survival (OS) rates after recurrence were 3.6 months and 9.9 months, respectively, and the 6‐month PFS rate after recurrence was 27.2%. On multivariate analysis, only age (P = .04) and MGMT promoter hypermethylation at recurrence, as determined by MethyLight technology (P = .0012) and methylation‐specific polymerase chain reaction (MSP) analysis (P = .004), were correlated with better PFS. On multivariate analysis, only MGMT promoter hypermethylation at recurrence, as determined by using MethyLight technology (P = .019) and MSP analysis (P = .046), was associated with better OS.

CONCLUSIONS:

MGMT methylation status was an important prognostic factor in patients with recurrent GBM who underwent surgery plus carmustine wafer implantation; therefore, it was useful in predicting the outcome of GBM therapy at recurrence. Cancer 2009. © 2009 American Cancer Society.     

Patterns of failure and comparison of different target volume delineations in patients with glioblastoma treated with conformal radiotherapy plus concomitant and adjuvant temozolomide

Purpose

To analyze the recurrence patterns in patients with newly diagnosed glioblastoma (GBM) treated with conformal radiotherapy (RT) plus concomitant and adjuvant temozolomide (TMZ), and to compare the patterns of failure according to different target volume delineations.

Methods and materials

One hundred and five patients with GBM which recurred after three-dimensional (3D) conformal RT plus TMZ were evaluated. The clinical target volume (CTV) used for our treatment planning (S’Andrea plans) consisted of residual tumor and resection cavity plus 2-cm margins according to recent randomized trials of the European Organisation for Research and Treatment of Cancer (EORTC). MRI scans showing tumor recurrences were fused with the planning computed tomography (CT), and the patterns of failure were analyzed dosimetrically using dose-volume histograms. For each patient a theoretical plan based on the addition of postoperative edema plus 2-cm margins according to current guidelines of Radiation Therapy Oncology Group (RTOG) was created and patterns of failure were evaluated.

Results

The median overall survival and progression-free survival were 14.2 months and 7.5 months, respectively. Recurrences were central in 79 patients, in-field in 6 patients, marginal in 6 patients, and distant in 14 patients. Analysis of O⁶-methylguanine-DNA-methyltransferase (MGMT) promoter methylation status showed different recurrence patterns of GBMs in patients with MGMT methylated compared with patients with MGMT unmethylated status. Recurrences occurred central/in-field and outside in 64% and 31% of methylated patients, and in 91% and 5.4% of unmethylated patients, respectively (P = 0.01). Patterns of failure were similar between the different treatment plans, however the median volume percent of brain irradiated to high doses was significantly smaller for our plans than for RTOG plans (P = 0.0001). Conclusion: Most of patients treated with RT plus concomitant and adjuvant RT have central recurrences, however distant new lesions may occur in more than 10% of patients. The use of target delineation using postoperative residual tumor and cavity plus 2-cm margins is associated with smaller volumes of normal brain irradiated to high doses as compared with plans including expanded edema, without a significant increase of the risk of marginal recurrences. Future clinical randomized studies need to compare the different planning methods in terms of efficacy and risk of late radiation-induced toxicity.     

A pilot study of hypofractionated radiation therapy with temozolomide for adults with glioblastoma multiforme

To evaluate the safety and efficacy of hypofractionated radiotherapy (RT) with a standard temozolomide (TMZ) regimen for adults with newly diagnosed glioblastoma multiforme (GBM), twenty-six consecutive adults (range 39–79 years) who met our enrollment criteria received short courses of hypofractionated RT (45 Gy in 15 fractions over three weeks) with concomitant TMZ at 75 mg/m²/d. After 28 days, TMZ was maintained at 150–200 mg/m²/d on five days for 12 cycles or until tumor progression or unacceptable toxicity. The primary end point was determined by overall survival (OS) and toxicity. Secondary assessed end points were: progression-free survival (PFS) at six months, health-related quality of life (HRQOL), and pseudo-progression. We assessed HRQOL by use of the Karnofsky performance status (KPS) and the Functional Assessment of Cancer Therapy–Brain (FACT-Br) Subscale. All 26 patients were evaluated for OS, PFS, and HRQOL. At a median follow-up of 20 months, the median OS was 15.6 months (95% confidence interval 9.0–22.2 months) with acceptable toxicity. PFS rate at six months was 65%. KPS and FACT-Br Subscale scores did not decline after this procedure. Pseudo-progression occurred in two (8%) patients. Adult patients with GBM benefitted from favorable OS and PFS rate as a result of the hypofractionated RT with TMZ. An additional advantage is that this procedure may reduce the course of treatment. Further studies using this procedure are warranted.     

Temozolomide and radiotherapy in newly diagnosed glioblastoma patients: O<Superscript>6</Superscript>-methylguanine-DNA methyltransferase (MGMT) promotor methylation status and Ki-67 as biomarkers for survival and response to treatment

Objective  

This phase II study aimed at investigating the correlation between O⁶-methylguanine-DNA methyltransferase (MGMT) promoter methylation and protein expression, together with Ki-67 labeling index (LI), to response, time to progression (TTP), and overall survival (OS) in newly diagnosed glioblastoma multiforme (GBM) patients treated with temozolomide (TMZ) concomitant with and adjuvant to radiotherapy (RT).     

IDH1 mutation and MGMT methylation status predict survival in patients with anaplastic astrocytoma treated with temozolomide-based chemoradiotherapy

Several molecular markers have been proposed as predictors of outcome in patients with high grade gliomas. We report a retrospective multicenter study of 97 consecutive adult patients with anaplastic astrocytoma (AA) treated with radiation therapy (RT) plus concomitant and adjuvant temozolomide (TMZ) between October 2004 and March 2012. Correlations between the isocitrate dehydrogenase 1 (IDH1) mutation and O-6-methylguanine-DNA methyltransferase (MGMT) promoter methylation with survival outcomes have been analyzed. At a median follow-up time of 46 months (range 12–89 months), median and 5-year overall survival rates were 50.5 months (95 % CI, 37.8–63.2) and 38 % (95 % CI, 25.7–50.7 %), and median and 5-year progression-free survival rates were 36 months (95 % CI, 28.5–44.0) and 22 % (95 % CI, 10–34 %), respectively. IDH1 mutation and MGMT promoter methylation were present in 54 and 60 % of evaluable patients, respectively. Multivariate Cox proportional hazards regression analysis showed that IDH1 mutation (P = 0.001), MGMT methylation (P = 0.01), age < 50 years (P = 0.02), and extent of resection (P = 0.04) were significantly associated with longer survival. Our study confirms the favorable prognostic value of IDH1 mutation and MGMT methylation in patients with AA treated with RT plus concomitant and adjuvant TMZ. The superiority of combined radiochemotherapy over other treatment modalities remains to be demonstrated.     

Chemoradiation for anaplastic oligodendrogliomas: clinical outcomes and prognostic value of molecular markers

Combination of procarbazine, lomustine and vincristine (PCV) with radiation therapy (RT) has been associated with longer survival in patients with anaplastic oligodendroglioma (AO) and anaplastic oligoastrocytoma (AOA), especially in those with chromosome 1p/19q codeletion. We report a multicenter retrospective study of 84 consecutive adult patients with AO and AOA treated with RT plus concomitant and adjuvant temozolomide (TMZ) between February 2004 and January 2011. Correlations between chromosome 1p/19q codeletion, isocitrate dehydrogenase1 (IDH1) mutation, and O-6-methylguanine-DNA methyltransferase (MGMT) promoter methylation with survival outcomes have been analyzed. For all 84 patients the median overall survival (OS) and progression-free survival rates were 55.6 and 45.2 months, respectively. Grade 3 or 4 hematological toxicity occurred in 17 % of patients. Chromosome 1p/19q codeletion was detected in 57 %, IDH1 mutation in 63 %, and MGMT promoter methylation in 74 % of evaluable patients. In multivariate analysis the presence of chromosome 1p/19q codeletion was associated with significant survival benefit (median OS 34 months in noncodeleted tumors and not reached in codeleted tumors; HR 0.16, 95 % CI 0.03–0.45; P = 0.005). IDH1 mutation was also of prognostic significance for longer survival (P = 0.001; HR 0.20, 95 % 0.06–0.41), whereas MGMT promoter methylation was only of borderline significance. The study indicates that RT with concomitant and adjuvant TMZ is a relatively safe treatment associated with longer survival in patients with 1p/19q codeleted and IDH1 mutated tumors. Results from ongoing randomized studies will be essential to clarify if RT plus TMZ may provide survival as good as or better than RT combined with PCV for patients with AO and AOA.     

Hypofractionated radiotherapy followed by adjuvant chemotherapy with temozolomide in elderly patients with glioblastoma

Objectives The optimal treatment for elderly patients (age >70 years) with glioblastoma (GBM) remains controversial. We conducted a prospective trial in 43 consecutive elderly patients with GBM treated with hypofractionated radiotherapy (RT) followed by adjuvant temozolomide. Patients and methods Forty-three patients 70 years of age or older with a newly diagnosed GBM and a Karnofsky performance status (KPS) ≥ 60 were treated with hypofractionated RT (6 fractions of 5 Gy each for a total of 30 Gy over 2 weeks) followed by up to 12 cycles of adjuvant temozolomide (150–200 mg/m² for 5 days during each 28 day cycle). The HRQOL was assessed with the EORTC Quality of Life Questionnaire C30. The primary endpoint was overall survival (OS). Secondary endpoints included progression free survival (PFS), toxicity and quality of life. Results The median OS was 9.3 months and the median PFS was 6.3 months. The 6 and 12 month survival rates were 86% and 35%, respectively. The 6 and 12 month PFS rates were 55% and 12%, respectively. In multivariate analysis KPS was the only significant independent predictive factor of survival (P = 0.008). Neurological deterioration occurred during or after RT in 16% of patients and was resolved in most cases with the use of steroids. Grade 3–4 hematologic toxicity occurred in 28% of patients during the adjuvant chemotherapy treatment with temozolomide. The treatment had no negative effect on HRQOL, however, fatigue (P = 0.02) and constipation (P = 0.01) scales worsened over time. Conclusions Hypofractionated RT followed by temozolomide may provide survival benefit maintaining a good quality of life in elderly patients with GBM. It may represent a reasonable therapeutic approach especially in patients with less favourably prognostic factors.     

Prognostic significance of O6-methylguanine-DNA methyltransferase protein expression in patients with recurrent glioblastoma treated with temozolomide

BACKGROUND: Temozolomide (TMZ) is active against newly diagnosed glioblastoma (GBM), and O(6)-methylguanine-DNA methyltransferase (MGMT) is implicated in resistance to TMZ and nitrosoureas. We evaluated the efficacy and safety of the standard 5-day TMZ regimen in patients with recurrent GBM after initial therapy including nitrosourea-based chemotherapy, in conjunction with an analysis of the prognostic value of MGMT protein expression regarding response to TMZ and survival. METHODS: From September 2003 to January 2007, 30 patients having recurrent GBM received 150-200 mg/m(2)/day of TMZ for five consecutive days every 28 days. Tumor tissue from 19 patients was analysed for MGMT protein expression using western blotting, and 17 of them were assessable for a response. RESULTS: The overall response rate was 23.5% (one complete response and three partial responses). Six patients had stable disease (35.3%). Median progression-free survival (PFS) time was 2.2 months, and median overall survival (OS) time was 9.9 months from the initiation of TMZ therapy. Patients with low MGMT protein expression had a significantly improved PFS (P = 0.016) and OS (P = 0.019) compared to those with high expression. Both low MGMT expression (P = 0.040) and re-resection at relapse (P = 0.014) persisted as significant independent favorable prognostic factors for OS. The most common grade 3 and 4 hematological toxicity was lymphopenia (22.2%). CONCLUSIONS: The standard 5-day TMZ regimen resulted in moderate antitumor activity with an acceptable safety profile in patients with nitrosourea-pretreated recurrent GBM, and protein expression of MGMT is an important prognostic factor for patients treated with TMZ even after recurrence.     

Efficacy of fractionated stereotactic reirradiation in recurrent gliomas: long-term results in 172 patients treated in a single institution.

PURPOSE: To evaluate the efficacy of fractionated stereotactic radiotherapy (FSRT) performed as reirradiation in 172 patients with recurrent low- and high-grade gliomas. PATIENTS AND METHODS: Between 1990 and 2004, 172 patients with recurrent gliomas were treated with FSRT as reirradiation in a single institution. Seventy-one patients suffered from WHO grade 2 gliomas. WHO grade 3 gliomas were diagnosed in 42 patients, and 59 patients were diagnosed with glioblastoma multiforme (GBM). The median time between primary radiotherapy and reirradiation was 10 months for GBM, 32 months for WHO grade 3 tumors, and 48 months for grade 2 astrocytomas. FSRT was performed with a median dose of 36 Gy in a median fractionation of 5 x 2 Gy/wk. RESULTS: Median overall survival after primary diagnosis was 21 months for patients with GBM, 50 months for patients with WHO grade 3 gliomas, and 111 months for patients with WHO grade 2 gliomas. Histologic grading was the strongest predictor for overall survival, together with the extent of neurosurgical resection and age at primary diagnosis. Median survival after reirradiation was 8 months for patients with GBM, 16 months for patients with grade 3 tumors, and 22 months for patients with low-grade gliomas. Only time to progression and histology were significant in influencing survival after reirradiation. Progression-free survival after FSRT was 5 months for GBM, 8 months for WHO grade 3 tumors, and 12 months for low-grade gliomas. CONCLUSION: FSRT is well tolerated and may be effective in patients with recurrent gliomas. Prospective studies are warranted for further evaluation.     

Favorable outcome in the elderly cohort treated by concomitant temozolomide radiochemotherapy in a multicentric phase II safety study of 5-ALA

The primary objective of this augmental, prospective, uncontrolled phase II multicentre trial was to assess adverse events (AE) associated with malignant glioma resection using 5-aminolevulinic (5-ALA). During accrual, the standard of adjuvant therapy changed to concomitant radiochemotherapy with adjuvant temozolomide (RT/TMZ). Thus, this study also provided a platform for investigating the influence of RT/TMZ on survival in patients with fluorescence-guided resections. Malignant glioma patients, aged 18–75 years and with a Karnofsky performance score (KPS) ≥70%, were eligible. Data were collected on adverse events, KPS, survival and adjuvant therapies. In 243 patients evaluable for safety, 6-week AE incidence was 51.9% (nervous system disorders: 30.0%). Three patients experienced four possibly drug-related AEs. Grade III/IV incidence was 18.9% (nervous system disorders: 10.7%). About 48 h after surgery, AE incidence was 26.3% (9.9% grade III/IV), which was related to overall survival. A total of 219 patients (glioblastoma 206; anaplastic astrocytoma: 13) qualified for efficacy analysis. Median overall survival was 14.1 months (95% CI: 12.0–16.6), but 16.3 (13–19.2) months in 122 glioblastoma patients receiving RT/TMZ compared to 11.9 (9.6–14.1) months in the remaining 84 patients (P = 0.0194). Older patients (≥60 years) had less adjuvant therapies than younger patients. Median survival of older glioblastoma patients with RT/TMZ was also significantly prolonged (16.3; 12.0–17.2 months vs. 11.2; 7.4–14.1, hazard ratio = 0.55; 0.32–0.92). Risks of surgery were similar to past experiences with 5-ALA. Ancillary analyses demonstrated surgical glioblastoma patients, including the elderly, to have derived benefit from RT/TMZ. Thus, older patients should not generally be excluded from accepted therapies (fluorescence-guided resection plus RT/TMZ).     

IDH mutation and MGMT promoter methylation in glioblastoma: results of a prospective registry

Background

The relative contribution of isocitrate dehydrogenase mutations (mIDH) and O6-methylguanine-DNA methyltransferase promoter methylation (methMGMT) as biomarkers in glioblastoma remain poorly understood.

Methods

We investigated the association between methMGMT and mIDH with progression free survival and overall survival in a prospectively collected molecular registry of 274 glioblastoma patients.

Results

For glioblastoma patients who underwent Temozolomide and Radiation Therapy, OS and PFS was most favorable for those with tumors harboring both mIDH and methMGMT (median OS: 35.8 mo, median PFS: 27.5 mo); patients afflicted glioblastomas with either mIDH or methMGMT exhibited intermediate OS and PFS (mOS: 36 and 17.1 mo; mPFS: 12.2 mo and 9.9 mo, respectively); poorest OS and PFS was observed in wild type IDH1 (wtIDH1) glioblastomas that were MGMT promoter unmethylated (mOS: 15 mo, mPFS: 9.7 mo). For patients with wtIDH glioblastomas, TMZ+RT was associated with improved OS and PFS relative to patients treated with RT (OS: 15.4 mo v 9.6 mo, p < 0.001; PFS: 9.9 mo v 6.5 mo, p < 0.001). While TMZ+RT and RT treated mIDH patients exhibited improved overall survival relative to those with wtIDH, there were no differences between the TMZ+RT or RT group. These results suggest that mIDH1 conferred resistance to TMZ. Supporting this hypothesis, exogenous expression of mIDH1 in independent astrocytoma/glioblastoma lines resulted in a 3–10 fold increase in TMZ resistance after long-term passage.

Conclusion

Our study demonstrates IDH mutation and MGMT promoter methylation status independently associate with favorable outcome in TMZ+RT treated glioblastoma patients. However, these biomarkers differentially impact clinical TMZ response.     

O6-Methylguanine DNA methyltransferase protein expression in tumor cells predicts outcome of temozolomide therapy in glioblastoma patients

O⁶-Methylguanine DNA methyltransferase (MGMT) is implicated as a major predictive factor for treatment response to alkylating agents including temozolomide (TMZ) of glioblastoma multiforme (GBM) patients. However, whether the MGMT status in GBM patients should be detected at the level of promoter methylation or protein expression is still a matter of debate. Here, we compared promoter methylation (by methylation-specific polymerase chain reaction) and protein expression (by Western blot) in tumor cell explants with respect to prediction of TMZ response and survival of GBM patients (n = 71). Methylated MGMT gene promoter sequences were detected in 47 of 71 (66%) cases, whereas 37 of 71 (52%) samples were scored positive for MGMT protein expression. Although overall promoter methylation correlated significantly with protein expression (χ² test, P < .001), a small subgroup of samples did not follow this association. In the multivariate Cox regression model, a significant interaction between MGMT protein expression, but not promoter methylation, and TMZ therapy was observed (test for interaction, P = .015). In patients treated with TMZ (n = 42), MGMT protein expression predicted a significantly shorter overall survival (OS; hazard ratio [HR] for death 5.53, 95% confidence interval [CI] 1.76–17.37; P = .003), whereas in patients without TMZ therapy (n = 29), no differences in OS were observed (HR for death 1.00, 95% CI 0.45–2.20; P = .99). These data suggest that lack of MGMT protein expression is superior to promoter methylation as a predictive marker for TMZ response in GBM patients.     

The added value of concurrently administered temozolomide versus adjuvant temozolomide alone in newly diagnosed glioblastoma

Purpose Temozolomide (TMZ), given concurrently with radiotherapy (RT) and as adjuvant monotherapy afterwards, has led to improved survival in glioblastoma multiforme (GBM). However, it is unclear whether its primary mechanism of action is through enhancement of radiation response, independent cytotoxicity, or both. We sought to determine the relative contribution of concomitant temozolomide in patients treated by concurrent and adjuvant TMZ versus adjuvant TMZ alone in the setting of newly diagnosed GBM. Methods and Materials We identified patients diagnosed with GBM and treated with surgery, involved-field radiotherapy, and chemotherapy at MGH between 2002 and 2004. Eligible patients received either adjuvant temozolomide alone (group 1) or temozolomide concurrently with RT followed by adjuvant TMZ (group 2). The primary endpoint of this retrospective analysis was overall survival (OS). Results Forty-three patients (group 1, n = 21; group 2, n = 22) were included in this study. The median follow-up was 33.7 months for surviving patients. There were no significant differences in baseline characteristics between these two groups. On univariate analysis, patients who received concurrent and adjuvant temozolomide experienced a 2-year OS of 51% and median survival of 25.5 months, compared with a 2-year OS of 36% and median survival of 15.6 months for group 1 patients (P < 0.05). On multivariable analysis, the hazard ratio (HR) favoring concurrent TMZ trended towards significance (HR = 0.51, P = 0.08) despite modest patient numbers. Conclusions Concurrent and adjuvant TMZ was associated with improved survival compared to adjuvant TMZ alone, highlighting the potentiation of radiation effect by temozolomide in the clinical setting. Statement of originality: This work is completely original and has not been published or presented elsewhere. John W. Henson and Bindu Avutu contributed equally to this publication.