Researchers have gained a better understanding of how polyps progress to colorectal cancer and what can be done to increase detection, according to studies presented at the Annual Scientific Meeting of the American College of Gastroenterology in San Antonio.
In one study, led by Robert Genta, MD, FACG, researchers analyzed a large nationwide dataset of over 500,000 patient records from a specialized gastrointestinal pathology lab to gain an understanding of the progression of sessile serrated adenomas (SSA) to dysplasia.
Researchers found that among those patients who underwent colonoscopy with a biopsy of abnormal tissue, approximately 41% had non-hyperplastic polyps. Among those with non-hyperplastic polyps, approximately 5% had SSA categorized as either low or high dysplasia, reflecting the degree of cellular abnormality.
“The interval for the progression from SSA to SSA with low-grade dysplasia can be estimated to be approximately seven years, and the further progression to high-grade dysplasia can be estimated at an additional four years,” Dr. Genta commented. “These polyps appear to advance at a slower rate than conventional adenomas.”
In another study, conducted by Douglas Rex, MD, FACG, and colleagues at Indiana University Medical Center found that when used in the right side of the colon, retroflexion may increase the diagnostic yield of polyps, particularly in men, older patients, and those with polyps found on forward examination. Specifically, 41% of the patients who had polyps identified on retroflexion had negative exams on forward examination. Of a total of 1,000 patients who underwent colonoscopy, retroflexion in the right side of the colon was successful in 945 patients.
“The risk of identifying a polyp on retroflexion was three times more likely among those who had a polyp detected on forward view compared to those patients who were negative on forward examination,” concluded Dr. Rex. “While the presence of a polyp on forward view predicted the detection of polyps in retroflexion in this study, the analysis revealed that older age and male gender were significant predictors of finding polyps on retroflexion after a negative forward exam.”