The currently accepted breast cancer staging standard at home and abroad is the TNM staging method jointly developed by the International Union Against Cancer (UICC) and the American Cancer Society in 2003 (T stands for primary tumor; N stands for lymphatic metastasis; M stands for distant metastasis).
1.Primary tumor (T) staging
Tx: the size of primary tumor cannot be measured; or cancer cells are found in sputum exfoliated cells, or bronchial flush fluid, but imaging and bronchoscopy do not reveal primary tumor.
To: no evidence of primary tumor.
Tis: carcinoma in situ (intraductal carcinoma, lobular carcinoma in situ, papillary Paget’s disease without a mass).
T1: primary lesion ≤ 2 cm in diameter.
T1mis: microinvasive carcinoma (tumor beyond the basement membrane) with a maximum diameter ≤ 0.1 cm.
T1a: tumor maximum diameter >0.1cm, but ≤0.5cm
T1b: tumor diameter >0.5cm, but ≤1.0cm
T1c: maximum diameter of tumor >1.0cm, but ≤2.0cm
T2: the maximum diameter of tumor >2.0cm, but ≤5.0cm
T3: tumor maximum diameter >5cm.
T4: tumor regardless of size, but directly invading chest wall or skin
T4a: tumor directly invades the chest wall, including the ribs, intercostal muscles and anterior serratus, but not the pectoralis muscle.
T4b: tumor surface skin edema (including cellulite), breast skin ulceration or micro nodules, limited to the ipsilateral breast.
T4c: including T4a and T4b
T4d: inflammatory breast cancer (extensive skin infiltration, surface redness and swelling, but not necessarily palpable mass under it).
2.Lymph node metastasis (N) staging
Nx: indeterminate lymph node condition (e.g., has been surgically removed)
N0: no regional lymph node enlargement.
N1: ipsilateral axillary lymph nodes that are enlarged and metastatic, but mobile.
N2a: ipsilateral axillary lymph nodes that are enlarged, metastatic, fused to each other, or adherent to other nearby tissues.
N3a: ipsilateral subclavian axillary lymph node enlargement and metastasis.
N3b: ipsilateral internal breast lymph node metastasis with ipsilateral axillary lymph node enlargement metastasis.
N3c: ipsilateral supraclavicular fossa lymph node enlargement metastasis.
3. Distant metastasis (M) staging
Mx: unable to evaluate the presence or absence of distant metastases
Mo: no distant metastasis.
M1: with distant metastasis.
4.TNM clinical staging
Stage 0: TisNoMo;
Stage 1: T1NoMo
Stage IIa: ToN1Mo,T1N1Mo,T2N0Mo.
Stage IIb: T2N1Mo,T3N0Mo.
Phase IIIa: T0N2Mo, T1N2Mo, T2N2Mo, T3N1Mo, T3N2Mo.
Phase IIIb: T4N0Mo, T4N1Mo, T4N2Mo.
Phase IIIc: any TN3Mo.
Phase IV: any T any NM1.