Testosterone addition during menopausal hormone therapy: effects on mammographic breast density.

Objective: To study the effect on mammographic breast density of testosterone addition during combined estrogen/progestogen therapy in postmenopausal women.

Methods: A prospective, randomized, double-blind, placebo-controlled trial. A total of 99 women were given 2 mg 17beta-estradiol and 1 mg norethisterone acetate in combination with either a testosterone patch (300 mug/24 h) or a placebo patch. Mammographic breast density at baseline and after 6 months was assessed by visual classification scales and by digitized quantification. A standardized questionnaire was used to quantify subjective breast symptoms.

Results: Visual classifications showed an increase in mammographic density in 18-30% of the women, with no significant differences between the treatment groups. The mean increase of the area of dense breast during treatment according to digitized assessment was 7.4% in the placebo group and 5.4% in the testosterone group. Breast symptoms showed a positive association with the increase in density (r(s) = 0.34; p < 0.01). Symptoms were most pronounced at 2 months of treatment. Density, both at baseline (r(s) = -0.35; p < 0.01) and change during treatment (r(s) = -0.28; p < 0.01) showed a negative association with free testosterone levels.

Conclusion: The addition of testosterone does not appear to influence mammographic breast density in women concurrently treated with a common oral estrogen/progestogen regimen for a period of 6 months.