EFFECT OF SCREENING STRATEGIES ON THE NATURAL HISTORY OF IBD-RELATED AND SPORADIC COLORECTAL CANCER

Background: Inflammatory bowel disease encompasses two types of idiopathic intestinal disease, ulcerative colitis (UC) and Crohn's disease (CD) that are differentiated by their location and depth of involvement in the bowel wall. Both of them are risk factors for the onset of colorectal cancer (CRC) and patients should undergo a specific endoscopic surveillance program. This study aimed to assess the burden of the missed surveillance for CRC in patients with UC and CD and to identify possible factors associated with morbidity.
Methods: Records of consecutive patients who underwent surgery for UC-related and CD-related adenocarcinoma in our institution were reviewed. Cancer cases occurring in UC and in CD were compared with 324 patients who underwent curative-intent surgery for a histologically confirmed sporadic CRC and participated in a multicenter study on the effect of screening on patients' outcomes in the Veneto region. Non-parametric tests, logistic regression analysis, and survival analysis were performed.
Results: In UC and CD patients, CRC diagnosed at screening colonoscopy was more frequently stage I or II (p=0.04) and nodal metastasis over nodal harvest ratio was significantly lower (p=0.02) than cancer diagnosed in symptomatic patients. Anti-TNF-alpha therapy was associated with a significantly decreased risk of CRC (OR= 0.27 (95% CI 0.08-0.83), p=0.02). The rate of CRC occurrence confirmed a significant trend to rise according to disease duration (p<0.0001). Finally, patients with sporadic CRC or UC and CD-related CRC diagnosed at screening colonoscopy showed significantly better survival than those diagnosed because of symptoms (p=0.02).
Discussion: Our study confirmed that endoscopic surveillance is effective not only in the early detection of preneoplastic lesions/CRC in UC but also in detecting early stages of UC-related cancer. Moreover, anti-TNF-α therapy can play a role in the chemoprevention in UC. The study also confirmed that endoscopic follow-up in CD is associated with the early detection of CRC lesions and with an earlier cancer stage at diagnosis.