Fertility preservation in breast cancer patients: IVF and embryo cryopreservation after ovarian stimulation with tamoxifen

Background: Breast cancer chemotherapy commonly causes premature ovarian failure and infertility. Because increased estrogen levels are thought to be potentially risky in breast cancer patients, natural cycle IVF (NCIVF) has been used to preserve fertility and treat infertility in these women. Methods: Twelve women with breast cancer received 40-60 mg tamoxifen for 6.9 ± 0.6 days beginning on days 2-3 of their menstrual cycle (15 cycles), and had IVF (TamIVF) with either fresh embryo transfer (six cycles) or cryopreservation (nine cycles). They were compared to a retrospective control group (n = 5) who had natural cycle IVF (NCIVF, nine cycles). Results: Cycle cancellation was significantly less frequent in TamIVF, compared with NCIVF (1/15 versus 4/9, P < 0.05). Compared with NCIVF, TamIVF patients had a greater number of mature oocytes (1.6 ± 0.3 versus 0.7 ± 0.2, P = 0.03) and embryos (1.6 ± 0.3 versus 0.6 ± 0.2, P = 0.02) per initiated cycle. TamIVF resulted in the generation of embryo(s) in every patient (12/12) while only three out of five patients had an embryo following NCIVF. Two out of six patients in TamIVF, and 2/5 in NCIVF conceived. One patient in the TamIVF group delivered a set of twins. After a mean follow up of 15 ± 3.6 months (range 3-54), none of the patients had a recurrence of cancer. Conclusions: Tamoxifen stimulation appears to result in a higher number of embryos and may provide a safe method of IVF and fertility preservation in breast cancer patients.