AUTHOR=Sun Guang-Yi , Jing Hao , Wang Shu-Lian , Song Yong-Wen , Jin Jing , Fang Hui , Liu Yue-Ping , Ren Hua , Tang Yu , Zhao Xu-Ran , Song Yu-Chun , Chen Si-Ye , Yang Zhuan-Bo , Chen Bo , Tang Yuan , Li Ning , Lu Ning-Ning , Qi Shu-Nan , Yang Yong , Li Ye-Xiong 

TITLE=Trastuzumab Provides a Comparable Prognosis in Patients With HER2-Positive Breast Cancer to Those With HER2-Negative Breast Cancer: Post Hoc Analyses of a Randomized Controlled Trial of Post-Mastectomy Hypofractionated Radiotherapy

JOURNAL=Frontiers in Oncology

VOLUME=10

YEAR=2021

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2020.605750

DOI=10.3389/fonc.2020.605750

ISSN=2234-943X

ABSTRACT=<sec><title>Background and Purpose</title><p>We investigated the locoregional effect of trastuzumab, and determined whether patients with human epidermal growth factor receptor (HER)2-positive breast cancer (BC) treated with trastuzumab could achieve comparable efficacy to that of patients with HER2-negative BC.</p></sec><sec><title>Materials and Methods</title><p>This was <italic>post hoc</italic> analyses of data of 793 BC patients from a randomized controlled trial comparing post-mastectomy hypofractionated radiotherapy with conventional fractionated radiotherapy. Survival rates were analyzed by the Kaplan–Meier method and compared by the log-rank test.</p></sec><sec><title>Results</title><p>Patients were classified into three groups: HER2-negative (HER2<sup>−</sup>; n = 547), HER2-positve with trastuzumab (HER2<sup>+</sup> + T; n = 136), and HER2-positive without trastuzumab (HER2<sup>+</sup> − T; n = 110). The HER2<sup>+</sup> + T group had significantly lower locoregional recurrence (LRR, 6.0% <italic>vs.</italic> 13.9%), distant metastasis (DM, 17.4% <italic>vs.</italic> 33.8%) and higher disease-free survival (DFS, 81.2% <italic>vs.</italic> 61.9%) at 5 years than that of the HER2<sup>+</sup> − T group (<italic>P</italic> &lt;.05). The HER2<sup>−</sup> group had significantly lower LRR (6.8% <italic>vs.</italic> 13.9%), DM (22.4% <italic>vs.</italic> 33.8%) and higher DFS (76.1% <italic>vs.</italic> 61.9%) at 5 years than that of the HER2<sup>+</sup> − T group (<italic>P</italic> &lt;.05). The difference in LRR, DM and DFS at 5 years was not significant between the HER2<sup>+</sup> + T group and HER2<sup>−</sup> group (<italic>P</italic> &gt;.05). Different annual LRR patterns was found among groups according to HR status.</p></sec><sec><title>Conclusion</title><p>Trastuzumab reduces LRR in patients with locally advanced HER2-positive BC who have received post-mastectomy radiotherapy. It provides comparable DFS to that with patients with HER2-negative BC.</p></sec>