Clinical outcomes of patients with multiple courses of radiosurgery for brain metastases from non-small cell lung cancer

We investigated the long-term clinical outcomes of patients who underwent multiple courses (≥ 5) of gamma knife radiosurgery (GKRS) due to recurrent brain metastases (BM) from non-small cell lung cancer (NSCLC). Between December 2001 and July 2019, consecutive 2571 patients underwent GKRS for BM from NSCLC. Clinical and radiological outcomes were investigated in 76 patients who underwent GKRS ≥ 5 times. The median follow-up period after the diagnosis of NSCLC was 54.6 months (range 14.5–159.1 months). The median number of GKRS procedures per patient was six (range 5–15). Actuarial post-GKRS survival rates at 1, 2, 3, 4, and 5 years following initial GKRS were 88.1%, 79.5%, 65.3%, 51.4%, and 37.3%, respectively. No significant difference in overall survival was observed between patients (n = 22) with whole-brain radiotherapy (WBRT) and patients (n = 54) without WBRT (p = 0.076). The incidence of radiation-induced leukoencephalopathy was 64% and 18% in patients with and without WBRT, respectively (p < 0.0001). Multiple courses of SRS are a tolerable and effective treatment option for recurrent BM from NSCLC. Repeat SRS may be an alternative treatment option to avoid or delay WBRT.