Double-blind controlled trial of progesterone vaginal cream treatment for cyclical mastodynia in women with benign breast disease.

The clinical effectiveness and safety of vaginal micronized progesterone treatment in mastodynia were evaluated in a double-blind placebo controlled study. Eighty regularly menstruating women affected by severe cyclical mastodynia were randomly assigned to two groups of 40 patients. One group was treated for 6 cycles from the 19th to the 25th day of the cycle with 4 g of vaginal cream containing 2.5% natural progesterone. The other group was similarly treated with placebo. The treatment was preceded by a control cycle. All patients reported every day their breast pain on a 100 mm visual linear analogue scale (VAS). The response of breast tenderness and nodularity to treatment was assessed by clinical examination. Vaginal progesterone resulted significantly more efficacious than placebo in reducing mean ratings of breast pain on VAS and mean scores of breast tenderness to touch. Success of treatment, defined as reduction greater than 50% of basal mean score of breast pain on VAS, was achieved in the 64.9% of patients treated with progesterone and in the 22.2% of patients receiving placebo (p < 0.01). Conversely, at the end of treatment, the improvement in breast nodularity showed a not statistically significant difference between the two groups. No major side-effects were detected.