Colonoscopy has become the number one gastrointestinal endoscopic procedure in the world and is considered the gold standard for detecting colorectal cancer (CRC) and its precursors. For a long time, it was thought to be close to perfect in preventing CRC, implying that the disease does virtually not occur soon after colonoscopy has been performed. However, an increasing body of epidemiological evidence questions this and demonstrates the occurrence of these so-called postcolonoscopy CRCs (PCCRCs) as a kind of interval cancers. The term interval cancer is taken from screening and describes the occurrence of cancer in the time interval between scheduled screening examinations.

Accordingly, colonoscopists fear the nightmare of facing a PCCRC diagnosis in their patients and want to know to which extent these interval cancers are preventable. Two intriguing papers address this question and explore the reasons for CRCs occurring soon after colonoscopy.1 ,2

One study comes from the USA and pooled data from eight prospective colonoscopy studies, for the most part clinical trials with different interventions, which included 9167 patients with adenomas removed at baseline colonoscopy. Overall, 58 CRCs (0.6% of all participants) were identified after a median follow-up of 4 years.1 The second …