A study from the August 21, 2012, issue of Annals of Internal Medicine shows that incomplete polyp removal and the lack of a follow-up colonoscopy within 5 years of initial polyp detection is strongly associated with risk for subsequent development of colorectal cancer.
Scientists examined 155 patients from a previously published population-based, case-control study who developed colon cancer within 10 years of polyp removal. They were compared with 260 control participants who also had polyp removal but did not develop cancer. Case and control participants were compared according to colonoscopy and polyp-related factors that could affect the development of cancer, such as the presence of multiple adenomas, polyp characteristics, and histologic findings.
Based on odds ratios and attributable fractions derived by using multiple logistic regression and the Levin formula, they determined that colonoscopy-related factors are more important than polyp characteristics in the calculation of colorectal cancer risk. Overall, nearly twice as many colorectal cancer cases were due to colonoscopy-related rather than polyp-related characteristics (41.1% versus 21.7%).
Study author Hermann Brenner, MD, of the German Cancer Research Center, and colleagues wrote, “These patterns underline the importance of efforts to optimize procedural aspects of colonoscopy, such as enduring complete removal of all polyps."