T₀ No evidence of tumor

Tis In Situ cancer (lobular, intraductal, and Padgets disease of nipple)

No palpable tumor

T₁ Tumor 2 cm. or less in diameter

T_1a Tumor not fixed to tissue, muscle

T_1b Tumor fixed to tissues

T₂ Tumor up to 5 cm. in diameter

T_2a Tumor not fixed to tissue

T_2b Tumor fixed to tissue

T₃ Tumor greater than 5 cm. in dia.

T_3a Tumor does not extend to pectoral tissue or muscle

T_3b Tumor fixed to tissue

T₄ Tumor of any size which extends to chest wall or skin

T_4a Tumor fixed to chest wall

T_4b Edema, ulceration of breast skin, satellite nodes on same breast

T_4c Both a and b above

N₀ No nodal involvement

N₁ Axillary nodal involvement

N₂ Axillary nodal involvement with nodes extended to one another or nearby structures

N₃ Subclavicular nodal involvement or edema of arm caused by lymphatic obstruction

M₀ No Metastasis

M₁ Metastasis present