Subtle nonpolypoid colorectal neoplasms were more predictive of colorectal cancer than the more obvious polypoid neoplasms, according to findings from a study of 1,819 adult patients.
Polypoid neoplasms are easy to detect during a colonoscopy, and they are routinely removed to prevent colorectal cancer. By contrast, nonpolypoid colorectal neoplasms (NP-CRNs) are flat or slightly depressed in shape and are harder to distinguish from the surrounding normal mucosa. Previous studies have shown that depressed NP-CRNs are more likely to be cancerous, but few studies have examined them as predictors of colorectal cancer.
In this cross-sectional study, Dr. Roy M. Soetikno of the Veterans Affairs Palo Alto (Calif.) Health Care System, and his colleagues reviewed the characteristics of colorectal neoplasms in asymptomatic and symptomatic adults.
The study included 616 asymptomatic patients (the screening patients), 654 asymptomatic patients with a personal or family history of colorectal neoplasms (surveillance patients), and 549 symptomatic patients. They had elective outpatient colonoscopies between July 2003 and June 2004 (JAMA 2008;299:1027–35). Average age was 64 years, 95% were men, and 79% were white. Those undergoing emergency colonoscopies were excluded.
NP-CRNs were found in 170 patients (9.4%). Prevalence in the screening, surveillance, and symptomatic subgroups was 5.8%, 15.4%, and 6.0%, respectively. In the screening group, nonpolypoid lesions were more than twice as likely as polypoid lesions to contain neoplasms, whereas in the surveillance and symptomatic groups, they were more than three times as likely to contain neoplasms.
“Nonpolypoid lesions accounted for 15% of neoplasms, [but] contributed to 54% of superficial carcinomas,” the authors said. NP-CRN lesions were almost 10 times as likely to be associated with in situ or submucosal invasive carcinoma, compared with polypoid lesions, regardless of size.
A total of 227 NP-CRNs were found; 209 were flat and 18 were depressed. Although the number of depressed neoplasms was too small to show statistical significance, 6 (33%) contained carcinoma, compared with 9 of the flat neoplasms (4.3%). The depressed NP-CRNs were also the smallest, averaging 9.77 mm in diameter, compared with an average of 19.2 mm for polypoid lesions and 15.9 mm for NP-CRNs overall. None of the researchers disclosed any conflicts of interest.
Nonpolypoid lesions accounted for 15% of neoplasms, [but] contributed to 54% of superficial carcinomas. DR. SOETIKNO