Graded functional diffusion map-defined characteristics of apparent diffusion coefficients predict overall survival in recurrent glioblastoma treated with bevacizumab

Diffusion imaging has shown promise as a predictive and prognostic biomarker in glioma. We assessed the ability of graded functional diffusion maps (fDMs) and apparent diffusion coefficient (ADC) characteristics to predict overall survival (OS) in recurrent glioblastoma multiforme (GBM) patients treated with bevacizumab. Seventy-seven patients with recurrent GBMs were retrospectively examined. MRI scans were obtained before and approximately 6 weeks after treatment with bevacizumab. Graded fDMs were created by registering datasets to each patient's pretreatment scan and then performing voxel-wise subtraction between post- and pretreatment ADC maps. Voxels were categorized according to the degree of change in ADC within pretreatment fluid-attenuated inversion recovery (FLAIR) and contrast-enhancing regions of interest (ROIs). We found that the volume of tissue showing decreased ADC within both FLAIR and contrast-enhancing regions stratified OS (log-rank, P < .05). fDMs applied to contrast-enhancing ROIs more accurately predicted OS compared with fDMs applied to FLAIR ROIs. Graded fDMs (showing voxels with decreased ADC between 0.25 and 0.4 μm(2)/ms) were more predictive of OS than traditional (single threshold) fDMs, and the predictive ability of graded fDMs could be enhanced even further by adding the ADC characteristics from the fDM-classified voxels to the analysis (log-rank, P < .001). These results demonstrate that spatially resolved diffusion-based tumor metrics are a powerful imaging biomarker of survival in patients with recurrent GBM treated with bevacizumab.     

Functional diffusion maps (fDMs) evaluated before and after radiochemotherapy predict progression-free and overall survival in newly diagnosed glioblastoma

Functional diffusion mapping (fDM) has shown promise as a sensitive imaging biomarker for predicting survival in initial studies consisting of a small number of patients, mixed tumor grades, and before routine use of anti-angiogenic therapy. The current study tested whether fDM performed before and after radiochemotherapy could predict progression-free and overall survival in 143 patients with newly diagnosed glioblastoma from 2007 through 2010, many treated with anti-angiogenic therapy after recurrence. Diffusion and conventional MRI scans were obtained before and 4 weeks after completion of radiotherapy and concurrent temozolomide treatment. FDM was created by coregistering pre- and posttreatment apparent diffusion coefficient (ADC) maps and then performing voxel-wise subtraction. FDMs were categorized according to the degree of change in ADC in pre- and posttreatment fluid-attenuated inversion recovery (FLAIR) and contrast-enhancing regions. The volume fraction of fDM-classified increasing ADC(+), decreasing ADC(-), and change in ADC(+/-) were tested to determine whether they were predictive of survival. Both Bonferroni-corrected univariate log-rank analysis and Cox proportional hazards modeling demonstrated that patients with decreasing ADC in a large volume fraction of pretreatment FLAIR or contrast-enhancing regions were statistically more likely to progress earlier and expire sooner than in patients with a lower volume fraction. The current study supports the hypothesis that fDM is a sensitive imaging biomarker for predicting survival in glioblastoma.     

Short-interval estimation of proliferation rate using serial diffusion MRI predicts progression-free survival in newly diagnosed glioblastoma treated with radiochemotherapy

Cell invasion, motility, and proliferation level estimate (CIMPLE) mapping is a new imaging technique that provides parametric maps of microscopic invasion and proliferation rate estimates using serial diffusion MRI data. However, a few practical constraints have limited the use of CIMPLE maps as a tool for estimating these dynamic parameters, particularly during short-interval follow-up times. The purpose of the current study was to develop an approximation for the CIMPLE map solution for short-interval scanning involving the assumption that net intervoxel tumor invasion does not occur within sufficiently short time frames. Proliferation rate maps created using the “no invasion” approximation were found to be increasingly similar to maps created from full solution during increasingly longer follow-up intervals (3D cross correlation, R ² = 0.5298, P = 0.0001). Results also indicate proliferation rate maps from the “no invasion” approximation had significantly higher sensitivity (82 vs. 64 %) and specificity (90 vs. 80 %) for predicting 6 month progression free survival and was a better predictor of time to progression during standard radiochemotherapy compared to the full CIMPLE solution (log-rank; no invasion estimation, P = 0.0134; full solution, P = 0.0555). Together, results suggest the “no invasion” approximation allows for quick estimation of proliferation rate using diffusion MRI data obtained from multiple scans obtained daily or biweekly for use in quantifying early treatment response.     

Quantitative volumetric analysis of conventional MRI response in recurrent glioblastoma treated with bevacizumab

Although the effects of bevacizumab on magnetic resonance images (MRIs) of recurrent glioblastoma multiforme (GBM) are well documented, to our knowledge, no studies have explicitly quantified the volumetric changes resulting from initial treatment, nor have there been studies examining the ability for volumetric changes in conventional MRI to predict progression-free survival (PFS) and overall survival (OS). In the current study, we retrospectively examined volumetric changes on conventional MRI scans in 84 patients with recurrent GBM. MRIs were obtained before (mean, 11 days) and after (mean, 42 days) treatment with bevacizumab. The volume of abnormal fluid-attenuated inversion recovery (FLAIR) signal intensity, the volume of contrast enhancement, and the ratio of the 2 were quantified for each patient before and after initial treatment. Results demonstrated that initial treatment with bevacizumab resulted in a significant decrease in both the volume of abnormal FLAIR signal and the volume of contrast enhancement. Initial, residual, and change in FLAIR volume were not predictive of PFS or OS. Initial contrast-enhancing volume was predictive of PFS but not OS. The pretreatment relative nonenhancing tumor ratio, defined as the ratio of FLAIR to contrast-enhancing volume, was found to be predictive of both PFS and OS.     

Tumor regrowth between surgery and initiation of adjuvant therapy in patients with newly diagnosed glioblastoma

To assess incidence and degree of regrowth in glioblastoma between surgery and radiation therapy (RT) and to correlate regrowth with presurgical imaging and survival, we examined images of 32 patients with newly diagnosed glioblastoma who underwent MR spectroscopic imaging (MRSI), perfusion-weighted imaging (PWI), and diffusion-weighted imaging (DWI) prior to surgery, after surgery, and prior to RT/temozolomide. Contrast enhancement (CE) in the pre-RT MR image was compared with postsurgical DWI to differentiate tumor growth from postsurgical infarct. MRSI and PWI parameters were analyzed prior to surgery and pre-RT. Postsurgical MRI indicated that 18 patients had gross total and 14 subtotal resections. Twenty-one patients showed reduced diffusion, and 25 patients showed new or increased CE. In eight patients (25%), the new CE was confined to areas of postsurgical reduced diffusion. In the other 17 patients (53%), new CE was found to be indicative of tumor growth or a combination of tumor growth and surgical injury. Higher perfusion and creatine within nonenhancing tumor in the presurgery MR were associated with subsequent tumor growth. High levels of choline and reduced diffusion in pre-RT CE suggested active metabolism and tumor cell proliferation. Median survival was 14.6 months in patients with interim tumor growth and 24 months in patients with no growth. Increased volume or new onset of CE between surgery and RT was attributed to tumor growth in 53% of patients and was associated with shorter survival. This suggests that reducing the time between surgery and adjuvant therapy may be important. The acquisition of metabolic and physiologic imaging data prior to adjuvant therapy may also be valuable in assessing regions of new CE and nonenhancing tumor.     

Survival with dacarbazine and fotemustine in newly diagnosed glioblastoma multiforme

A total of 55 patients with histologically proven glioblastoma multiforme (total gross resection: n=24, subtotal resection: n=20, stereotactic biopsy: n=11) were treated with the combination of dacarbazine (D) (200 mg m(-2)) and fotemustine (F) (100 mg m(-2)) and concomitant radiotherapy (2 Gy day(-1), 5 days per week using limited fields up to 60 Gy) to assess efficacy and toxicity of this regimen. Survival (median survival, 12-, 18- and 24-month survival rates) and time to progression (median time to progression (TTP), 6-month progression-free survival) were analysed by Kaplan-Meier's method. A total of 268 (range 1-8, median: 5) cycles were administered. Median survival is 14.5+ (range: 0.5-40+) months, and the 12-, 18- and 24-month survival rates are 58, 29 and 23%, respectively. Median TTP from the start of D/F therapy is 9.5+ (range: 0.5-33+) months. The 6-month progression-free survival is 54%. Partial remissions were observed in 3.6%. Main toxicity was thrombocytopenia. Five patients were excluded from further D/F application, four patients because of prolonged thrombocytopenia NCI-CTC grades 3 and 4 and one patient because of whole body erythrodermia. One patient died because of septic fever during thrombocytopenia and leukopenia NCI-CTC grade 4 after the first cycle. No other toxicities of NCI-CTC grade 3 or 4 occurred. The treatment is feasible in a complete outpatient setting and the results of the D/F regimen justify further investigations with these compounds.     

Serial analysis of imaging parameters in patients with newly diagnosed glioblastoma multiforme

The objective of this study was to test the predictive value of serial MRI data in relation to clinical outcome for patients with glioblastoma multiforme (GBM). Sixty-four patients with newly diagnosed GBM underwent conventional MRI and diffusion-weighted and perfusion-weighted imaging postsurgery and prior to radiation/chemotherapy (pre-RT), immediately after RT (post-RT), and every 1-2 months thereafter until tumor progression, up to a maximum of 1 year. Tumor volumes and perfusion and diffusion parameters were calculated and subject to time-independent and time-dependent Cox proportional hazards models that were adjusted for age and MR scanner field strength. Larger volumes of the T2 hyperintensity lesion (T2ALL) and nonenhancing lesion (NEL) at pre-RT, as well as increased anatomic volumes at post-RT, were associated with worse overall survival (OS). Higher normalized cerebral blood volumes (nCBVs), normalized peak height (nPH) and normalized recirculation factors (nRF) at pre-RT, and nCBV at post-RT, in the T2ALL and NEL, were associated with shorter progression-free survival (PFS). From pre- to post-RT, there was a reduction in nCBV and nPH and an increase in apparent diffusion coefficient (ADC). Patients with lower nRF values at pre-RT, or a larger increase in nRF from pre-RT to post-RT, had significantly longer PFS. Time-dependent analysis showed that patterns of changes in ADC and anatomic volumes were associated with OS, while changes in nCBV, nPH, and the contrast-enhancing volume were associated with PFS. Our studies suggest that quantitative MRI variables derived from anatomic and physiological MRI provide useful information for predicting outcome in patients with GBM.     

High-dose-rate stereotactic brachytherapy for patients with newly diagnosed glioblastoma multiformes

Purpose: To evaluate high-dose-rate (HDR) stereotactic brachytherapy (STBT) for glioblastoma multiforme (GBM). Materials and methods: Between August 1994 and December 1998, 28 patients with newly diagnosed GBM underwent surgery, external-beam radiotherapy (EBRT) and HDR STBT. STBT eligibility criteria included unifocal lesions, residual tumor <6cm in maximum diameter, supratentorial lesions, tumors not crossing the midline, tumors without subependymal spread and Karnofsky performance status (KPS) >60. STBT was delivered over five consecutive days with two fractions per day for a total median dose of 30Gy. Twenty-eight STBT eligible GBM patients treated with surgery and EBRT only over the same period were matched controls. Results: Median survival times for the STBT group and controls were 19.5 versus 12.5 months; one and two year survival rates were 89% versus 42% and 61% versus 28%, respectively (p=0.12). Using multivariate analysis, age, KPS and HDR STBT were significant factors predicting survival. By RPA class, 2-year survival rates for STBT and controls were: III – 78% versus 50%; IV – 40% versus 0%; V – 21% versus 15%, respectively. Corresponding median survival times in months were: 41.6 versus 21.2 (p = 0.39); 16.7 versus 12.1 (p = 0.36); 18.7 versus 10.6 (p = 0.02). No major complications were found in the STBT arm. Conclusions: Because of small patient numbers, median survival time increases were only statistically significant in the RPA Class V patients, but a strong survival time trend emerged favoring patients undergoing HDR STBT. Further prospective study is warranted to fully assess the merits of this technique for GBM management.     

Response assessment during chemoradiation using a hypercellular/hyperperfused imaging phenotype predicts survival in patients with newly diagnosed glioblastoma

BackgroundAdversely prognostic hypercellular and hyperperfused regions of glioblastoma (GBM) predict progression-free survival, and are a novel target for dose-intensified chemoradiation (chemoRT) recently implemented in a phase II clinical trial. As a secondary aim, we hypothesized that dose-intensified chemoRT would induce greater mid-treatment response of hypercellular/hyperperfused tumor regions vs standard chemoradiation, and that early response would improve overall survival (OS).MethodsForty-nine patients with newly diagnosed GBM underwent prospective, multiparametric high b value diffusion-weighted MRI (DW-MRI) and perfusion dynamic contrast-enhanced MRI (DCE-MRI) pre-RT and 3-4 weeks into RT. The hypercellular tumor volume (TV_HCV, mean contralateral normal brain + 2SD) and hyperperfused tumor volume (TV_CBV, contralateral normal frontal gray matter + 1SD) were generated using automated thresholding. Twenty-six patients were enrolled on a dose-escalation trial targeting TV_HCV/TV_CBV with 75 Gy in 30 fractions, and 23 non-trial patients comprised the control group. OS was estimated using the Kaplan-Meier method and compared using the log-rank test. The effect of TV_HCV/TV_CBV and Gd-enhanced tumor volume on OS was assessed using multivariable Cox proportional-hazard regression.ResultsMost patients had gross total (47%) or subtotal resection (37%), 25% were MGMT-methylated. Patients treated on the dose-escalation trial had significantly greater reduction in TV_HCV/TV_CBV (41% reduction, IQR 17%-75%) vs non-trial patients (6% reduction, IQR 6%-22%, P = .002). An increase in TV_HCV/TV_CBV during chemoRT was associated with worse OS (adjusted hazard ratio [aHR] 1.2, 95%CI 1.0-1.4, P = .02), while pre-treatment tumor volumes (P > .5) and changes in Gd-enhanced volume (P = .9) were not.ConclusionsMultiparametric MRI permits identification of therapeutic resistance during chemoRT and supports adaptive strategies in future trials.     

Early measures of cognitive function predict survival in patients with newly diagnosed glioblastoma

Cognitive dysfunction is a common manifestation of primary brain tumors. We evaluated the association between early cognitive dysfunction and prognosis in a cohort of patients with newly diagnosed glioblastoma. Ninety-one patients who completed neuropsychological assessment after tumor resection but before further treatment were identified in the MD Anderson Neuropsychology database. The relationship between performance on cognitive testing and survival was evaluated using not only Cox proportional hazards models that included clinical factors such as age and KPS but also the Kaplan-Meier method. Median survival time from surgery was 20.7 months. Rates of impairment on cognitive testing ranged from 7.1% for Similarities, to 60.0% for Hopkins Verbal Learning Test-Revised Total Recall. As continuous variables, the Clinical Trial Battery Composite, Trail Making Test Part B, and Controlled Oral Word Association test were associated with survival. Impairment on the Trail Making Test Part B, Controlled Oral Word Association, Similarities, and Digit Span were associated with mortality. Kaplan-Meier analysis demonstrated the survival impact of these tests on the group as a whole and in select patient subgroups defined by classification by the Radiation Therapy Oncology Group (RTOG) Recursive Partitioning Analysis (RPA). Cognitive impairment as measured by specific neuropsychological tests is independently associated with poor prognosis in patients with newly diagnosed glioblastoma, and this effect remains significant even within patient subgroups defined by RTOG RPA class. Executive function and attention are the cognitive domains most closely associated with prognosis in this analysis.     

Prognostic factors for survival in 676 consecutive patients with newly diagnosed primary glioblastoma

Reliable data on large cohorts of patients with glioblastoma are needed because such studies differ importantly from trials that have a strong bias toward the recruitment of younger patients with a higher performance status. We analyzed the outcome of 676 patients with histologically confirmed newly diagnosed glioblastoma who were treated consecutively at a single institution over a 7-year period (1997-2003) with follow-up to April 30, 2006. Survival probabilities were 57% at 1 year, 16% at 2 years, and 7% at 3 years. Progression-free survival was 15% at 1 year. Prolongation of survival was significantly associated with surgery in patients with a good performance status, whatever the patient's age, with an adjusted hazard ratio of 0.55 (p < 0.001) or a 45% relative decrease in the risk of death. Radiotherapy and chemotherapy improved survival, with adjusted hazard ratios of 0.61 (p = 0.001) and 0.89 (p = 0.04), respectively, regardless of age, performance status, or residual tumor volume. Recurrence occurred in 99% of patients throughout the follow-up. Reoperation was performed in one-fourth of these patients but was not effective, whether performed within 9 months (hazard ratio, 0.86; p = 0.256) or after 9 months (hazard ratio, 0.98; p = 0.860) of initial surgery, whereas second-line chemotherapy with procarbazine, lomustine, and vincristine (PCV) or with temozolomide improved survival (hazard ratio, 0.77; p = 0.008). Surgery followed by radiotherapy and chemotherapy should be considered in all patients with glioblastoma, and these treatments should not be withheld because of increasing age alone. The benefit of second surgery at recurrence is uncertain, and new trials are needed to assess its effectiveness. Chemotherapy with PCV or temozolomide seems to be a reasonable option at tumor recurrence.     

Oncological patterns of care and outcome for 952 patients with newly diagnosed glioblastoma in 2004

This report, an audit requested by the French government, describes oncological patterns of care, prognostic factors, and survival for patients with newly diagnosed and histologically confirmed glioblastoma multiforme (GBM) in France. The French Brain Tumor DataBase, which is a national multidisciplinary (neurosurgeons, neuropathologists, radiotherapists, neurooncologists, epidemiologists, and biostatisticians) network, prospectively collected initial data for the cases of GBM in 2004, and a specific data card was used to retrospectively collect data on the management and follow-up care of these patients between January 1, 2004, and December 1, 2006. We recorded 952 cases of GBM (male/female ratio 1.6, median age 63.9 years, mean preoperative Karnofsky performance status [KPS] 79). Surgery consisted of resection (RS; n = 541) and biopsy (n = 411); 180 patients did not have subsequent oncological treatment. After surgery, first-line treatment (n = 772) consisted of radiotherapy (RT) and temozolomide (TMZ) concomitant +/− adjuvant in 314 patients, RT alone in 236 patients, chemotherapy (CT) alone in 157 patients, and other treatment modalities in 65 patients. Median overall survival was 286 days (95% CI, 266–314) and was significantly affected by age, KPS, and tumor location. Median survival (days, 95% CI) associated with these main strategies, when analyzed by a surgical group, were as follows: RS + RT-TMZ_(n=224): 476 (441–506), biopsy + RT-TMZ_(n=90): 329 (301–413), RS + RT_(n=147): 363 (331–431), biopsy + RT_(n=89): 178 (153–237), RS + CT_(n=61): 245 (190–361), biopsy + CT_(n=96): 244 (198–280), and biopsy only_(n=118): 55 (46–71). This study illustrates the usefulness of a national brain tumor database. To our knowledge, this work is the largest report of recent GBM management in Europe.     

Pulsed radiation therapy for the treatment of newly diagnosed glioblastoma

BackgroundPulsed radiation therapy (PRT) has shown effective tumor control and superior normal-tissue sparing ability compared with standard radiotherapy (SRT) in preclinical models and retrospective clinical series. This is the first prospective trial to investigate PRT in the treatment of patients with newly diagnosed glioblastoma (GBM).MethodsThis is a single-arm, prospective study. Patients with newly diagnosed GBM underwent surgery, followed by 60 Gy of PRT with concurrent temozolomide (TMZ). Each day, a 2-Gy fraction was divided into ten 0.2-Gy pulses, separated by 3-minute intervals. Patients received maintenance TMZ. Neurocognitive function (NCF) and quality of life (QoL) were monitored for 2 years using the Hopkins Verbal Learning Test‒Revised and the European Organisation for Research and Treatment of Cancer QLQ-C30 QoL questionnaire. Change in NCF was evaluated based on a minimal clinically important difference (MCID) threshold of 0.5 standard deviation.ResultsTwenty patients were enrolled with a median follow-up of 21 months. Median age was 60 years. Forty percent underwent subtotal resection, and 60% underwent gross total resection. One patient had an isocitrate dehydrogenase (IDH)–mutated tumor. Median progression-free survival (PFS) and overall survival (OS) were 10.7 and 20.9 months, respectively. In a post-hoc comparison, median OS for the prospective cohort was longer, compared with a matched cohort receiving SRT (20.9 vs 14 mo, P = 0.042). There was no decline in QoL, and changes in NCF scores did not meet the threshold of an MCID.ConclusionsTreatment of newly diagnosed GBM with PRT is feasible and produces promising effectiveness while maintaining neurocognitive function and QoL. Validation of our results in a larger prospective trial warrants consideration.     

Use of metformin and outcome of patients with newly diagnosed glioblastoma: Pooled analysis

Metformin has been linked to improve survival of patients with various cancers. There is little information on survival of glioblastoma patients after use of metformin. We assessed the association between metformin use and survival in a pooled analysis of patient data from 1,731 individuals from the randomized AVAglio, CENTRIC and CORE trials. We performed multivariate Cox analyses for overall survival (OS) and progression-free survival (PFS) comparing patients' use of metformin at baseline and/or during concomitant radiochemotherapy (TMZ/RT). Further exploratory analyses investigated the effect of metformin with a history of diabetes and nonfasting glucose levels in relation to OS or PFS of glioblastoma patients. Metformin alone or in any combination was not significantly associated with OS or PFS (at baseline, hazard ratio [HR] for OS = 0.87; 95% confidence interval [CI] = 0.65–1.16; HR for PFS = 0.84; 95% CI = 0.64–1.10; during TMZ/RT HR for OS = 0.97; 95% CI = 0.68–1.38; HR for PFS = 1.02; 95% CI = 0.74–1.41). We found a statistically nonsignificant association of metformin monotherapy with glioblastoma survival at baseline (HR for OS = 0.68; 95% CI = 0.42–1.10; HR for PFS = 0.57; 95% CI = 0.36–0.91), but not during the TMZ/RT period (HR for OS = 0.90; 95% CI = 0.51–1.56; HR for PFS = 1.05; 95% CI = 0.64–1.73). Diabetes mellitus or increased nonfasting glucose levels were not associated with a difference in OS or PFS in our selected study population. Metformin did not prolong survival of patients with newly diagnosed glioblastoma in our analysis. Additional studies may identify patients with specific tumor characteristics that are associated with potential benefit from treatment with metformin, possibly due to metabolic vulnerabilities.     

Challenges for the functional diffusion map in pediatric brain tumors

Background

The functional diffusion map (fDM) has been suggested as a tool for early detection of tumor treatment efficacy. We aim to study 3 factors that could act as potential confounders in the fDM: areas of necrosis, tumor grade, and change in tumor size.

Methods

Thirty-four pediatric patients with brain tumors were enrolled in a retrospective study, approved by the local ethics committee, to examine the fDM. Tumors were selected to encompass a range of types and grades. A qualitative analysis was carried out to compare how fDM findings may be affected by each of the 3 confounders by comparing fDM findings to clinical image reports.

Results

Results show that the fDM in areas of necrosis do not discriminate between treatment response and tumor progression. Furthermore, tumor grade alters the behavior of the fDM: a decrease in apparent diffusion coefficient (ADC) is a sign of tumor progression in high-grade tumors and treatment response in low-grade tumors. Our results also suggest using only tumor area overlap between the 2 time points analyzed for the fDM in tumors of varying size.

Conclusions

Interpretation of fDM results needs to take into account the underlying biology of both tumor and healthy tissue. Careful interpretation of the results is required with due consideration to areas of necrosis, tumor grade, and change in tumor size.     

The timing of cranial radiation in elderly patients with newly diagnosed glioblastoma multiforme

There are few and conflicting studies on the optimal timing of initial cranial radiation in the treatment of glioblastoma multiforme (GBM) but none of them have addressed this issue in the elderly population. We used the linked Surveillance, Epidemiology, and End Results (SEER) Medicare database to investigate whether the time interval from surgery to initiation of radiation is a significant prognostic factor for survival in subjects aged ≥65 years with newly diagnosed GBM. Cox modeling was used to assess the effect of waiting time on overall survival. We identified a total of 1,375 patients, 296 with biopsies and 1,079 with resections. The median time to the initiation of radiotherapy was 15 days post operation (interquartile range 12–21). In the univariate Cox analysis of those who had debulking surgeries, a waiting time of >22 days showed a significant inverse relationship with survival (hazard ratio [HR] = 0.82, 95% CI 0.70–0.97, p = 0.02), but after adjustment for confounders, it was not a statistically significant factor in the final Cox model (HR = 0.99, 95% CI 0.97–1.01, p = 0.14). Therefore, waiting time was not a significant prognostic factor for subjects with biopsies in both the univariate and multivariate analyses. Although effort should be made to initiate radiotherapy as soon as possible after surgical resection/biopsy, a brief delay similar to that experienced by our cohort does not have a significant impact on survival.     

A study of concurrent radiochemotherapy with paclitaxel in glioblastoma multiforme

Despite advances in neurosurgery and radiotherapy, the prognosis of patients with glioblastoma multiforme remains poor. Reports in the literature about the radiosensitizing properties of paclitaxel stimulated the authors to conduct a study using paclitaxel concurrently with radiation in a group of 18 patients who had residual disease postoperatively. Paclitaxel was delivered weekly as an intravenous infusion in a dose of 60 mg/m ² along with radiation to the primary lesion. A total of 108 cycles of paclitaxel was given. All the patients tolerated the treatment well. The main side effects were haematological, and neuropathy which was self-limiting. The overall 1-year survival rate was 70%, with 12 patients alive at 13 months. The median survival has not yet been reached although it is more than 13 months. Thus, paclitaxel can be safely delivered concomitantly with radiation in patients with glioblastoma multiforme. Larger, randomized trials are required to establish the comparative efficacy of paclitaxel as a radiosensitizer in glioblastoma multiforme.     

Increased sensitivity to radiochemotherapy in IDH1 mutant glioblastoma as demonstrated by serial quantitative MR volumetry

Background

Isocitrate dehydrogenase 1 (IDH1) mutations have been linked to favorable outcomes in patients with glioblastoma multiforme (GBM). Recent in vitro experiments suggest that IDH1 mutation sensitizes tumors to radiation damage. We hypothesized that radiographic treatment response would be significantly different between IDH1 mutant versus wild-type GBMs after radiotherapy (RT) and concurrent temozolomide (TMZ).

Methods

A total of 39 newly diagnosed GBM patients with known IDH1 mutational status (10 IDH1 mutants), who followed standard therapy and had regular post-contrast T1W (T1+C) and T2W/ fluid-attenuated inversion recovery (FLAIR) images in the 6-month period after starting RT, were enrolled. The volume of contrast-enhancing and FLAIR hyperintensity were calculated from each scan. Linear and polynomial regression techniques were used to estimate the rate of change and temporal patterns in tumor volumes.

Results

IDH1 mutant GBMs demonstrated a favorable response to RT/TMZ in the study period, as demonstrated by 10 of 10 mutants showing radiographic response (decreasing V_T1+C), compared with 13 of 29 wild-types (P < .001). During the study period, V_T1+C and V_FLAIR changed at −3.6% per week and +0.6% per week in IDH1 mutant tumors, respectively, as compared with +0.8% per week and +5.2% per week in IDH1 wild-type tumors (P = .0076 and P = .0118, respectively). Amongst the radiographic responders, IDH1 mutant GBMs still demonstrated significant progression-free and overall survival benefit. Aggregated tumor kinetics by group showed significant lower rate in IDH1 mutant GBMs in specific periods: >105 days for V_FLAIR and 95–120 and >150 days for V_T1+C from starting RT/TMZ.

Conclusions

The current study supports the hypothesis that IDH1 mutant GBMs are more sensitive to radiochemotherapy than IDH1 wild-type GBMs.     

Potential new gene therapy option with sitimagene ceradenovec for newly diagnosed patients with glioblastoma multiforme

Glioblastoma multiforme (GBM) is associated with a poor prognosis with a 5-year survival rate of less than 5%, making GBM one of the most aggressive neoplastic malignancies. However significant strides have been made over the past few years with respect to understanding the pathophysiology as well as treatment modalities. The use of local therapies, particularly gene therapy, has been evaluated, but have yet to make a major clinical impact on treatment of GBM. In a study published by Westphal and colleagues in The Lancet Oncology, the use of sitimagene ceradenovec, a first generation replication-deficient adenovirus containing a prodrug converting enzyme, herpes-simplex virus thymidine kinase, followed by intravenous ganciclovir administration and standard therapy was evaluated compared with standard therapy alone. Patients who received sitimagene ceradenovec had improved time to death or re-intervention, but did not show improvement in overall survival. Patients receiving sitimagene ceradenovec experienced more adverse effects related to treatment, including seizures and hyponatremia. While further studies need to be conducted to determine clinical significance, gene therapy appears to be a viable approach for patients who may be resistant to chemotherapy.     

Utility of three-dimensional anisotropy contrast magnetic resonance axonography for determining condition of the pyramidal tract in glioblastoma patients with hemiparesis

Background and purpose: Three-dimensional anisotropy contrast magnetic resonance axonography (3DAC) is a technique for diffusion weighted magnetic resonance imaging (DWI) that offers reliable visualization of the pyramidal tracts. This study evaluated condition of the pyramidal tract using 3DAC in glioblastoma patients with hemiparesis. Methods: In 18 glioblastoma patients before surgery, 3DAC findings of the pyramidal tract responsible for hemiparesis were compared with finding from proton density-weighted imaging (PDWI). To estimate extent of pyramidal tract destruction, fractional anisotropy (FA) values using diffusion tensor magnetic resonance imaging were examined for both the responsible and non-pathological pyramidal tracts. Results: In all five patients for whom PDWI indicated no hyperintense foci in the responsible pyramidal tract, 3DAC demonstrated no change in color. When PDWI revealed hyperintense foci, 3DAC showed two types of findings: no color change (five patients); or obscured dark area (six patients). When 3DAC showed a dark area, mean FA value in the responsible tract was significantly lower than that for the non-pathological tract.Conclusion: When PDWI indicates hyperintense foci on the pyramidal tract, 3DAC allows prediction of pyramidal tract condition, such as large tumor invasion.