TNM Classification for Breast Cancer
The American Joint Committee on Cancer (AJCC) provides two principal groups for breast cancer staging: anatomic, which is based on extent of cancer as defined by tumor size (T), lymph node status (N), and distant metastasis (M); and prognostic, which includes anatomic TNM plus tumor grade and the status of the biomarkers human epidermal growth factor receptor 2 (HER2), estrogen receptor (ER), and progesterone receptor (PR). The prognostic stage group is preferred for patient care and is to be used for reporting of all cancer patients in the United States. [1, 2]
In turn, prognostic stages are divided into clinical and pathological groups. Pathological stage applies to patients who have undergone surgery as the initial treatment for breast cancer. It includes all information used for clinical staging plus findings at surgery and pathological findings from surgical resection. Pathological prognostic stage does not apply to patients who received neoadjuvant therapy (systemic agents or radiation prior to surgical resection). [1, 2, 3] See the tables below.
Table. TNM Classification for Breast Cancer (Open Table in a new window)
Primary tumor (T) |
|
TX |
Primary tumor cannot be assessed |
T0 |
No evidence of primary tumor |
Tis |
Carcinoma in situ |
Tis (DCIS) |
Ductal carcinoma in situ |
Tis (Paget) |
Paget disease of the nipple NOT associated with invasive carcinoma and/or carcinoma in situ (DCIS) in the underlying breast parenchyma. Carcinomas in the breast parenchyma associated with Paget disease are categorized on the basis of the size and characteristics of the parenchymal disease, although the presence of Paget disease should still be noted |
T1 |
Tumor ≤ 20 mm in greatest dimension |
T1mi |
Tumor ≤ 1 mm in greatest dimension |
T1a |
Tumor > 1 mm but ≤ 5 mm in greatest dimension (round any measurement >1.0-1.9 mm to 2 mm) |
T1b |
Tumor > 5 mm but ≤ 10 mm in greatest dimension |
T1c |
Tumor > 10 mm but ≤ 20 mm in greatest dimension |
T2 |
Tumor > 20 mm but ≤ 50 mm in greatest dimension |
T3 |
Tumor > 50 mm in greatest dimension |
T4 |
Tumor of any size with direct extension to the chest wall and/or to the skin (ulceration or skin nodules), not including invasion of dermis alone |
T4a |
Extension to chest wall, not including only pectoralis muscle adherence/invasion |
T4b |
Ulceration and/or ipsilateral satellite nodules and/or edema (including peau d’orange) of the skin, which do not meet the criteria for inflammatory carcinoma |
T4c |
Both T4a and T4b |
T4d |
Inflammatory carcinoma |
Regional lymph nodes (N) |
|
Clinical |
|
cNX |
Regional lymph nodes cannot be assessed (eg, previously removed) |
cN0 |
No regional lymph node metastasis (on imaging or clinical examination) |
cN1 |
Metastasis to movable ipsilateral level I, II axillary lymph node(s) |
cN1mi |
Micrometastases (approximately 200 cells, larger than 0.2 mm, but none larger than 2.0 mm) |
cN2 |
Metastases in ipsilateral level I, II axillary lymph nodes that are clinically fixed or matted; or in ipsilateral internal mammary nodes in the absence of clinically evident axillary lymph node metastases |
cN2a |
Metastases in ipsilateral level I, II axillary lymph nodes fixed to one another (matted) or to other structures |
cN2b |
Metastases only in ipsilateral internal mammary nodes and in the absence of axillary lymph node metastases |
cN3 |
Metastases in ipsilateral infraclavicular (level III axillary) lymph node(s), with or without level I, II axillary node involvement, or in ipsilateral internal mammary lymph node(s) with level I, II axillary lymph node metastasis; or metastases in ipsilateral supraclavicular lymph node(s), with or without axillary or internal mammary lymph node involvement |
cN3a |
Metastasis in ipsilateral infraclavicular lymph node(s) |
cN3b |
Metastasis in ipsilateral internal mammary lymph node(s) and axillary lymph node(s) |
cN3c |
Metastasis in ipsilateral supraclavicular lymph node(s) |
Note: (sn) and (f) suffixes should be added to the N category to denote confirmation of metastasis by sentinel node biopsy or fine needle aspiration/core needle biopsy, respectively. |
|
Pathologic (pN) |
|
pNX |
Regional lymph nodes cannot be assessed (for example, previously removed, or not removed for pathologic study) |
pN0 |
No regional lymph node metastasis identified histologically, or isolated tumor cell clusters (ITCs) only. Note: ITCs are defined as small clusters of cells ≤ 0.2 mm, or single tumor cells, or a cluster of < 200 cells in a single histologic cross-section; ITCs may be detected by routine histology or by immunohistochemical (IHC) methods; nodes containing only ITCs are excluded from the total positive node count for purposes of N classification but should be included in the total number of nodes evaluated |
pN0(i) |
No regional lymph node metastases histologically, negative IHC |
pN0(i+) |
ITCs only in regional lymph node(s) |
pN0(mol-) |
No regional lymph node metastases histologically, negative molecular findings (reverse transcriptase polymerase chain reaction [RT-PCR]) |
pN0(mol+) |
Positive molecular findings by RT-PCR; no ITCs detected |
pN1 |
Micrometastases; or metastases in 1-3 axillary lymph nodes and/or in internal mammary nodes; and/or in clinically negative internal mammary nodes with micrometastases or macrometastases by sentinel lymph node biopsy |
pN1mi |
Micrometastases (200 cells, > 0.2 mm but none > 2.0 mm) |
pN1a |
Metastases in 1-3 axillary lymph nodes (at least 1 metastasis > 2.0 mm) |
pN1b |
Metastases in ipsilateral internal mammary lymph nodes, excluding ITCs, detected by sentinel lymph node biopsy |
pN1c |
Metastases in 1-3 axillary lymph nodes and in internal mammary sentinel nodes (ie, pN1a and pN1b combined) |
pN2 |
Metastases in 4-9 axillary lymph nodes; or positive ipsilateral internal mammary lymph nodes by imaging in the absence of axillary lymph node metastases |
pN2a |
Metastases in 4-9 axillary lymph nodes (at least 1 tumor deposit > 2.0 mm) |
pN2b |
Clinically detected* metastases in internal mammary lymph nodes with or without microscopic confirmation; with pathologically negative axillary lymph nodes |
pN3 |
Metastases in ≥ 10 axillary lymph nodes; or in infraclavicular (level III axillary) lymph nodes; or positive ipsilateral internal mammary lymph nodes by imaging in the presence of one or more positive level I, II axillary lymph nodes; or in > 3 axillary lymph nodes and micrometastases or macrometastases by sentinel lymph node biopsy in clinically negative ipsilateral internal mammary lymph nodes; or in ipsilateral supraclavicular lymph nodes |
pN3a |
Metastases in ≥ 10 axillary lymph nodes (at least 1 tumor deposit > 2.0 mm); or metastases to the infraclavicular (level III axillary lymph) nodes |
pN3b |
pN1a or pN2a in the presence of cN2b (positive internal mammary nodes by imaging) or pN2a in the presence of pN1b |
pN3c |
Metastases in ipsilateral supraclavicular lymph nodes |
*"Clinically detected" is defined as detected by imaging studies (excluding lymphoscintigraphy) or by clinical examination and having characteristics highly suspicious for malignancy or a presumed pathologic macrometastasis on the basis of FNA biopsy with cytologic examination. |
|
Distant metastasis (M) |
|
M0 |
No clinical or radiographic evidence of distant metastasis |
cM0(i+) |
No clinical or radiographic evidence of distant metastases in the presence of tumor cells or deposits no larger than 0.2 mm detected microscopically or by molecular techniques in circulating blood, bone marrow, or other nonregional nodal tissue in a patient without symptoms or signs of metastase |
cM1 |
Distant metastases detected by clinical and radiographic means |
pM1 |
Any histologically proven metastases in distant organs; or if in non-regional nodes, metastases > 0.2 mm |
Table. Histologic grade (Open Table in a new window)
Histologic grade (G) |
|
GX |
Grade cannot be assessed |
G1 |
Low combined histologic grade (favorable) |
G2 |
Intermediate combined histologic grade (moderately favorable) |
G3 |
High combined histologic grade (unfavorable) |
Table. Anatomic stage/prognostic groups (Open Table in a new window)
Stage |
T |
N |
M |
0 |
Tis |
N0 |
M0 |
IA |
T1 |
N0 |
M0 |
IB |
T0 |
N1mi |
M0 |
|
T1 |
N1mi |
M0 |
IIA |
T0 |
N1 |
M0 |
|
T1 |
N1 |
M0 |
|
T2 |
N0 |
M0 |
IIB |
T2 |
N1 |
M0 |
|
T3 |
N0 |
M0 |
IIIA |
T0 |
N2 |
M0 |
|
T1 |
N2 |
M0 |
|
T2 |
N2 |
M0 |
|
T3 |
N1 |
M0 |
|
T3 |
N2 |
M0 |
IIIB |
T4 |
N0 |
M0 |
|
T4 |
N1 |
M0 |
|
T4 |
N2 |
M0 |
IIIC |
Any T |
N3 |
M0 |
IV |
Any T |
Any N |
M1 |
Notes:
-
T1 includes T1mi.
-
T0 and T1 tumors with nodal micrometastases (N1mi) are staged as Stage IB.
-
T2, T3, and T4 tumors with nodal micrometastases (N1mi) are staged using the N1 category.
-
M0 includes M0(i+)
-
The designation pM0 is not valid; any M0 is clinical.
-
If a patient presents with M1 disease prior to neoadjuvant systemic therapy, the stage is considered stage IV and remains stage IV regardless of response to neoadjuvant therapy.
-
Stage designation may be changed if postsurgical imaging studies reveal the presence of distant metastases, provided the studies are performed within 4 months of diagnosis in the absence of disease progression, and provided the patient has not received neoadjuvant therapy.
-
Staging following neoadjuvant therapy is designated with “yc” or “yp” prefix to the T and N classification. No anatomic stage group is assigned if there is a complete pathologic response (pCR) to neoadjuvant therapy, for example, ypT0ypN0cM0.
Table. Clinical prognostic stage (Open Table in a new window)
TNM |
Grade |
HER2 |
ER |
PR |
Stage |
Tis N0 M0 |
Any |
Any |
Any |
Any |
0 |
T1 N0 M0 T0 N1mi M0 T1 N1mi M0 |
G1 |
Positive |
Positive |
Positive |
IA |
Negative |
|||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
|||
Negative |
|||||
Negative |
Positive |
||||
Negative |
IB |
||||
G2 |
Positive |
Positive |
Positive |
IA |
|
Negative |
|||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
|||
Negative |
|||||
Negative |
Positive |
||||
Negative |
IB |
||||
G3 |
Positive |
Positive |
Positive |
IA |
|
Negative |
|||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
|||
Negative |
IB |
||||
Negative |
Positive |
||||
Negative |
|||||
T0 N1 M0 T1 N1 M0 T2 N0 M0 |
G1 |
Positive |
Positive |
Positive |
IB |
Negative |
IIA |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
IB |
||
Negative |
IIA |
||||
Negative |
Positive |
||||
Negative |
|||||
G2 |
Positive |
Positive |
Positive |
IB |
|
Negative |
IIA |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
IB |
||
Negative |
IIA |
||||
Negative |
Positive |
||||
Negative |
IIB |
||||
G3 |
Positive |
Positive |
Positive |
IB IIA |
|
Negative |
|||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
|||
Negative |
IIB |
||||
Negative |
Positive |
||||
Negative |
|||||
T2 N1 M0 T3 N0 M0 |
G1 |
Positive |
Positive |
Positive |
IB |
Negative |
IIA |
||||
Negative |
Positive |
||||
Negative |
IIB |
||||
Negative |
Positive |
Positive |
IIA |
||
Negative |
IIB |
||||
Negative |
Positive |
||||
Negative |
|||||
G2 |
Positive |
Positive |
Positive |
IB |
|
Negative |
IIA |
||||
Negative |
Positive |
||||
Negative |
IIB |
||||
Negative |
Positive |
Positive |
IIA |
||
Negative |
IIB |
||||
Negative |
Positive |
||||
Negative |
IIIB |
||||
G3 |
Positive |
Positive |
Positive |
IB |
|
Negative |
IIB |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
|||
Negative |
IIIA |
||||
Negative |
Positive |
||||
Negative |
IIIB |
||||
T0 N2 M0 T1 N2 M0 T2 N2 M0 T3 N1 M0 T3 N2 M0 |
G1 |
Positive |
Positive |
Positive |
IIA |
Negative |
IIIA |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
IIA |
||
Negative |
IIIA |
||||
Negative |
Positive |
||||
Negative |
IIIB |
||||
G2 |
Positive |
Positive |
Positive |
IIA |
|
Negative |
IIIA |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
IIA |
||
Negative |
IIIA |
||||
Negative |
Positive |
||||
Negative |
IIIB |
||||
G3 |
Positive |
Positive |
Positive |
IIB |
|
Negative |
IIIA |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
|||
Negative |
IIIB |
||||
Negative |
Positive |
||||
Negative |
IIIC |
||||
T4 N0 M0 T4 N1 M0 T4 N2 M0 Any T N3 M0 |
G1 |
Positive |
Positive |
Positive |
IIIA |
Negative |
IIIB |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
|||
Negative |
|||||
Negative |
Positive |
||||
Negative |
IIIC |
||||
G2 |
Positive |
Positive |
Positive |
IIIA |
|
Negative |
IIIB |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
|||
Negative |
|||||
Negative |
Positive |
||||
Negative |
IIIC |
||||
G3 |
Positive |
Positive |
Positive |
IIIB |
|
Negative |
|||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
|||
Negative |
IIIC |
||||
Negative |
Positive |
||||
Negative |
|||||
Any T Any N M1 |
Any |
Any |
Any |
Any |
IV |
ER=estrogen receptor; PR=progesterone receptor |
Table. Pathological prognostic stage (Open Table in a new window)
TNM |
Grade |
HER2 |
ER |
PR |
Stage |
Tis N0 M0 |
Any |
Any |
Any |
Any |
0 |
T1 N0 M0 T0 N1mi M0 T1 N1mi M0 |
G1 |
Positive |
Positive |
Positive |
IA |
Negative |
|||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
|||
Negative |
|||||
Negative |
Positive |
||||
Negative |
|||||
G2 |
Positive |
Positive |
Positive |
||
Negative |
|||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
|||
Negative |
|||||
Negative |
Positive |
||||
Negative |
IB |
||||
G3 |
Positive |
Positive |
Positive |
IA |
|
Negative |
|||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
|||
Negative |
|||||
Negative |
Positive |
||||
Negative |
IB |
||||
T0 N1 M0 T1 N1 M0 T2 N0 M0 |
G1 |
Positive |
Positive |
Positive |
IA |
Negative |
IB |
||||
Negative |
Positive |
||||
Negative |
IIA |
||||
Negative |
Positive |
Positive |
IA |
||
Negative |
IB |
||||
Negative |
Positive |
||||
Negative |
IIA |
||||
G2 |
Positive |
Positive |
Positive |
IA |
|
Negative |
IB |
||||
Negative |
Positive |
||||
Negative |
IIA |
||||
Negative |
Positive |
Positive |
IA |
||
Negative |
IIA |
||||
Negative |
Positive |
||||
Negative |
|||||
G3 |
Positive |
Positive |
Positive |
IA IIA |
|
Negative |
|||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
IB |
||
Negative |
IIA |
||||
Negative |
Positive |
||||
Negative |
|||||
T2 N1 M0 T3 N0 M0 |
G1 |
Positive |
Positive |
Positive |
IA |
Negative |
IIB |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
IA |
||
Negative |
IIB |
||||
Negative |
Positive |
||||
Negative |
|||||
G2 |
Positive |
Positive |
Positive |
IB |
|
Negative |
IIB |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
IB |
||
Negative |
IIB |
||||
Negative |
Positive |
||||
Negative |
|||||
G3 |
Positive |
Positive |
Positive |
IB |
|
Negative |
IIB |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
IIA |
||
Negative |
IIB |
||||
Negative |
Positive |
||||
Negative |
IIIA |
||||
T0 N2 M0 T1 N2 M0 T2 N2 M0 T3 N1 M0 T3 N2 M0 |
G1 |
Positive |
Positive |
Positive |
IB |
Negative |
IIIA |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
IB |
||
Negative |
IIIA |
||||
Negative |
Positive |
||||
Negative |
|||||
G2 |
Positive |
Positive |
Positive |
IB |
|
Negative |
IIIA |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
IB |
||
Negative |
IIIA |
||||
Negative |
Positive |
||||
Negative |
IIIB |
||||
G3 |
Positive |
Positive |
Positive |
IIA |
|
Negative |
IIIA |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
IIA |
||
Negative |
IIIA |
||||
Negative |
Positive |
||||
Negative |
IIIC |
||||
T4 N0 M0 T4 N1 M0 T4 N2 M0 Any T N3 M0 |
G1 |
Positive |
Positive |
Positive |
IIIA |
Negative |
IIIB |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
IIIA |
||
Negative |
IIIB |
||||
Negative |
Positive |
||||
Negative |
|||||
G2 |
Positive |
Positive |
Positive |
IIIA |
|
Negative |
IIIB |
||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
IIIA |
||
Negative |
IIIB |
||||
Negative |
Positive |
||||
Negative |
IIIC |
||||
G3 |
Positive |
Positive |
Positive |
IIIB |
|
Negative |
|||||
Negative |
Positive |
||||
Negative |
|||||
Negative |
Positive |
Positive |
|||
Negative |
IIIC |
||||
Negative |
Positive |
||||
Negative |
|||||
Any T Any N M1 |
Any |
Any |
Any |
Any |