Is lymph node metastasis the only concern in high-risk submucosal colorectal cancer following endoscopic resection?

Endoscopic resection represents a curative therapy for Tis colorectal cancer (carcinoma in situ; intraepithelial or invasion of the lamina propria) as it has no risk of lymph node metastasis (1-3). However, lymph node metastasis occurs in 7-15% of T1 colorectal cancers (invasion of submucosa) (4-10). In order to achieve curative resection of submucosal colorectal cancer, predictors for lymph node metastasis have been evaluated in many studies (7,9-14) and found to be depth of submucosal invasion (1,000 and 3,000 μm for nonpedunculated and pedunculated submucosal colorectal cancers, respectively), lymphovascular invasion, and poorly-differentiated adenocarcinoma (11,15,16). In cases of submucosal colorectal cancer with no risk factors for lymph node metastasis, no further treatments such as surgical resection appear to be necessary following complete endoscopic resection. Conversely, additional surgery has been recommended for high-risk submucosal colorectal cancer (11).