different condition than primary bone cancer, which is cancer that actually begins in bone tissue. In this case, cancer cells break off from another "primary" tumor and enter the bloodstream. The blood is a medium of metastasis, allows the cancerous cells to spread, and the cancer affects bone tissue.

The spread of malignant cancer cells to bone.

Cancer that has spread to the bone. Also called secondary bone cancer. Cancers that have spread to the bone are called metastasized cancer, and the tumors known as metastases, or, in singular form, a metastasis.