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Colon Cancer Treatment (PDQ®)

  • Updated: 02/08/2013

Table 4. Definitions of TNM Stage III

Stage TNMa,b Dukesc MACd Description Illustration 
IIIAT1–T2, N1/N1c, M0CC1T1 = Tumor invades submucosa.
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Stage IIIA colorectal cancer; shows a cross-section of the colon/rectum and a two-panel inset. Each panel shows the layers of the colon/rectum wall: mucosa, submucosa, muscle layers, and serosa. Also shown are a blood vessel and lymph nodes. First panel shows cancer in the mucosa, submucosa, muscle layers, and 2 lymph nodes. Second panel shows cancer in the mucosa, submucosa, and 5 lymph nodes.
T2 = Tumor invades muscularis propria.
N1 = Metastases in 1–3 regional lymph nodes.
T1, N2a, M0CC1N1c = Tumor deposit(s) in the subserosa, mesentery, or nonperitonealized pericolic or perirectal tissues without regional nodal metastasis.
N2a = Metastases in 4–6 regional lymph nodes.
M0 = No distant metastasis.
IIIBT3–T4a, N1/N1c, M0CC2T1 = Tumor invades submucosa.
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Stage IIIB colorectal cancer; shows a cross-section of the colon/rectum and a two-panel inset. Each panel shows the layers of the colon/rectum wall: mucosa, submucosa, muscle layers, and serosa. Also shown are a blood vessel and lymph nodes. First panel shows cancer in all layers, spreading through the serosa, and in 3 lymph nodes. Second panel shows cancer in all layers and in 5 lymph nodes. Third panel shows cancer in the mucosa, submucosa, muscle layers, and 7 lymph nodes.
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
N1 = Metastases in 1–3 regional lymph nodes.
N1c = Tumor deposit(s) in the subserosa, mesentery, or nonperitonealized pericolic or perirectal tissues without regional nodal metastasis.
T2–T3, N2a, M0CC1/C2N2a = Metastases in 4–6 regional lymph nodes.
N2b = Metastases in ≥7 regional lymph nodes.
T1–T2, N2b, M0CC1M0 = No distant metastasis.
IIICT4a, N2a, M0CC2T3 = Tumor invades through the muscularis propria into pericolorectal tissues.
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Stage IIIC colorectal cancer; shows a cross-section of the colon/rectum wall and a three-panel inset. Each panel shows the layers of the colon/rectum wall: mucosa, submucosa, muscle layers, and serosa. Also shown are a blood vessel and lymph nodes. First panel shows cancer in all layers, spreading through the serosa, and in 4 lymph nodes. Second panel shows cancer in all layers and in 7 lymph nodes. Third panel shows cancer in all layers, spreading through the serosa, in 2 lymph nodes, and spreading to nearby organs.
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
T3–T4a, N2b, M0CC2N1 = Metastases in 1–3 regional lymph nodes.
N2 = Metastases in ≥4 regional lymph nodes.
N2a = Metastases in 4–6 regional lymph nodes.
T4b, N1–N2, M0CC3N2b = Metastases in ≥7 regional lymph nodes.
M0 = No distant metastasis.

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.
The explanations for superscripts a–g are at the end of Table 5.