Effectivity of involved-field radiotherapy for recurrent brain metastasis in patients with small-cell lung cancer.

Objectives:To investigate the outcome difference of whole brain radiotherapy (WBRT) and involved-field radiotherapy (IFRT) in limited-stage small-cell lung cancer (LS-SCLC) patients with recurrent brain metastases (BMs) after prophylactic cranial irradiation (PCI). Methods:A retrospective analysis was carried out in 68 LS-SCLC patients who underwent WBRT or IFRT owing to the occurrence of recurrent BMs after PCI from 2009 to 2020. Results:The median overall survival (OS) of all patients was 11.43 months [95% confidence interval (CI) 9.39-13.48 months]. In the paired comparison of OS, the IFRT group had a significantly longer survival time than the WBRT group in all patients [17.80 months vs. 8.47 months; hazard ratio (HR), 0.393, 95% CI, 0.213-0.728; P = 0.002] and 46 matched patients (18.23 months vs. 8.73 months; HR, 0.411, 95% CI, 0.195-0.865; P = 0.019). In terms of the intra-cranial progression-free survival (iPFS), there was no significant difference between the WBRT group and IFRT group before matching (5.93 months vs. 7.30 months; HR, 0.644, 95% CI, 0.373-1.112; P = 0.111); similarly, no statistical difference was detected between the WBRT group and IFRT group after matching (5.33 months vs. 8.10 months; HR, 0.623, 95% CI, 0.323-1.199; P = 0.152). Meanwhile, of the 41 patients with symptoms, 27 cases (65.9%) had symptom relief, showing tolerable toxicity without unexpected toxicity during the observation. Conclusions:Compared with WBRT, IFRT exhibits better survival benefits for LS-SCLC patients with recurrent BMs after PCI. Re-irradiation for BMs exhibits advantages of symptom relief and tolerable side effects.