Topical Endoxifen for Mammographic Density Reduction-A Randomized Controlled Trial.

Area of Science:

• Oncology
• Dermatology
• Pharmacology

Background:

• Breast cancer incidence is rising, yet primary prevention options are limited.
• Tamoxifen reduces breast cancer risk but has systemic side effects, hindering its use in primary prevention.
• Mammographic density is a key indicator for breast cancer risk and therapy response.

Purpose of the Study:

• To evaluate the efficacy of topical Z-endoxifen in reducing mammographic density.
• To assess the safety and tolerability of topical Z-endoxifen for breast cancer prevention.
• To investigate the pharmacokinetic profile of topically administered Z-endoxifen.

Main Methods:

• A randomized, placebo-controlled trial involving 90 women.
• Participants received placebo, 10 mg, or 20 mg of topical Z-endoxifen for six months.
• Mammographic density and patient-reported symptoms were assessed at baseline and study completion.

Main Results:

• A significant, dose-dependent reduction in mammographic density was observed.
• Increased plasma concentrations of Z-endoxifen were detected, indicating systemic absorption.
• High discontinuation rates occurred due to skin rashes, although no major systemic side effects were reported.

Conclusions:

• Topical endoxifen demonstrated potential in reducing mammographic density, a breast cancer risk factor.
• Skin irritation was a significant issue, limiting the suitability of topical endoxifen for widespread breast cancer prevention.
• Further research is needed to optimize delivery or explore alternative formulations for topical breast cancer prevention.