[Patterns of metachronous adenoma after colorectal cancer surgery].

BACKGROUND/AIMS: After colorectal cancer surgery, colonoscopic surveillance should be done for prevention and early detection of secondary cancer. This study aimed to identify the group with high risk of developing colorectal adenoma after curative surgery of colorectal cancer.

METHODS

We retrospectively investigated the medical records of the subjects of 130 patients who had been examined using colonoscopy before and after the curative surgery.

RESULTS

The average age was 59.4 years. Synchronous adenomas were in 42 patients (32.3%). The occurrence rate was significantly high in men (38.8%) than women (22.0%). After the operation, the mean interval of examining colonoscopy was 11.6 months (3-24 months) and metachronous adenomas were detected in 26 patients (20.0%). The patients who have both metachronous and synchronous adenomas were observed in 13/42 (30.9%) and the patients of metachronous adenomas without synchronous adenomas were observed in 13/88 (14.8%). The occurrence rate of metachronous adenomas with synchronous adenomas was significantly high. The frequency of synchronous adenomas didn't increase with age. However, the frequency of metachronous adenomas increased with age: 0/9 (0%) under 40 years, 7/49 (14.3%) in 41-61 years and 19/72 (26.4%) over 61 years. The occurrence rate was higher in men (26.3%) than women (10.0%).

CONCLUSIONS

The occurrence rate of metachronous adenomas after colorectal cancer surgery was higher in the patients with synchronous adenomas, male gender and old aged patients.