Objective: To evaluate the effectiveness of vitamin E, evening primrose oil (EPO), and the combination of vitamin E and EPO for pain control in women with cyclical mastalgia.
Procedure: A double-blind, randomized, placebo-controlled trial was conducted at two U.S. academic medical centers. Eighty-five women with premenstrual cyclical breast discomfort were enrolled. Participants were randomly assigned to one of four six-month oral treatments: vitamin E (1,200 IU per day), EPO (3,000 mg per day), vitamin E (1,200 IU per day) plus EPO (3,000 mg per day), or double placebo. The primary outcome measure was change in breast pain, measured by the modified McGill Pain Questionnaire at enrollment and at six months.
Results: Forty-one patients completed the study. Intent-to-treat analysis (pretesting and post testing) showed a difference in worst-pain improvement with the treatments EPO (p=0.005), vitamin E (p=0.04), and EPO plus vitamin E (p=0.05), but no difference with placebo (p=0.93). Results from two-sample t-test showed a nonsignificant decrease in cyclical mastalgia individually for the three treatment groups compared with the placebo group (EPO, p=0.18; vitamin E, p=0.10; and EPO plus vitamin E, p=0.16). The data were also analyzed with the separation test by Aickin, which showed a trend toward a reduction of cyclical mastalgia with vitamin E and EPO individually and in combination.
Conclusion: Daily doses of 1,200 IU vitamin E, 3,000 mg EPO, or vitamin E and EPO in combination at these same dosages taken for six months may decrease the severity of cyclical mastalgia.