Long-term antimüllerian hormone patterns differ by cancer treatment exposures in young breast cancer survivors.

<bold>Objective: </bold>To compare antimüllerian hormone (AMH) patterns by cancer status and treatment exposures across 6 years after incident breast cancer using administrative data.<bold>Design: </bold>In a cross-sectional design, AMH levels in patients who developed incident breast cancer between ages 15-39 years during 2005-2019 were matched 1:10 to levels in females without cancer in the OptumLabs Data Warehouse. Modeled AMH patterns were compared among cyclophosphamide-based chemotherapy, non-cyclophosphamide-based chemotherapy, no chemotherapy, and no breast cancer groups.<bold>Setting: </bold>Commercially insured females in the United States.<bold>Patient(s): </bold>Females with and without breast cancer.<bold>Exposure(s): </bold>Breast cancer, cyclophosphamide- and non-cyclophosphamide-based chemotherapy.<bold>Main Outcome Measure(s): </bold>AMH levels.<bold>Result(s): </bold>A total of 233 patients with breast cancer (mean age, 34 years; standard deviation, 3.7 years) contributed 278 AMH levels over a median of 2 years (range, 0-6.7 years) after diagnosis; 52% received cyclophosphamide-based chemotherapy, 17% received non-cyclophosphamide-based chemotherapy (80% platinum-based), and 31% received no chemotherapy. A total of 2,777 matched females without cancer contributed 2,780 AMH levels. The pattern of AMH levels differed among the 4 groups. Among females without cancer and breast cancer survivors who did not undergo chemotherapy, AMH declined linearly over time. In contrast, among those who received cyclophosphamide-based and noncyclophosphamide-based chemotherapy, a nonlinear pattern of AMH level of initial fall during chemotherapy, followed by an increase over 2-4 years, and then by a plateau over 1-2 years before a decline was observed.<bold>Conclusion(s): </bold>In breast cancer survivors, AMH levels from administrative data supported ovarian toxicity of non-cyclophosphamide-based chemotherapy in breast cancer and efficiently depicted the timing and duration of changes in ovarian reserve to reflect the residual reproductive lifespan. [ABSTRACT FROM AUTHOR]