Entacapone and prostate cancer in Parkinson's disease patients: A large Veterans Affairs healthcare system study.

BACKGROUND

An increased incidence of prostate cancer was observed in Parkinson's disease (PD) patients treated with entacapone during a pre-approval randomized clinical trial; the relation has not been robustly investigated in the U.S. ambulatory setting.

OBJECTIVE

To investigate whether entacapone is associated with prostate cancer and to assess whether the associations are correlated with advanced disease at the time of cancer diagnosis.

METHODS

Using data from the Department of Veterans Affairs healthcare system, new-user cohorts were created of PD patients treated with add-on entacapone or add-on dopamine agonist/monoamine oxidase B inhibitors between January 2000 and December 2014. Patients were followed on-treatment for occurrence of prostate cancer, identified via linkage to the VA cancer registry.

RESULTS

Mean follow-up time was 3.1 and 4.0 years in the entacapone and control cohort, respectively. There were 17,666 subjects meeting study criteria (mean age, 74 (SD 8.6) years); the entacapone-treated group comprised 5,257 subjects. Twenty-three prostate cancer cases occurred in the entacapone cohort and ninety-seven in the control cohort. The overall incidence of prostate cancer was 1.8 per 1,000 person-years of risk. There was no difference in risk of prostate cancer between the cohorts for increased duration of entacapone intake (adjusted HR: 1.08; 95% confidence interval: 0.46-2.51 for cumulative exposure of ≥2 years). Time since starting drug therapy and cumulative dose (mg) also do not suggest a difference in prostate cancer risk between cohorts.

CONCLUSIONS

Prolonged therapy with entacapone was not associated with increased prostate cancer incidence; however, findings suggest a higher severity of prostate cancer.