Clinical Breast Imaging: A Patient Focused Teaching File, 1st Edition

Appendix: Breast Cancer TNM Classification and Stage Grouping

Primary Tumor (same for clinical and pathologic classification)

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 with no tumor

T1

tumor 2 cm or less in greatest dimension

T1mic

microinvasion 0.1 cm or less in greatest dimension

T1a

tumor >0.1 cm but not >0.5 cm in greatest

dimension

 

T1b

tumor >0.5 cm but not >1 cm in greatest

dimension

 

T1c

tumor >1 cm but not >2 cm in greatest dimension

T2

tumor >2 cm but not >5 cm in greatest dimension

T3

tumor >5 cm in greatest dimension

T4

tumor of any size with direct extension to chest wall or skin

T4a

extension to chest wall but not including pectoral muscle

T4b

edema (peau d'orange) or ulceration of the skin of the breast, or satellite skin nodules confined to the same breast

T4c

both T4a and T4b

T4d

inflammatory carcinoma

Regional Lymph Node (pathologic, pN)

pNX

regional lymph nodes cannot be assessed (previously removed or not excised)

pN0

No regional lymph node metastasis histologically; no additional examination for isolated tumor cells (ITC)

pN0(i-)

No regional lymph node metastasis histologically, negative immunohistochemical (IHC) studies

pN0(i+)

No regional lymph node metastasis histologically, positive IHC, no IHC cluster >0.2 mm

pN0(mol-)

No regional lymph node metastasis histologically; negative molecular findings (reverse transcriptase/polymerase chain reaction, RT-PCR)

pN0(mol+)

No regional lymph node metastasis histologically; positive molecular reaction (RT-PCR)

pN1

metastasis in 1 to 3 axillary lymph nodes and/or internal mammary lymph nodes with microscopic disease detected by sentinel lymph node dissection but not clinically apparent (not detected by imaging studies or clinical examination)

pN1mi

micrometastasis (>0.2 mm, none >2.0 mm)

pN1a

metastasis in 1 to 3 axillary lymph nodes

pN1b

metastasis in internal mammary lymph nodes with microscopic disease detected by sentinel lymph node but not clinically apparent (not detected by imaging studies or clinical examination)

pN1c

metastasis in 1 to 3 axillary lymph nodes and in internal mammary lymph nodes with microscopic disease detected by sentinel lymph node dissection but not clinically apparent (not detected by imaging studies or clinical examination). If associated with >3 positive axillary lymph nodes, the internal mammary nodes are classified as pN3b

pN2

metastasis in 4 to 9 axillary lymph nodes, or in clinically apparent internal mammary lymph nodes in the absence of axillary lymph node metastasis

pN2a

metastasis in 4 to 9 axillary lymph nodes (at least one tumor deposit >2.0 mm)

pN2b

metastasis in clinically apparent (detected by imaging studies, excluding lymphoscintigraphy or clinical examination) internal mammary lymph nodes in the absence of axillary lymph node metastasis

pN3

metastasis in 10 or more axillary lymph nodes, or in infraclavicular lymph nodes, or in clinically apparent ipsilateral internal mammary lymph nodes in the presence of 1 or more positive axillary lymph node; or in >3 axillary lymph nodes with clinically negative microscopic metastasis in internal mammary lymph nodes; or in ipsilateral supraclavicular lymph nodes

pN3a

metastasis in 10 or more axillary lymph nodes (at least one tumor deposit >2.0 mm), or metastasis to the infraclavicular lymph nodes

pN3b

metastasis in clinically apparent ipsilateral mammary lymph nodes in the presence of 1 or more positive axillary lymph nodes; or in >3 axillary lymph nodes and in internal mammary lymph nodes with microscopic disease detected by sentinel lymph node dissection but not clinically apparent

pN3c

metastasis in ipsilateral supraclavicular lymph nodes

(sn) = sentinel lymph node

If surgery occurs after the patient has received neoadjuvant chemotherapy, hormonal therapy, immunotherapy, or radiation therapy, the prefix “y” is used with the TNM classification

Distant Metastasis

MX

distant metastasis cannot be assessed

M0

no distant metastasis

M1

distant metastasis

Stage 0

Tis

N0

M0

Stage I

T1

N0

M0

Stage IIA

T0

N1

M0

 

T1

N1

M0

 

T2

N0

M0

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

Stage IIIB

T4

N0

M0

 

T4

N1

M0

 

T4

N2

M0

Stage IIIC

Any T

N3

M0

Stage IV

Any T

Any N

M0

 



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