Risk assessment of brain metastasis after prophylactic cranial irradiation for 550 limited stage small cell lung cancer patients with remission after radiochemotherapy / 中华放射肿瘤学杂志

ABSTRACT

Objective:To evaluate the risk and prognostic factors of brain metastasis (BM) after prophylactic cranial irradiation (PCI) in limited stage small cell lung cancer (LS-SCLC) patients with complete and partial remission (CR/PR) after radiochemotherapy.Methods:Baseline data of 550 patients with LS-SCLC who obtained CR/PR after chemoradiotherapy and received PCI in Zhejiang Cancer Hospital between 2002 and 2017 were collected. The risk of BM and clinical prognosis were retrospectively analyzed. The survival analysis was performed by Kaplan-Meier method. Multivariate prognostic analysis was conducted byCox models.Results:The overall BM rate after PCI was 15.6%(86/550), with 9%(4/43), 13%(7/52), and 16.5%(75/455) for stage Ⅰ, Ⅱ and Ⅲ patients, respectively. The median overall survival (OS) for the entire cohort was 27.9 months, and the 5-year OS rate was 31.0%. The OS was 24.9 and 30.2 months for patients with or without BM, and the 5-year OS rates were 8.9% and 36.1%( P<0.001). BM was an independent factor of OS ( P<0.001). Clinical staging remained the influencing factor of OS and BM-free survival ( P<0.001, P=0.027). Having tumors of ≥5 cm in diameter significantly increased the risk of BM ( P=0.034) rather than the OS ( P=0.182). The median OS of patients aged<60 years was significantly longer than those aged ≥60 years (34.9 months vs. 24.6 months, P=0.001). The median OS of patients irradiated with 2 times/d was 29.8 months, significantly longer than 24.5 months of those irradiated with 1 time/d ( P=0.013). Age, sex, radiotherapy fraction and efficacy of radiochemotherapy (CR/PR) were not associated with the incidence rate of BM (all P>0.05). Conclusions:SCLC patients with tumors of ≥5 cm in diameter may have a higher risk of developing BM after PCI. Patients aged<60 years achieve better OS compared with their counterparts aged ≥60 years.