SHORTened Duration of TAMoxifen

September 1, 2026 updated by: Mridula George, MD, Rutgers, The State University of New Jersey

SHORTened Duration of TAMoxifen for Risk Reduction in Breast Intraepithelial Neoplasms in Post-menopausal Women

The purpose of this study is to learn whether a shorter-duration, low-dose tamoxifen regimen can reduce the risk of developing breast cancer or breast cancer recurrence in post-menopausal women who are at increased risk for breast cancer.

Study Overview

Status

Active, not recruiting

Conditions

Intervention / Treatment

Detailed Description

The patients to be entered in this protocol will be post-menopausal women diagnosed with ductal carcinoma in situ (DCIS), lobular carcinoma in situ (LCIS), atypical ductal hyperplasia, and atypical lobular hyperplasia (ALH) OR post-menopausal women with an elevated 5-year Gail model risk (> 1.66%) but with no prior history of breast intraepithelial or invasive cancers

Potential subjects will be recruited by the treating investigator and approached to participate in the study during consultation for the treatment and management of their disease as an alternative treatment option.

Subjects from all racial/ethnic groups are eligible for this study if they meet the eligibility criteria

Study Type

Interventional

Enrollment (Estimated)

250

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

    • New Jersey
      • New Brunswick, New Jersey, United States, 08901
        • Rutgers Cancer Institute

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

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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Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Low dose Tamoxifen
Low-dose tamoxifen will be administered at 10 mg orally every other day for 18 months.
Low dose Tamoxifen for 18 months.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Low Dose Tamoxifen
Time Frame: 18 Months
To evaluate the efficacy of a de-escalated, 18-month regimen of low-dose tamoxifen (10 mg every other day) in reducing the risk of disease recurrence or invasive breast cancer in post-menopausal women with breast intraepithelial neoplasia or an elevated 5-year Gail model risk.
18 Months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Evaluation of Tamoxifen Tolerability
Time Frame: 18 months
Incidence of endometrial cancer or thromembolic events.
18 months
To evaluate the Incidence of other invasive events
Time Frame: 18 months
Incidence of LCIS or atypical hyperplasia in ipsilateral or contralateral breast.
18 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Investigators

  • Principal Investigator: Mridula George, MD, Rutgers Cancer Institute

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

September 1, 2026

Primary Completion (Estimated)

July 1, 2028

Study Completion (Estimated)

July 1, 2029

Study Registration Dates

First Submitted

September 1, 2026

First Submitted That Met QC Criteria

September 1, 2026

First Posted (Actual)

September 8, 2026

Study Record Updates

Last Update Posted (Actual)

September 8, 2026

Last Update Submitted That Met QC Criteria

September 1, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Other Study ID Numbers

  • 042606

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.