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Colon Cancer Treatment (PDQ®)

  • Updated: 02/08/2013

Table 5. Definitions of TNM Stage IV

Stage TNMa,b Dukesc MACd Description Illustration 
IVAAny T, Any N, M1aTX = Primary tumor cannot be assessed.
T0 = No evidence of primary tumor.
Tis = Carcinoma in situ: intraepithelial or invasion of lamina propria.e
T1 = Tumor invades submucosa.
T2 = Tumor invades muscularis propria.
T3 = Tumor invades through the muscularis propria into pericolorectal tissues.
T4a = Tumor penetrates to the surface of the visceral peritoneum.f
T4b = Tumor directly invades or is adherent to other organs or structures.f,g
NX = Regional lymph nodes cannot be assessed.
N0 = No regional lymph node metastasis.
N1 = Metastases in 1–3 regional lymph nodes.
N1a = Metastasis in 1 regional lymph node.
N1b = Metastases in 2–3 regional lymph nodes.
N1c = Tumor deposit(s) in the subserosa, mesentery, or nonperitonealized pericolic or perirectal tissues without regional nodal metastasis.
N2 = Metastases in ≥4 regional lymph nodes.
N2a = Metastases in 4–6 regional lymph nodes.
N2b = Metastases in ≥7 regional lymph nodes.
M1a = Metastasis confined to 1 organ or site (e.g., liver, lung, ovary, nonregional node).
IVBAny T, Any N, M1bTX = Primary tumor cannot be assessed.
T0 = No evidence of primary tumor.
Tis = Carcinoma in situ: intraepithelial or invasion of lamina propria.e
T1 = Tumor invades submucosa.
T2 = Tumor invades muscularis propria.
T3 = Tumor invades through the muscularis propria into pericolorectal tissues.
T4a = Tumor penetrates to the surface of the visceral peritoneum.f
T4b = Tumor directly invades or is adherent to other organs or structures.f,g
NX = Regional lymph nodes cannot be assessed.
N0 = No regional lymph node metastasis.
N1 = Metastases in 1–3 regional lymph nodes.
N1a = Metastasis in 1 regional lymph node.
N1b = Metastases in 2–3 regional lymph nodes.
N1c = Tumor deposit(s) in the subserosa, mesentery, or nonperitonealized pericolic or perirectal tissues without regional nodal metastasis.
N2 = Metastases in ≥4 regional lymph nodes.
N2a = Metastases in 4–6 regional lymph nodes.
N2b = Metastases in ≥7 regional lymph nodes.
M1b = Metastases in >1 organ/site or the peritoneum.

T = primary tumor; N = regional lymph nodes; M = distant metastasis.
Reprinted with permission from AJCC: Colon and rectum. In: Edge SB, Byrd DR, Compton CC, et al., eds.: AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer, 2010, pp 143-164.
acTNM is the clinical classification, and pTNM is the pathologic classification. The y prefix is used for those cancers that are classified after neoadjuvant pretreatment (e.g., ypTNM). Patients who have a complete pathologic response (ypT0, N0, cM0) may be similar to stage group 0 or I. The r prefix is to be used for those cancers that have recurred after a disease-free interval (rTNM).
bA satellite peritumoral nodule in the pericolorectal adipose tissue of a primary carcinoma without histologic evidence of residual lymph node in the nodule may represent discontinuous spread, venous invasion with extravascular spread (V1/2), or a totally replaced lymph node (N1/2). Replaced nodes should be counted separately as positive nodes in the N category, whereas discontinuous spread or venous invasion should be classified and counted in the site-specific factor category Tumor Deposits.
cDukes B is a composite of better (T3, N0, M0) and worse (T4, N0, M0) prognostic groups, as is Dukes C (any T, N1, M0 and any T, N2, M0).
dMAC is the modified Astler-Coller classification.
eTis includes cancer cells confined within the glandular basement membrane (intraepithelial) or mucosal lamina propria (intramucosal) with no extension through the muscularis mucosae into the submucosa.
fDirect invasion in T4 includes invasion of other organs or other segments of the colorectum as a result of direct extension through the serosa, as confirmed on microscopic examination (e.g., invasion of the sigmoid colon by a carcinoma of the cecum) or, for cancers in a retroperitoneal or subperitoneal location, direct invasion of other organs or structures by virtue of extension beyond the muscularis propria (i.e., respectively, a tumor on the posterior wall of the descending colon invading the left kidney or lateral abdominal wall; or a mid or distal rectal cancer with invasion of prostate, seminal vesicles, cervix, or vagina).
gTumor that is adherent to other organs or structures, grossly, is classified cT4b. However, if no tumor is present in the adhesion, microscopically, the classification should be pT1–4a depending on the anatomical depth of wall invasion. The V and L classifications should be used to identify the presence or absence of vascular or lymphatic invasion whereas the PN site-specific factor should be used for perineural invasion.