Incidence and Outcomes of Prostate Cancer in Patients With Inflammatory Bowel Disease: A Canadian Population-Based Study

Introduction: Prostate cancer is the most common cancer among men, and recent studies have shown an increased risk of prostate cancer in those with inflammatory bowel disease (IBD). Yet, other than expert recommendations for PSA screening in patients above 40 with ileal-pouch anastomoses, the screening and treatment guidelines for prostate cancer in men with IBD do not differ from the general population. The goals of our study were to assess if patients with IBD are: 1) at increased odds of prostate cancer; 2) at increased odds of advanced cancer and death, and, 3) receiving different first-line treatments for prostate cancer. Methods: We conducted a population-based matched cohort study using a Canadian population-based administrative database from April 2002 to March 2018 to identify patients with IBD (n = 17,022), and age- and sex-matched 10-to-1 to healthy controls (n = 136,819). Specific data was then obtained from a cancer-specific database. Average annual percentage change (AAPC) in age standardized incidence of prostate cancer was calculated using Poisson regression. Comparisons were done using either Wilcoxon Rank-sum or Fisher’s exact tests. Odds ratios (ORs) and their 95% confidence intervals (95%CI) were calculated using conditional logistic regression for the overall odds of prostate cancer diagnosis and logistic regression for ORs specific to only those with prostate cancer. Results: Of the patients included, 1.58% of patients with IBD were diagnosed with prostate cancer, in comparison to 2.65% in the control group [OR 0.65, (95%CI 0.57, 0.73)]. From 2002 to 2018 the incidence of prostate cancer decreased in those with IBD (AAPC=-3.65%; 95%CI -6.56, -0.64) and in the control group (AAPC=-1.74%; 95%CI: -2.56, -0.92). The median age of diagnosis of prostate cancer was similar between the two groups (P = 0.83). Among patients with prostate cancer, those with IBD had an increased odds of having stage IV prostate cancer (OR 2.94 [95%CI: 1.95, 4.42]), as well as having surgery as their first line of treatment (OR 1.3 [95%CI: 1.03, 1.69]). The odds of death from prostate cancer were increased among patients with IBD (OR 2.46 [95%CI: 1.47, 4.09]). Conclusion: While prostate cancer was less common in those with IBD compared to controls, a diagnosis of prostate cancer is associated with more advanced stage and mortality in these patients. Further studies assessing the risk of prostate cancer in patients with IBD are critical in adapting our cancer screening and treatment options to this population (Table 1). Table 1. - Incidence, age and stage of diagnosis, treatment and death of prostate cancer in patients with IBD. Average annual percent change shows the change in incidence of prostate cancer from April 1, 2002 to March 31, 2018. Odds ratios (OR) with 95% confidence intervals (CI) compare outcomes (diagnosis of prostate cancer, stage at diagnosis, treatment, and mortality) in those with IBD as compared to controls IBD (n = 269) Control group (n = 3628) Odds Ratio (95%CI) Average annual percentage change (%) -3.65 (95% CI: -6.56, -0.64) -1.74 (95%CI: -2.56, -0.92) Being diagnosed with Prostate Cancer: 0.65 (0.57, 0.73) Median age in years (Q1, Q3) 66 (60, 73) 67 (60,73) Stage at diagnosis (n, %) I & II 165 (61.3%) 2282 (62.9%) 0.94 (0.94, 1.46) III 23 (9.4%) 328 (10.6%) 0.94 (0.60, 1.46) IV 31 (12.7%) 154 (5.0%) 2.93 (1.95, 4.42) Unknown/Missing data 26 (9.7%) 864 (23.8%) First-line treatment Surgery 130 (48.3%) 1503 (41.4%) 1.32 (1.03, 1.69) Hormone-based therapy 59 (21.9%) 761 (21.0%) 1.06 (0.78, 1.43) Radiotherapy 15 (5.9%) 409 (11.3%) 0.46 (0.27, 0.79) Surveillance/No treatment 64 (23.8%) 939 (25.6%) 0.89 (0.67, 1.20) Death Prostate cancer death 36 (13.3%) 73 (2.0%) 2.46 (1.47, 4.09)