Definition
Bone cancer is a rare disease in which cancer cells grow in the bone tissue. Cancer occurs when cells in the body (in this case bone cells) divide without control or order. Normally, cells divide in a regulated method. If cells keep dividing uncontrollably when new cells are not needed, a mass of tissue forms. This is called a growth or tumor. The term cancer refers to malignant tumors, which can invade nearby tissues and spread to other parts of the body. A benign tumor does not invade or spread.
Cancer may form in the bone or spread to the bone from another site in the body. When cancer starts in bone tissue, it is called primary bone cancer. When cancer cells travel to the bone from another site in the body, it is called secondary or metastatic cancer to the bone. Types of bone cancer include:
- Osteosarcoma—a cancerous tumor of the bone, usually of the arms, legs, or pelvis; the most common primary cancer
- Chondrosarcoma—cancer of the cartilage; the second most common primary cancer
- Ewing's sarcoma—tumors that usually develop in the cavity of the leg and arm bones
- Fibrosarcoma and malignant fibrous histiocytoma—cancers that develop in soft tissues (eg, tendons, ligaments, fat, muscle) and move to the bones of the legs, arms, and jaw
- Giant cell tumor—a primary bone tumor that is malignant (cancerous) only about 10% of the time; most common in the arm or leg bones
- Chordoma—primary bone tumor that usually occurs in the skull or spine
The sooner bone cancer is treated, the better the outcome. If you suspect you have this condition, contact your doctor right away.
Causes
The cause of primary bone cancer is unknown. Genetics play a major role in most cases. Conditions that cause increased bone breakdown and regrowth over an extended period increase the risk of tumor development. This explains why osteosarcoma in children is most common during the adolescent growth spurt.
Risk Factors
Risk factors that can increase your chance of getting bone cancer include:
- Paget's disease (a noncancerous bone condition)
- Exposure to radiation
- Family history of bone cancer
Certain types of bone cancer have specific risk factors:
-
Osteosarcoma:
- Age: 10-30 years old
- Sex: male
- Inherited cancer syndromes, including Li-Fraumani and Rothmund-Thompson syndromes
- Retinoblastoma (a rare eye cancer)
- Bone marrow transplantation
-
Chondrosarcoma:
- Age: older than 20 years old
- Multiple exostoses (an inherited condition that results in bumps on bones)
-
Ewing’s sarcoma:
- Age: younger than 30 years old
-
Fibrosarcoma and malignant fibrous histiocytoma:
- Age: middle-aged and elderly
-
Giant cell tumor:
- Age: young and middle-aged
Symptoms
Symptoms of bone cancer vary, depending on the location and size of the tumor.
Symptoms may include:
- Pain at the tumor location
- Swelling or a lump at the location of the tumor
- Deep bone pain severe enough to wake you up
- Unexplained weight loss
- Fatigue
- Trouble breathing
- Fever or night sweats
- Bone fractures (rarely)
These symptoms may also be caused by other, less serious health conditions. Anyone experiencing these symptoms should see a doctor.
Diagnosis
The doctor will ask about symptoms and medical history. A physical exam will be done.
- Your doctor may need to check the level of the enzyme alkaline phosphatase. This can be done with a blood test.
- Your doctor may need to look for evidence of bone tumors. This can be done with a bone scan.
- Your doctor may need to test a sample of your bone tissue. This can be done with a biopsy.
- Your doctor may need pictures of your bodily structures. This can be done with:
Treatment
After cancer is found, staging tests are performed to find out if the cancer has spread and, if so, to what extent. Treatment depends on the type, stage, and location of the cancer. It also depends on your overall health. Talk with your doctor about the best treatment plan for you. Treatment options include:
Radiation Therapy
Radiation therapy for bone cancer uses radiation to kill cancer cells and shrink tumors. Radiation may be:
- External radiation therapy—radiation directed at the tumor from a source outside the body
- Internal radiation therapy—radioactive materials placed into the body near the cancer cells
Chemotherapy
Chemotherapy is the use of drugs to kill cancer cells. Chemotherapy may be given in many forms, including: pill, injection, and via a catheter (tube). The drugs enter the bloodstream and travel through the body, killing mostly cancer cells, but also some healthy cells. The most common chemotherapy drugs used to treat bone cancer include:
- Methotrexate with calcium
- Leucovorin
- Doxorubicin
- Cisplatin
- Ifosfamide
- Etoposide
Surgery
Surgery for bone cancer involves the removal of a cancerous tumor, nearby tissues, and possible nearby lymph nodes. Surgery may require amputation of the limb with cancer. Whenever possible, doctors try to remove the cancerous part of the bone without amputating. In this case, metal plates or a bone graft replaces the cancerous tissue that has been removed.
Sometimes, adding radiation therapy or chemotherapy can help avoid the need for amputation. If the tumor is large or aggressive, or the risk of it spreading is high, chemotherapy and radiation therapy may be added to help prevent it from returning. This is also done to prevent it from spreading to distant organs.
Myeloablative Therapy with Stem Cell Support
For cancer that has spread, intense chemotherapy is sometimes given to kill cancer cells. This therapy also destroys the bone marrow. Stem cells, which have the ability to develop into other types of cells, are then given to replace the lost bone marrow.
Special Treatment Considerations for Certain Cancer Types
- Osteosarcoma—Chemotherapy given before and after surgery will often cure osteosarcoma and can allow for limb-sparing surgery in people who might have otherwise required amputation.
- Ewing’s sarcoma—Since Ewing’s sarcoma is very responsive to chemotherapy, its treatment often involves several weeks of chemotherapy followed by surgical removal or radiation therapy, then several more months of chemotherapy.
- Fibrosarcoma and malignant fibrous histiocytoma—These conditions are usually treated with surgery to remove the cancerous tumor and a one-inch margin of healthy tissue surrounding it.