Breast Cancer Staging 

Updated: Dec 13, 2017
  • Author: Joseph A Sparano, MD; Chief Editor: Marie Catherine Lee, MD, FACS  more...
  • Print

TNM Classification for Breast Cancer

The TNM classification for staging of breast cancer is provided below. [1]

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 (LCIS)

Lobular carcinoma in situ

Tis (Paget)

Paget disease of the nipple NOT associated with invasive carcinoma and/or carcinoma in situ (DCIS and/or LCIS) in the underlying breast parenchyma. Carcinomas in the breast parenchyma associated with Paget disease are categorized based on 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

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)

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

NX

Regional lymph nodes cannot be assessed (eg, previously removed)

N0

No regional lymph node metastasis

N1

Metastasis to movable ipsilateral level I, II axillary lymph node(s)

N2

Metastases in ipsilateral level I, II axillary lymph nodes that are clinically fixed or matted or in clinically detected* ipsilateral internal mammary nodes in the absence of clinically evident axillary lymph node metastasis

N2a

Metastases in ipsilateral level I, II axillary lymph nodes fixed to one another (matted) or to other structures

N2b

Metastases only in clinically detected* ipsilateral internal mammary nodes and in the absence of clinically evident level I, II axillary lymph node metastases

N3

Metastases in ipsilateral infraclavicular (level III axillary) lymph node(s), with or without level I, II axillary node involvement, or in clinically detected * ipsilateral internal mammary lymph node(s) and in the presence of clinically evident level I, II axillary lymph node metastasis; or metastasis in ipsilateral supraclavicular lymph node(s), with or without axillary or internal mammary lymph node involvement

N3a

Metastasis in ipsilateral infraclavicular lymph node(s)

N3b

Metastasis in ipsilateral internal mammary lymph node(s) and axillary lymph node(s)

N3c

Metastasis in ipsilateral supraclavicular lymph node(s)

*"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 fine-needle aspiration (FNA) biopsy with cytologic examination.

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. Note: Isolated tumor cell clusters (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+)

Malignant cells in regional lymph node(s) ≤ 0.2 mm (detected by hematoxylin-eosin [H&E] stain or IHC, including ITC)

pN0(mol-)

No regional lymph node metastases histologically, negative molecular findings (reverse transcriptase polymerase chain reaction [RT-PCR])

pN0(mol+)

Positive molecular findings (RT-PCR) but no regional lymph node metastases detected by histology or IHC

pN1

Micrometastases; or metastases in 1-3 axillary lymph nodes and/or in internal mammary nodes, with metastases detected by sentinel lymph node biopsy but not clinically detected†

pN1mi

Micrometastases (> 0.2 mm and/or > 200 cells, but none > 2.0 mm)

pN1a

Metastases in 1-3 axillary lymph nodes (at least 1 metastasis > 2.0 mm)

pN1b

Metastases in internal mammary nodes, with micrometastases or macrometastases detected by sentinel lymph node biopsy but not clinically detected†

pN1c

Metastases in 1-3 axillary lymph nodes and in internal mammary lymph nodes, with micrometastases or macrometastases detected by sentinel lymph node biopsy but not clinically detected†

pN2

Metastases in 4-9 axillary lymph nodes or in clinically detected‡ internal mammary lymph nodes 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

Metastases in clinically detected‡ internal mammary lymph nodes in the absence of axillary lymph node metastases

pN3

Metastases in ≥ 10 axillary lymph nodes; or in infraclavicular (level III axillary) lymph nodes; or in clinically detected‡ ipsilateral internal mammary lymph nodes in the presence of ≥ 1 positive level I, II axillary lymph nodes; or in > 3 axillary lymph nodes and in internal mammary lymph nodes, with micrometastases or macrometastases detected by sentinel lymph node biopsy but not clinically detected†; 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

Metastases in clinically detected‡ ipsilateral internal mammary lymph nodes in the presence of ≥ 1 positive axillary lymph nodes; or in > 3 axillary lymph nodes and in internal mammary lymph nodes, with micrometastases or macrometastases detected by sentinel lymph node biopsy but not clinically detected†

pN3c

Metastases in ipsilateral supraclavicular lymph nodes

*Classification is based on axillary lymph node dissection, with or without sentinel lymph node biopsy. Classification based solely on sentinel lymph node biopsy without subsequent axillary lymph node dissection is designated (sn) for "sentinel node"—for example, pN0(sn).

† "Not clinically detected" is defined as not detected by imaging studies (excluding lymphoscintigraphy) or not detected by clinical examination.

‡ "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, but deposits of molecularly or microscopically detected tumor cells in circulating blood, bone marrow, or other nonregional nodal tissue that are no larger than 0.2 mm in a patient without symptoms or signs of metastases

M1

Distant detectable metastases as determined by classic clinical and radiographic means and/or histologically proven > 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