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Table 5 TNM staging principles for the most common rectal neoplasms: anal (anal canal) and rectal (ampulla) carcinoma, carcinoid and gastrointestinal stromal tumors (GIST) according to the current classification of International Agency for Research on Cancer/World Health Organization [42]

From: Magnetic resonance imaging and endorectal ultrasound for diagnosis of rectal lesions

 

Anal carcinoma

Rectal carcinoma

Carcinoid of the rectum

GIST

T

Primary tumor

   

TX

Primary tumor cannot be assessed

Primary tumor cannot be assessed

Primary tumor cannot be assessed

Primary tumor cannot be assessed

T0

No evidence of primary tumor

No evidence of primary tumor

No evidence of primary tumor

No evidence of primary tumor

Tis

Carcinoma in situ, Bowen disease, high-grade squamous interepithelial lesion (HSIL), anal interepithelial neoplasia II-III (AIN II-III)

Carcinoma in situ: intraepithelial or invasion of lamina propria

  

T1

Tumor 2 cm or less in the greatest dimension

Tumor invades submucosa

Tumor invades lamina propria or submucosa and is no greater than 2 cm in size

Tumor 2 cm or less in greater dimension

T1a – tumor less than 1 cm in size

T1b – tumor 1 to 2 cm in size

T2

Tumor more than 2 cm but not more than 5 cm in the greatest dimension

Tumor invades muscularis propria

Tumor invades muscularis propria or is greater than 2 cm in size

Tumor more than 2 cm but not more than 5 cm

T3

Tumor more than 5 cm in the greatest dimension

Tumor invades subserosa or into non-peritonealized perirectal tissues

Tumor invades subserosa or non-peritonealized perirectal tissues

Tumor more than 5 cm but not more than 10 cm

T4

Tumor of any size invades adjacent organ(s), e.g., vagina, urethra, bladder (direct invasion of rectal wall, perianal skin, subcutaneous tissue or the sphincter muscle(s) alone is not classified as T4)

Tumor perforates visceral peritoneum (T4a) and/or directly invades other organs or structures (T4b)

Tumor perforates peritoneum or invades other organs

Tumor more than 10 cm in the greatest dimension

N

Regional lymph nodes

   

NX

Regional lymph nodes cannot be assessed

Regional lymph nodes cannot be assessed

Regional lymph nodes cannot be assessed

Regional lymph nodes cannot be assessed

N0

No regional lymph nodes metastasis

No regional lymph nodes metastasis

No regional lymph node metastasis

No regional lymph nodes metastasis

N1

Metastasis in perirectal lymph nodes

Metastasis in 1 to 3 regional lymph nodes

Regional lymph node metastasis

Regional lymph node metastasis

N1a - Metastasis in 1 regional lymph node

N1b – Metastasis in 2 to 3 regional lymph nodes

N1c Tumor deposit(s), i.e. satellites, in the subserosa or in non-peritonalized pericolic or perirectal soft tissue without regional lymph node metastasis

N2

Metastasis in unilateral internal iliac and/or inguinal lymph nodes

Metastasis in 4 or more regional lymph nodes

  

N2a - metastasis in 4 to 6 more regional lymph nodes

N2a - metastasis in 7 or more regional lymph nodes

N3

Metastasis in perirectal and inguinal lymph nodes and/or bilateral internal iliac and/or bilateral inguinal lymph nodes

   

M

Distal metastasis

   

M0

No distal metastasis

No distal metastasis

No distal metastasis

No distal metastasis

M1

Distal metastasis

Distal metastasis

Distal metastasis

Distal metastasis

M1a – metastasis confined to one organ

M1b – metastasis in more than one organ or the peritoneum