Comparison of two dose levels of stereotactic radiosurgery for 1-3 brain metastases from non-small cell lung cancer

Aim: Two dose groups of patients treated with stereotactic radiosurgery (SRS) alone for 1-3 brain metastases from non-small cell lung cancer (NSCLC) were compared for outcomes. Patients and Methods: Based on the SRS dose administered to the margins of the brain lesions, 46 patients were assigned to groups treated with 15-18 Gy (n=13) or with 20 Gy (n=33). Seven additional factors were investigated: age (<58 vs. >59 years), gender, Karnofsky performance score (KPS 70-80 vs. 90-100), number of brain metastases (1 vs. 2-3), histology (adenocarcinoma vs. other) extracerebral metastases and interval from NSCLC diagnosis to SRS (<6 vs. >6 months). Results: Local control rates for 15-18-Gy and 20-Gy groups were 75% and 92% at one year (p=0.043). SRS dose was significant on multivariate analysis (p=0.030). SRS dose was not associated with freedom from new brain metastases (p=0.24) or survival (p=0.37). Conclusion: SRS with 20 Gy resulted in better control of the irradiated metastases than 15-18 Gy did.