Published online Nov 14, 2017. doi: 10.3748/wjg.v23.i42.7609
Peer-review started: August 31, 2017
First decision: September 20, 2017
Revised: October 2, 2017
Accepted: October 26, 2017
Article in press: October 26, 2017
Published online: November 14, 2017
Post-colonoscopy colorectal cancers (PCCRC) has been recognized as a key quality indicator for colonoscopy. The data of PCCRC has been reported from Western counties, however that from Asian countries is lacking. Theoretically, HD colonoscopy has the potential to reduce the incidence of PCCRC, but clinical data related to this issue are still insufficient.
The PCCRC rate at two academic centers might help to set a benchmark for the quality of colonoscopy in Asian countries, where data on PCCRC are scarce.
To investigate the PCCRC rate for HD colonoscopy compared with that for standard-definition colonoscopy reported previously.
We retrospectively examined the medical records of consecutive adult patients with CRC between 2010 and 2015 at Sano Hospital (SH) and Dokkyo Medical University Koshigaya Hospital (DMUKH) in Japan. Patients with CRC diagnosed within 6 to 36 mo of HD colonoscopy were classified as a PCCCRC group, and the others as a non-PCCRC group. The primary outcome was the PCCRC rate with HD colonoscopy. The secondary outcomes were factors associated with PCCRC and possible reason for occurrence of early and advanced PCCRC.
We analyzed 851 patients with 892 CRCs including 11 of PCCRC and 881 of non-PCCRC. The PCCRC rate was 1.7% (8/471) at SH and 0.7% (3/421) at DMUKH. Factors significantly associated with PCCRC were smaller size, a shallower invasion depth, a non-polypoid macroscopic appearance, and an earlier stage. The leading possible reason was non-polypoid shape for early PCCRC and blinded location for advanced PCCRC.
We demonstrated the lower PCCRC rate for high-definition colonoscopy compared for standard-definition colonoscopy reported previously (0.7%-1.7% vs 1.8%-9.0%). Technological advance from standard-definition to high-definition colonoscopy has the potential to reduce the incidence of PCCRC.
Early PCCRC may be missed by inconspicuous macroscopic type, and advanced PCCRC by the position in blinded location. Endoscopists should be aware that even large advanced CRC can be easily missed during colonoscopy. We should learn the reason why we missed CRC during colonoscopy and prevent the PCCRC in the future. The development of accessory devices and new modalities are expected to improve observation in “blind” areas of the colon and decrease the PCCRC.