Colorectal cancer is the second leading cause of cancer death in the United States.
Prevention has focused on the detection and removal of polypoid neoplasms.
Data are limited on the significance of nonpolypoid colorectal neoplasms.
Dr Roy Soetikno and colleagues determined the prevalence of nonpolypoid colorectal neoplasms in a veterans hospital population, and characterized their association with colorectal cancer.
The researchers undertook a cross-sectional study at a veterans hospital in California with 1819 patients undergoing elective colonoscopy from 2003 to 2004.
| The prevalence of nonpolypoid colorectal neoplasms in the subpopulations for screening was 6%|
|Journal of the American Medical Association|
The researchers' main outcome measures included endoscopic appearance, location, size, histology, and depth of invasion of neoplasms.
The overall prevalence of nonpolypoid colorectal neoplasms was 9%.
The prevalence of nonpolypoid colorectal neoplasms in the subpopulations for screening, surveillance, and symptoms was 6%, 15%, and 6%.
The overall prevalence of nonpolypoid colorectal neoplasms with in situ or submucosal invasive carcinoma was 0.8%.
In the screening population, the prevalence was 0.3%.
Overall, nonpolypoid colorectal neoplasms were more likely to contain carcinoma than polypoid lesions, irrespective of the size.
The positive size-adjusted association of nonpolypoid colorectal neoplasms with in situ or submucosal invasive carcinoma was also observed in subpopulations for screening and surveillance.
The team noted that the depressed type had the highest risk.
Nonpolypoid colorectal neoplasms containing carcinoma were smaller in diameter as compared with the polypoid ones.
The team observed that procedure times did not change appreciably as compared with historical controls.
Dr Soetikno's team concluded, "In this group of veteran patients, nonpolypoid colorectal neoplasms were relatively common lesions diagnosed during routine colonoscopy."
"They had a greater association with carcinoma compared with polypoid neoplasms, irrespective of size."