Treatment of brain metastases in patients with non-small cell lung cancer (NSCLC) by stereotactic linac-based radiosurgery: prognostic factors.

A restrospective study of patients with brain metastases from non-small cell lung cancer (NSCLC) is performed to identify patients who benefit from radiosurgery and to determine prognostic factors for survival. Eighty-six consecutive patients with a total of 110 brain metastases from NSCLC were treated with linac-based radiosurgery. Six patients with eight brain metastases who received radiosurgery as a focal boost to whole brain radiotherapy where excluded. Median age at treatment was 60 years. Median dose was 20 Gy/80%-isodose. A chi(2)-test was used to identify potential prognostic factors for local control of brain metastases and survival of the patients. Median follow-up was 6 months (range 1 1/2-77 months) with 17/80 patients still alive. Median actuarial survival was significantly longer (P<0.004) in patients with metachronous onset of brain metastases in comparison to synchronous onset (8.3 vs. 3.3 months). Survival was significantly increased after radiosurgery in the absence of extracranial tumor progression (P<0.03). Eleven patients (14%) developed new brain metastases after radiosurgery after a latency of median 5 months. Actuarial local control rate was 96% after 3 months. Local control was significantly increased with a prescribed dose > or=18 Gy/80%-isodose (P<0.01). We conclude that especially patients with poor prognostic factors and a limited number of brain metastases may be palliatively treated with radiosurgery alone. This approach allows to effectively control CNS manifestation of the disease and can be integrated into chemotherapeutic protocols.