Benign breast disease: studies of prostaglandin E2, steroids, and thermographic effects of inhibitors of prostaglandin biosynthesis.

Plasma levels of estradiol (E2), prostaglandin (PG)E2, and progesterone (P) were measured in both phases of the menstrual cycle in 22 women with benign mastopathies and in 5 normal women. In both phases of the cycle, PGE2 blood levels were significantly higher in patients with benign mastopathies than in normal women. In contrast, the plasma levels of both steroids were lower in patients than in controls. An estrogen-directed synthesis of PGE2 is proposed. In 10 patients, breast thermogenic response to inhibitors of PG biosynthesis (aspirin and indomethacin) revealed a cooling effect in 4 cases, a partly positive response in 3 cases, and no response in 3 cases. The 7 cases with positive responses also had a deficiency of variable magnitude of both steroids without an unbalanced P/E2 ratio. In contrast, patients with a negative thermographic response manifested very low levels of progesterone and a low P/E2 ratio. The significance of patients' unresponsiveness to inhibitors of PGE2 biosynthesis is discussed, as well as the implications with regard to breast cancer.