Latrogenic infertility as a result of cancer treatment has a profound effect on long-term quality of life in survivors of reproductive-age cancers. Oocyte cryopreservation prior to cancer treatment has been associated with improved quality of life, with a potential ability to reduce long-term decision-related regret in cancer survivors. Though letrozole plus gonadotropin and and tamoxifen plus gonadotropin are currently routinely used worldwide in ovarian stimulation cycles for fertility preservation in patients with estrogen-receptor-positive breast cancer, it is not clear which of the two might lead to improved oocyte yield. Improved knowledge about the efficacy of these medications, with regard to oocyte yield, has the potential to significantly improve quality of life in reproductive-age breast cancer survivors.
Our primary objective is to determine whether concomitant administration of tamoxifen 20 mg oral with gonadotropins (tamoxifen-gonadotropin) versus a starting dose of letrozole 5 mg oral with gonadotropins (letrozole-gonadotropin) will result in a difference in mature oocyte yield during our routine ovarian stimulation protocol for fertility preservation for Estrogen-Receptor-Positive (ER+) breast cancer.
Specific Aims: Each of the following aims will include a primary comparison and secondary comparisons.
Primary aim: The primary aim will be to compare patients with ER+ breast cancer who are treated with letrozole-gonadotropin versus patients with ER+ breast cancer who are treated tamoxifen-gonadotropin with regard to ovarian stimulation outcomes.
Secondary Aim: We will repeat the above comparisons among patients with ER+ breast cancer who are treated with tamoxifen-gonadotropin versus a prospectively-obtained reference group of patients with Estrogen-Receptor-Negative (ER-) breast cancer who are treated gonadotropin alone. We will then again repeat the above comparisons among patients with ER+ breast cancer who are treated letrozole-gonadotropin versus patients with ER- breast cancer who are treated gonadotropin alone.
Experimental Design and Methods:
The target population is reproductive-age women who have been recently diagnosed with ER+ breast cancer and choose to undergo oocyte or embryo cryopreservation prior to chemotherapy treatment. All eligible women will be asked to join the study at their initial University of California, San Francisco (UCSF) fertility preservation consult. Study participants will be recruited from the Reproductive Endocrinology Clinic at University of California, San Francisco Center for Reproductive Health. A consecutive sample with ER- disease will also be recruited at the same type of visit. They will be asked to take part in the gonadotropin only stimulation group, which will be used for a secondary aim.