Staging Anal Cancer

Explanation: Primary tumor (T) TX: primary tumor cannot be assessed T0: no evidence of primary tumor Tis: carcinoma in situ (Bowen disease, high-grade squamous intraepithelial lesion [HSIL], anal intraepithelial neoplasia II-III [AIN II-III]) T1: tumor 2 cm or less in greatest dimension T2: tumor >2 cm but <5 cm in greatest dimension T3: tumor >5 cm in greatest dimension T4: tumor of any size invades adjacent organ(s), e.g. vagina, urethra, bladder (Note: direct invasion of the rectal wall, perirectal skin, subcutaneous tissue, or the sphincter muscle(s) is not classified as T4) Regional lymph nodes (N) Nx: regional lymph nodes cannot be assessed N0: no regional lymph node metastasis N1: metastasis in regional lymph nodes N1a: metastases in inguinal, mesorectal, and/or internal iliac lymph nodes N1b: metastases in external iliac lymph nodes N1c: metastases in external iliac and in inguinal, mesorectal, and/or internal iliac lymph nodes Distant metastasis (M) Mx: distant metastasis cannot be assessed M0: no distant metastasis M1: distant metastasis (Note: involvement of para-aortic or more distant lymph nodes is considered M1) AJCC Staging: Stage 0: Tis N0 M0 Stage I: T1 N0 M0 Stage II: T2, T3 N0 M0 Stage IIIA: T1, T2, T3 N1 M0 Stage IIIB: T4 N0/N1 OR T1, T2, T3 with N1b or N1c Stage IV: Any T, any N, M1