The TNM-classification is used to divide anal cancer into stages. TNM assesses the tumor (T), lymph nodes (N), and metastases (M), at the time of diagnosis.
Tumor infiltration (T)
- Tis carcinoma in situ
- T1 Tumor ≤ 2 cm in diameter
- T2 Tumor > 2 cm, but < 5 cm in diameter
- T3 Tumor ≥ 5 cm in diameter
- T4 Tumor infiltration into neighboring organs (vagina, urethra, bladder, prostate) irrespective of size. Infiltration of sphincter muscle alone is not classified as T4.
Lymph node status (N)
- N0 No regional lymph nodes
- N1 Metastases in peri- or mesorectal lymph nodes
- N2 Metastases in unilateral internal iliac and/or inguinal lymph nodes
- N3 Metastases in peri- or mesorectal and inguinal lymph nodes and/or bilateral internal iliac and/or inguinal lymph nodes
- NX Regional lymph nodes cannot be assessed
- M0 No metastases
- M1 Metastases