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Colon Cancer Treatment (Professional) (cont.)

Cellular Classification of Colon Cancer

Histologic types of colon cancer include the following:

  • Adenocarcinoma (most colon cancers).
    • Mucinous (colloid) adenocarcinoma.
    • Signet ring adenocarcinoma.
  • Scirrhous tumors.
  • Neuroendocrine.[1] Tumors with neuroendocrine differentiation typically have a poorer prognosis than pure adenocarcinoma variants.

References:

  1. Saclarides TJ, Szeluga D, Staren ED: Neuroendocrine cancers of the colon and rectum. Results of a ten-year experience. Dis Colon Rectum 37 (7): 635-42, 1994.

Stage Information for Colon Cancer

Treatment decisions should be made with reference to the TNM classification [1] rather than to the older Dukes or the Modified Astler-Coller classification schema.

The American Joint Committee on Cancer (AJCC) and a National Cancer Institute–sponsored panel recommended that at least 12 lymph nodes be examined in patients with colon and rectal cancer to confirm the absence of nodal involvement by tumor.[2,3,4] This recommendation takes into consideration that the number of lymph nodes examined is a reflection of the aggressiveness of lymphovascular mesenteric dissection at the time of surgical resection and the pathologic identification of nodes in the specimen. Retrospective studies demonstrated that the number of lymph nodes examined in colon and rectal surgery may be associated with patient outcome.[5,6,7,8]

AJCC Stage Groupings and TNM Definitions

The AJCC has designated staging by TNM classification to define colon cancer.[1] The same classification is used for both clinical and pathologic staging.[1]

Table 1. Definitions of TNM Stage 0

StageTNMa,bDukescMACdDescriptionIllustration
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 ofTable 5.
0
Tis, N0, M0
Tis = Carcinomain situ: intraepithelial or invasion of lamina propria.e

Stage 0 colon/rectal carcinoma in situ; shows a cross-section of the colon/rectum. An inset shows the layers of the colon/rectum wall with abnormal cells in the mucosa layer. Also shown are the submucosa, muscle layers, serosa, a blood vessel, and lymph nodes.
N0 = No regional lymph node metastasis.
M0 = No distant metastasis.

Table 2. Definitions of TNM Stage I

StageTNMa,bDukescMACdDescriptionIllustration
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 ofTable 5.
I
T1, N0, M0
A
A
T1 = Tumor invades submucosa.

Stage I colorectal cancer; shows a cross-section of the colon/rectum. An inset shows the layers of the colon/rectum wall with cancer in the mucosa, submucosa, and muscle layers. Also shown are the serosa, a blood vessel, and lymph nodes.
T2 = Tumor invades muscularis propria.
N0 = No regional lymph node metastasis.
T2, N0, M0AB1M0 = No distant metastasis.

Table 3. Definitions of TNM Stage II

StageTNMa,bDukescMACdDescriptionIllustration
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 ofTable 5.
IIA
T3, N0, M0
B
B2
T3 = Tumor invades through the muscularis propria into pericolorectal tissues.

Stage II colorectal cancer; shows a cross-section of the colon/rectum 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 stage IIA with cancer in the mucosa, submucosa, muscle layers, and serosa. Second panel shows stage IIB with cancer in all layers and spreading through the serosa. Third panel shows stage IIC with cancer spreading to nearby organs.
N0 = No regional lymph node metastasis.
M0 = No distant metastasis.
IIBT4a, N0, M0BB2T4a = Tumor penetrates to the surface of the visceral peritoneum.f
N0 = No regional lymph node metastasis.
M0 = No distant metastasis.
IICT4b, N0, M0BB3T4b = Tumor directly invades or is adherent to other organs or structures.f,g
N0 = No regional lymph node metastasis.
M0 = No distant metastasis.

Table 4. Definitions of TNM Stage III

StageTNMa,bDukescMACdDescriptionIllustration
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 ofTable 5.
IIIA
T1–T2, N1/N1c, M0
C
C1
T1 = Tumor invades submucosa.

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.
IIIB
T3–T4a, N1/N1c, M0
C
C2
T1 = Tumor invades submucosa.

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.
IIIC
T4a, N2a, M0
C
C2
T3 = Tumor invades through the muscularis propria into pericolorectal tissues.

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.

Table 5. Definitions of TNM Stage IV

StageTNMa,bDukescMACdDescriptionIllustration
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.
a cTNM 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).
b A 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.
c Dukes 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).
d MAC is the modified Astler-Coller classification.
e Tis 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.
f Direct 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).
g Tumor 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.
IVA
Any T, Any N, M1a
TX = Primary tumor cannot be assessed.

Stage IV colon cancer; shows other parts of the body where colon cancer may spread, including lymph nodes, lung, liver, abdominal wall, and ovary. Inset shows cancer spreading through the blood and lymph nodes to other parts of the body.
T0 = No evidence of primary tumor.
Tis = Carcinomain 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 = Carcinomain 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.

References:

  1. 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 143-64.
  2. Colon and rectum. In: American Joint Committee on Cancer.: AJCC Cancer Staging Manual. 6th ed. New York, NY: Springer, 2002, pp 113-124.
  3. Compton CC, Greene FL: The staging of colorectal cancer: 2004 and beyond. CA Cancer J Clin 54 (6): 295-308, 2004 Nov-Dec.
  4. Nelson H, Petrelli N, Carlin A, et al.: Guidelines 2000 for colon and rectal cancer surgery. J Natl Cancer Inst 93 (8): 583-96, 2001.
  5. Swanson RS, Compton CC, Stewart AK, et al.: The prognosis of T3N0 colon cancer is dependent on the number of lymph nodes examined. Ann Surg Oncol 10 (1): 65-71, 2003 Jan-Feb.
  6. Le Voyer TE, Sigurdson ER, Hanlon AL, et al.: Colon cancer survival is associated with increasing number of lymph nodes analyzed: a secondary survey of intergroup trial INT-0089. J Clin Oncol 21 (15): 2912-9, 2003.
  7. Prandi M, Lionetto R, Bini A, et al.: Prognostic evaluation of stage B colon cancer patients is improved by an adequate lymphadenectomy: results of a secondary analysis of a large scale adjuvant trial. Ann Surg 235 (4): 458-63, 2002.
  8. Tepper JE, O'Connell MJ, Niedzwiecki D, et al.: Impact of number of nodes retrieved on outcome in patients with rectal cancer. J Clin Oncol 19 (1): 157-63, 2001.
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