Stereotactic radiosurgery for patients with 10 or more brain metastases

The JLGK0901 study showed the non-inferiority of stereotactic radiosurgery (SRS) alone as the initial treatment for 5-10 as compared to 2-4 brain metastases (BM) in terms of overall survival and most secondary endpoints [Lancet Oncol 2014;15:387-395]. A trend for patients with 5-10 tumors to undergo SRS alone has since become apparent. The next step is to reappraise whether results of SRS treatment alone for tumor numbers ≥10 differ from those for 2-9 tumors. During the past 2 decades, several retrospective studies have demonstrated the SRS alone treatment strategy to have certain benefits for carefully selected patients with ≥10 BM, i.e., a sufficiently long survival period with lower incidences of neurological death, neurological deterioration, local recurrence, and SRS-related complications. Herein, we introduce our Mito experiences with SRS for ≥10 BM, employing a case-matched study on 934 patients, 467 each in groups with 2-9 BM and ≥10 BM. Post-SRS treatment results, i.e., median survival time, neurological death-free survival time and cumulative incidences of local recurrence, repeat SRS for new lesions, neurological deterioration, and SRS-related complications, were not inferior for patients with ≥10 BM as compared to those with 2-9 BM. We conclude that patients with ≥10 tumors are not unfavorable candidates for SRS alone.