Postcolonoscopy colorectal cancer: Prevalence, categorization and root-cause analysis based on the World Endoscopic Organization system

AIMS

The World Endoscopy Organization (WEO) recommends that endoscopy units implement a process to identify postcolonoscopy colorectal cancer (PCCRC). The aims of this study were to assess the 3-year PCCRC rate and to perform root-cause analyses and categorization in accordance with the WEO recommendations.

PATIENTS AND METHODS

Cases of colorectal cancers (CRCs) in a tertiary care center were retrospectively included from January 2018 to December 2019. The 3-year and 4-year PCCRC rates were calculated. A root-cause analysis and categorization of PCCRCs (interval and type A, B, C noninterval PCCRCs) were performed. The level of agreement between two expert endoscopists was assessed.

RESULTS

A total of 530 cases of CRC were included. A total of 33 were deemed PCCRCs (age 75.8±9.5 years; 51.5% women). The 3-year and 4-year PCCRC rates were 3.4% and 4.7%, respectively. The level of agreement between the two endoscopists was acceptable either for the root-cause analysis (k=0.958) or for the categorization (k=0.76). The most plausible explanations of the PCCRCs were 8 "likely new PCCRCs", 1 (4%) "detected, not resected", 3 (12%) "detected, incomplete resection", 8 (32%) "missed lesion, inadequate examination", and 13 (52%) "missed lesion, adequate examination". Most PCCRCs were deemed noninterval Type C PCCRCs (N=17, 51.5%).

CONCLUSION

WEO recommendations for root-cause analysis and categorization are useful to detect areas for improvement. Most PCCRCs were avoidable and were likely due to missed lesions during an otherwise adequate examination.

Big data approach in the field of gastric and colorectal cancer research

Big data is characterized by three attributes: volume, variety,, and velocity. In healthcare setting, big data refers to vast dataset that is electronically stored and managed in an automated manner and has the potential to enhance human health and healthcare system. In this review, gastric cancer (GC) and postcolonoscopy colorectal cancer (PCCRC) will be used to illustrate application of big data approach in the field of gastrointestinal cancer research. Helicobacter pylori (HP) eradication only reduces GC risk by 46% due to preexisting precancerous lesions. Apart from endoscopy surveillance, identifying medications that modify GC risk is another strategy. Population-based cohort studies showed that long-term use of proton pump inhibitors (PPIs) associated with higher GC risk after HP eradication, while aspirin and statins associated with lower risk. While diabetes mellitus conferred 73% higher GC risk, metformin use associated with 51% lower risk, effect of which was independent of glycemic control. Nonetheless, nonsteroidal anti-inflammatory drugs (NA-NSAIDs) are not associated with lower GC risk. CRC can still occur after initial colonoscopy in which no cancer was detected (i.e. PCCRC). Between 2005 and 2013, the rate of interval-type PCCRC-3y (defined as CRC diagnosed between 6 and 36 months of index colonoscopy which was negative for CRC) was 7.9% in Hong Kong, with >80% being distal cancers and higher cancer-specific mortality compared with detected CRC. Certain clinical and endoscopy-related factors were associated with PCCRC-3 risk. Medications shown to have chemopreventive effects on PCCRC include statins, NA-NSAIDs, and angiotensin-converting enzyme inhibitors/angiotensin receptor blockers.

Postcolonoscopy Colorectal Cancer in a Referral Center for Colorectal Cancer: Prevalence and Risk Factors

Background and Aims

Colonoscopy is effective to detect and remove colorectal lesions. However, after a negative colonoscopy, cancers could be detected during the interval follow-up. This study was designed to identify characteristics and risk factors for postcolonoscopy colorectal cancer - interval type.

Methods

Medical records of individuals who were newly diagnosed with colorectal cancer between January 2018 and December 2019 were reviewed. Clinical, demographic, and endoscopic variables were analyzed. Those with the diagnosis of colorectal cancer between two consecutive colonoscopies performed within the appropriated surveillance range were considered to have postcolonoscopy colorectal cancer - interval type. A comparison between the group of patients with non-postcolonoscopy colorectal cancer - interval type and the group of patients with postcolonoscopy colorectal cancer - interval type was then performed.

Results

During the study period, 491 patients were newly diagnosed with colorectal cancer. Among them, 61 (12.4%) had postcolonoscopy colorectal cancer - interval subtype. Postcolonoscopy colorectal cancer - interval type was three times more prevalent on the proximal colon (p = 0.014) and was associated with the presence of two or more cardiovascular risk factors (aOR = 4.25; p = 0.016), cholecystectomy in the past (aOR = 10.09; p = 0.019), and family history of colorectal cancer on a first-degree relative (aOR = 4.25; p = 0.006). Moreover, isolated cardiovascular risk factors revealed a protective effect for the absence of all cardiovascular risk factors (aOR = 20; p = 0.034). The ROC curve associated with the multivariate model revealed a predictive power of 77.8% (p < 0.001).

Conclusions

Postcolonoscopy colorectal cancer - interval type is more common in the proximal colon and in patients with a family history (first-degree relative) of colorectal cancer, two or more cardiovascular risk factors, and a history of cholecystectomy. All of these are easily detectable in clinical practice and may be of extreme importance in the control of postcolonoscopy colorectal cancer in the near future.

Advanced Colon Cancer after Curative Resection of Intramucosal Adenocarcinoma with Endoscopic Submucosal Dissection

Endoscopic resection, particularly endoscopic submucosal dissection (ESD), for colorectal cancers enables a precise pathological diagnosis and safe R0 resection. The recurrence rate after ESD is generally extremely low, with annual surveillance colonoscopy recommended. However, surveillance may not be considered for super-elderly patients owing to their condition. This is a case report of an 85-year-old man in whom curative resection was achieved for an intramucosal adenocarcinoma with ESD. The patient presented with a hypoechoic mass located in his lower right abdomen, diagnosed via surveillance abdominal ultrasound. He had undergone curative ESD for intramucosal cecal cancer 2 years prior. Colonoscopy revealed a type 2 epithelial tumor at the proximal aspect of the ESD scar. Ileocolic resection with lymph node dissection was performed. An epithelial tumor and well-differentiated adenocarcinoma but not a submucosal tumor was detected in the mucosal layer. The lesion was diagnosed not as a local recurrence after ESD but as a newly emerged original advanced cancer. After ESD for colorectal cancer, a newly developed advanced cancer may occur at the site of the ESD scar in a shorter term than usual. Surveillance colonoscopy after ESD is necessary even for super-elderly patients.