TNM classification

Information source http://cancernet.nci.nih.gov

The American Joint Committee on Cancer (AJCC) staging system provides a strategy for grouping patients with respect to prognosis. Therapeutic decisions are formulated in part according to staging categories but primarily according to lymph node status, estrogen- and progesterone-receptor levels in the tumor tissue, menopausal status, and the general health of the patient.

The AJCC has designated staging by TNM classification.

Stage Information

The American Joint Committee on Cancer (AJCC) staging system provides a strategy for grouping patients with respect to prognosis. Therapeutic decisions are formulated in part according to staging categories but primarily according to lymph node status, estrogen- and progesterone-receptor levels in the tumor tissue, menopausal status, and the general health of the patient.

The AJCC has designated staging by TNM classification.

TNM definitions

Primary tumor (T):

TX: Primary tumor cannot be assessed T0: No evidence of primary tumor Tis: Carcinoma in situ; intraductal carcinoma, lobular carcinoma in situ, or
Paget's disease of the nipple with no associated tumor.
Note: Paget's disease associated with a tumor is classified according
to the size of the tumor.
T1: Tumor 2.0 cm or less in greatest dimension
T1mic: Microinvasion 0.1 cm or less in greatest dimension
T1a: Tumor more than 0.1 but not more than 0.5 cm in greatest dimension
T1b: Tumor more than 0.5 cm but not more than 1.0 cm in greatest dimension
T1c: Tumor more than 1.0 cm but not more than 2.0 cm in greatest dimension
T2: Tumor more than 2.0 cm but not more than 5.0 cm in greatest dimension T3: Tumor more than 5.0 cm in greatest dimension T4: Tumor of any size with direct extension to (a) chest wall or (b) skin,
only as described below.
Note: Chest wall includes ribs, intercostal muscles, and serratus
anterior muscle but not pectoral muscle.
T4a: Extension to chest wall
T4b: Edema (including peau d'orange) or ulceration of the skin of the
breast or satellite skin nodules confined to the same breast

T4c: Both of the above (T4a and T4b)
T4d: Inflammatory carcinoma*


*Note: Inflammatory carcinoma is a clinicopathologic entity characterized
by diffuse brawny induration of the skin of the breast with an erysipeloid
edge, usually without an underlying palpable mass.1 Radiologically
there may be a detectable mass and characteristic thickening of the skin
over the breast. This clinical presentation is due to tumor embolization
of dermal lymphatics with engorgement of superficial capillaries.


Regional lymph nodes (N):

NX: Regional lymph nodes cannot be assessed (e.g., previously removed)
N0: No regional lymph node metastasis
N1: Metastasis to movable ipsilateral axillary lymph node(s)
N2: Metastasis to ipsilateral axillary lymph node(s) fixed to each other or
to other structures

N3: Metastasis to ipsilateral internal mammary lymph node(s)

Pathologic classification (pN):

pNX: Regional lymph nodes cannot be assessed (not removed for pathologic
study or previously removed)

pN0: No regional lymph node metastasis
pN1: Metastasis to movable ipsilateral axillary lymph node(s)
pN1a: Only micrometastasis (none larger than 0.2 cm)
pN1b: Metastasis to lymph node(s), any larger than 0.2 cm
pN1bi: Metastasis in 1 to 3 lymph nodes, any more than 0.2 cm and all
less than 2.0 cm in greatest dimension

pN1bii: Metastasis to 4 or more lymph nodes, any more than 0.2 cm and
all less than 2.0 cm in greatest dimension

pN1biii: Extension of tumor beyond the capsule of a lymph node
metastasis less than 2.0 cm in greatest dimension

pN1biv: Metastasis to a lymph node 2.0 cm or more in greatest dimension


pN2: Metastasis to ipsilateral axillary lymph node(s) fixed to each other
or to other structures

pN3: Metastasis to ipsilateral internal mammary lymph node(s)

Distant metastasis (M):

MX: Presence of distant metastasis cannot be assessed
M0: No distant metastasis
M1: Distant metastasis present (includes metastasis to ipsilateral
supraclavicular lymph nodes)

AJCC stage groupings

Stage 0

Tis, N0, M0

Stage I

T1,* N0, M0

*T1 includes T1mic

Stage IIA

T0, N1, M0 T1,* N1,** M0 T2, N0, M0

*T1 includes T1mic **The prognosis of patients with pN1a disease is similar to that of patients
with pN0 disease.


Stage IIB

T2, N1, M0
T3, N0, M0

Stage IIIA

T0, N2, M0 T1,* N2, M0 T2, N2, M0 T3, N1, M0 T3, N2, M0

*T1 includes T1mic

Stage IIIB

T4, Any N, M0
Any T, N3, M0

Stage IV

Any T, Any N, M1