Drug use disorder and risk of incident and fatal prostate cancer among Swedish men: a nationwide epidemiological study

Purpose Prostate cancer is the second most common cancer in men and a leading cause of cancer mortality worldwide. Men with drug use disorders (DUD) may potentially be at high risk for prostate cancer mortality because of delayed diagnosis and/or undertreatment. In this study, we aimed to investigate prostate cancer incidence, mortality, and stage at time of diagnosis among men with DUD compared to the general male population in Sweden. Methods We performed a follow-up study based on Swedish national register data for the period January 1997-December 2016. The study was based on 1,361,532 men aged 50-75 years at inclusion, of whom 9,259 were registered with DUD. Cox regression analysis was used to compute adjusted hazard ratios (HRs) for incident and fatal prostate cancer, and cancer stage at time of diagnosis, associated with DUD. Results DUD was associated with a slightly increased risk of incident prostate cancer (HR: 1.07, 95% confidence interval [CI] 1.00-1.14, p = 0.048) and substantially higher risk of fatal prostate cancer (HR: 1.59, 95% CI 1.40-1.82, p < 0.001), adjusted for age, socioeconomic factors, and comorbidities related to tobacco smoking and alcohol use disorder. No association was found between DUD and prostate cancer stage at diagnosis. Conclusions Men with DUD have an increased risk of fatal prostate cancer, possibly related to undertreatment in this patient population. Our findings should raise attention among medical staff and decision-makers towards a disadvantaged group of men in need of easily accessible prostate cancer evaluation and treatment.