The Frequency of Synchronous Adenomas Detected At Colonoscopic Removal of Early Colorectal Cancers

Abstract

Background and Aims: Synchronous adenomas are often detected when colonoscopic removals of early colorectal cancers are carried out. The study aimed to evaluate whether or not the removed early cancers had any characteristics associated with the presence of synchronous adenoma. Methods: The study included a total of 253 early colorectal cancers (221 intramucosal and 32 submucosal invasive cancers), which were colonoscopically removed in our hospital during past 10 years. We analyzed the relationships between the following characteristics of resected early cancers and the presence of synchronous adenomas : location, tumor size, endoscopic configuration, histology, and depth of invasion. Results: The overall percentage of synchronous adenoma at colonoscopic removals of early colorectal cancers was 43.5%. Almost half of the resected early cancers were associated with synchronous adenoma(s) during colonoscopy. With regard to the location of removed cancers the prevalences of synchronous adenoma(s) were 45.2% (right colon), 45.8% (left colon), and 38.0% (rectum), respectively. No difference was statistically observed according to the location of original tumor. Regarding the size of removed cancers the prevalences of synchronous adenoma(s) were 56.4% (<10 mm), 38.4% (10 mm-20 mm), and 27.5% (>20 mm). Prevalence of adenoma(s) became to be lower according to the size up of removed tumor (p < 0.005). Regarding the endoscopic configuration of removed cancers the prevalences of synchronous adenoma(s) were 48.8% (pedunculated type), 45.1% (sessile type), 31.3% (flat type), and 24.2% (superficial spreading type), respectively. Polypoid type cancer (pedunculated or sessile type) had higher prevalences of synchronous adenoma(s) when compared to those of non-polypoid type (flat or superficial spreading type) (p < 0.05). As to the histology of removed cancers the prevalences of synchronous adenoma(s) were 43.4% (tubular adenocarcinoma), and 43.6% (villous adenocarcinoma), respectively. No statistical difference was observed between them. As to the depth of invasion the prevalences of synchronous adenoma (s) were 46.2% (m), and 25.0% (sm). Adenomas were less frequent with submucosal invasive cancers (p < 0.05). Conclusion: The characteristics of colonoscopically removed early cancers might influence on the prevalence of adenomas at colonoscopy. Size, configuration, and depth of invasion of removed cancers might be significant factors which influence on the frequency of synchronous adenomas.