Feasibility and economic assessment of chromocolonoscopy for detection of proximal serrated neoplasia within a population-based colorectal cancer screening programme (CONSCOP): an open-label, randomised controlled non-inferiority trial

Abstract

Background Most post-colonoscopy interval colorectal cancers are proximal; serrated polyps are often precursors to these cancers and are considered difficult to detect. We assessed the safety, feasibility, and economic effect of chromocolonoscopy on detection of proximal serrated neoplasia. Methods We did an open-label, multicentre, randomised, controlled non-inferiority trial including patients from Bowel Screening Wales centres. Participants who tested positive for faecal occult blood and who were eligible for and considered fit to have colonoscopy (patients with known cases of polyposis syndromes, Lynch syndrome, and chronic inflammatory disease were excluded) were randomly assigned (1:1; with the use of minimisation, stratified by centre with an 80:20 random element) to either standard white light colonoscopy (standard group) or chromocolonoscopy (indigo carmine dye [0•2%]; chromocolonoscopy group) using a secure, internet-based, computerised, randomisation system that used centralised, dynamic allocation. Participants were followed up for 1 year and data from index colonoscopies and associated clearance procedures were analysed. All proximal polyps were reviewed by an expert pathologist panel. The main outcome on which power was based was time taken to perform the colonoscopy procedure, defined as from the time when the scope was inserted to withdrawal from the anus, assessed in the per-protocol population. The non-inferiority margin was 15 min. This trial is complete and is registered with ClinicalTrials.gov, number NCT01972451.

Optimal Endoscopic Treatment and Surveillance of Serrated Polyps

“…25,26 Rates of complications with cold snare polypectomy are very low and intra procedural bleeding, 1.8% in one large series, is usually controlled with injection or endoscopic clipping. 17 Perforations, which are more of concern with hot snare, are exceptionally rare with cold snare. Majority of the bleed with cold snare are immediate and self-limiting.…”

“…Detection can be improved by withdrawing slowly, using high definition colonoscope 15 and chromoendoscopy (dye spray) ( Table 1). [16][17][18] Some early data suggests the use of Endocuff may support SSL (SSA/ P) detection with a 15% detection rate with Endocuff versus a 3% rate with standard colonoscopy (p=0.001). 19 A colonoscope with a large balloon at the bending section which slows withdrawal and compresses folds (G-EYE colonoscope; Smart Medical Systems Ltd., Ra'anana, Israel) also improved serrated lesion detection rates in a large randomized controlled study (2.7% vs 0.8%, p=0.036).…”

Guidelines for the management of hereditary colorectal cancer from the British Society of Gastroenterology (BSG)/Association of Coloproctology of Great Britain and Ireland (ACPGBI)/United Kingdom Cancer Genetics Group (UKCGG)

“…Advanced colonoscopic imaging can assist in making a diagnosis of polyposis by revealing additional lesions required to meet diagnostic criteria: diagnoses of adenomatous polyposis may be missed if dye spray is not used,104 and there is similar evidence from the CONSCOP study that the identification of serrated polyps is enhanced through the use of pancolonic dye spray 105…”

Morphology and Molecular Features of Rare Colorectal Carcinoma Histotypes

“…This could explain the morphologic heterogeneity of tumors arising in the right colon, in older patients which are usually BRAF mutated. These CRCs are thought to develop rapidly and may in part explain interval cancers [6]. These new insights into the molecular pathogenesis of CRC have contributed to the distinction of right- and left-sided CRCs, identifying them as two distinct clinical, pathological and molecular entities [7].…”