Efficacy and prognostic analysis of chest wall boost radiotherapy in stage T 4 breast cancer patients after modified radical mastectomy / 中华放射肿瘤学杂志

ABSTRACT

Objective:To analyze the efficacy of chest wall boost radiotherapy in stage T 4 breast cancer patients after modified radical mastectomy. Methods:A retrospective analysis was performed on the data of 148 stage T 4 breast cancer patients who were admitted from 2000 to 2016 and received radiotherapy after modified radical mastectomy. There were 57 cases in the chest wall boost radiotherapy group and 91 cases in the conventional dose group. Radiotherapy was performed by conventional+ chest wall electron beam, three-dimensional conformal+ chest wall electron beam, intensity modulated radiotherapy+ chest wall electron beam irradiation. EQD 2 at the boost group was >50Gy. All patients received neoadjuvant chemotherapy. Kaplan-Meier method was used to analyze survival; Logrank was used to test differences; and Cox model was used to do multivariate prognostic analysis. Results:The median follow-up time was 67.2 months. The 5-year rates of chest wall recurrence (CWR), locoregional recurrence (LRR), disease-free survival (DFS), and overall survival (OS) were 9.9%, 16.2%, 58.0%, and 71.4%, respectively. The 5-year rates of CWR, LRR, DFS, and OS with and without chest wall boost radiotherapy were 14% vs. 7%, 18% vs. 15%, 57% vs. 58%, 82% vs. 65%( P>0.05), respectively. Multivariate analysis showed that chest wall boost radiotherapy had no significant effect on prognosis ( P>0.05). Among 45 patients in the recurrent high-risk group, boost radiotherapy seemed to have higher OS rate ( P=0.058), DFS rate ( P=0.084), and lower LRR rate ( P=0.059). Conclusions:Stage T 4 breast cancer patients had strong heterogeneity. Chest wall boost radiotherapy did not apparently benefit all patients. For patients with 2-3 high risk factors including positive vascular tumor embolus, pN 2-N 3, and hormone receptor negative, chest wall boost radiotherapy showed a trend of improving efficacy.