An analysis of risk factors for brain metastases after prophylactic cranial irradiation for limited-stage small-cell lung cancer

Abstract

Objective To evaluate the high-risk factors for brain metastases after prophylactic cranial irradiation (PCI), and to provide a basis for personalized treatment. Methods A retrospective analysis was performed in 188 patients with limited-stage small-cell lung cancer who received PCI in our hospital from 2005 to 2010. The Kaplan-Meier method was used to calculate the cumulative rate of brain metastases. The log-rank test and the Cox model were used for the univariate and multivariate analyses of the potential factors for the cumulative incidence of brain metastases, respectively. Results In the 188 patients, 31(16.5%) had brain metastases. The 1-, 2-, and 3-year cumulative incidence rates of brain metastases were 4%, 15%, and 20%, respectively. The univariate analysis showed that staged Ⅲ disease before treatment, elevated levels of tumor markers, incomplete remission after chemoradiotherapy, and local-regional relapse were risk factors for high incidence of brain metastases (P=0.044, 0.037, 0.005, 0.007). The multivariate analysis revealed that incomplete remission after chemoradiotherapy and local-regional relapse after chemoradiotherapy were risk factors for high incidence of brain metastases after PCI (P=0.003, 0.040). Conclusions Patients with incomplete remission or local-regional relapse after chemoradiotherapy have high incidence of brain metastases after PCI. For those patients, a frequent follow-up of the central nervous system plus salvage cranial irradiation might provide an alternative to PCI. Key words: Small cell carcinoma, lung/prophylactic cranial irradiation; Brain metastasis; Risk factor