TNM Classification for Anal Cancer
The American Joint Committee on Cancer (AJCC) tumor/node/metastasis (TNM) classification and staging system for anal cancer are provided below. [1, 2, 3]
Table 1. TNM Classification for Anal Cancer (Open Table in a new window)
Primary tumor (T) |
|
TX |
Primary tumor cannot be assessed |
T0 |
No evidence of primary tumor |
Tis |
High-grade squamous intraepithelial lesion (previously termed carcinoma in situ, Bowen disease, anal intraepithelial neoplasia II–III, high-grade anal intraepithelial neoplasia) |
T1 |
Tumor ≤ 2 cm 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) (eg, vagina, urethra, bladder) |
Regional lymph nodes (N) |
|
NX |
Regional lymph nodes cannot be assessed |
N0 |
No regional lymph node metastasis |
N1 |
Metastasis in inguinal, mesorectal, internal iliac, or external iliac nodes N1a - Metastasis in inguinal, mesorectal, or internal iliac lymph nodes N1b - Metastasis in external iliac lymph nodes N1c - Metastasis in external iliac with any N1a nodes |
Distant metastasis (M) |
|
M0 |
No distant metastasis |
M1 |
Distant metastasis |
Table 2. Anatomic stage/prognostic group (Open Table in a new window)
Stage |
T |
N |
M |
0 |
Tis |
N0 |
M0 |
I |
T1 |
N0 |
M0 |
IIA |
T2 |
N0 |
M0 |
IIB |
T3 |
N0 |
M0 |
IIIA |
T1-T2 |
N1 |
M0 |
IIIB |
T4 |
N0 |
M0 |
IIIC |
T3-T4 |
N1 |
M0 |
IV |
Any T |
Any N |
M1 |
Table 3. Histologic Grade (Open Table in a new window)
Grade | Definition |
---|---|
GX | Grade cannot be determined |
G1 | Well differentiated (low grade) |
G2 | Moderately differentiated (low grade) |
G3 | Poorly differentiated (high grade) |
G4 | Undifferentiated (high grade) |