Hormonal factors predictive of fertility in patients with breast cancer interrupting adjuvant endocrine therapy to attempt pregnancy in POSITIVE trial.

Purpose: The POSITIVE trial showed that premenopausal women with breast cancer (BC) can safely pause adjuvant endocrine treatment (ET) to attempt conception. 74 % of patients conceived spontaneously or through assisted reproductive technology (ART); Investigating hormonal factors that predict fertility was a key secondary endpoint.

Methods: Hormonal factors were assessed in non-pregnant women at months 3, 6, and 12 after ET interruption.