Role of prophylactic cranial irradiation for elderly patients with limited-disease small-cell lung cancer: inverse probability of treatment weighting using propensity score.

Studies of prophylactic cranial irradiation (PCI) focused on elderly patients with small-cell lung cancer (SCLC) are rarely conducted. We aimed to identify whether there is a survival benefit of prophylactic cranial irradiation (PCI) in elderly patients using a single institution's retrospective data. A total of 234 patients with limited-disease SCLC (LD-SCLC) treated with thoracic chemoradiotherapy were evaluated; of these, 139 patients received PCI. To minimize treatment selection bias, patients were adjusted using the propensity score on factors associated with receipt of PCI. Cox proportional hazard model and Kaplan-Meier analyses were used to identify which subgroup may benefit from PCI. Median follow-up time was 22 months (range 1-150 months). PCI was associated with favorable brain metastasis-free survival, disease-specific survival, and overall survival in the entire population [hazard ratios (HR) 0.588, 95% confidence interval (CI) 0.338-1.024, P = 0.060; HR 0.477, 95% CI 0.331-0.687, P < 0.001; HR 0.543, 95% CI 0.383-0.771, P = 0.001, respectively). However, PCI had no significant relationship with overall survival in patients aged ≥65 years with cT3-4 disease and/or females gender (HR 0.817, 95% CI 0.098-6.849, P = 0.853; HR 1.082, 95% CI 0.114-10.227, P = 0.946, respectively). The benefits and risks of PCI in elderly patients with LD-SCLC need to be scrutinized, especially in those with high T stage tumors and/or females.