Flat or depressed colorectal neoplasms are more likely than polyps to contain in situ or submucosal carcinoma, according to a study released Wednesday. Unfortunately, these nonpolypoid lesions may be missed by colon cancer screening methods, according to gastroenterologists based in Palo Alto, CA.
Flat or depressed colorectal neoplasms are more likely than polyps to contain in situ or submucosal carcinoma, according to a study released Wednesday. Unfortunately, these nonpolypoid lesions may be missed by colon cancer screening methods, according to gastroenterologists based in Palo Alto, CA.
"Nonpolyoid colorectal neoplasms are more difficult to detect by colonoscopy or CT colonography because the subtle findings can be difficult to distinguish from those of normal mucosa," wrote Dr. Roy Soetikno and colleagues in the Journal of the American Medical Association (2008;299:1027-1035).
The group set out to determine the prevalence of nonpolypoid colorectal neoplasms in 1819 patients who underwent standard colonoscopy screening at the VA Palo Alto Health Care System over a one-year period. Of the 1819 patients, the majority were white men.
The authors pointed out that flat polyps occur most commonly in the Japanese patient population. As a result, a faculty exchange program was undertaken between gastroenterologists and pathologists at the Palo Alto facility and endoscopy centers in Tokyo and Kashiwa, Japan.
Polyps in this study were classified using the Japanese Society for Cancer of the Colon and Rectum classification system: Pedunculated or semipedunculated lesions were considered polypoid, while completely flat or depressed lesions were deemed nonpolypoid.
When appropriate, patients with polyps were treated with biopsy, polypectomy, or surgery. Patients who had one or more polypoid neoplastic lesions removed were followed at one year with another colonoscopy exam for lesion recurrence.
The results showed 42% of the study cohort had at least one superficial colorectal neoplasm. Flat or depressed lesions were diagnosed in 9.35% of that subgroup. The prevalence of flat lesions was 8.58%, while the prevalence of depressed lesions was 0.99%.
"Although nonpolypoid lesions accounted for only 15% of neoplasms, they contributed to 54% of superficial carcinomas," Soetikno's group wrote. "Nonpolypoid morphology was strongly associated with findings of in situ or submucosal invasive carcinoma (odds ratio, 11.1; 95% confidence interval, 4.98-24.8)."
Overall, for patients undergoing colonoscopy screening, the prevalence of nonpolypoid lesions was 5.8%. For those undergoing surveillance, the prevalence jumped to 15.8%. They authors suggested that flat or depressed lesions fall into the pool of polyps that are commonly missed because of incomplete surgical removal or because they are fast-growing interval lesions.
For more information from the Diagnostic Imaging archives:
Virtual colonoscopy performs well in large new study
CT colonography bests conventional screening in cost-effectiveness test
CT colonography matches gold standard in eagerly awaited ACRIN trial results
AI Algorithm Comparable to Radiologists in Differentiating Small Renal Masses on CT
May 14th 2024An emerging deep learning algorithm had a lower AUC and sensitivity than urological radiologists for differentiating between small renal masses on computed tomography (CT) scans but had a 21 percent higher sensitivity rate than non-urological radiologists, according to new research.
Appealing Prior Authorization Denials: Can it be Effective for Emerging Technologies?
May 14th 2024While radiologists and other providers may be discouraged by insurer denials saying the use of a technological advance is “unproven and investigational,” 82 percent of appeals for prior authorization denials were approved in 2021.
Current Insights and Emerging Roles for Contrast-Enhanced Mammography
May 10th 2024In a recent lecture at the 2024 ARRS Annual Meeting, Jordana Phillips, MD, discussed the role of contrast-enhanced mammography in staging breast cancer, evaluating response to neoadjuvant chemotherapy and recalls from screening.