Breast cancer stages, TNM and UICC explained

When breast cancer is found, the stage describes how far it has advanced. The basis is the TNM classification: T stands for the size of the tumor, N (nodes) for whether the lymph nodes are involved, and M for distant metastases.

The TNM classification leads to the following stages:

• Stage 0: a precursor, a carcinoma in situ that is still confined to one spot.
• Stage I: a small, locally confined tumor with no lymph node involvement and no distant metastases.
• Stage II: a larger tumor or mild lymph node involvement, no distant metastases.
• Stage III: more advanced, with greater involvement of the surrounding lymph nodes or growth into the skin or chest wall.
• Stage IV: distant metastases are present, regardless of tumor size and lymph nodes.

Stages 0 and I are considered early, II and III advanced, and IV metastatic. The stage is key to planning treatment individually. The surgery