Abstract P4-11-08: Impact of ovarian stimulation for fertility preservation in young women with breast cancer: Updated survival and pregnancy outcomes

Abstract

Abstract Background: Chemotherapy (CTx) and hormone therapy may impair fertility in women with breast cancer (BC) by direct gonadotoxicity or delayed childbearing. Inconsistent data regarding the safety and efficacy of ovarian stimulation for fertility preservation (FP) in BC may limit clinician referral and patient uptake of FP. We previously examined the effect of FP on BC recurrence and herein present updated survival and pregnancy outcomes in relation to FP from an expanded BC cohort. Methods: Women aged ≤ 40 years diagnosed with stage I-III BC between 2007-2018 referred to one of six cancer centres and to a reproductive endocrinologist in British Columbia, Canada were identified from a central database. Clinicopathologic, treatment and outcome characteristics were compared using uni/multivariate Cox and logistic regression analyses for survival and pregnancy outcomes, respectively, for patients who did and did not undergo FP prior to systemic cancer treatment. Results: 158 patients were identified. Sixty-four (41%) had lymph node involvement, 119 (75%) had ER-positive and 39 (25%) had HER2-positive BC. The 72 (46%) patients who underwent FP were more likely to be younger (mean age 33 vs 34 y, p=0.030), ECOG 0 (p=0.013), have CTx (p<0.001) and GnRH agonist during CTx (p=0.010) compared to patients with no FP. Tumor stage, ER/HER2/BRCA-positivity, BMI, radiation and number of existing children were not associated with decision to pursue FP (p>0.05). After a median follow-up of 4.7 years, BC recurrence occurred in 15 (17%) non-FP patients and 9 (13%) FP patients (Table 1). FP did not affect overall survival by univariate (HR 0.9; 95% CI 0.7-1.3) or multivariate analysis controlling for age, BMI, ECOG/ER/HER2 status, tumor stage and receipt of CTx or radiation (HR 1.0, 95% CI 0.7-1.4). Post-diagnosis, 22 (31%) FP patients and 11 (13%) non-FP patients had ≥ 1 pregnancy (Table 2). The use of assisted reproductive technology (ART) was similar in both groups. Patients who had FP were 2.8 times more likely (p=0.013) to conceive at least once. The results remained significant on multivariate analysis controlling for age, BMI, ECOG status and baseline parity (p=0.030). Non-FP patients had a 31% higher miscarriage rate than those who did (p=0.26). Conclusions: FP was not associated with an increased risk of locoregional recurrence, distant recurrence or death over a follow-up period of 3-11 years, supporting its safety in young women with BC. Despite more often receiving CTx, patients who underwent FP were significantly more likely to conceive after BC than those who did not, even when accounting for differences in patient profiles. This may relate to greater use of GnRH agonists during CTx, known to protect ovarian function, and stronger desires for future childbearing in patients who pursued FP. Although there was similar use of ART in both groups, the higher pregnancy rate and more successful reproductive outcomes in FP patients support the value and promotion of pre-oncologic treatment FP in young BC patients early in their disease trajectory, to enhance survivorship family planning. Table 1.Survival outcomes of patients.CharacteristicNo FP (n=86)FP (n=72)p-valueRecurred [n (%)]0.85Locoregional6 (7)4 (6)Distant9 (10)5 (7)Deceased [n (%)]8 (9)4 (6)0.38 Table 2.Characteristics of first pregnancies in patients conceiving after diagnosis.CharacteristicNo FP (n=11)FP (n=21)p-valuePregnancy outcome [n (%)]0.26Completed3 (27)11 (52)Miscarriage7 (64)7 (33)Ongoing1 (9)3 (14)Pregnancy interval from diagnosis [n (%)]0.29≤ 2 y04 (19)2-5 y8 (73)13 (62)> 5 y3 (27)4 (19)Type of conception [n (%)]0.52Natural9 (82)15 (71)Assisted2 (18)6 (29) Citation Format: Megan E Tesch, Ying Wang, Chloe Lim, Ying Hui Xu, Shaina Lee, Kirstin Perdrizet, Dan Yokom, Ellen Warner, Jeffrey Roberts, Caroline Lohrisch. Impact of ovarian stimulation for fertility preservation in young women with breast cancer: Updated survival and pregnancy outcomes [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-11-08.