Clinical Implication of Enlarged Prostate in Patients with the Ileal Pouch-anal Anastomosis for Inflammatory Bowel Disease

Background: Enlarged prostate is often noticed in patients with ileal pouch-anal anastomosis (IPAA) in our clinical practice. The aims were to identify the factors associated with enlarged prostate and to investigate its clinical implications. Methods: IPAA patients with available prostate imaging after IPAA were included. Prostate length and width were measured in the axial plane and height in coronal plane. Prostate volume was calculated with the formula (length × width × height) × π/6. A volume greater than 40 cm3 was used to define enlarged prostate. Results: Prostate enlargement was found in 58 (24.8%) out of 234 patients. Factors associated with prostate enlargement included advanced age at imaging examination (55.6 ± 11.5 vs. 41.3 ± 13.6 years, P < 0.0001), age at pouch surgery (46.0 ± 11.8 vs. 32.5 ± 12.9 years, P<0.0001), and the presence of an S-pouch (6.9% vs. 1.1%, P = 0.03). Postoperative use of biologics was less common in patients with enlarged prostate (5.2% vs. 17%, P = 0.03). However, pouch duration was comparable (10.0 ± 5.9 vs. 8.8 ± 6.8 years, P = 0.2) and pouch failure rate was similar. A trend towards an increased risk for acute pouchitis in patients with enlarged prostate was noticed (19% vs. 9.1%, P = 0.06). The association of S-pouch (odds ratio: 7.2, 95% confidence interval: 1.1 - 46.4) and enlarged prostate remained significant after adjusting for age, acute pouchitis, and redo pouch on multivariate analysis. Conclusions: Prostate enlargement appears to be uncommon after IPAA and it was associated with S-pouch configuration and advanced age. Enlarged prostate in the setting of IPAA does not seem to have adverse impact on pouch outcomes, although there is a trend in correlation between enlarged prostate and acute pouchitis.