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Fertility Preservation for Estrogen-Sensitive Tumors

This study is for women newly diagnosed with breast cancer who want to preserve their fertility before starting chemotherapy. It compares two common approaches for ovarian stimulation (helping your ovaries produce eggs): Tamoxifen (an oral medication) plus gonadotropins, versus Letrozole (an oral medication) plus gonadotropins. The main goal is to see which approach leads to a higher number of mature eggs (oocytes) that can be retrieved for future use. You may be able to join if you are between 18 and 50 years old, have a new breast cancer diagnosis, and have not yet started chemotherapy. The study aims to enroll about 309 participants, but its current status is unclear.

Study design
This is an interventional study comparing two different drug combinations for ovarian stimulation. It plans to enroll about 309 participants.
What's involved
You would undergo ovarian stimulation and oocyte retrieval prior to your cancer treatment. The primary endpoint, mature oocyte yield, is measured up to 2 weeks.
Compensation
Not stated in the trial record.
Follow-up
The primary outcome of mature oocyte yield is measured up to 2 weeks after the intervention.

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NCT03011684

Fertility Preservation Using Tamoxifen and Letrozole in Estrogen Sensitive Tumors Trial

Recruiting
PHASE3Ages 18–50InterventionalTreatment
University of California, San Francisco
~309 participants
Updated 2026-06-04 on ClinicalTrials.gov
What's tested:TamoxifenLetrozole

At a glance

Recruiting sites
1 of 1 listed site is recruiting right now
RecruitingSuspended, closed, or not yet open
What they're measuring
Mature Oocyte Yield
Measured over Up to 2 weeks

Conditions

Infertility

Explore related trials

Breast Carcinoma

Where it's being run

1 sites across 1 states
California1

Study leadership

  • Mitchell Rosen, MD · PRINCIPAL_INVESTIGATOR · University of California, San Francisco

Who to contact

Rebecca Wong
[email protected]
415-353-4305
Email the study team

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Do you actually qualify for this trial?

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Eligibility criteria

Inclusion

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

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

What this trial measures

  • Mature Oocyte YieldUp to 2 weeks

    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. An Effect Size of 3 mature oocytes, based on clinically significant difference of 2 embryos to transfer. An average of 2 embryos are transferred per freeze-thaw cycle. If \~75% of mature oocytes will become embryos that can be frozen, then 3 mature oocytes should yield \~2 embryos for transfer. This effect size would effectively mean an additional event of embryos transferred.