In so doing appropriate treatment strategies and estimation of prognosis can be determined. The staging of rectal cancer is relatively straight forward and closely approximates the staging of colon cancer. Modified Duke A Tumor penetrates into the mucosa of the bowel wall but no further. Tumor penetrates into and through the muscularis propria of the bowel wall. Tumor invades muscularis propria.
Tumor invades through the muscularis propria into the subserosa, or into the perirectal tissues.
No regional lymph node metastasis. Metastasis in 1 to 3 regional lymph nodes. Metastasis in 4 or more regional lymph nodes. No distant metastasis. Distant metastasis present.