Standard (60 Gy) or short-course (40 Gy) irradiation plus concomitant and adjuvant temozolomide for elderly patients with glioblastoma: A propensity-matched analysis

Purpose: To evaluate 2 specific radiation schedules, each combined with temozolomide (TMZ), assessing their efficacy and safety in patients aged ≥65 years with newly diagnosed glioblastoma (GBM). Methods and Materials: Patients aged ≥65 years with Karnofsky performance status (KPS) ≥60 who received either standard (60 Gy) or short-course (40 Gy) radiation therapy (RT) with concomitant and adjuvant TMZ between June 2004 and October 2013 were retrospectively analyzed. A propensity score analysis was executed for a balanced comparison of treatment outcomes. Results: A total of 127 patients received standard RT-TMZ, whereas 116 patients underwent short-course RT-TMZ. Median overall survival and progression-free survival times were similar: 12 months and 5.6 months for the standard RT-TMZ group and 12.5 months and 6.7 months for the short-course RT-TMZ group, respectively. Radiation schedule was associated with similar survival outcomes in either unadjusted or adjusted analysis. O6-methylguanine-DNA methyltransferase promoter methylation was the most favorable prognostic factor (P=.0001). Standard RT-TMZ therapy was associated with a significant rise in grade 2 and 3 neurologic toxicity (P=.01), lowering of KPS scores during the study (P=.01), and higher posttreatment dosing of corticosteroid (P=.02). Conclusions: In older adults with GBM, survival outcomes of standard and short-course RT-TMZ were similar. An abbreviated course of RT plus TMZ may represent a reasonable therapeutic approach for these patients, without loss of survival benefit and acceptable toxicity.