Abstract
BACKGROUND: Synchronous neoplastic lesions are usually present in patients with colorectal cancer (CRC) at diagnosis or postoperative follow-up endoscopy. However, few studies have been published about the clinicopathological features of synchronous lesions, especially those of synchronous advanced neoplasia. This study aimed to describe synchronous lesions in patients with CRC because this knowledge may be useful for preventing the development of metachronous cancer. MATERIAL AND METHODS: We retrospectively reviewed 261 primary CRC cases with synchronous lesions referred to our hospital during a 4-year period. Personal history, habits, family history, characteristics of index cancer, and synchronous lesions were assessed. RESULTS: In total, the 261 patients with CRC had 812 synchronous adenomas and 146 advanced neoplasia. Diminutive, small, and large polyps made up 66.7%, 20.2%, and 13.1% of all lesions, respectively; 9.3% of diminutive and small adenomas were advanced neoplasia, and 45.2% of synchronous advanced lesions were subcentimeter polyps. Both synchronous non-advanced lesions and advanced lesions developed most frequently in the distal colon, followed by the proximal colon, and were least frequently found in the rectum (P < 0.001). Older age (P = 0.04) and male gender (P = 0.001) were associated with the presence of advanced neoplasia in CRC cases with synchronous neoplastic lesions. Meanwhile, the use of aspirin may be associated with a lower incidence of advanced neoplasia (P = 0.04). CONCLUSION: Patients diagnosed with CRC require detailed clearing of the remainder of the colon at baseline coloscopy or postoperative follow-up examination, and we should take a more cautious approach to synchronous subcentimeter polyps in this group of patients.