Can a shorter tamoxifen course still shield High-Risk women from breast cancer?
NCT ID NCT07806630
First seen Sep 08, 2026 · Last updated Sep 09, 2026 · Updated 1 time
Summary
This study tests whether taking low-dose tamoxifen for 18 months can reduce the risk of invasive breast cancer in post-menopausal women who are at high risk. Participants include those with certain non-invasive breast lesions or an elevated Gail model risk score. The goal is to see if a shorter, lower-dose regimen offers protection with fewer side effects than the standard longer treatment.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- Tamoxifen (low-dose, 10 mg every other day for 18 months)
- What this could lead to
- If successful, this could offer a shorter, lower-dose option to reduce breast cancer risk in high-risk post-menopausal women, potentially with fewer side effects than the standard longer course.
- What could go wrong
- This is a phase 2 trial, so results are preliminary. The shorter regimen may not reduce risk as effectively as standard tamoxifen, and side effects like endometrial cancer or blood clots remain possible.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 2
Tests whether the treatment actually works, and watches for side effects, in a larger group.
- Participants
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About 250 people
The number the study aims to enrol. It can still change while the study runs.
- Started
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Sep 2026
- Expected to finish
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Jul 2029
An estimate. End dates often move.
- Lead sponsor
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Other sponsor
The registry's catch-all category, for sponsors it does not file as a company, a government agency, or a research network.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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30 years and older
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: * 1\. Patient at high risk for invasive breast cancer (either A or B) A. Post-menopausal women diagnosed with ductal carcinoma in situ (DCIS), Lobular carcinoma in situ (LCIS), atypical ductal hyperplasia (ADH), and atypical lobular hyperplasia (ALH) who meet the following criteria: * DCIS/LCIS * Lesion size ≤3cm * Low or intermediate grade * Lesion completely excised by surgical excision * Margins \>2cm for DCIS * Estrogen receptor (ER) positive and/or Progesterone receptor positive (defined as ≥10%) * ADH/ALH o Lesion completely excised by surgical excision B. Patients at increased risk of breast cancer based on Gail model criteria (5- year risk ≥1.66%) without prior history of DCIS, LCIS, atypical hyperplasia, or invasive breast cancer. 2\. No history of pathogenic germline mutations that increase the lifetime risk of breast cancer. If genetic testing was not done, then patients must have no more than two first-degree relatives diagnosed with breast cancer. 3\. Should have received adjuvant radiation for DCIS, if recommended by the radiation oncologist. 4\. No prior history of invasive carcinoma, DCIS, LCIS, ADH, and/or ALH in bilateral breasts. 5\. ECOG performance status ≤ 2 6. No use of hormone replacement therapy for at least 5 years. Exclusion Criteria: 1. Evidence of invasive or microinvasive breast cancer. 2. Current use of dicumarols and CYP2D6 inhibitors, such as selective serotonin reuptake inhibitors. 3. Patients who have had a bilateral mastectomy for risk reduction. 4. Prior history of any malignancy in the last 5 years (except squamous cell carcinoma/basal cell carcinoma of skin) 5. Patients who are known to be pregnant 6. Patients who cannot voluntarily provide informed consent. Evidence of dementia, altered mental status, or any psychiatric condition that would prohibit understanding or rendering of informed consent. 7. Life expectancy of less than 1 year per treating physician. 8. Prior treatment with tamoxifen or an aromatase inhibitor. \-
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As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Rutgers Cancer Institute
New Brunswick, New Jersey, 08901, United States