International multicenter study of stereotactic radiosurgery for bladder cancer brain metastases

Abstract

Purpose: Bladder cancer rarely metastasizes to the brain. This study was performed to evaluate stereotactic radiosurgery (SRS) for the management of bladder cancer brain metastases.

Methods: Cases of bladder cancer brain metastases treated with SRS were collected by members of the International Radiosurgery Research Foundation (IRRF) and outcome data was analyzed for patients with at least one clinical or imaging follow-up.

Results: 103 patients received SRS for 301 brain metastases. Median age at SRS was 68 and 73.8% of patients were male. Median KPS was 80%. Median time from primary to brain metastases diagnosis was 18 months. At the time of SRS, 50% of patients had other systemic metastases. The median number of metastases treated was 1, and median cumulative SRS volume was 1.16 cc. Most patients had single fraction SRS using a median margin dose of 18 Gy. At the time of analysis, 9.7% of patients were alive. Median survival after SRS was 7 months. Local control was achieved for 89.3% of metastases, 42% of patients developed new remote brain metastases, and 4.9% had leptomeningeal dissemination. Subsequent management included repeat SRS in 21.7%, surgical resection in 8.8% and WBRT in 7.6% of patients. At last follow-up, 32.1% of patients had improvement of their symptoms, whereas 38.5% remained stable. Adverse radiation effects occurred in 4.3% of treated metastases. On multivariate analyses, KPS ≥ 80% and non-urothelial histology predicted improved survival, while absence of corticosteroid intake predicted longer tumor control.

Conclusion: Bladder cancer brain metastases can be safely managed with SRS.

Keywords: Bladder cancer; Brain metastases; Gamma knife; Stereotactic radiosurgery.