Type of adjuvant endocrine therapy and disease-free survival in patients with early HR-positive/HER2-positive BC: analysis from the phase III randomized ShortHER trial

The optimal adjuvant endocrine therapy for HR-positive/HER2-positive breast cancer patients is unknown. We included in this analysis 784 patients with HR-positive/HER2-positive BC from the randomized ShortHER trial of adjuvant trastuzumab (1 year vs 9 weeks) + chemotherapy. At a median follow-up of 8.7 years, patients who received AI had a significantly better DFS vs patients who received TAM or TAM-AI: 8-yr DFS 86.4 vs 79.7%, log-rank P = 0.013 (HR 1.52, 95% CI 1.09-2.11). In multivariate analysis, the type of endocrine therapy maintained a significant association with DFS (HR 1.64, 95% CI 1.07-2.52, p = 0.025 for TAM/TAM-AI vs AI). Among premenopausal patients aged <= 45 years, the use of GnRHa was associated with longer DFS: 8-yr DFS rate 85.2 vs 62.6% (log-rank p = 0.019, HR 0.41, 95% CI 0.19-0.88). In this post-hoc analysis of the ShortHER trial adjuvant treatment with AI was independently associated with improved DFS. Subgroup analysis in premenopausal patients suggests benefits with ovarian suppression.

Automated summary

The optimal adjuvant endocrine therapy for HR-positive/HER2-positive breast cancer patients is unknown. In this analysis of the ShortHER trial, 784 patients with HR-positive/HER2-positive BC were included, and it was found that AI treatment was associated with significantly better disease-free survival (DFS) compared to TAM or TAM-AI treatment. Among premenopausal patients aged <= 45 years, the use of GnRHa was also associated with longer DFS.