This single site study will be conducted at the Shaw Cancer Center in Edwards, Colorado testing the hypothesis that Losartan will decrease the development of radiation induced fibrosis in breast cancer patients. A block, double-blinded, placebo-controlled, randomized phase II trial will be utilized to test this hypothesis.~Study participants will be blocked by surgical intervention (breast conserving surgery vs. mastectomy) and then randomized, 1:1, into the treatment and control arms for a total of four study arms. The research team and study participants will be blinded to the study arm and a placebo will be used to reduce detection bias in the reporting of outcomes. Selection bias will be minimized through the randomization of study arms.~Study participants will be prescribed 12.5mg capsules of placebo or the study drug, Losartan, to be taken by mouth twice daily. The treatment start date will be the day that subject begins radiation therapy. Radiation therapy will continue to be prescribed in accordance with local clinic procedures. Treatment with the study intervention will continue for one year upon completion of radiation therapy. All participants will be assessed for fibrosis, cosmetic outcomes, and incidence of reoperation for two years following the completion of radiation therapy.
A randomized, double-blind, placebo-controlled trial assessing Losartan in reducing radiation induced fibrosis in breast cancer patients undergoing standard of care radiation therapy after surgery.