Improving trainee colonoscopy performance by investigating the withdrawal time from individual colonic segments: a single-center observational study

BACKGROUND

The colonoscopy withdrawal time (WT) and adenoma detection rate (ADR) are widely used quality indicators for colonoscopy. However, no study has investigated the appropriate colonoscopy WTs of individual colonic segments that will allow trainees to achieve a higher ADR. Thus, we analyzed for the first time the relationship between colonoscopy WT and the ADR/polyp detection rate (PDR) in the proximal, left-sided and entire colon among trainees.

METHODS

This retrospective study involved 611 consecutive patients who underwent colonoscopy from March 2018 to March 2019 performed by 6 trainees in the Endoscopy Center of Shanghai General Hospital. The WTs for the individual colonic segments and any significant findings of colonoscopies were retrospectively retrieved from the trainees' records and verified in the endoscopy center database. ADR/PDR was defined as the number of colonoscopies detecting at least 1 polyp/adenoma divided by the total number of colonoscopies. Comparisons of PDR and ADR between the 2 groups were conducted using chi-square test. Multilevel analysis was performed to consider individual differences among the 6 trainees. Multilevel binary logistic regression analysis was performed to analyze the factors that influenced the PDR, ADR and advanced adenoma detection rate (AADR) for the entire colon, and trainee status was included as a random effect.

RESULTS

The mean WTs were 4.20±1.09, 4.27±1.12, and 8.48±1.87 minutes for the proximal, left-sided, and entire colon, respectively. A longer WT [odds ratio (OR) 1.499, 95% confidence interval (CI): 1.381-1.628, P<0.001; OR 1.409, 95% CI: 1.265-1.569, P<0.001, respectively] was significantly associated with a higher PDR and ADR. The PDR (P<0.001) and ADR (P<0.001) were significantly higher when the WT was >4 minutes than when the WT was ≤4 minutes in both the proximal and left-sided colon, while the PDR (P<0.001) and ADR (P<0.001) were significantly higher when the WT was >8 minutes in the entire colon.

CONCLUSIONS

In order to improve trainee colonoscopy performance, trainees were recommended to have WTs of at least 4 minutes in the proximal colon, 4 minutes in the left-sided colon and 8 minutes in the entire colon during negative screening colonoscopies.

Evaluation of the vascular anatomy of the left-sided colon focused on the accessory middle colic artery: a single-centre study of 734 patients

AIM

Surgery for colorectal cancer located in the splenic flexure is difficult to perform because of the complex anatomy. Recently, in addition to the middle colic artery and left colic artery (LCA), the accessory middle colic artery (AMCA) has been recognized as a feeding artery for the left-sided colon. This study aimed to evaluate the vascular anatomy of the splenic flexure focusing on the AMCA in a large number of patients.

METHOD

A total of 734 patients who underwent CT before surgery for colorectal cancer were enrolled. We retrospectively evaluated the vascular anatomy using both two- and three-dimensional CT angiography.

RESULTS

The AMCA existed in 36.4% of the cases (n = 267). In many cases, it originated from the superior mesenteric artery (n = 228, 85.4%). The AMCA had a common trunk with the transverse pancreatic artery in 54 patients (20.2%). The frequency of the presence of the AMCA was associated with the branching pattern of the LCA, and was more frequent when the LCA was absent (P < 0.001).

CONCLUSION

The presence of the AMCA is not rare and the AMCA has some branching patterns; therefore, recognizing it preoperatively and intra-operatively is important, being especially careful when the LCA is absent.

Right- vs. Left-Sided Metastatic Colorectal Cancer: Differences in Tumor Biology and Bevacizumab Efficacy

There is evidence of a different response to treatment with regard to the primary tumor localization (right-sided or left-sided) in patients with metastatic colorectal cancer (mCRC). We analyzed the different outcomes and biomolecular characteristics in relation to tumor localization in 122 of the 370 patients with metastatic colorectal cancer enrolled onto the phase III prospective multicenter “Italian Trial in Advanced Colorectal Cancer (ITACa)”, randomized to receive first-line chemotherapy (CT) or CT plus bevacizumab (CT + B). RAS and BRAF mutations; baseline expression levels of circulating vascular endothelial growth factor (VEGF), endothelial nitric oxide synthase (eNOS), cyclooxygenase-2 (COX2), ephrin type-B receptor 4 (EPHB4), hypoxia-inducible factor 1-alpha (HIF-1α), lactate dehydrogenase (LDH), and high-sensitivity C reactive protein (hs-CRP); and inflammatory indexes such as the neutrophil-to-lymphocyte ratio, platelet-lymphocyte rate and systemic immune-inflammation index were evaluated. Patients with right-sided tumors showed a longer median progression-free survival in the CT + B arm than in the CT group (12.6 vs. 9.0 months, respectively, p = 0.017). Baseline inflammatory indexes were significantly higher in left-sided tumors, whereas eNOS and EPHB4 expression was significantly higher and BRAF mutation more frequent in right-sided tumors. Our data suggest a greater efficacy of the CT + B combination in right-sided mCRC, which might be attributable to the lower inflammatory status and higher expression of pro-angiogenic factors that appear to characterize these tumors.