| [ Summary ] |
Grading the extent of invasion in the submucosa is important in deciding on the indications for colectomy in colorectal carcinomas, with invasion limited to the submucosa. There are basically two different classifications for grading the invasion of submucosa. In one classification, submucosa were equally divided into three levels. In the other classification, the vertical length of the invasion below the muscularis mucosa is a factor in determining the grades of submucosal invasion. In both of these classifications, difficulties in identifying the level of muscularis mucosa are often the problem. There are advantages and disadvantages in the two different classifications. Based on the analysis of our own materials, an invasion length of less than 1,000 micro m in the vertical direction is considered to be within the safe limit of invasion for colonoscopic resection, provided there are no other histological risk factors associated with lymphnode metastasis. |