DISORDERED NOCTURNAL PROLACTIN REGULATION IN WOMEN WITH BREAST-CANCER

Abstract

Mean 24 h prolactin concentrations were determined in 25 female control subjects, 16 women with benign breast masses and 23 subjects with breast cancer. This evaluation performed before breast surgery revealed significantly decreased (P < 0.02) nocturnal (12 a.m. to 7 a.m.) prolactin concentrations in 12 postmenopausal breast cancer subjects that contrasted with significantly increased (P < 0.05) nocturnal prolactin levels in 5 luteal-phase premenopausal women with breast cancers. Prolactin concentrations in patients with benign breast disease were not significantly different from control subjects. Two of the premenopausal breast cancer patients had marked preoperative elevations in their mean 24 h prolactin levels, and they were 2 of the 3 subjects who have since died. Nocturnal prolactin secretion was significantly decreased (P < 0.03) in 4 premenopausal breast cancer patients when they were studied 1 yr after surgery. It remained the same in the 8 postmenopausal breast cancer patients similarly evaluated. Although disordered prolactin regulation was found in these women with breast cancer, its role in the etiology and progression of human cancer is still uncertain.