Whole-brain radiotherapy plus SIB or SRS for brain metastases in small cell lung cancer / 中华放射肿瘤学杂志

ABSTRACT

Objective:To evaluate the value of whole-brain radiotherapy (WBRT) combined with simultaneous integrated boost (SIB) and WBRT plus sequential stereotactic radiosurgery (SRS) in the treatment of small-cell lung cancer (SCLC) patients with brain metastases (BM).Methods:A retrospective analysis was performed among 135 SCLC patients with BM who were admitted to Tianjin Medical University Cancer Institute and Hospital from 2007 to 2023. They all received cisplatin- or carboplatin-based first-line chemotherapy and WBRT with 94 patients receiving thoracic radiotherapy after chemotherapy. All patients were divided into the WBRT+SIB ( n=66) and WBRT+SRS groups ( n=69) according to the treatment methods. After propensity score matching (PSM), 63 patients were assigned into each group. The primary endpoints were overall survival (OS) and brain metastasis-related local control (BMRLC) rates. Categorical data, such as gender and age, were compared by Chi-square test. OS and BMRLC were calculated by Kaplan-Meier method. The survival curves between two groups were compared by log-rank test. The risk factors of OS and BMRLC were assessed by multivariate Cox regression models. Results:In all the patients, the median follow-up time was 24.9 (range 6.30-109.57) months. The 2-year OS and BMRLC rates were 49.0% and 85.0%, respectively. Cerebral necrosis occurred in 2 patients. Multivariate analysis revealed that shorter time interval of BM after diagnosis (≤10 months) ( P=0.041), control of extracranial progression ( P=0.029), and lower diagnosis-specific graded prognostic assessment (DS-GPA) (≥2) ( P=0.006) significantly improved OS. After PSM, the 2-year OS rate in the WBRT+SIB group was significantly higher than that in the WBRT+SRS group ( P=0.041), while the 2-year BMRLC rate was not significantly improved ( P=0.203). In the DS-GPA<2 subgroup, the OS in the WBRT+SIB group was significantly higher than that in the WBRT+SRS group ( P=0.016), whereas no significant difference was observed in BMRLC between two groups ( P=0.205). In the DS-GPA≥2 subgroup, no significant difference was found in OS between two groups ( P=0.266), while BMRLC in the WBRT+SIB group was significantly lower compared with that in the WBRT+SRS group ( P=0.027). Conclusions:WBRT+SIB is more suitable for SCLC patients with BM than WBRT+SRS. However, WBRT+SRS yields higher local control for DS-GPA≥2 patients.