Hereditary colorectal cancer syndromes and inflammatory bowel disease: results from a registry-based study.

Purpose: In this study, we investigated the progression of high-grade dysplasia (HGD)/CRC in patients with hereditary colorectal cancer syndromes (HCSS) and concomitant inflammatory bowel diseases (IBDs).

Methods: We described the natural history of a series of patients with confirmed diagnosis of hereditary colorectal cancer syndromes (HCCSs) and concomitant IBDs who were referred to the Hereditary Digestive Tumors Registry at the Fondazione IRCCS Istituto Nazionale dei Tumori of Milan.

Results: Between January 1989 and April 2024, among 450 patients with APC-associated polyposis and 1050 patients with Lynch syndrome (LS), we identified six patients with IBDs (five with UC, one with ileal penetrating CD) and concomitant HCCSs (five with LS, one with APC-associated polyposis). Three patients developed CRC (two patients with stage IIA, and one with stage IIIA); in one patient, CRC occurred over a median follow-up of 12 months after IBD diagnosis, while in two, both conditions were diagnosed simultaneously. The median age at initial diagnosis of CRC was 33 years (range 27-41). Five patients (83.3%) underwent surgical procedures (three colonic resections for carcinoma and two for other reasons). Most of them progressed to precancerous or cancerous colonic lesions at a young age. Notably, all patients with CRC had a diagnosis of UC.

Conclusion: IBD patients with coexistent HCCSs can develop early CRC onset at an advanced stage. These patients should be always referred to tertiary referral centers for strict surveillance programs and early surgical management of advanced colorectal neoplastic lesions. Noninvasive biomarkers of neoplastic changes are advocated to further improve the management of IBD patients with HCCSs.