2002 American Joint Committee on Cancer (AJCC) TNM Staging System for the Anal Cancer

TX: Primary tumor cannot be assessed
T0: No evidence of primary tumor
Tis: Carcinoma in situ
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 invades adjacent organ(s), e.g., vagina, urethra, bladder

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 and/or inguinal node(s)
N3: Metastasis in perirectal and inguinal lymph nodes and/bilateral internal iliac and/or inguinal lymph nodes

Stage 0: Tis N0 M0
Stage I: T1 N0 M0
Stage II: T2 N0 M0, T3 N0 M0
Stage IIIA: T1 N1 M0, T2 N1 M0, T3 N1 M0, T4 N0 M0
Stage IIIB: T4 N1 M0, Any T N2 M0, Any T N3 M0
Stage IV: Any T Any N M1