Recruiting
Phase 3

Tamoxifen & Letrozole

Sponsor:

UCLA

Code:

NCT03011684

Conditions

Infertility

Eligibility Criteria

Sex: Female

Age: 18 - 50

Healthy Volunteers: Not accepted

Interventions

Tamoxifen

Letrozole

Study Details

Brief summary:

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.

Conditions

Infertility

Study ID

NCT03011684

Start date

Jul 21, 2016

Status verified date

Jun, 2026

Completion date

Mar 31, 2028

Anticipated

Primary completion date

Mar 31, 2028

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: Female

Age: 18 - 50

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • New breast cancer diagnosis
  • Has not yet begun chemotherapy
  • Desires to undergo ovarian stimulation and oocyte retrieval prior to cancer treatment
  • Age 18 years old or greater

Exclusion Criteria:

  • 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 diagnosis
  • 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

Study Design

Enrollment

309 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Randomized ER Positive Participants (Letrozole)

Participants will receive 5 mg of letrozole with the first day of non-investigational gonadotropin (letrozole-gonadotropin) and stopped on the day of oocyte retrieval.

experimental: Randomized ER Positive Participants (Tamoxifen)

Participants will receive 20 mg of tamoxifen with the first day of non-investigational gonadotropin (tamoxifen-gonadotropin) and stopped on the day of oocyte retrieval

no intervention: ER Negative (ER-) Participants

Participants whose disease is ER negative will be consented and used as a reference cohort and will receive no study related medication. The Gonadotropin received is non-investigational and part of usual care.

Interventions

Tamoxifen

Given orally

Letrozole

Given orally

Primary outcome measure

  • Mature Oocyte Yield [ Time Frame: Up to 2 weeks ]

Central Contacts and Locations

Central contacts

Rebecca Wong

415-353-4305Rebecca.Wong@ucsf.edu

Locations

University of California at San Francisco

Recruiting

San Francisco, California, United States, 94143

Contacts

Rebecca Wong

415-353-4305Rebecca.Wong@ucsf.edu

Principal Investigator:

Mitchell Rosen, M.D.

More Information

Sponsor

University of California, San Francisco

Last update posted

Jun 4, 2026

Last verified

Jun, 2026

Keywords

  • Fertility Preservation
  • Breast Cancer

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University of California, San Francisco on 2026-06-04.