Characteristics of Interval Colorectal Cancer: A Canadian Retrospective Population-Level Analysis from Newfoundland...

Area of Science:

• Gastroenterology
• Oncology
• Public Health

Background:

• Interval colorectal cancers (ICRCs) are diagnosed between surveillance colonoscopies.
• Most ICRCs are thought to originate from lesions missed during index colonoscopies.
• Predicting ICRC risk and identifying procedural factors for missed lesions remains challenging.

Purpose of the Study:

• To examine the incidence and characteristics of ICRC in Newfoundland and Labrador (NL), Canada.
• To analyze population-level data on ICRC from 2001-2018, covering 67% of the province.
• To identify potential risk factors associated with ICRC, particularly right-sided tumors.

Main Methods:

• Population-level analysis of ICRC cases diagnosed 3-60 months after the last colonoscopy.
• Data collection covered 67% of the NL population between 2001 and 2018.
• Univariate and multivariable logistic regression analyses were used to assess risk factors.

Main Results:

• The estimated ICRC rate was up to 9.3%.
• Median age at diagnosis was 67.1 years, with a median interval of 2.9 years.
• 57% of tumors were proximal to the splenic flexure; 53% presented as local disease. No significant correlations were found between right-sided ICRC and colonoscopy indication, bowel preparation, polyp size, completion rates, or stage.

Conclusions:

• Improvements in synoptic reporting and national registries are crucial.
• Identifying risk factors and reducing ICRC frequency requires enhanced data collection and analysis.
• Further research is needed to understand and mitigate the causes of missed lesions during colonoscopy.