Clinical trial of danazol for benign breast disease.

A clinical trial of danazol was undertaken in 30 patients with severe fibrocystic disease of the breasts. Twenty-three of the patients continued the drug for five or six months to allow adequate evaluation. Partial or complete relief of breast pain, tenderness, and nodularity occurred in all patients studied. One previously unsuspected carcinoma of the breast was discovered after three months of therapy. Side effects from the drug were generally mild. Recurrence of symptoms and physical findings occurred in most patients after the drug was discontinued but have not been as severe as prior to therapy.