Use of terbinafine and risk of death in patients with prostate cancer: A population‐based cohort study

Terbinafine is used for the treatment of several superficial fungal infections. In silico analyses and animal models suggest that terbinafine might have an anti‐tumor effect. We aimed to explore whether subsequent administration of terbinafine might be associated with a lower mortality rate in patients with prostate cancer. We identified patients diagnosed with prostate cancer between July 2005 and December 2014 from the Swedish Cancer Registry, and linked them to the Swedish Prescribed Drug Register to ascertain subsequent use of terbinafine. A total of 799 patients received oral treatment of terbinafine during the study period with a mortality rate of 18.6 per 1,000 person‐years. Compared to patients who did not use terbinafine and adjusting for a range of confounding factors, patients that received oral treatment of terbinafine had a decreased risk of death from prostate cancer (HR, 0.53; 95% CI, 0.38–0.73) and a decreased risk of death overall (HR, 0.64; 95% CI, 0.52–0.77). To account for indication bias, we further identified 907 patients who received topical use of terbinafine. However, the risk of death from prostate cancer in patients with topical use of terbinafine was 0.92 (95% CI 0.74–1.12) and the risk of death overall was 1.03 (95% CI 0.91–1.17) as compared to the controls, which suggests that there was no association between risk of death in patients with prostate cancer with topical use of terbinafine. These findings suggest that this drug's potential anti‐tumor effect needs to be explored further.