Neoplastic lesions outside diseased area in inflammatory bowel disease patients: A national cohort study

Abstract Background Patients with inflammatory bowel diseases (IBD) are at increased risk of dysplasia and colitis-associated cancer (CAC). The presentation of (pre)neoplastic lesions (low-grade dysplasia (LGD), high-grade dysplasia (HGD) or colorectal cancer (CRC) is reported to vary depending if the lesions are located inside disease area (IDA) or outside diseased area (ODA). The primary aim was to analyse the characteristics and prognostic of IDA compared with ODA neoplastic lesions in a large cohort of IBD patients. Methods We performed a multicentre retrospective pathological data collection from 7 tertiary referral regional or academic IBD centres in Belgium. Clinical, endoscopic and pathological data were retrieved through retrospective electronic chart review. From the IBD pathology databases, 1183 colorectal lesions were identified in 541 IBD patients: 415 developed dysplasia (77%) and 126 CRC (23%) during their follow-up. Biopsies and surgical specimen were centrally reviewed by an expert IBD pathologist to confirm the diagnosis of dysplasia and/or CRC. Results Demographic and clinical variables of the study population are summarised in Table 1. More patients with IDA lesions had HGD (9%) or CAC (27%) during their follow-up compared with the group of patients with ODA lesions (3% of HGD and 11% of CRC) (p < 0,0001). Mortality was higher in patients with IDA than in those with ODA lesions (p < 0.05). When comparing IBD patients with IDA lesions and CAC (=111) to those with ODA lesions and sporadic CRC (n = 15), median age at IBD diagnosis was lower (29 (IQR:22–49) vs. 41(IQR:28–54) years; p = 0.0001). Characteristics of the 1183 neoplastic lesions are summarised in Table 2. IDA lesions were more frequently non-visible, non-polypoid and ≥ 1 cm than ODA lesions (p < 0.0001). ODA sporadic CRC was more frequently located in the right colon compared with IDA CAC (5/16 (31%) vs. 21/133 (16%), p < 0.01). Conclusion Neoplastic lesions outside the diseased area were more likely to be visible, polypoid, < 1cm, in the right colon and diagnosed at endoscopy than inside disease area lesions. A lower prevalence of HGD and Cancer were reported with neoplastic lesions outside the diseased area.