Osteoclasts destroy the old bone and osteoblasts deposit new minerals and build new bone.
Cancer cells that have spread to the bone produce chemicals that influence the activity of these cells, upsetting the normal balance. This commonly causes small holes in the bone due to overactivity of the osteoclasts. They are not a treatment for the cancer itself but may help to reduce the breakdown of the bone and so reduce the risk of fracture and discomfort. Increasingly, doctors are recommending the long-term use of biophosphonates as a way of treating bone pain, preventing broken bones and reducing the need for radiotherapy treatment. Some bisphosphonates can be taken by mouth as tablets but these must be taken on an empty stomach an hour before food.