Shorter-course whole-brain radiotherapy for brain metastases in elderly patients

Purpose: Many patients with brain metastases receive whole-brain radiotherapy (WBRT) alone. Using 10 × 3 Gy in 2 weeks is the standard regimen in most centers. Regarding the extraordinarily poor survival prognosis of elderly patients with multiple brain metastases, a shorter WBRT regimen would be preferable. This study compared 10 × 3 Gy with 5 × 4 Gy in elderly patients (≥65 years). Methods and Materials: Data from 455 elderly patients who received WBRT alone for brain metastases were retrospectively analyzed. Survival and local (= intracerebral) control of 293 patients receiving 10 × 3 Gy were compared with 162 patients receiving 5 × 4 Gy. Eight additional potential prognostic factors were investigated including age, gender, Karnofsky performance score (KPS), primary tumor, number of brain metastases, interval from tumor diagnosis to WBRT, extracerebral metastases, and recursive partitioning analysis (RPA) class. Results: The 6-month overall survival rates were 29% after 5 × 4 Gy and 21% after 10 × 3 Gy (p = 0.020). The 6-month local control rates were 12% and 10%, respectively (p = 0.32). On multivariate analysis, improved overall survival was associated with KPS ≥ 70 (p < 0.001), only one to three brain metastases (p = 0.029), no extracerebral metastasis (p = 0.012), and lower RPA class (p < 0.001). Improved local control was associated with KPS ≥ 70 (p < 0.001), breast cancer (p = 0.029), and lower RPA class (p < 0.001). Conclusions: Shorter-course WBRT with 5 × 4 Gy was not inferior to 10 × 3 Gy with respect to overall survival or local control in elderly patients. 5 × 4 Gy appears preferable for the majority of these patients.