Ovarian Function Suppression in HR-Positive, HER2-Positive Breast Cancer: An Exploratory Analysis of the HERA Trial

Data on the effectiveness of ovarian function suppression (OFS) in premenopausal patients with hormone receptor (HR)-positive, HER2-positive breast cancer are sparse. We investigated the prognostic impact of incorporating OFS in premenopausal women with HER-positive, HR-positive breast cancer, drawing on data from the HERceptin Adjuvant (HERA) trial.

We examined patient-level data from the HERA trial (BIG1-01) to assess whether adding OFS enhances disease-free survival (DFS) and overall survival (OS) in premenopausal women with early-stage HR-positive, HER2-positive breast cancer. Additionally, we explored differences in prognosis between types of oral antiestrogens, specifically tamoxifen (TAM) and aromatase inhibitors (AIs).

A total of 965 patients were included in our analysis; 501 (51.9%) received TAM only, and 464 (48.1%) underwent endocrine therapy with OFS. The addition of OFS independently correlated with enhanced DFS (hazard ratio, 0.68; 95% CI, 0.53-0.87; P=.002) and OS (hazard ratio, 0.62; 95% CI, 0.44-0.85; P=.003). The 10-year DFS rates were 70.9% with OFS versus 59.6% with TAM only, whereas the 10-year OS rates were 84.7% with OFS versus 74.0% with TAM only. Among the patients treated with OFS, AI was associated with favorable survival outcomes compared with TAM.

Our findings suggest that adding OFS to adjuvant endocrine therapy may improve survival outcomes in premenopausal women with HR-positive, HER2-positive breast cancer who are receiving chemotherapy and HER2-targeted therapy, and are at high risk of relapse.

gov identifier: NCT00045032.