Colorectal Cancer Risk in IBD
Colorectal cancer risk and IBD
Patients with IBD appear to be at notably increased risk of colorectal cancer compared to the general population [1-3], with one recent study demonstrating a 7% colorectal cancer risk after 30 years of disease . Patients with at least 8 years disease duration and colonic involvement are at increased risk of colorectal cancer (excluding patients with only ulcerative proctitis, or with Crohn’s disease and less than 1/3 of the colon involved). Patients at risk of colorectal cancer should be enrolled in a dysplasia surveillance plan as this appears to reduce the risk of colorectal cancer. Surveillance typically includes colonoscopy every 1-3 years, depending on individual patient risk [6, 7].
Risk factors and surveillance intervals
In patients at high risk, consider ~1 year surveillance intervals. High risk features include: primary sclerosing cholangitis (PSC), prior history of dysplasia or colonic strictures, or strong family hx of colorectal cancer (e.g., 1st degree relative with CRC < age 50). Patients with low to moderate risk may be surveyed every 2-3 years. Moderate risk features include: extensive colitis with moderate inflammatory burden, family hx of CRC in first degree relative > age 50 and possibly extensive inflammatory polyps or pseudopolyps [6, 8]
Most colonic dysplasia should be visible, hence a thorough high-quality exam is essential. High definition colonoscopes are preferred. Use of dye spray (chromoendoscopy) may have additional benefits for detecting dysplasia[9-13]. Random biopsies are typically performed in 4 quadrant fashion every 10cm. However, yield from random biopsies is low and this could be skipped if chromoendoscopy is utilized.
Management of Endoscopic lesions
Any visible polyps or lesions should be endoscopically resected if feasible and the specimen should be sent in a separately labeled jar. If a lesion has indistinct borders or is not amenable to resection, biopsy sample should be taken and sent in a separate jar[6, 8].
Management of Dysplasia
A diagnosis of dysplasia should ideally be confirmed by two experienced pathologists. Dysplasia should be managed closely and aggressively to prevent progression to cancer. For any confirmed case of high-grade dysplasia or multi-focal low-grade dysplasia, proctocolectomy should be recommended. For isolated unifocal dysplasia, options include proctocolectomy or close colonoscopic surveillance.