The median survival time of patients with brainstem metastases left untreated has been reported as 1 month.[15,16] The prognosis improves for patients who receive treatment but depends on the intracranial response to treatment as well as control of extracranial disease. On multi-institutional analysis of patients treated with radiosurgery for brainstem metastases, median survival was 5.6 months, and 1-year survival was 32.7%. Chen and colleagues report an objective response rate of 59% in 642 patients across 17 studies. The 1-year local control rate was 86% in 1,410 patients across 31 studies who had brainstem metastases treated with SRS. There was a 33% 1-year overall survival in 1,254 patients across 27 studies and 2-year survival of 13% in 959 patients across 22 studies. Only 2.7% of deaths after treatment were attributable to progression of the brainstem metastasis, among 703 patients pooled from 19 studies; 68.6% died from systemic disease, and 18.7% died from non-brainstem intracranial disease.
Various studies have associated longer survival with control of extracranial disease, higher Karnofsky performance status (KPS), and class I or II recursive partitioning analysis (RPA) at time of treatment.[16–23] Other favorable prognostic factors have been reported without consensus in the literature, including lower number of brain metastases, non-melanoma histology and smaller tumor volume.[8,24,25]
Chin Clin Oncol. 2022;11(2):15 © 2022 AME Publishing Company