654 Inflammatory Bowel Disease and Risk of Interval Colorectal Carcinoma: What’s Missing in Surveillance Endoscopy?

Abstract

Colorectal carcinomas in ulcerative colitis patients are more commonly missed endoscopically compared to those in other symptomatic patients. They may present as flat lesions on a background of colitis, making them harder to visualise. Those presenting after negative colonoscopies are termed interval cancers, and account for up to 50% of colorectal cancers in patients with inflammatory bowel disease (IBD). Professional bodies recommend the use of chromoendoscopy for IBD surveillance to improve diagnostic yield by allowing targeted biopsies of non-polypoid lesions. We present an asymptomatic missed cancer in a patient with UC following a complete white light surveillance colonoscopy. After the sole endoscopic finding of a small, raised rectal lesion, found to be dysplastic, a CT scan incidentally demonstrated a missed ascending colon tumour. Had chromoendoscopy been used, this cancer may have been detected initially. This case report demonstrates that missed tumours remain a problem during surveillance endoscopy for IBD.