How do bone metastases affect the bone?
To understand how bone metastases affect bone, let’s look at the life cycle of normal bone. Normal bone is an active tissue throughout life (1). Small areas of bone are constantly being worn away by special cells called osteoclasts (1). The chemicals that made up the worn away bone are reabsorbed into the blood (1). New bone is then built up by other cells, called osteoblasts (1). Osteoblasts take chemicals from the blood to create this new bone (1). This process of breakdown and buildup is coordinated by hormones and other chemicals that the cells secrete into the blood to communicate with one another (1). In areas of bone metastases where cancer has spread to bone, the bone damage is greater than would be expected from just the tumor pressing on the bone (1). In fact, tumor cells secrete chemicals that stimulate osteoclasts (1). The osteoclasts wear away portions of bones (reabsorption) leaving holes in the bone, called osteolytic lesions (3). The tumor cells can also secrete chemica
