Phase II Study of Low-Dose Tamoxifen to Reduce Breast Density and Lower Breast Cancer Risk in Premenopausal Women

What this Trial Is About

Researchers are evaluating low-dose tamoxifen to reduce breast density in premenopausal women who have a higher than average risk of developing breast cancer. This phase II trial aims to find the best tamoxifen dose by using a response-guided approach, adjusting the dose based on changes in breast density. Breast density is an important risk factor, and tamoxifen is a drug that blocks estrogen effects in the breast and is approved for breast cancer prevention. Participants receive tamoxifen starting at 5 mg once daily for six months. If their breast density reduces by 10% or more, they continue the same dose for another 12 months. Those with less than 10% reduction increase to 10 mg daily for six months, then continue or escalate to 20 mg daily based on further response. Mammograms and blood samples are collected at screening and during the study, with optional biopsies to study biomarkers. During the trial, participants undergo mammography, blood tests, and questionnaires to monitor drug levels, biological responses, symptoms, and adherence to tamoxifen. The main outcome is breast density reduction measured up to 18 months. After finishing the treatment, participants have a follow-up visit four weeks later to assess safety and outcomes. The study also explores genetic factors and the impact of tamoxifen on breast cancer risk estimates.

Finding the Best Tamoxifen Dose for Breast Cancer Risk Reduction in Premenopausal Women, RENAISSANCE Trial