Bone metastasis

Metastasis is the spread of cancer cells from one site to another, resulting in the formation of secondary or metastatic tumours.  For example, when breast cancer cells spread (metastasize) to the bone, the resulting secondary tumour(s) would be referred to as metastatic breast cancer of the bone.  In the case of breast cancer metastasis, seventy percent of cancer cells migrate to the bone, forming tumours at multiple sites.  These secondary tumours are often aggressive and produce significant pain and severe osteolytic bone lesions.

General information on metastasis: link here