T
TX - Primary tumor cannot be assessed
T0 - No evidence of primary tumor
Tis - Carcinoma in situ: intraepithelial or invasion of lamina propria
T1 - Tumor invades submucosa
T2 - Tumor invades muscularis propria
T3 - Tumor invades through the muscularis propria into the pericolorectal tissues
T4a - Tumor penetrates to the surface of the visceral peritoneum
T4b - Tumor directly invades or is adherent to other organs or structures
N
NX - Regional lymph nodes cannot be assessed
N0 - No regional lymph node metastasis
N1a - Metastasis in 1 regional lymph node
N1b - Metastasis in 2-3 regional lymph nodes
N1c - Tumor deposit(s) in the subserosa, mesentery, or nonperitonealized pericolic or perirectal tissues without regional nodal metastasis
N2a - Metastasis in 4-6 regional lymph nodes
N2b - Metastasis in 7 or more regional lymph nodes
M
MX - Distal mts cannot be assessed
M0 - No distant metastasis
M1a - Metastasis confined to 1 organ or site (eg, liver, lung, ovary, nonregional node)
M1b - Metastases in more than 1 organ/site or the peritoneum