Depth of submucosal invasion in the sessile and superficial types of submucosal invasive colorectal carcinoma: objective versus subjective measurement.

BACKGROUND/AIMS: When endoscopic resection (ER) is performed for submucosal invasive colorectal carcinoma (SICC), it may be difficult to determine whether to perform follow-up observation or surgical resection with lymph node dissection. The Japanese Guidelines provide guidelines for additional treatment after ER. Depth of submucosal invasion (SM depth) is measured in the same manner for both the sessile type and the superficial type. We compared the SM depth in the sessile and superficial types of SICC. METHODOLOGY: Among patients who underwent surgical resection of SICC between 1990 and 2010, this study included 118 consecutive patients with SICC. The SM depth in the sessile and superficial macroscopic morphological types was evaluated on the basis of both objective and subjective measurement of SM depth. RESULTS: The SM depth overall was significantly greater in the sessile type (p < 0.0001). In SM1 cancer, no significant difference was seen between the two groups. In SM2 and SM3 cancer, SM depth in the sessile type was significantly greater than that in the superficial type (p < 0.0001). CONCLUSIONS: In the basis of subjective measurement of SM depth, it was suggested that the sessile and superficial types of SICC may need to be evaluated separately to determine the correlation.