Health & Environmental Research Online (HERO)


Print Feedback Export to File
2723776 
Journal Article 
Male Breast Cancer and 5 alpha-Reductase Inhibitors Finasteride and Dutasteride 
Bird, ST; Brophy, JM; Hartzema, AG; Delaney, JAC; Etminan, M 
2013 
1 
Journal of Urology
ISSN: 0022-5347
EISSN: 1527-3792 
190 
5 
1811-1814 
English 
23665270 
WOS:000325471400058 
PURPOSE: We examined the association between 5α-reductase inhibitors and male breast cancer.

MATERIALS AND METHODS: Study participants were men 40 to 85 years old, with prescription and medical coverage, enrolled in the United States IMS LifeLink™ Health Plan claims database between 2001 and 2009. Cases required a primary breast cancer diagnosis (ICD-9-CM 175.x) on 2 different dates and a procedural code for mastectomy or lumpectomy/partial mastectomy with evidence of continuous care (radiation/chemotherapy or diagnoses in 2 or more months). Eligible controls were within 5 years in age and had duration of prior health care enrollment within 6 weeks. Risk set sampling selected 20 controls per case. We assessed the rate ratio for male breast cancer with 5α-reductase inhibitor exposure using conditional logistic regression. Analyses were stratified by duration of health care enrollment before diagnosis (1 year or more, 2 years or more and 3 years or more), each incremental 180 and 365 days of cumulative 5α-reductase inhibitor exposure, and period specific time frames before diagnosis (years 1, 2 and 3).

RESULTS: We identified 339 breast cancer cases matched to 6,780 controls. No statistically significant associations were observed between 5α-reductase inhibitors and breast cancer regardless of exposure assessment before the index date (1 year or more-RR 0.70, 95% CI 0.34-1.45; 2 years or more-RR 0.59, 95% CI 0.24-1.48; or 3 years or more-RR 0.75, 95% CI 0.27-2.10). Each subsequent 180 days (RR 1.02, 95% CI 0.67-1.53) and 365 days (RR 1.03, 95% CI 0.45-2.37) of cumulative 5α-reductase inhibitor therapy and period specific rate ratios also showed null associations.

CONCLUSIONS: The lack of an association in our study suggests that the development of breast cancer should not influence the prescribing of 5α-reductase inhibitor therapy. 
breast neoplasms, male; 5-alpha reductase inhibitors