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
To investigate the post-colonoscopy colorectal cancer (PCCRC) rate for high-definition (HD) colonoscopy compared with that for standard-definition colonoscopy reported previously.
Using medical records at Sano Hospital (SH) and Dokkyo Medical University Koshigaya Hospital (DMUKH), we retrospectively obtained data on consecutive patients diagnosed as having CRC between January 2010 and December 2015. The definition of PCCRC was diagnosis of CRC between 7 and 36 mo after initial high-definition colonoscopy that had detected no cancer, and patients were divided into a PCCRC group and a non-PCCRC group. The primary outcome was the rate of PCCRC for HD colonoscopy. The secondary outcomes were factors associated with PCCRC and possible reason for occurrence of early and advanced PCCRC.
Among 892 CRC patients, 11 were diagnosed as having PCCRC and 881 had non-PCCRC. The PCCRC rate was 1.7% (8/471) at SH and 0.7% (3/421) at DMUKH. In comparison with the non-PCCRC group, the PCCRC group had a significantly higher preponderance of smaller tumors (39 mm vs 19 mm, P = 0.002), a shallower invasion depth (T1 rate, 25.4% vs 63.6%, P = 0.01), a non-polypoid macroscopic appearance (39.0% vs 85.7%, P = 0.02) and an earlier stage (59.7% vs 90.9%, P = 0.03). Possible reasons for PCCRC were “missed or new” in 9 patients (82%), “incomplete resection” in 1 (9%), and “inadequate examination’” in 1 (9%). Among 9 “missed or new” PCCRC, the leading cause was non-polypoid shape for early PCCRC and blinded location for advanced PCCRC.
The PCCRC rate for HD colonoscopy was 0.7%-1.7%, being lower than that for standard-definition colonoscopy (1.8%-9.0%) reported previously employing the same methodology.
Core tip: Technological advance from standard-definition to high-definition colonoscopy has the potential to reduce the incidence of post-colonoscopy colorectal cancer (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%). Our data might help to set a benchmark for the quality of colonoscopy in Asian countries, where data on PCCRC are scarce. We firstly analyzed the possible reasons for both early and advanced “missed or new” PCCRC cases and found differences between the two groups. The leading cause was non-polypoid shape for early PCCRC and blinded location for advanced PCCRC.