4.3 Article

Metformin Decreases Circulating Androgen and Estrogen Levels in Nondiabetic Women With Breast Cancer

Journal

CLINICAL BREAST CANCER
Volume 13, Issue 6, Pages 433-438

Publisher

CIG MEDIA GROUP, LP
DOI: 10.1016/j.clbc.2013.08.012

Keywords

Dehydroepiandrosterone sulfate; Estradiol; IGF1; Randomized trial; Testosterone

Categories

Funding

  1. Assessorato alla Sanita Regione Piemonte
  2. Fondazione CRT
  3. Compagnia di San Paolo di Torino

Ask authors/readers for more resources

These are further data from a randomized controlled trial designed to test the effect of different doses of metformin in patients with breast cancer (BC) and without diabetes, with the aim of modifying the hormonal parameters linked to BC prognosis. A dose of 1500 mg/d of metformin causes significant reductions of the levels of free testosterone and estradiol. Introduction: Diabetic patients treated with metformin have a lower risk of developing BC or a better BC prognosis. Metformin might reduce cancer growth through direct antiproliferative effects or through indirect mechanisms, particularly the reduction of insulin. In a randomized study on nondiabetic BC patients in natural menopause with high testosterone levels, we observed a significant decrease in insulin and in testosterone levels with metformin 1500 mg/d compared with 1000 mg/d. We present the results of a new analysis of our study on the effect of metformin on the bioavailability of sex hormones. Patients and Methods: One hundred twenty-four eligible women were initially invited to take metformin 500 mg/d for 3 months. The 108 women who completed the first 3 months continued the study using 1000 mg/d for 1 month. The women were then randomized into 2 groups, and, for the subsequent 5 months, 1 group increased the dose to 1500 mg/d, and the other group continued with 1000 mg/d. Results: Ninety-six women completed the study, 43 receiving metformin 1500 mg/day, and 53 receiving 1000 mg/day. The women receiving 1500 mg/d showed a greater and significant reduction of free testosterone (-29%) and estradiol (-38%), a borderline significant reduction of estrone and insulin-like growth factor-1, and a nonsignificant reduction of androstenedione. They also showed a nonsignificant increase of dehydroepiandrosterone sulfate. Conclusion: Metformin does not interfere with the production of dehydroepiandrosterone sulfate. Besides, it decreases estradiol levels, basically through the reduction of testosterone. These hormonal changes might have clinical relevance. (C) 2013 Elsevier Inc. All rights reserved.

Authors

I am an author on this paper
Click your name to claim this paper and add it to your profile.

Reviews

Primary Rating

4.3
Not enough ratings

Secondary Ratings

Novelty
-
Significance
-
Scientific rigor
-
Rate this paper

Recommended

No Data Available
No Data Available