[Advanced neoplasm detection and its associated factors in colonoscopic surveillance of endoscopically resected early colorectal cancer].

Background/aims: Early colon cancer can be effectively diagnosed and treated by colonoscopy, and surveillance colonoscopy is necessary to detect precursor lesions or new early colon cancer. We analyzed the surveillance results of patients with endoscopically resected early colon cancer to evaluate the detection rate of advanced neoplasia and its associated factors.

Methods: We conducted a retrospective study at Soonchunhyang University Seoul Hospital, from May 2003 to December 2011. Patients who underwent endoscopic resection for early colon cancer, showed mucosal and submucosal invasion on histopathologic examination, and received surveillance colonoscopy at least once were enrolled in the current study. Patients who underwent operation and those who were lost during surveillance period were excluded.

Results: Among a total of 305 patients diagnosed with early colon cancer, 211 patients met our inclusion criteria. Of these patients, 15 (7.1%) advanced neoplasias were detected at first colonoscopy. One hundred ninety-eight patients (93.8%) underwent surveillance colonoscopy within one year and 14 (7.0%) advanced neoplasias were detected in this group of patients. When patients with and without advanced neoplasia at first surveillance colonoscopy performed within one year were compared, inadequate bowel preparation (OR, 18.237; 95% CI, 3.741-88.895; p<0.001) and three or more colon polyps (OR, 9.479; 95% CI, 1.103-81.452; p=0.040) were significant risk factors for detecting advanced neoplasia.

Conclusions: Considering the high detection rate of advanced neoplasia at first surveillance colonoscopy in patients with endoscopically resected early colon cancer, surveillance interval should be within one year, especially when the bowel preparation has been inadequate and three or more colon polyps have been detected.