SHORTened Duration of TAMoxifen

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: High Risk for Invasive Breast Cancer
• Intervention / Treatment: Drug: Tamoxifen; Drug: Tamoxifen (Nolvadex)

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

Study Locations

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

Participation Criteria

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

How is the study designed?

Design Details

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

Number of Arms

1

Arms and Interventions

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

What is the study measuring?

Primary Outcome Measures

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

Collaborators and Investigators

• Sponsor: Rutgers, The State University of New Jersey
• Investigators: Principal Investigator: Mridula George, MD, Rutgers Cancer Institute

Study record dates

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

• Additional Relevant MeSH Terms: Organic Chemicals; Hydrocarbons; Hydrocarbons, Cyclic; Hydrocarbons, Aromatic; Benzene Derivatives; Stilbenes; Benzylidene Compounds; Tamoxifen
• 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