The impact of Prophylactic cranial irradiation on the prognosis of patients with limited-stage small cell lung cancer in the MRI era

Abstract

Abstract Purposes To evaluate the impact of prophylactic cranial irradiation (PCI) on the prognosis of patients with limited-stage small cell lung cancer (SCLC) in the era of MRI surveillance. Methods Limited-stage SCLC patients with complete remission (CR) or partial remission (PR) of tumor after definitive chemo-radiotherapy (CRT) were retrospectively analyzed. Survival data were calculated by Kaplan-Meier methods, Cox proportional hazards model was applied for multivariate prognostic analysis. Results Between June 2002 and January 2017, 620 patients with limited-stage SCLC were accrued in our study. After CRT, 228 (36.8%) patients achieved CR, of whom, 29 patients did not receive PCI, among the rest 199 patients, 172 (86.4%) received brain MRI to exclude brain metastasis (BM) before PCI. With a median follow-up time of 25.6 months, the cumulative BM rate was 17.1% and 37.9% in patients who received or did not receive PCI (P = 0.011). The median survival time was 30.2 months and 30.5 months, respectively and the 1 -, 3 -, 5-year survival rates were 93.7%, 42.9%, 35.8% and 83.4%, 46.5%, 41.9%, respectively (P = 0.98). Multivariate analysis indicated that baseline KPS ≥ 90 was a favorable independent prognostic factor for OS in CR patients (HR: 0.33, 95% CI: 0.23–0.46, P = 0.000). After CRT, 392 (63.2%) patients achieved PR, 53 cases did not receive PCI and 310 (91.4%) of the remaining 339 patients received brain MRI before PCI. With a median follow-up time of 15.5 months, the cumulative brain metastasis rate was 12.7% and 46.2% respectively (P = 0.000). The median survival time was 25.7 months and 18.6 months, respectively. The 1 -, 3 -, and 5-year survival rates were 87.6%, 40.2%, 29.2% and 75.7%, 16.7%, 10.3% (P = 0.000). Baseline KPS ≥ 90 (HR: 0.32, 95% CI: 0.25–0.41, P = 0.000) and PCI (HR: 0.57, 95% CI: 0.41–0.79, P = 0.001) were favorable prognostic factors for OS in PR patients. Conclusions In this study, PCI significantly reduced the incidence of BM in patients with limited-stage SCLC who were evaluated as CR and PR after CRT, but it has no significantly positive impact on overall survival in CR patients. Further prospective randomized studies were warranted.

Keywords

• Small cell lung cancer
• Limited stage
• Prophylactic cranial irradiation
• Study on the prognosis