Leuprolide Acetate Plus Aromatase Inhibition for Male Breast Cancer

Abstract

TO THE EDITOR: Approximately 1% of breast cancer occurs in male patients, yet little information is available on the optimal treatment of this disease. 1 Male patients with breast cancer are more likely than female patients to have tumors positive for estrogen and/or progesterone receptors. 2 However, the hormonal environment in male patients differs from that in female patients; thus hormone therapies that are effective in women may or may not be effective in male patients. In particular, the role of aromatase inhibitors in male patients is unclear. Preclinical data suggest that aromatase inhibitors maybelesseffectiveinmen.Inanimalmodels,chronicadministration of aromatase inhibitors was associated with significant increases in follicular stimulating hormone and testosterone and no change in levels of estradiol. 3 A possible explanation for this finding is that the increaseinfollicularstimulatinghormoneandtestosteronecouldlead to an increase in substrate for aromatization via a feedback loop. Aromataseinhibitorshavealsobeentestedinhealthymalevolunteers and resulted in a 50% decrease in estradiol but an increase in testosterone levels. 4 To our knowledge, seven cases of men with breast cancer treated with aromatase inhibitors have been reported in the literature. One series offive patients reported no responses, 5 and two case reports have documented responses to aromatase inhibitors. 6,7 We now wish to report two cases of male patients treated with a combinationofleuprolideacetateandaromataseinhibitors.Therationale