A primary bone cancer is a cancer which starts and develops in the bone. Sometimes, cancer cells from a primary tumour elsewhere in the body can break away from that tumour and spread to the bones via the bloodstream or lymphatic system.

This forms a secondary bone cancer, which is a tumour in the bone originating from elsewhere in the body. The spread of cancer to other areas of the body is known as metastasis and is a large factor in patientsā€™ survival aspects.