Prognostic Impact of Histologic Subtype in Non-Small Cell Lung Cancer Patients Treated with Gamma Knife Radiosurgery: Retrospective Analysis of 104 Patients.

AIM In this study, factors affecting survival, local failure, distant brain failure, whole brain failure and whole-brain radiation therapy (WBRT) free survival according to histological subtypes were investigated in patients with brain metastases from non-small cell lung cancer (NSCLC). MATERIAL AND METHODS Patients with positive pathology reports for adenocarcinoma (ACA) and squamous cell carcinoma (SCC) were included in the study. Seventy-eight ACA and 26 SCC patients were included in the study. Patients with previous history of cerebral metastasis surgery and WBRT were excluded from the study. RESULTS The median survival was calculated as 12.6 months for patients with ACA and 5.9 months for patients with SCC. One-year distant brain failure was calculated as 65.1% in ACA patients and 39.6% in SCC patients. One-year whole brain failure was calculated as 58.1% in ACA patients and 39.6% in SCC patients. The one-year freedom from WBRT rate was calculated as 72.8% in ACA patients and 56.3% in SCC patients. SCC histology was considered as a significant factor in deterioration of overall survival in multivariate analysis. SCC histology, the increase in the number of metastases and RPA class were factors that caused an increase in distant brain failure. Also, SCC histology, the increase in the number of metastases and RPA class were factors that caused an increase in whole brain failure. CONCLUSION SCC histology may be an important prognostic factor for overall survival. Also, due to high distant brain failure rate in SCC histology, WBRT can be added to treatment early.