The clinical outcome of postoperative radiotherapy using hybrid planning technique in left breast cancer after breast‐conserving surgery

BACKGROUND: The purpose of this study is to observe the preliminary clinical outcome and acute toxicity of hybrid intensity modulated radiotherapy and volumetric modulated arc therapy planning technique with simultaneous integrated boost (SIB). METHODS: From November 2015 to December 2018, 149 female patients with left‐side breast cancer who underwent adjuvant radiotherapy with hybrid IMRT and VMAT planning technique with SIB were reviewed retrospectively. The primary endpoint was acute toxicities and the secondary endpoints were local recurrence‐free survival (LRFS), distant metastasis‐freesurvival (DMFS), disease‐free survival (DFS), and overall survival (OS). RESULTS: The median age was 52 years old and median follow‐up was 43.4 months. Eighty‐six percent of patients had acute grade 0 to grade1 dermatitis and 14% had grade 2 dermatitis. No acute radiation pneumonitis, esophagitis, or cardiovascular events were recorded during follow‐up. The 3‐year LRFS, DMFS, DFS, and OS rates were 95.1%, 95.1%, 90.3%, and 97.9%, respectively. The subgroup analysis revealed that patients with lymphovascular invasion had more local recurrence rate and worse DFS rate. Patients with advanced N stage had the trend of worse DMFS. CONCLUSION: In conclusion, the hybrid IMRT and VMAT technique is feasible, safe and has less acute radiation related toxicities in SIB postoperative radiotherapy for left‐sided breast cancer.