Trends of Colonic Neoplasia in US Outpatient Endoscopy Centers

A variety of studies have shown rising trends in the occurrence of colorectal cancer in younger patients as opposed to falling trends among older patients aged 55 years or more. We hypothesized that the time trends of benign colonic precursor lesions would reveal similar patterns.

The present study was designed to test this hypothesis in a large nationwide sample of the US population undergoing colonoscopy in community-based endoscopy centers.

The Inform Diagnostics database is an electronic repository of histopathologic records of patients distributed throughout the USA. A cross-sectional study analyzed the detection rates of sessile serrated adenomas (SSA), hyperplastic polyps (HP), tubular adenomas (TA), traditional serrated adenomas (TSA), or adenocarcinomas (colorectal cancer, CRC) in 2,910,174 colonoscopies done 2008-2020.

During the 13-year time period, the rate of SSA showed a significant rise, both in patients younger and older than 55 years. HP and TA both showed a significant decline during the same time period. The trends of CRC in the older age group decreased significantly between 2008 (or its peak in 2012) and 2020. The trends of CRC in the younger age group increased significantly between 2008 and its peak in 2017.

The age-specific time trends of benign and malignant colonic neoplasia are characterized by dissimilar temporal patterns. Such dissimilarity could suggest that besides a set of shared risk factors that affect all types of colonic neoplasia alike, there is yet another set of environmental risk factors that specifically influence malignant transformation.