P-449 Live birth rates after breast cancer among women who desired a child: a French regional study
Authors: Charpentier P , Cavalieri M , Desmoulins I , Fauque P , Coutant C 
Published: June 2023

Abstract

Study question
What are the live birth rates after breast cancer (BC) among women who desired a child?

Summary answer
In our cohort, after treatment for a BC, a live birth is achieved for 36.2% of woman who desire a child.

What is known already
In France, BC is the most common cancer among women under the age of 40. From 38 to 70% of women have not fulfilled their parental plans at the time of diagnosis. The gonadotoxicity of the treatments and the follicular physiological decline linked to age can become an obstacle to this project. Many studies on the subject do not take into account the desire for pregnancy or are interested in the pregnancy rate rather than the birth rate.

Study design, size, duration
In our retrospective, descriptive and observational study, 386 patients treated for BC at the regional BC treatment center (CGFL) between January 2011 and December 2018 (at least 4 years after their treatments), were identified. A total 192 patients met the inclusion criteria (aged 18-39 years old and histologically proven breast cancer). We excluded metastatic cancers, cancer in situ and pregnant patients at diagnosis. In January 2022, eligible participants were contacted.

Participants/materials, setting, methods
A total of 124 patients agreed to participate in the study. The included patients filled out a self-questionnaire concerning information about their desire for pregnancy after the breast cancer treatments, live births after breast cancer treatments and the place of fertility preservation. Data were collected from the patient’s electronic medical and therapeutic records. The primary endpoint of this study was the live birth rate.

Main results and the role of chance
The patient participation rate was 64.6%. The mean age at diagnosis was 33.7 years old. Fertility was preserved by oocyte cryopreservation in 13.8% of patients (17/124).
Among women who desired a child after BC and in whom pregnancy had been approved, the overall rate of live births was 36.2% (21/58). Most achieved pregnancies were spontaneous (90.5%). No factor was significantly associated with the absence of obtaining birth (i.e. the BC biological subtype or the different BC treatments received). Of these 21 patients, 3 had cryopreserved their oocytes but none used them.
Among 23 patients who had a fertility preservation consultation, 17 preserved via oocyte cryopreservation. Only one patient (5.9%) used her preserved oocytes resulting in a miscarriage.
When patients were medically allowed to start a pregnancy the median time to conception in patients who received chemotherapy was 8 months [1.0 - 60.0] vs 2 months [1.0 - 7.0] in women who did not receive chemotherapy.

Limitations, reasons for caution
Even though our BC-patients’ cohort is a good reflection of the all-French population of one region (Burgundy) since all patients are treated almost exclusively at the CGFL, the main limitations are the retrospective nature, the declarative character, and a short follow-up for the last included patients.

Wider implications of the findings
The non-negligible proportion of live births following spontaneous pregnancy after breast cancer allows us to be reassuring for patients. However, the emergence of new chemotherapy protocols whose consequences on long-term gonadotoxicity are still not well known requires further studies and prompts the promotion of fertility preservation as a precautionary measure.

Trial registration number
sans objet