Comparison of oncological outcomes of premenopausal with ovarian function suppression versus postmenopausal women in ER+/HER2- breast cancer.

BACKGROUND

The Rx for positive node endocrine-responsive breast cancer trial highlighted that premenopausal (PRE) women who underwent chemotherapy exhibited superior survival rates compared to postmenopausal (POST) counterparts, but showed worse survival without chemotherapy. This raises the question whether application of ovarian function suppression (OFS) in PRE women aligns with their cancer biology, treatment response, and outcomes observed in POST women.

METHODS

Data from the Seoul National University Hospital breast cancer cohort focusing on patients with stage pT1-3, pN0-1, estrogen receptor-positive (ER+), and HER2-negative breast cancer were analyzed. Survival outcomes, including invasive disease-free survival (iDFS) and distant relapse-free survival (DRFS), were compared between PRE women receiving OFS and POST women, with chemotherapy usage as a stratification factor. Propensity score matching was performed.

RESULT: We analyzed 3483 patients, comprising 2901 POST and 582 PRE women with OFS. In the cohort without chemotherapy, the 10-year iDFS rates were 90.3 % and 88.3 % (hazard ratio [HR], 1.32; p = 0.16), and 10-year DRFS rates were 94.3 % and 96.1 % (HR, 0.78; p = 0.41) for POST and PRE women with OFS, respectively. Among women treated with chemotherapy, 10-year iDFS rates were 83.0 % and 79.5 % (HR, 1.21; p = 0.37), and DRFS rates were 86.7 % and 85.7 % (HR, 1.14; p = 0.58) for POST and PRE women with OFS, respectively. These results remained consistent after PSM.

CONCLUSION

Oncological outcomes of PRE women receiving OFS were comparable to those of POST women with ER+ and HER2-early breast cancer, irrespective of chemotherapy administration.