Low radiotherapy dose is suitable for brain metastases in SCLC compared with high dose

Liming Xu; Kunning Zhang; Haonan Han; Han Sun; Yajing Yuan; Jun Wang; Lujun Zhao; Ping Wang

doi:10.3389/fonc.2023.1245506

Low radiotherapy dose is suitable for brain metastases in SCLC compared with high dose

Front Oncol. 2023 Sep 15:13:1245506. doi: 10.3389/fonc.2023.1245506. eCollection 2023.

Authors

Liming Xu¹, Kunning Zhang¹, Haonan Han², Han Sun³, Yajing Yuan⁴, Jun Wang^{1

5}, Lujun Zhao¹, Ping Wang¹

Affiliations

¹ Department of Radiation Oncology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China.
² Hubei Key Laboratory of Tumor Microenvironment and Immunotherapy, College of Basic Medical Sciences, China Three Gorges University, Yichang, China.
³ Department of Radiation Oncology, Cancer Center/National Clinical Research, Center for Cancer/Cancer Hospital & Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, China.
⁴ Department of Anesthesia, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin's Clinical Research Center for Cancer, Tianjin, China.
⁵ Department of Radiation Oncology, Tianjin Cancer Hospital Airport Hospital, Tianjin, China.

Abstract

Objective: This study was designed to evaluate the suitable radiotherapy dose in SCLC patients with BM.

Methods: A retrospective analysis was performed among 121 patients on the prognosis of BM of SCLC who were admitted to our hospital from 2013 to 2023. They all received first line chemotherapy. 80 patients of them received TRT after chemotherapy. The Chi square method was used to compare the categorical data. Univariate survival analysis was estimated by Kaplan Meier method and the logrank was used to compare survival curves between groups. A multivariate prognostic analysis was made by the Cox proportional hazard model. The iOS and iLC of two groups of low dose and high dose were analyzed after propensity score matching (PSM).

Results: In all the patients, the median follow-up time was 18.6 months (range 6.30~85.7), the 2-year iOS and iLC rates were 15.4% and 70.3%, respectively, and cerebral necrosis occurred in 2 patients. In univariate analysis related to iOS, extracranial disease control (p=0.023), higher DS-GPA (≥2) (p=0.016), immunotherapy (p=0.049), low-dose(p=0.030), and WBRT+SIB (p=0.009) were significantly associated with an increase in survival rate. After PSM, the 2-year iOS of low dose (n=49) was significantly higher than that of high dose (n=49) (P=0.025), while the 2-year iLC was not significantly improved (P=0.267). In DS-GPA < 2 subgroup, the iOS of low dose group was significantly higher than that of high dose group (p=0.019). In the DS-GPA ≥ 2 subgroup, the 2-year iLC of the low dose group was significantly inferior than that of the high dose group (p=0.044).

Conclusions: The iLC was improved along with increasing radiotherapy dose, but high dose had inferior iOS compared to low dose, while there were not significantly improving iLC when radiotherapy BED >56Gy. But in patients with DS-GPA≥2 subgroup, high dose brought better iLC benefits.

Keywords: brain metastases; carcinoma; prognosis; radiotherapy; small cell lung cancer.

Grants and funding

This study was supported by the National Natural Science Foundation of China (No.81502656 and No. 81501140).