Risk factors associated with brain metastases in patients with limited-stage small-cell lung cancer after prophylactic cranial irradiation

Purpose: Prophylactic cranial irradiation (PCI) has been the standard of practice for patients with limitedstage small-cell lung cancer after concurrent chemoradiotherapy (CRT), however, high brain metastasis rate and potential neurotoxicity limit the benefits from PCI. Thus, we conducted a retrospective study to identify the risk factors associated with brain metastases and provide evidence for personalized PCI. Methods: Between 2005 and 2010, 188 patients with limited-stage SCLC were included in the study, chi-square test and Cox proportional hazards analysis were used to assess the risk factors associated with brain metastases. Results: The median follow-up duration was 28 months (from 5 to 99 months), and the median survival time was 28 months. One-year, 2-year overall and 3-year overall survival (OS) rates were 95%, 69%, 55%, respectively. Thirty-one patients were diagnosed with brain metastases. One-year, 2-year and 3-year cumulative incidence of brain metastases were 4%, 15%, 20%, respectively. Univariate analysis showed that stage III before treatment (P=0.044), elevated levels of tumor markers (P=0.037), failure to achieve complete remission after CRT (P=0.005), and local-regional recurrence (P=0.007) were significantly associated with an increased risk of brain metastases. However, multivariate analysis indicated only failure to achieve complete remission after CRT (P=0.003) and local-regional recurrence (P=0.040) were independent factors predicting brain metastases. Conclusions: In conclusion, our study suggests that patients with local-regional recurrence or failed to achieve complete remission after CRT have higher risk of brain metastases. Close follow-up with brain MRI followed by salvage cerebral irradiation may be an alternative to PCI for those patients, which should be verified by random clinical trials.