Amiodarone and the risk of cancer: A nationwide population-based study

BACKGROUND: In postmarketing surveillance, the US Food and Drug Administration has reported the development of lung masses, thyroid cancer, and skin cancer after amiodarone therapy. METHODS: Using the Taiwan National Health Insurance Research database, the authors conducted a population-based cohort study. Patients who were treated with amiodarone between 1997 and 2008 were enrolled. Those with antecedent cancer were excluded. Standardized incidence ratios (SIRs) of cancers were calculated to compare the cancer incidence of the study cohort with that of the general population. A multivariate Cox regression model was used to evaluate the association between cumulative defined daily doses (cDDDs) of amiodarone and cancer occurrence. RESULTS: The study included 6418 subjects, with a median follow-up of 2.57 years. A total of 280 patients developed cancer. The risk of cancer increased with borderline significance (SIR, 1.12; 95% confidence interval [95% CI], 0.99-1.26 [P =.067]). Male patients had a higher risk (SIR, 1.18; 95% CI, 1.02-1.36 [P =.022]). The total cohort of patients and the male patients with > 180 cDDDs within the first year were found to have SIRs of 1.28 (95% CI, 1.00-1.61; P =.046) and 1.46 (95% CI, 1.11-1.89; P =.008), respectively. After adjustment for age, sex, and comorbidities, the hazards ratio was 1.98 (95% CI, 1.22-3.22; P =.006) for the high tertile of cDDDs compared with the low tertile. CONCLUSIONS: The results of the current study indicate that amiodarone may be associated with an increased risk of incident cancer, especially in males, with a dose-dependent effect.