Clinical characteristics and disease outcomes in ER+ breast cancer: a comparison between HER2+ patients treated with trastuzumab and HER2- patients

• Published in: BMC cancer Vol. 21; no. 1; pp. 1 - 807
• Main Authors: Li, Shuai, Wu, Jiayi, Huang, Ou, He, Jianrong, Zhu, Li, Chen, Weiguo, Li, Yafen, Chen, Xiaosong, Shen, Kunwei
• Format: Journal Article
• Language: English
• Published: London BioMed Central Ltd 13.07.2021; BioMed Central; BMC
• Subjects: Breast cancer; Cancer therapies; Chemotherapy; Drug therapy; Endocrine therapy; ErbB-2 protein; Escalation; HER2; Hormone receptor; Medical prognosis; Menopause; Menstruation; Metastasis; Monoclonal antibodies; Multivariate analysis; Patient outcomes; Patients; Prognosis; Radiation therapy; Regression analysis; Surgery; Survival; Targeted cancer therapy; Trastuzumab; Tumors; Womens health; China
• ISSN: 1471-2407; 1471-2407
• DOI: 10.1186/s12885-021-08555-4

Background Trastuzumab has changed the prognosis of HER2+ breast cancer. We aimed to investigate the prognosis of ER+/HER2+ patients treated with trastuzumab, thus to guide escalation endocrine treatment in ER+ breast cancer. Methods ER-positive early breast cancer patients operated at Ruijin Hospital between Jan. 2009 and Dec. 2017 were retrospectively included. Eligible patients were grouped as HER2-negative (HER2-neg) or HER2-positive with trastuzumab treatment (HER2-pos-T). Kaplan-Meier analysis and Cox proportional hazards model were used to compare the disease-free survival (DFS) and overall survival (OS) between these two groups. Results A total of 3761 patients were enrolled: 3313 in the HER2-neg group and 448 in the HER2-pos-T group. Patients in the HER2-pos-T group were associated with pre/peri-menopause, higher histological grade, LVI, higher Ki-67 level, lower ER and PR levels (all P < 0.05). At a median follow-up of 62 months, 443 DFS events and 191 deaths were observed. The estimated 5-year DFS rate was 89.7% in the HER2-neg group and 90.2% in the HER2-pos-T group (P = 0.185), respectively. Multivariable analysis demonstrated that patients in the HER2-pos-T group had a better DFS than patients in the HER2-neg group (HR 0.52, 95% CI: 0.37-0.73, P < 0.001). The estimated 5-year OS rates were 96.0% and 96.3% in the two groups, respectively (P = 0.133). Multivariate analysis found that HER2-pos-T group was still associated with significantly better OS compared with the HER2-neg group (HR 0.38, 95% CI: 0.22-0.67, P = 0.037). Conclusion ER+/HER2+ breast cancer patients treated with trastuzumab were associated with superior outcome compared with ER+/HER2- patients, indicating HER2-positivity itself may not be an adverse factor for ER+ patients in the era of trastuzumab. Keywords: Breast cancer, Hormone receptor, HER2, Trastuzumab, Endocrine therapy, Escalation