The Who, What, Where, When and Sometimes, Why.

Metastases and Staging

The letter “M’ in the TNM breast cancer staging system shows the presence or absence of metastases.

Cancer has either spread beyond the breast and nearby lymph nodes to other areas of the body (M1) or it has not (M0).


No metastases



The following is a 3D interactive model showing breast cancer and possible areas of metastases (spread).

Tests for metastases include:

  • Bone scans (to look for bone metastases)
  • Blood tests (to check for liver or bone metastases)
  • X-rays or CT scans (to look for lung, liver, abdominal or pelvis metastases)
  • PET scans (to look for metastases throughout the body)

Learn about treatment for metastatic breast cancer.

Learn more about breast cancer staging.

Updated 12/21/23