What is the difference between primary bone cancer and secondary bone cancer?

Primary bone cancer refers to cancers that start in the bone.  Secondary bone cancer is cancer that spreads to the bone from another part of the body.

Primary bone cancer is rare, with approximately 2,400 new cases diagnosed each year in the United States.

More commonly, bones are the site of tumors that result from the spread (metastasis) of cancer from other parts of the body such as the breasts, lungs or prostate.

Bone metastases can cause pain and can lead to other symptoms such as hypercalcemia (abnormally high levels of calcium in the blood).