Impact of standard care on elderly glioblastoma patients

Efficacy, Outcome, and Safety of Elderly Patients with Glioblastoma in the 5-ALA Era: Single Center Experience of More Than 10 Years

Simple Summary

In the next decades, the incidence of patients with glioblastoma (GBM) will markedly increase due to the growth of the elderly population. Despite the increasing incidence of GBM, elderly patients are frequently excluded from clinical studies and thus, only few data are available specifically focusing on the elderly population. In the current study, we aimed to investigate the efficacy, outcome, and safety of surgically-treated GBM including resections and biopsies in the 5-ALA era in a large elderly cohort of altogether 272 patients. Our data of this large elderly cohort demonstrate for the first time the clinical utility and safety of 5-ALA fluorescence in GBM for improved tumor visualization in both resections as well as biopsies. Therefore, we recommend the use of 5-ALA not only in resections, but also in open/stereotactic biopsies to optimize the neurosurgical management of elderly GBM patients.

Abstract

Background: In the next decades, the incidence of patients with glioblastoma (GBM) will increase due to the growth of the elderly population. Fluorescence-guided resection using 5-aminolevulinic acid (5-ALA) is widely applied to achieve maximal safe resection of GBM and is identified as a novel intraoperative marker for diagnostic tissue during biopsies. However, detailed analyses of the use of 5-ALA in resections as well as biopsies in a large elderly cohort are still missing. The aim of this study was thus to investigate the efficacy, outcome, and safety of surgically- treated GBM in the 5-ALA era in a large elderly cohort. Methods: All GBM patients aged 65 years or older who underwent neurosurgical intervention between 2007 and 2019 were included. Data on 5-ALA application, intraoperative fluorescence status, and 5-ALA-related side effects were derived from our databank. In the case of resection, the tumor resectability and the extent of resection were determined. Potential prognostic parameters relevant for overall survival were analyzed. Results: 272 GBM patients with a median age of 71 years were included. Intraoperative 5-ALA fluorescence was applied in most neurosurgical procedures (n = 255/272, 88%) and visible fluorescence was detected in most cases (n = 252/255, 99%). In biopsies, 5-ALA was capable of visualizing tumor tissue by visible fluorescence in all but one case (n = 91/92, 99%). 5-ALA administration did not result in any severe side effects. Regarding patient outcome, smaller preoperative tumor volume (<22.75 cm³), gross total resection, single lesions, improved postoperative neurological status, and concomitant radio-chemotherapy showed a significantly longer overall survival. Conclusions: Our data of this large elderly cohort demonstrate the clinical utility and safety of 5-ALA fluorescence in GBM for improved tumor visualization in both resections as well as biopsies. Therefore, we recommend the use of 5-ALA not only in resections, but also in open/stereotactic biopsies to optimize the neurosurgical management of elderly GBM patients.

Adjuvant Radiation in Older Patients With Glioblastoma: A Retrospective Single Institution Analysis

OBJECTIVES

Standard 6-week and hypofractionated 3-week courses of adjuvant radiation therapy (RT) are both options for older patients with glioblastoma (GBM), but deciding the optimal regimen can be challenging. This analysis explores clinical factors associated with selection of RT course, completion of RT, and outcomes following RT.

MATERIALS AND METHODS

This IRB-approved retrospective analysis identified patients ≥70 years old with GBM who initiated adjuvant RT at our institution between 2004 and 2016. We identified factors associated with standard or hypofractionated RT using the Cochran-Armitage trend test, estimated time-to-event endpoints using the Kaplan-Meier method, and found predictors of overall survival (OS) using Cox proportional hazards models.

RESULTS

Sixty-two patients with a median age of 74 (range 70-90) initiated adjuvant RT, with 43 (69%) receiving standard RT and 19 (31%) receiving hypofractionated RT. Selection of short-course RT was associated with older age (p = 0.04) and poor KPS (p = 0.03). Eight (13%) patients did not complete RT, primarily for hospice care due to worsening symptoms. After a median follow-up of 37 months, median OS was 12.3 months (95% CI 9.0-15.1). Increased age (p < 0.05), poor KPS (p < 0.0001), lack of MGMT methylation (p < 0.05), and lack of RT completion (p < 0.0001) were associated with worse OS on multivariate analysis. In this small cohort, GTV size and receipt of standard or hypofractionated RT were not associated with OS.

CONCLUSIONS

In this cohort of older patients with GBM, age and KPS was associated with selection of short-course or standard RT. These regimens had similar OS, though a subset of patients experienced worsening symptoms during RT and discontinued treatment. Further investigation into predictors of RT completion and survival may help guide adjuvant therapies and supportive care for older patients.

Lack of survival advantage among re-resected elderly glioblastoma patients: a SEER-Medicare study

BACKGROUND

The survival benefit of re-resection for glioblastoma (GBM) remains controversial, owing to the immortal time bias inadequately considered in many studies where re-resection was treated as a fixed, rather than a time-dependent factor. Using the Surveillance, Epidemiology, and End Results-Medicare (SEER-Medicare) database, we assessed treatment patterns for older adults and evaluated the association between re-resection and overall survival (OS), accounting for the timing of re-resection.

METHODS

This retrospective cohort study included elderly patients (age ≥66) in the SEER-Medicare linked database diagnosed with GBM between 2006 and 2015 who underwent initial resection. Time-dependent Cox regression was used to assess the association between re-resection and OS, controlling for age, gender, race, poverty level, geographic region, marital status, comorbidities, receipt of radiation + temozolomide, and surgical complications.

RESULTS

Our analysis included 3604 patients with median age 74 (range: 66-96); 54% were men and 94% were white. After initial resection, 44% received radiation + temozolomide and these patients had a lower hazard of death (hazard ratio [HR]: 0.28, 95% confidence interval [CI]: 0.26-0.31, P < .001). In total, 9.5% (n = 343) underwent re-resection. In multivariable analyses, no survival benefit was seen for patients who underwent re-resection (HR: 1.12, 95% CI: 0.99-1.27, P = .07).

CONCLUSIONS

Re-resection rates were low among elderly GBM patients, and no survival advantage was observed for patients who underwent re-resection. However, patients who received standard of care at initial diagnosis had a lower risk of death. Older adults benefit from receiving radiation + temozolomide after initial resection, and future studies should assess the relationship between re-resection and OS taking the time of re-resection into account.

Hypofractionated versus standard radiation therapy in combination with temozolomide for glioblastoma in the elderly: a meta-analysis

BACKGROUND

There is no clear consensus regarding the optimal treatment for glioblastoma (GBM) in the elderly. Hypofractionated radiation therapy (hRT) has emerged as a viable and comparable radiation regime compared to standard radiation therapy (sRT), however the survival effect of temozolomide (TMZ) with hRT is uncertain. The aim of this meta-analysis was to evaluate survival outcomes of hRT + TMZ vs sRT + TMZ in this specific demographic.

METHODS

Searches of 7 electronic databases from inception to January 2019 were conducted following the appropriate guidelines. Articles were screened against pre-specified criteria. The progression free survival (PFS) and overall survival (OS) metrics were then extracted and pooled by meta-analysis evaluating mean difference (MD).

RESULTS

A total of 7 individual comparative studies describing hRT + TMZ vs sRT + TMZ (n = 917) respectively satisfied inclusion criteria. Meta-analysis by random-effects modelling indicated that compared to sRT + TMZ, hRT + TMZ resulted in comparable PFS (MD 0.3 months; 95% CI - 2.4 to 2.9; I² = 91.7%; P-effect = 0.85) and significantly shorter OS (MD - 3.5 months; 95% CI - 6.3 to - 0.6; I² = 98.9%; P-effect = 0.02). Subgroup analysis between age definitions of elderly of > 65 vs > 70 years old both demonstrated the same significant trend with no statistical difference between the groups.

CONCLUSION

The combination of hRT + TMZ is feasible in well-selected elderly GBM cases, and appears to confer a statistically comparable PFS compared to sRT + TMZ. However, expectations that the OS with hRT + TMZ is comparable to that of sRT + TMZ in all elderly GBM presentations should be tempered. It is likely a specific subgroup of elderly GBM patients will benefit greatly from the addition of TMZ to hRT, and greater investigation is needed to identify their characteristics.