Standardized birth rates and access to assisted reproductive technology among female cancer patients in the United States.

12105 Background: Fertility after cancer is critically under-defined on a national scale, reflecting a substantial gap in survivorship care. We constructed a novel longitudinal dataset to describe 1) live births and 2) use of assisted reproductive technology (ART) among female cancer patients from 2004-2022. Methods: We linked population-based cancer registry data (2004–2018 in 12 states; 2004–2011 in California) with live birth certificates and the Society for Assisted Reproductive Technology database (2004-2022), which captures ~90% of ART cycles nationally, to create a dataset integrating oncologic characteristics, obstetric outcomes, and ART utilization. Female patients aged 15-45 at diagnosis of cancer were included. The primary outcome was the standardized birth ratio (SBR) >9 months after cancer diagnosis stratified by age, race/ethnicity, cancer site, stage, and receipt of systemic therapy calculated using Centers for Disease Control (CDC) general population birth rates from the 13 states. Secondary outcome was ART use after cancer diagnosis (≥1 autologous oocyte/embryo cryopreservation or embryo transfer cycles). Patients were categorized by expected fertility detriment, defined as pelvic malignancy and/or receipt of chemotherapy, hormone therapy, or abdominal/pelvic radiation. Associations with ART were evaluated with Cox proportional hazards models adjusted for age, cancer stage, insurance, and race/ethnicity. Person-years accrued from diagnosis date to first post-diagnosis birth/use of ART, death, age 51 (oldest age a post-cancer birth was observed), or December 31, 2022. The study was approved by the institutional review board. Results: 286,198 female cancer patients were included, with 25,586 babies born to 19,713 women over a mean follow up of 8.3 years. The overall SBR compared to the general population was 0.38 [0.36, 0.40], with lowest rates in gynecologic and breast cancers (0.22[0.18, 0.27], 0.26[0.23, 0.30]). 46.2% (n=9,110) of patients with births had thyroid cancer or lymphoma. Median time from diagnosis to birth was 3.27 years (2.00-5.27). Only 1.56% (n=5343) of the cohort used ART, with highest use among patients with breast cancer (n=2506, 46.9%). Expected fertility detriment was associated with higher hazard of ART use (aHR 2.37, 95% CI 2.20, 2.54), specifically cryopreservation (5.53[4.89, 6.26]). The 2022 live birth rate from our cohort (44.0%, 70/159) paralleled national trends (42.5%) reported from 457 fertility clinics by the CDC (p=0.69). Conclusions: The burden of infertility among reproductive-aged cancer patients is profound, with observed birth rates less than half that of the general population. Among patients who access ART, however, birth rates mirror those published by fertility clinics nationally. Despite this, ART services among cancer patients are underused, highlighting unmet needs in survivorship care delivery.