关键词: 小细胞肺癌, 放射疗法, 脑转移, 模型

Abstract:

Objective To investigate the risk factors of brain metastases in patients with limited-stage small cell lung cancer （SCLC） undergoing preventive brain radiotherapy after remission and to construct prediction model. Methods A total of 231 patients with limited-stage SCLC who received chemoradiotherapy and achieved remission in 3201 Hospital from January 2015 to January 2023 were selected as the study objects. Logistic regression was used to analyze the influencing factors on the occurrence of brain metastases after remission in patients with limited-stage SCLC who received preventive brain radiotherapy. Binary logistic regression was used to construct a prediction model. Receiver operator characteristic （ROC） curve was used to evaluate the diagnostic efficacy of each indicator and the prediction model on the occurrence of brain metastases in patients. Results The median follow-up time of the whole group was 73 months， and 42 cases of brain metastases occurred， with an incidence rate of 18.18%. There were statistically significant differences in the incidence of brain metastases among patients with different T stage （Z=-4.97， P<0.001）， clinical stage （Z=-8.17， P<0.001）， and time from initial treatment to thoracic radiotherapy （χ²=21.38， P<0.001）. Multivariate analysis showed that T stage （stage T₃： OR=6.29， 95%CI： 1.58-25.06， P=0.009； stage T₄： OR=12.91， 95%CI： 3.74-44.57， P<0.001）， clinical stage （stageⅡ， OR=8.75， 95%CI： 2.89-26.51， P<0.001； stage Ⅲ， OR=18.43， 95%CI： 7.24-46.92， P<0.001）， and time from initial treatment to thoracic radiotherapy （OR=0.25， 95%CI： 0.11-0.56， P=0.001） were independent influencing factors on the occurrence of brain metastases after remission in patients with limited-stage SCLC who received preventive brain radiotherapy. The diagnostic prediction model based on the above indicators was logit（P）=-19.91+1.84× stage T₃ +2.56× stage T₄+2.17× stage Ⅱ+2.91× stage Ⅲ-1.38× time from initial treatment to thoracic radiotherapy. ROC curve analysis showed that the area under the curve of T stage， clinical stage， time from initial treatment to thoracic radiotherapy， and the diagnostic prediction model for predicting the occurrence of brain metastasis after remission in patients with limited-stage SCLC who received preventive brain radiotherapy were 0.728， 0.660， 0.687， and 0.846， respectively， and the area under the curve of the diagnostic prediction model was significantly larger than those of the other indicators （all P<0.05）. Conclusion T stage， clinical stage and the time from initial treatment to thoracic radiotherapy are all influential factors for the occurrence of brain metastases after remission in patients with limited-stage SCLC who received preventive brain radiotherapy. The diagnostic prediction model based on the above indicators can help to guide clinicians to accurately screen patients at high risk of brain metastases in the early stage.

Key words: Small cell lung carcinoma, Radiotherapy, Brain metastasis, Models