True bone cancer is uncommon, but cancer can also spread to bones from other parts of the body. Christian Ogilvie, MD, associate professor in the University of Minnesota Medical School Department of Orthopedic Surgery, explains the difference and how bone cancer is diagnosed and treated.
How do bone cancer and metastatic differ?
Usually when we say bone cancer, we’re referring to cancer that starts in the bone. That’s called primary bone cancer. Metastatic cancer starts somewhere else in the body and travels to the bone. It keeps the name of the original cancer -- for example, metastatic prostate cancer. Cancer that spreads to the bone is much more common than cancer that starts in the bone.
How does cancer spread to the bones?
One way that it spreads is through the vein system. From your neck down to your hips, you have connected networks of veins. Blood can travel from one vein to another. Once cancer gets into your blood, it can go anywhere from your shoulders to your hips if the conditions are right. Cancer can spread from organs to bones, or from bone to bone this way. The spine has a large system of veins, and its bones are most likely to be affected by cancer.
What causes bone cancer?
High-dose radiation is a risk factor. A few inherited conditions cause bone cancer, but they’re rare. One is Paget’s disease. It involves a high degree of bone activity, where bone is being destroyed and remade at a very fast rate. Rapid cell division increases the risk of an error where cancer can pop up.
What are the symptoms?
The main symptom is pain. A later symptom would be swelling as the tumor grows. Pain in the bone that doesn’t have another good explanation needs to be checked out.
How is bone cancer diagnosed?
Imaging tests such as X-rays look for abnormalities in the bone. If the X-ray finds anything, we need to do a biopsy. Needle biopsies are done when possible. In some cases, we have to do a surgical biopsy to get enough tissue.
How is it treated?
Most primary bone cancers are treated with chemotherapy first. Then we take the tumor out surgically, which may also involve reconstructing the bone. It’s typical to have more chemotherapy after surgery, to treat small amounts of the tumor that have already spread.
For metastatic cancer, there’s a two-fold strategy. Low-dose radiation will stop the tumor from growing and also help with pain. We also use body-wide treatments such as chemotherapy or hormone therapy. If the bone bears a lot of weight, like the legs, we may need to reinforce it with a rod, plate, or cement to fix a break or prevent it from breaking.
What is the outlook for people diagnosed with bone cancer?
The outlook has improved a great deal since the introduction of chemotherapy. Cure rates for some primary bone cancers like osteosarcoma are 70%. Researchers are looking for new treatments that will improve the outcome even more.
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