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.