Medically reviewed by Katherine A. Janeway, MD
Cancer affecting the bones may be primary (a cancer that develops within the bone) or metastatic (spreading to bones from elsewhere in the body). Many primary bone tumors are benign (noncancerous), but others are malignant. Treatment options for bone tumors include surgery, chemotherapy, radiation therapy, cryosurgery (freezing cancer cells) and targeted therapies that interact with specific molecules involved in cancer growth.
Types of bone cancers
There are several types of primary bone cancers, which are categorized as sarcomas and are rare, comprising less than 1% of all cancers.
- Osteosarcoma is the most common primary bone tumor. It typically occurs in the arm near the shoulder and in the leg near the knee in children and adolescents but can also occur in older adults.
- Chondrosarcoma begins in cartilage and most often forms in the pelvis, upper leg, and shoulder, and mainly occurs in adults over age 40.
- Ewing sarcoma is a fast-growing tumor that usually arises in bone but may also begin in soft tissue. The risk is highest in children and adolescents.
- Chordoma is a very rare tumor that forms in bones of the spine.
Treatment for bone tumors
Osteosarcoma is generally treated with surgery to remove the entire tumor if possible. Several types of surgery are employed in treating osteosarcoma, and patients may receive chemotherapy prior to surgery to allow time for planning the surgery and to eliminate cancer cells that may have spread beyond the primary tumor location.
Limb-sparing surgery is aimed at removing the tumor in an arm or leg without amputation; in some cases, tissue and bone that is removed may be replaced with a graft from another part of the patient’s body or an implant of artificial bone or metal prosthesis.
In some cases, when it isn’t possible to spare the arm or leg while removing the tumor, the limb is amputated, and the patient may have a prosthesis worn on the outside of the body designed to replace the limb.
A highly specialized surgical procedure called rotationplasty is sometimes used when a child has a bone tumor such as osteosarcoma or Ewing sarcoma that occurs near the knee. In this procedure, surgeons remove the bottom of the thighbone, the knee, and the upper shinbone. Then the lower leg is rotated 180 degrees and attached to the thighbone. The foot is now on the end of the thigh backwards and can function like a knee.
Patients with osteosarcoma who undergo surgery to remove all clinically detectable disease typically undergo chemotherapy either before or following surgery: chemotherapy is a very important part of treatment and is aimed at treating cancer cells that may have spread outside the initial tumor location, decreasing the risk of relapse.
Although osteosarcoma cells are not very vulnerable to radiation, radiation therapy is sometimes used. A radioactive drug known as samarium can be used to treat osteosarcoma that has returned or relapsed or spread to bones outside of the primary site. It can help relieve pain caused by bone cancer.
A number of targeted drugs are being used or studied in clinical trials to treat osteosarcoma. They include:
- Kinase inhibitors, like regorafenib and cabozantinib
- mTOR inhibitors such as everolimus
- Monoclonal antibodies that are given by infusion and attach to cancer cells
Some of these drugs carry drugs, toxins, or radioactive substances directly to cancer cells.
So far, trials of immunotherapy, such as treatment with checkpoint inhibitors that help the body’s immune system fight cancer, show that this approach does not work in osteosarcoma.
Because primary bone tumors are relatively rare, patients and families often seek out medical centers that have a lot of experience in treating these cancers, such as Dana-Farber/Boston Children’s Cancer and Blood Disorders Center. Bone tumors require a team approach; specialists who might be involved in a patient’s team include an orthopedic surgeon, a medical or pediatric oncologist, radiation oncologists, pathologist, and physiatrist (a doctor who directs rehabilitation and physical therapy).