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Anus and perianal area



Reviewer: Nat Pernick, M.D. (see Reviewers page)
Revised: 15 April 2013, last major update April 2005
Copyright: (c) 2003-2013, PathologyOutlines.com, Inc.


● No changes from AJCC 6th edition to AJCC 7th edition
● This staging system applies to anal canal tumors but excludes perianal tumors, melanoma, carcinoid tumors and sarcoma
● Use skin staging system for perianal tumors (arise from skin or distal to squamous mucocutaneous junction)
● Anal canal tumors now tend to be staged clinically, as treatment is often non-surgical
● However, treatment of perianal carcinomas is primarily surgical
● Stage tumors overlapping the anorectal junction as anal tumors if epicenter is distal to or 2 cm or less proximal from dentate line, and as rectal tumors if epicenter is more than 2 cm proximal to dentate line

Primary tumor (T)

TX: Primary tumor cannot be assessed
T0: No evidence of primary tumor
Tis: Carcinoma in situ (Bowen’s disease, high grade squamous intraepithelial lesion/HSIL, anal intraepithelial neoplasia/AIN II-III)
T1: Tumor 2 cm or less in greatest dimension
T2: Tumor more than 2 cm but not more than 5 cm in greatest dimension
T3: Tumor more than 5 cm in greatest dimension
T4: Tumor of any size that invades adjacent organ(s): vagina, urethra, bladder

● Note: direct invasion of the rectal wall, perirectal skin, subcutaneous tissue or sphincter muscle is not classified as pT4

Regional lymph nodes (N)

NX: Regional lymph nodes cannot be assessed
N0: No regional lymph node metastasis
N1: Metastasis in perirectal lymph node(s)
N2: Metastasis in unilateral internal iliac or inguinal lymph node(s)
N3: Metastasis in perirectal and inguinal lymph nodes or bilateral internal iliac or inguinal lymph nodes

● Regional lymph nodes: perirectal (anorectal, perirectal, lateral sacral), internal iliac (hypogastric), inguinal (superficial)

Isolated tumor cells (ITC) - not part of TNM

● ITC are single cells or small clusters of cells 0.2 mm or less, found by routine H&E, immunohistochemistry, PCR or other
● Lymph nodes or distant sites with ITC are classified as pN0 or pM0

pN0 (i+): ITC detectable by any morphologic method but not histologically
pN0 (i-): ITC not detectable by any morphologic method or histologically
pN0 (mol+): ITC detectable by any molecular method but not histologically
pN0 (mol-): ITC detectable by any molecular method or histologically

Distant metastases

M0: No distant metastasis
M1: Distant metastasis

Stage grouping and 5 year survival (squamous, nonsquamous)

Stage 0: Tis N0 M0
Stage I: T1 N0 M0 (71.4%, 59.1%)
Stage II: T2-T3 N0 M0 (63.5%, 52.9%)
Stage IIIA: T1-T3 N1 M0 or T4 N0 M0 (48.1%, 37.7%)
Stage IIIB: T4 N1 M0 or Any T N2-N3 M0 (43.2%, 24.4%)
Stage IV: Any T, Any N, M1 (20.9%, 7.4%)

Alternative staging

A: Intraepithelial or superficially invasive
B: Penetrate into muscularis propria or adjacent pelvic tissue
C: Regional nodal metastases
D: Massive local spread or distant metastases; unresectable

End of Anus and perianal area > Miscellaneous > Staging

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