Surveillance Colonoscopy

Patients with long-standing ulcerative colitis (UC) have an increased risk of developing colorectal cancer (CRC). The risk of CRC is associated with disease duration and extent, and histological and endoscopic severity of inflammation. UC-associated CRC is often accompanied by dysplasia, which is a neoplastic lesion itself and is assumed to be pre-cancerous lesions. Patients with long-standing UC are recommended to undergo regular surveillance colonoscopy, which utilizes dysplasia as a marker of synchronous or metachronous development of CRC. Chromoendoscopy can increase the detection rate of dysplasia in surveillance colonoscopy, and is replacing the traditional step-biopsy method. Dysplasia is histologically categorized as high-grade (HGD) or low-grade dysplasia (LGD) and is endoscopically classified to visible or invisible lesions. Visible dysplasia with distinct border can be resected endoscopically, followed by close surveillance. In case of invisible dysplasia (detected by step biopsy), colectomy is recommended for patients with HGD. The management of invisible LGD is controversial.