Abstract 232P
Background
Several studies have demonstrated the safety of pregnancy in breast cancer (BC) survivors. However, many patients face infertility after (neo)adjuvant BC therapy and require fertility treatments (FT). The safety of FT after BC remission remains undefined due to the poor evidence on the prognostic impact of increased estrogen exposure not followed by anticancer treatments. Therefore, the safety of FT in BC survivors has become a research priority.
Methods
This is a retrospective multicenter study including BC survivors of less than 40 years at BC diagnosis who underwent FT between January 2006 and December 2016 with ≥ 2 years of follow-up after FT. They were compared to a non-exposed (NE) group of BC survivors who did not perform FT, matched (2:1) for BRCA status, BC stage, anticancer treatment, length of disease-free period (not inferior to the time between BC diagnosis and first FT in the FT group), and age at diagnosis when feasible. Exclusion criteria were: stage IV at diagnosis, BC during pregnancy, pre-existing neoplasia or ovarian failure. FT included controlled ovarian stimulation, clomiphene citrate, and hormone replacement therapy for embryo transfer.
Results
A total of 39 eligible patients were matched with 73 NE patients. There was no statistical difference between the two groups for BRCA mutation status, stage, estrogen receptor, progesterone receptor, HER2 status, use of chemotherapy or adjuvant endocrine therapy. Differences were observed for age (mean 31.8 (3.9) vs.34.2 (3.6) years in FT and NE groups, respectively; P< 0.001) and nulliparity at diagnosis (89.7% vs.46.6%, respectively; P< 0.001). Median follow-up time from BC diagnosis was 9 (4 – 22) and 12 (6 – 19) years in the FT and NE groups, respectively (P= 0.004). FT were performed at a mean age of 37.1 (4.6) years old. During FT, median estrogen peak level was 696.5 pg/ml (139.7 – 4130). In the FT group, 59% conceived after BC vs.26% in NE group (P= 0.001). BC relapsed in 7.7% versus 20.5% women in FT and NE groups (OR 2.88, 95% CI 0.81 – 10.2, P= 0.10); time to relapse was 6.7 (2.5) vs.7.5 (3.0) years after the initial BC diagnosis, respectively (P= 0.65).
Conclusions
This is the largest cohort study with the longest follow-up providing reassuring data regarding the use of FT in BC survivors who had an unfulfilled desire for pregnancy.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Erasme University Hospital (Universite Libre de Bruxelles).
Funding
Télévie- FNRS Fonds Erasme.
Disclosure
M. De Vos: Advisory/Consultancy, outside the submitted work: CooperSurgical; Speaker Bureau/Expert testimony, outside the submitted work: MSD; Speaker Bureau/Expert testimony, outside the submitted work: Gedeon-Richter; Speaker Bureau/Expert testimony, outside the submitted work: Ferring. M. Lambertini: Advisory/Consultancy, Speaker Bureau/Expert testimony, outside the submitted work: Roche; Speaker Bureau/Expert testimony, outside the submitted work: Theramex; Speaker Bureau/Expert testimony, outside the submitted work: Takeda; Speaker Bureau/Expert testimony, outside the submitted work: Lilly. I. Demeestere: Advisory/Consultancy, outside the submitted work: Roche; Speaker Bureau/Expert testimony, outside the submitted work: Novartis. All other authors have declared no conflicts of interest.