Colon tumor
Staging of colonic carcinoma (AJCC 7th Edition)

Author: Charanjeet Singh, M.D. (see Authors page)

Revised: 21 November 2017, last major update May 2012

Copyright: (c) 2003-2017,, Inc.

PubMed search: staging [title] colonic carcinoma

See also Staging-AJCC 8th Edition

Cite this page: Singh C. Staging of colonic carcinoma (AJCC 7th Edition). website. Accessed May 21st, 2018.

TNM staging of colorectal carcinoma (AJCC 7th Edition)
Primary tumor (pT)
  • TX: primary tumor cannot be assessed
  • T0: no evidence of primary tumor
  • Tis: carcinoma in situ: i.e. intraepithelial or invasion of lamina propria, but not through muscularis mucosa into submucosa
  • 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

  • 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
  • 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 (for example, invasion of the sigmoid colon by a carcinoma of the cecum) or for cancers in a retroperitoneal or sub peritoneal location, direct invasion of other organs or structures by virtue of extension beyond the muscularis propria (that is, 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)
  • 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
Regional lymph nodes (pN)
  • NX: regional lymph nodes cannot be assessed
  • N0: no regional lymph node metastasis
  • N1: metastasis in 1 - 3 regional lymph nodes
  • N1a: metastasis in one 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
  • N2: metastasis in 4 or more regional lymph nodes
  • N2a: metastasis in 4 - 6 regional lymph nodes
  • N2b: metastasis in 7 or more regional lymph nodes

  • 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

  • 10 - 15 lymph nodes are required for accurate staging (Eur J Cancer 2005;41:2071)
  • Increasing number of negative nodes in Stage IIIB / C disease has favorable prognostic value (J Clin Oncol 2006;24:3570)
  • Sentinel node staging with cytokeratin is highly accurate for clusters of tumor cells; isolated cytokeratin+ cells may not represent tumor (Arch Pathol Lab Med 2003;127:673, Arch Pathol Lab Med 2000;124:1759)
  • Most lymph nodes with metastases are 5 mm or less
  • Nodal metastases often have involvement of surrounding veins
  • Presence of micrometastases currently has no definitive value
Distant Metastasis (pM)
  • M0: no distant metastasis
  • M1: distant metastasis
  • M1a: metastasis confined to one organ or site (e.g. liver, lung, ovary and nonregional node)
  • M1b: metastases in more than one organ / site or the peritoneum
Stage grouping and survival
  • Note: 5 year survival is based on AJCC 6th classification (J Natl Cancer Inst 2004;96:1420)

  • Stage 0: Tis N0 M0 (100%)
  • Stage I: T1-T2 N0 M0 (93%)
  • Stage IIA: T3 N0 M0 (85%)
  • Stage IIB: T4a N0 M0 (72%)
  • Stage IIC: T4b N0 M0 (72%)
  • Stage IIIA: T1-T2 N1/N1c M0 or T1 N2a M0 (83%)
  • Stage IIIB: T3-T4a N1/N1c M0 or T2-T3 N2a M0 or T1-T2 N2b M0 (64%)
  • Stage IIIC: T4a N2a M0 or T3-T4a N2b M0 or T4b N1-N2 M0 (44%)
  • Stage IVA: any T, any N, M1a (8%)
  • Stage IVB: any T, any N, M1b (8%)
Residual tumor (R factor)
  • Tumor remaining in patient after surgical resection

  • RX: presence of residual tumor cannot be assessed
  • R0: no residual tumor; margins histologically negative
  • R1: microscopic residual tumor (corresponds to positive resection margin)
  • R2: macroscopic residual tumor (either positive margins or gross disease remains after resection)

  • References: Arch Pathol Lab Med 2006;130:318 (staging problems)
TNM staging of colorectal carcinoma (AJCC 8th Edition)
Pending - Implementation begins 1 January 2018, see Staging-AJCC 8th Edition

Definition / general
  • Previous staging systems are 1932 Dukes staging system for rectal carcinomas applied to colon carcinomas or 1954 Astler-Coller modification of Dukes staging
  • Appendiceal adenocarcinomas or anal carcinomas are classified differently
  • Examination of all mesentery may be necessary to ensure correct pN status in pN1 cases (Mod Pathol 2004;17:402)
Dukes staging (not currently used)
  • Designed for rectum, but was often applied to entire colon

  • A: growth limited to wall of rectum
  • B: extension of growth to extra rectal tissues, no metastasis to regional lymph nodes
  • C: metastases in regional lymph nodes, modified in 1935 to C1 and C2 stages
    • C1: metastases to regional lymph nodes
    • C2: metastases to lymph nodes at point of mesenteric blood vessel ligature
  • D: distant metastases (not part of original classification)
Astler-Coller classification (not currently used)
  • A: lesion limited to mucosa
  • B1: lesion involves muscularis propria but does not penetrate through it
  • B2: lesion penetrates through the muscularis propria
  • C1: metastatic tumor in lymph nodes but the tumor itself is still confined to the bowel wall
  • C2: metastatic tumor in lymph nodes and tumor itself has penetrated through the entire bowel wall

  • Per Rosai, call stage B if no identifiable muscularis propria layer between tumor and serosal surface
Diagrams / tables

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Staging related diagrams

Gross images

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Sentinel lymph nodes

Microscopic (histologic) images

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Sentinel lymph nodes