Data on prophylactic cranial irradiation (PCI) after complete resection of SCLC are limited. The purpose of this study was to investigate the impact of PCI in this population.

We retrospectively identified completely resected SCLC at the Shanghai Chest Hospital between January 2006 and January 2014.

A total of 349 patients (115 patients who received PCI [the PCI-treated cohort] and 234 patients who did not [the non-PCI-treated cohort]) were included in the study. The results demonstrated that the PCI-treated cohort had longer overall survival than the non-PCI-treated cohort among patients with pathologic stage (p-stage) II (hazard ratio [HR] = 0.54, 95% confidence interval [CI]: 0.30-0.99, p = 0.047) and p-stage III (HR = 0.54, 95% CI: 0.34-0.86, p = 0.009) disease. Among patients with p-stage III disease, there was a significantly higher risk for cerebral recurrence from the time of diagnosis in the non-PCI-treated cohort (p = 0.018). With regard to patients with p-stage I disease, neither overall survival benefit (HR = 1.61, 95% CI: 0.68-3.83, p = 0.282) nor risk for cerebral recurrence (p = 0.389) was significant between the PCI-treated and non-PCI-treated cohorts.

The data presented in the current study support using PCI in patients with p-stage II/III disease but not in patients with p-stage I disease. A relatively lower risk for brain metastases in p-stage I patients might explain the inferior efficacy of PCI in this population.