Loprinzi, C.L., Michalak, J.C., Quella, S.K., O’Fallon, J.R., Hatfield, A.K., Nelimark, R.A., … Oesterling, J.E. (1994). Megestrol acetate for the prevention of hot flashes. New England Journal of Medicine, 331, 347–352.

The study was done to assess the efficacy and short-term toxicity of low-dose megestrol acetate as a treatment for hot flashes in women with breast cancer and in men who had undergone androgen-deprivation therapy for prostate cancer.

Subjects were randomly assigned to receive megestrol 20 mg twice a day for 4 weeks followed by placebo for 4 weeks.or placebo for 4 weeks then megestrol for 4 weeks. Subjects received no medication for the first 7 days.

Of the enrolled subjects, 163 cpmpleted the study. They included women with a history of breast cancer and men who had undergone surgical or medical orchiectomy. All had at least one hot flash per month. Women were stratified according to duration of hot flashes (9 months cut point). Men were stratified by medical or surgical orchiectomy and duration of androgen ablation.

The study was a double-blind, randomized, crossover trial.

Participants kept hot flash diaries,  recording the number and severity of hot flashes each day. They also recorded  appetite changes, fluid retention, and vaginal problems.

During the first 4 week medication period, megestrol was associated with decreased frequency of hot flashes for both men and women. Crossover analysis was not performed because of carryover effects of medication.

There was an insufficient washout period to allow for crossover analysis.