Villous component as a marker for synchronous and metachronous colorectal adenomas.

To determine whether patients with colorectal adenomas containing a villous component (+vc group) have a higher incidence of synchronous or metachronous colorectal adenomas, 527 consecutive cases of completely removed colorectal adenoma were used. Synchronous adenomas were detected in 22.6 percent and 19.0 percent of the patients in the +vc and -vc groups, respectively. In the analysis of metachronous adenomas, 164 patients who had been followed for 1 to 11 years (mean, 3.31 years) were included. The cumulative adenoma-free rate according to Kaplan-Meier tended to be lower in the +vc group, the difference being statistically significant 1.0 to 1.2 years after treatment of the initial adenoma and the two curves being different based on the generalized Wilcoxon test. The numbers of newly detected adenomas annually were 1.76 and 0.86, and their annual incidences were 1.09 and 0.59 times, in the +vc and -vc groups, respectively. These results suggest the importance of the villous component as a predictor of metachronous colorectal adenomas.