Is digoxin use for cardiovascular disease associated with risk of prostate cancer?

PURPOSE: Digoxin is a commonly used medication for heart failure and cardiac arrhythmias that has recently been suggested as a novel chemotherapeutic agent. Preclinical studies of prostate cancer (PCa) have shown anti-tumor activity with digoxin. We explore the relationship between use of digoxin and PCa risk. METHODS: Data from a population-based case-control study of incident cases aged 35-74 years at PCa diagnosis in 2002-2005 in King County, Washington were available. Controls were identified by random digit dialing and frequency matched by age. Use of digoxin was determined from in-person questionnaires regarding medical and prescription history. The relationship of digoxin use with PCa risk was evaluated with logistic regression. RESULTS: One thousand one cases of PCa and 942 controls were analyzed. The prevalence of digoxin use in controls was 2.7%, and use was positively correlated with age. In multivariate analysis adjusting for age, race, PSA screening, and family history of PCa, digoxin use was associated with a reduction in the odds ratio of PCa (OR 0.58, 95% CI: 0.30-1.10). Among those with ≥3 PSA tests over the preceding 5 years (546 cases, 380 controls), digoxin use was associated with a stronger reduction of PCa risk (OR 0.44, 95% CI: 0.20-0.98). CONCLUSION: These data indicate digoxin use may be associated with a reduction in risk of PCa. Given the potential mechanisms by which digoxin may exert an anti-neoplastic effect and other recent studies showing a negative association between digoxin use and PCa, further research is warranted.