Difference between revisions of "Colorectal cancer staging"

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==TNM staging system==
==TNM staging system==
===Tumour stage===
===Tumour stage===
*Tis - in situ (intramucosal).
*Tis - in situ ([[Intramucosal colorectal carcinoma|intramucosal]]).
*T1 - into submucosa (through mucularis mucosae).
*T1 - into submucosa (through mucularis mucosae).
**This is '''different than elsewhere''', e.g. in the ''small bowel'' tumour cells in the ''lamina propria'' is defined as T1.  The rationale for the ''T1'' definition in CRC is that no lymphatics are present in the mucosa, ergo no risk of distant spread.
**This is '''different than elsewhere''', e.g. in the ''small bowel'' tumour cells in the ''lamina propria'' is defined as T1.  The rationale for the ''T1'' definition in CRC is that no lymphatics are present in the mucosa, ergo no risk of distant spread.
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Note:
Note:
*High-grade dysplasia, "intramucosal colorectal carcinoma", and "[[colorectal adenocarcinoma in situ]]" are used interchangeably by many in the colon and rectum.
*High-grade dysplasia, "intramucosal colorectal carcinoma", and "[[colorectal adenocarcinoma in situ]]" are used interchangeably by many in the colon and rectum.
**High-grade dysplasia is the preferred term - see ''"[[intramucosal colorectal carcinoma]]"''.
**''High-grade dysplasia'' is the preferred term - see ''"[[intramucosal colorectal carcinoma]]"''.
**If one were to splitting hairs: ''adenocarcinoma in situ'' is ''invasion into the lamina propria'', high-grade dysplasia does not have lamina propria invasion. Ergo, the difference amounts to seeing a [[desmoplastic stroma]] (adenocarcinoma) or not seeing one (dysplasia).


===Nodes stage===
===Nodes stage===

Revision as of 01:11, 19 April 2016

This article deals with colorectal cancer staging.

General

TNM staging is very widely used. There is also the Dukes' system, which in many respects is quite similar.[1]

TNM staging system

Tumour stage

  • Tis - in situ (intramucosal).‡
  • T1 - into submucosa (through mucularis mucosae).
    • This is different than elsewhere, e.g. in the small bowel tumour cells in the lamina propria is defined as T1. The rationale for the T1 definition in CRC is that no lymphatics are present in the mucosa, ergo no risk of distant spread.
  • T2 - into muscularis propria.
  • T3 - into fat beyond musclaris propria.
  • T4a - invasion of the visceral peritoneum.
  • T4b - grows into something else.

Note:

Nodes stage

  • N0 - no positive nodes.
  • N1 - 1-3 positive nodes.
  • N2 - 4+ positive nodes.
    • N2a - 4-6 positive nodes.
    • N2b - 7+ positive nodes.

Notes:

  • Memory device for N2 = 4+ +ve LNs: the number four in chinese sounds like death.[2]

Overall stage

Simple version

Tumour/node grade for stage:[3]

  • Stage I - T1 or T2 N0 M0.
  • Stage II - T3 or T4 N0 M0.
  • Stage III - Tx N1 or N2 M0.
  • Stage IV - Tx Nx M1.

Complex version

Detailed tumour/node grade for stage:[4]

  • Stage I - T1 or T2.
  • Stage IIA - T3.
  • Stage IIB - T4.
  • Stage IIIA - T1 N1 or T2 N1.
  • Stage IIIB - T3 N1 or T4 N1.
  • Stage IIIC - Tx N2.
  • Stage IV - Tx Nx M1.

See also

References

  1. URL: http://www.cancerresearchuk.org/about-cancer/type/bowel-cancer/treatment/dukes-stages-of-bowel-cancer. Accessed on: 12 January 2016.
  2. URL: http://en.wikipedia.org/wiki/Numbers_in_Chinese_culture#Four. Accessed on: 28 June 2011.
  3. Shiau, Carolyn; Toren, Andrew (2006). Toronto Notes 2006: Comprehensive Medical Reference (Review for MCCQE 1 and USMLE Step 2) (22nd edition (2006) ed.). Toronto Notes for Medical Students, Inc.. pp. GS27. ISBN 978-0968592861.
  4. http://www.cancer.org/docroot/CRI/content/CRI_2_4_3X_How_is_colon_and_rectum_cancer_staged.asp