Glioblastoma in the elderly: the effect of aggressive and modern therapies on survival

Objective: The prognosis of elderly patients with glioblastoma (GBM) is universally poor. Currently, few studies have examined postoperative outcomes and the effects of various modern therapies such as bevacizumab on survival in this patient population. In this study, the authors evaluated the effects of various factors on overall survival in a cohort of elderly patients with newly diagnosed GBM.

Methods: A retrospective review was performed of elderly patients (≥ 65 years old) with newly diagnosed GBM treated between 2004 and 2010. Various characteristics were evaluated in univariate and multivariate stepwise models to examine their effects on complication risk and overall survival.

Results: A total of 120 patients were included in the study. The median age was 71 years, and sex was distributed evenly. Patients had a median Karnofsky Performance Scale (KPS) score of 80 and a median of 2 neurological symptoms on presentation. The majority (53.3%) of the patients did not have any comorbidities. Tumors most frequently (43.3%) involved the temporal lobe, followed by the parietal (35.8%), frontal (32.5%), and occipital (15.8%) regions. The majority (57.5%) of the tumors involved eloquent structures. The median tumor size was 4.3 cm. Every patient underwent resection, and 63.3% underwent gross-total resection (GTR). The vast majority (97.3%) of the patients received the postoperative standard of care consisting of radiotherapy with concurrent temozolomide. The majority (59.3%) of patients received additional agents, most commonly consisting of bevacizumab (38.9%). The median survival for all patients was 12.0 months; 26.7% of patients experienced long-term (≥ 2-year) survival. The extent of resection was seen to significantly affect overall survival; patients who underwent GTR had a median survival of 14.1 months, whereas those who underwent subtotal resection had a survival of 9.6 months (p = 0.038). Examination of chemotherapeutic effects revealed that the use of bevacizumab compared with no bevacizumab (20.1 vs 7.9 months, respectively; p < 0.0001) and irinotecan compared with no irinotecan (18.0 vs 9.7 months, respectively; p = 0.027) significantly improved survival. Multivariate stepwise analysis revealed that older age (hazard ratio [HR] 1.06 [95% CI1.02-1.10]; p = 0.0077), a higher KPS score (HR 0.97 [95% CI 0.95-0.99]; p = 0.0082), and the use of bevacizumab (HR 0.51 [95% CI 0.31-0.83]; p = 0.0067) to be significantly associated with survival.

Conclusion: This study has demonstrated that GTR confers a modest survival benefit on elderly patients with GBM, suggesting that safe maximal resection is warranted. In addition, bevacizumab significantly increased the overall survival of these elderly patients with GBM; older age and preoperative KPS score also were significant prognostic factors. Although elderly patients with GBM have a poor prognosis, they may experience enhanced survival after the administration of the standard of care and the use of additional chemotherapeutics such as bevacizumab.