Chemotherapy-induced ovarian failure in young women with early breast cancer: Prospective analysis of four randomised neoadjuvant/adjuvant breast cancer trials

Young women receiving chemotherapy for early breast cancer (EBC) have a high probability for ovarian failure, defined by chemotherapy-induced amenorrhea (CIA) as a surrogate. CIA is insufficiently reliable and reproducible. We analysed chemotherapy-induced ovarian failure (CIOF) by assessing hormone parameters, CIA, and antral follicle count (AFC). Blood samples of women aged ≤45 years treated with anthracycline/taxane-based chemotherapy for EBC from four neoadjuvant/adjuvant trials were collected at baseline, at the end of treatment (EOT), and at 6, 12, 18, and 24 months after EOT. Centrally assessed oestradiol (cutoff 12.4IU/L) were used to define CIOF for patients with baseline premenopausal hormone levels, anti-Müllerian hormone (AMH), and AFC to assess ovarian reserve. Further analyses included CIA, regain of premenopausal hormone levels, and disease-free survival (DFS) also in subgroups. Six hundred ninety-six patients aged ≤45 years had premenopausal hormone levels at baseline. Overall, 85.1% (592/696) experienced CIOF at EOT, and 147 of 592 had further hormone measurements after EOT. Of those, 32.7% (48/147) regained premenopausal hormone levels after 6 months, 57.9% (66/114) regained premenopausal hormone levels after 12 months, 83.0% (73/88) regained premenopausal hormone levels after 18 months, and 89.2% (74/83) regained premenopausal hormone levels after 24 months. After 24 months, 72.4% (21/29) of patients without CIOF and 100% (14/14) with CIOF had low AMH levels. Four-year DFS without CIOF versus CIOF was 65.9% versus 84.6% (hazard ratio [HR] = 2.09, 95% confidence interval [CI]: 1.37–3.19; P