Risk of Colorectal Cancer in Patients With Advanced Versus Nonadvanced Adenoma
Posted: Thursday, July 19, 2018
Patients diagnosed with an advanced adenoma at diagnostic colonoscopy may have a significantly higher risk of developing colorectal cancer than those with a nonadvanced adenomas. The findings, which came from a study published in JAMA Oncology, indicate that a nonadvanced adenoma may not be associated with an increased risk of colorectal cancer. Benjamin Click, MD, of the University of Pittsburgh, was the initial author of this multicenter, prospective cohort study.
The study authors evaluated participants from the Prostate, Lung, Colorectal, and Ovarian Cancer randomized clinical trial of flexible sigmoidoscopy; follow-up ranged from 1993 to 2013. Dr. Click and colleagues assessed 15,935 men and women aged 55 to 74 years old who underwent colonoscopy after an abnormal flexible sigmoidoscopy screening. After the initial colonoscopy, 7,985 patients had no adenoma (50.1%), 5,068 patients (31.8%) had a nonadvanced adenoma, and 2,882 patients had an advanced adenoma (18.1%).
After a median follow-up of 13 years, the colorectal cancer incidence rates per 10,000 person-years of observation were 20.0 for advanced adenoma, 9.1 for nonadvanced adenoma, and 7.5 for no adenoma. The investigators found that patients with an advanced adenoma were significantly more likely to develop colorectal cancer than those without an adenoma (rate ratio = 2.7) and had a higher risk of death compared with those with no adenoma (rate ratio = 2.6). Mortality risks between those with and without an advanced adenoma were not significantly different (rate ratio = 1.2).