Tamoxifen Study

November 1, 2016 updated by: NSABP Foundation Inc

To assess the impact of tamoxifen on development of breast cancer, coronary heart disease, and bone fractures. The National Cancer Institute initiated the prevention trial under its National Surgical Adjuvant Breast and Bowel Project (NSABP). The National Heart, Lung, and Blood Institute provided support to obtain blood pressure and lipid measurements, and lipoprotein and selected coagulation factor measurements in a subsample.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Drug: tamoxifen

Detailed Description

BACKGROUND:

Tamoxifen is nominally called an 'anti-estrogen' although it has some estrogen-agonist activities and tends to increase plasma endogenous estrogen levels. Several studies have confirmed that it decreases plasma total cholesterol and LDL-cholesterol and a review of mortality in patients taking tamoxifen as adjuvant therapy for breast cancer indicates a decreased number of vascular deaths in women on tamoxifen compared to those not on this agent.

DESIGN NARRATIVE:

Subjects were randomized to receive 10 mg of tamoxifen two times a day or to placebo. The primary endpoint was prevention of invasive breast cancer. The secondary endpoint was the effects on fatal and nonfatal cardiovascular events (coronary heart disease, stroke, and thromboembolic disease) and fractures. A total of 13,388 women at increased risk for breast cancer were randomly assigned to receive either tamoxifen (20 milligrams per day) or placebo. Cardiovascular follow-up was available for 13,194 women. The median follow-up was 57 months; the mean follow-up was 49 months. During long-term follow-up, 76 percent of the tamoxifen participants were compliant with the study therapy; 83 percent were compliant through 24 months of follow-up. To evaluate the effects of tamoxifen in women with and without pre-existing heart disease, the 13,388 women enrolled at the 131 clinical sites were divided into subgroups of those with and without a self-reported history of clinical coronary heart disease, defined as myocardial infarction or angina prior to randomization. Medical records for subjects with suspected cardiovascular events were collected by the clinical sites and forwarded to the NSABP Operations Center for adjudication by investigators who were blinded to treatment assignment. Primary cardiovascular events included fatal myocardial infarction, Q-wave myocardial infarction, and non-Q-wave myocardial infarction. Secondary cardiovascular events included unstable angina (angina requiring hospitalization) and severe angina (angina requiring revascularization). All subjects were included in the analysis using the intent-to-treat principle.

Study Type

Interventional

Phase

Phase 3

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

35 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

Genders Eligible for Study

Female

Description

Women over the age of 35 with a 5-year predicted breast cancer risk of at least 1.66 percent or a history of lobular breast carcinoma in situ, life expectancy of 10 years or more, breast examination and mammogram without evidence of cancer, no hormonal therapy within three months prior to randomization, and no history of deep venous thrombosis or pulmonary embolism. .

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: Prevention
Allocation: Randomized

Collaborators and Investigators

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

Sponsor

NSABP Foundation Inc

Collaborators

National Cancer Institute (NCI)

Publications and helpful links

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General Publications

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

May 1, 1992

Study Completion

November 1, 1995

Study Registration Dates

First Submitted

October 27, 1999

First Submitted That Met QC Criteria

October 27, 1999

First Posted (Estimate)

October 28, 1999

Study Record Updates

Last Update Posted (Estimate)

November 2, 2016

Last Update Submitted That Met QC Criteria

November 1, 2016

Last Verified

August 1, 2001

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

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