Recurrence rates of colorectal adenomas after polypectomy are widely recognized.
However, little is known of the incidence in individuals with no neoplastic lesions initially.
In this study, researchers from Japan evaluated incidence and recurrence rates of colorectal neoplasms in a large cohort of asymptomatic patients using annual colonoscopies.
The research team analyzed 6225 subjects (4659 male) participating in an annual colonoscopic screening program. Participants all completed 3 or more colonoscopies between 1988 and 2002.
The patients were divided into 3 groups according to the findings of their initial 2 colonoscopies. There were 4084 subjects who had no neoplasm, 1818 with adenomas less than 10 mm, and 323 with advanced lesions.
Mean age at the second colonoscopy was 48.8 years.
|For advanced lesions, the incidence rate was 0.21% per year.|
The team determined that for all types of colorectal neoplasms, the incidence rate in those with no initial neoplasm was 7% per year.
However, recurrence rates in participants with small adenomas and advanced lesions were 19% and 23% per year, respectively.
The researchers found that for advanced lesions, the incidence rate was 0.21% per year. The recurrence rate in subjects with small adenomas and advanced lesions were 0.64% and 1.88% per year, respectively.
The team found that colorectal neoplasms were more likely to develop in males and older subjects.
Dr Yamaji and colleagues concluded, "Although recurrence rates after polypectomy were elevated, the incidence rates in subjects with no neoplastic lesions initially were quite high".