Differences between features of adenoma in the rectum versus sigmoid colon.

OBJECTIVE

Although the prevalence of cancer in the rectosigmoid is high compared with that in the more proximal colon, the features of cancer developing from an adenoma have yet to be elucidated. The aim of this study is to examine the clinicopathological relationship between cancer and adenoma in the rectosigmoid.

METHODS

A total of 340 adenomas located in the rectosigmoid in 255 patients were retrospectively examined regarding such clinicopathological factors as location and the grade of dysplasia.

RESULTS

The prevalence of adenoma was 102 in the rectum and 238 in the sigmoid colon, respectively, whereas the prevalence of adenoma with high-grade dysplasia was 39 in the rectum and 48 in the sigmoid colon, respectively. This prevalence of adenoma with high-grade dysplasia was thus significantly higher in the rectum than in the sigmoid colon (p < 0.02).

CONCLUSIONS

These findings suggest the possibility of different types of cancer development between adenoma of the rectum and sigmoid colon.