Dr. Venslow Greaves, radiation oncologist at the Radiation Oncology Centre of Jamaica Limited in Kingston, notes that cancer, by definition, is a disease that has the ability to spread from point of origin to anywhere in the body.

So it is with bone cancer, which often appears after malignant cells metastasise from other areas - breaking off and spreading via the blood stream and lymphatic system to other organs, as well as the bone.

According to Greaves, primary bone cancer (which originates in the bone) is pretty rare.

He notes: "Most of the bone cancer which I have seen are metastases. Osteosarcoma arising from the growing edge of the bone is rare."

Radiotherapy

At www.cancerbackup.com it is noted that people who have had previous high doses of radiotherapy to an area that includes bones, have a slightly increased risk of developing cancer of that bone. But this, they say, is still a very small risk, and most people who have radiotherapy will never develop a primary bone cancer.

It is also noted that people who have a type of long-term disease of the bone, known as Paget's disease, have an increased risk of developing an osteosarcoma.

If one has had a benign (non-cancerous) bone tumour known as a osteochondroma or a chondroma, one will have a slightly increased risk of developing a chondrosarcoma.

It is sometimes thought that an injury or knock to a bone can cause cancer to develop, but thereis very little evidence to suggest that an injury will cause bone cancer. An injury may draw attention to a bone cancer that is already there.

According to Dr. Greaves, the symptoms of bone cancer depend on its origination. If it originates in a long bone, such as the tibia or femur, the cancer may present with pain, swelling or even as fracture. When you do X-rays you see abnormal depositions of bone and calcium.

Certain cancers, Dr. Greaves notes, including breast, prostate and lung, are more likely to spread to the bone.

The treatment, of course, depends on type of cancer.

For osteosarcoma, the treatment is surgery along with chemotherapy, unless it is in a difficult site for surgery, such as vertebra or bones of the back, in which case radiation will be tried.

Early detection

Success of treatment, however, depends on how early cancer is detected. If it is detected from the very early stages, the prognosis is pretty good, the oncologist states.

In this case, you will be able to do surgery along with chemotherapy and eradicate it all together. For advanced stages, it is accepted that this may not be curable.

Bone cancer which has spread to the lung - osteosarcoma included - is usually incurable.

- Outlook Team