High Risk of Colorectal Cancer After High-Grade Dysplasia in Inflammatory Bowel Disease Patients

There are limited data on colorectal cancer (CRC) risk after high-grade dysplasia in inflammatory bowel disease.

To determine the long-term CRC and neoplasia risk after a first diagnosis of high-grade dysplasia in inflammatory bowel disease, and to assess utilisation of high-grade dysplasia treatment strategies over the past three decades.

In this nationwide retrospective cohort study, patients with colonic inflammatory bowel disease and high-grade dysplasia diagnosis between 1991 and 2021 were extracted from the Dutch nationwide pathology databank (PALGA). The primary outcome was the cumulative incidence of metachronous CRC. Kaplan-Meier curves were used to show proctocolectomy-free survival per decade.

CRC was diagnosed in 348 of 1220 patients (28.5%). Of these, 204 (16.7%) were diagnosed with CRC within 6 months after the first high-grade dysplasia diagnosis and were considered synchronous patients. Metachronous CRC was diagnosed in 144 of 1016 patients (14.2%) after a median of 3.6 years. The 1-, 5- and 10-year cumulative incidences of metachronous CRC after high-grade dysplasia were 2.9%, 9.9% and 15.5%, respectively. The 1-, 5- and 10-year cumulative incidences of metachronous neoplasia were 18.3%, 51.2% and 68.0%, respectively. Proctocolectomy-free survival after high-grade dysplasia decreased over time.

The risk of synchronous and metachronous CRC after a diagnosis of high-grade dysplasia underlines the high-risk profile of this subgroup of patients with inflammatory bowel disease. The possible advantages of colon-sparing treatment should be balanced with the higher risk of metachronous CRC and the subsequent need for stringent endoscopic surveillance.