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Selective Estrogen Receptor Modulator

Tamoxifen vs. TamGel for Breast Cancer Risk Reduction

Phase 2
Led By Amy Degnim, M.D.
Research Sponsored by Amy C. Degnim
Eligibility Criteria Checklist
Specific guidelines that determine who can or cannot participate in a clinical trial
Must have
Female (sex that was assigned at birth)
Ipsilateral intact breast with histology confirmation of atypical ductal or lobular hyperplasia, or LCIS, within the last 5 years, whether surgically excised or not
Must not have
Current users of potent inhibitors of tamoxifen metabolism. The potent inhibitors of tamoxifen metabolism are: bupropion, cinacalcet, fluoxetine, paroxetine, quinidine
Identification of a clinically suspicious mass on examination
Screening 3 weeks
Treatment Varies
Follow Up 48 months
Awards & highlights


This trial will study breast tissue changes after taking Tamoxifen, a drug used to treat breast cancer.

Who is the study for?
This trial is for women with a specific breast condition called atypical hyperplasia or LCIS, who can return for follow-up and handle questionnaires. They must have an ECOG status ≤1 (which means they're fully active or restricted in physically strenuous activity but ambulatory), use effective birth control, avoid sun exposure on breasts, and have good organ function. Pregnant women, recent thromboembolism patients, those treated for breast cancer within 2 years, or users of certain drugs are excluded.Check my eligibility
What is being tested?
The study compares the effects of oral Tamoxifen versus a topical gel form (TamGel) against a placebo in altering breast tissue over a short period. Women will be randomly assigned to one of these treatments to see how each affects their condition.See study design
What are the potential side effects?
Possible side effects include hot flashes, vaginal dryness or discharge, mood swings, blood clots (rarely), vision changes like cataracts (long-term use), and an increased risk of uterine cancer (for those still with a uterus).

Eligibility Criteria

Inclusion Criteria

You may be eligible if you check “Yes” for the criteria below
I was assigned female at birth.
My breast has abnormal cells confirmed in the last 5 years, not necessarily removed.
I am fully active or have some restrictions but can still care for myself.

Exclusion Criteria

You may be eligible for the trial if you check “No” for criteria below:
I am not taking medications like bupropion or fluoxetine that affect tamoxifen.
I have a lump that doctors are concerned about.
I have had endometrial cancer before.
I have used medications like tamoxifen or letrozole in the past 5 years.
I have had a suspicious breast mass or was diagnosed with breast cancer in the last 5 years.
I haven't had chemotherapy in the last 2 years.
I have skin issues on my breast like eczema or open sores.


Screening ~ 3 weeks
Treatment ~ Varies
Follow Up ~48 months
This trial's timeline: 3 weeks for screening, Varies for treatment, and 48 months for reporting.

Treatment Details

Study Objectives

Outcome measures can provide a clearer picture of what you can expect from a treatment.
Primary outcome measures
The purpose of this research is to evaluate short-term changes in background breast tissue induced by oral tamoxifen or 4-OHT gel in women with atypical hyperplasia or lobular carcinoma in situ (LCIS).

Trial Design

3Treatment groups
Experimental Treatment
Group I: Topical 4-OHT (4-hydroxytamoxifen) gel 4 mg/each breast/dayExperimental Treatment2 Interventions
Topical 4-OHT (4-hydroxytamoxifen) gel 4 mg/each breast/day +oral placebo
Group II: Oral Tamoxifen 10 mg/dayExperimental Treatment2 Interventions
Oral Tamoxifen 10 mg/day
Group III: ControlExperimental Treatment2 Interventions
Oral and gel placebo
First Studied
Drug Approval Stage
How many patients have taken this drug
Completed Phase 3
FDA approved

Research Highlights

Information in this section is not a recommendation. We encourage patients to speak with their healthcare team when evaluating any treatment decision.
Mechanism Of Action
Side Effect Profile
Prior Approvals
Other Research
The most common treatments for Breast Lobular Carcinoma in Situ (LCIS) include Selective Estrogen Receptor Modulators (SERMs) like Tamoxifen, which block estrogen's effects on breast tissue. These treatments are crucial for LCIS patients because they target the hormonal pathways that often drive the growth of breast cancer cells. By blocking estrogen receptors, SERMs prevent estrogen from binding to these receptors, thereby inhibiting the proliferation of potentially cancerous cells. This is particularly important for LCIS patients, as the condition is often hormone receptor-positive, meaning that the cancer cells grow in response to estrogen. Understanding these mechanisms helps in tailoring effective treatment plans that can reduce the risk of progression to invasive breast cancer.
Duct carcinoma in situ: A personal perspective.Preoperative chemotherapy and endocrine therapy in patients with breast cancer.

Find a Location

Who is running the clinical trial?

Amy C. DegnimLead Sponsor
National Cancer Institute (NCI)NIH
13,748 Previous Clinical Trials
40,959,297 Total Patients Enrolled
944 Trials studying Breast Cancer
1,544,008 Patients Enrolled for Breast Cancer
Amy Degnim, M.D.Principal InvestigatorMayo Clinic
1 Previous Clinical Trials
22 Total Patients Enrolled

Media Library

Tamoxifen (Selective Estrogen Receptor Modulator) Clinical Trial Eligibility Overview. Trial Name: NCT04570956 — Phase 2
Breast Cancer Research Study Groups: Oral Tamoxifen 10 mg/day, Topical 4-OHT (4-hydroxytamoxifen) gel 4 mg/each breast/day, Control
Breast Cancer Clinical Trial 2023: Tamoxifen Highlights & Side Effects. Trial Name: NCT04570956 — Phase 2
Tamoxifen (Selective Estrogen Receptor Modulator) 2023 Treatment Timeline for Medical Study. Trial Name: NCT04570956 — Phase 2
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