Colorectal carcinoma/staging

Two classification systems are commonly used to classify colorectal cancer - TNM and Dukes.

=== TNM classification ===
 * T = tumor (Tis = carcinoma in situ, T1 = submucosa, T2 = muscularis propria, T3 = subserosa, pericolic or perirectal tissues, T4a = visceral peritoneum, T4b = other organs or structures)
 * N = regional lymph node involvement (N0 = no LN involvement, N1a = 1 regional lymph node, N1b = 2-3 regional lymph nodes, N1c = satellites without regional lymph nodes, N2a = 4-6 regional LNs, N2b = 7 or more regional LNs, Nx = undetected number of affected lymph nodes - less than 12 LNs from bowel resection examined)
 * M = distant metastases (M0 = no distant metastases, M1a = 1 organ, M1b = more than 1 organ, peritoneum)

=== Duke's classification ===