Effect of different doses of metformin on serum testosterone and insulin in non-diabetic women with breast cancer: a randomized study
Abstract
UNLABELLED: This is a randomized controlled trial to test the effect of different doses of metformin in patients with breast cancer and without diabetes, with the aim of modifying the hormonal and metabolic parameters linked to breast cancer prognosis. Analysis of the results suggest that the dose of 1500 mg/d of metformin causes a significant reduction of insulin and testosterone serum levels.
BACKGROUND: Serum levels of insulin and testosterone may affect both breast cancer (BC) incidence and prognosis. Metformin reduces hyperglycemia and insulin levels in patients with diabetes. In women without diabetes and with polycystic ovary syndrome, metformin lowers both insulin and testosterone levels. Patients with diabetes who are treated with metformin showed a lower risk of cancer; a protective effect of metformin also was observed for BC. Recently, studies on metformin use for prevention or treatment of BC have been proposed in patients who are not diabetic. The aim of the present study was to test the effect of different doses of metformin on serum levels of insulin and testosterone in those postmenopausal patients with breast cancer and without diabetes who have basal testosterone levels ≥0.28 ng/mL (median value).
PATIENTS AND METHODS: A total of 125 eligible women were initially invited to take metformin 500 mg/d for 3 months. The 108 women who completed the first 3 months were invited to continue the study with metformin 1000 mg/d (500 mg twice a day [b.i.d.]) for 1…
How strong is the evidence?
Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 125 participants or records.
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