| [ Summary ] |
Of 2,622 patients who underwent total colonoscopy more than twice at the TF clinic, 8 patients were detected with PCCRC. Most of the 8 cases were "missed" LST-NG or depressed like cancer. Although it is currently assumed in Western countries that sessile serrated lesions (SSLs) may be the likely culprit lesions for post-colonoscopy colorectal cancer (PCCRC) in many cases, there were no SSLs in these eight PCCRC cases.
The development of current techniques and devices to easily detect superficial depressed cancer (IIc) will be a long-awaited innovation. Current colonoscopic screening with IIc has evolved over time with advances in endoscopic technology, such that conventional white-light imaging (WLI) is being increasingly replaced with image-enhanced endoscopy (IEE) with narrow-band imaging (NBI) as the mainstay for screening. Prospective screening for cecal diminutive adenomas sequentially with WLI, NBI, and chromoendoscopy (CE) show that cecal diminutive adenomas are detected most frequently with CE, followed by NBI and WLI, suggesting the usefulness of CE. However, the difficulty in detecting IIc submarined under a pool of dye solutions can be considered a disadvantage of CE during TCS. Furthermore, a comparison of WLI and NBI without CE shows the superiority of NBI over WLI in detecting non-granular-type (LST-NG) tumors and IIc. Depressed and reactive elevated areas of depressed tumors are visualized as whitish and brownish, respectively, on NBI, which together constitute the so-called "O-ring sign", which characterize the NBI findings of IIc. In the future, IIc may be detected efficiently by any colonoscopist at various experiential levels. We hope to develop new colonoscopic technology, devices, and artificial intelligence (AI). |