TNM Definitions

Primary tumor

• TX Primary tumor cannot be assessed
• T0 No evidence of primary tumor
• Tis Carcinoma in situ
• T1 Tumor 2 cm or less in greatest dimension
• T2 Tumor more than 2 cm but not more than 5 cm in greatest dimension
• T3 Tumor more than 5 cm in greatest dimension
• T4 Tumor of any size with direct extension into chest wall (not including pectoral muscles) or skin edema or skin ulceration or satellite skin nodules confined to the same breast or inflammatory carcinoma.

Regional lymph node involvement

• NX Regional lymph nodes cannot be assessed
• N0 No regional lymph node involvement
• N1 Metastasis to movable ipsilateral axillary lymph node(s)
• N2 Metastasis to ipsilateral axillary lymph node(s) fixed to one another or to other structures
• N3 Metastasis to ipsilateral internal mammary lymph nodes.

Distant metastasis

• MX Presence of distant metastasis cannot be assessed
• M0 No distant metastasis
• M1 Distant metastasis present, including ipsilateral supraclavicular lymph nodes.

Examinations necessary for staging:

• Clinical examination
• Mammography
• Biopsy & anatomopathological examination
• Radiological examinations and bone scans to assess the presence of distant metastasis (based on clinical findings).