Fertility Preservation Using Tamoxifen and Letrozole in Estrogen Sensitive Tumors Trial

Conditions:Women's Studies, Infertility
Therapuetic Areas:Reproductive
Age Range:18 - 50
Start Date:January 2017
End Date:December 2019
Contact:Mitchell Rosen, MD
Phone:415 353 7475

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Iatrogenic 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

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.

- Primary comparison:

1) To determine if the assigned stimulation regimen will result in a difference in
mature (meiosis II) oocyte yield in patients with breast cancer who undergo ovarian
stimulation for fertility preservation.

- Secondary comparison:

1. To compare estrogen, progesterone, and androgen levels during the ovarian
stimulation cycle.

2. To compare estrogen, letrozole, and tamoxifen levels in follicular fluid.

3. To compare duration of stimulation (days) and total gonadotropin dose
(international units of FSH).

4. To assess embryo quality, if applicable, on day 3 and day 5 of embryo culture, a
measure of the developmental competence of the oocytes.

- Experimental comparison:

1. To compare clinical pregnancy rates when cryopreserved tissue is eventually
utilized among patients from the assigned stimulation regimens. This comparison is
labeled experimental because of the remoteness of such an outcome from our present

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:

Study population:

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 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.

Inclusion/Exclusion Criteria:

- Inclusions:

- New breast cancer diagnosis

- Has not yet begun chemotherapy

- Desires to undergo ovarian stimulation and oocyte retrieval prior to cancer

- Age 18 years old or greater

- Exclusions:

- Chemotherapy has already commenced or been completed

- History of recurrent breast cancer (with a prior history of chemotherapy)

- Stage IV breast cancer diagnosis (metastases remote from the breast)

- Patient's oncologist advises against the trial - in which case they can choose to
receive stimulation with letrozole+gonadotropin

- Does not plan to undergo ovarian stimulation and oocyte retrieval prior to

- Any significant concurrent disease, illness, or psychiatric disorder that would
compromise patient safety or compliance, interfere with consent, study
participation, follow-up, or interpretation of study results

- Age less than 18 years old
We found this trial at
San Francisco, California 94143
Principal Investigator: Mitchell Rosen, M.D.
San Francisco, CA
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