Bone cancer starts in the cells of your bones and can spread to other parts of your body

Bone cancer is a disease in which malignant (cancerous) cells form in bone tissue. Unlike most cancers that start elsewhere and spread to bone, primary bone cancer originates in the bone itself. The cancer cells grow abnormally and can damage healthy bone tissue, weaken the bone's structure, and eventually spread to the lungs, other bones, or nearby soft tissue like muscle.

Bone cancer is rare — it accounts for less than 1% of all cancers. It can occur at any age but is most common in children and young adults, particularly during periods of rapid bone growth. The disease develops when something goes wrong in the DNA of bone cells, causing them to multiply uncontrollably instead of following the normal cycle of growth and death.

Key Takeaways

  • Bone cancer originates in bone tissue itself, unlike cancers that spread to bone from elsewhere in the body.
  • The three main types are osteosarcoma (most common), Ewing sarcoma, and chondrosarcoma, each arising from different types of bone cells.
  • Common warning signs include persistent bone pain, swelling near a bone, and a lump you can feel under the skin.
  • Diagnosis involves imaging tests like X-rays and MRI, plus a biopsy to confirm cancer cells are present.
  • Treatment typically combines surgery to remove the tumor with chemotherapy, and sometimes radiation therapy.

The three main types of bone cancer

Osteosarcoma is the most common type, accounting for about 35% of primary bone cancers. It develops from osteoblasts, the cells that form new bone. Osteosarcoma typically occurs in the long bones of the legs (around the knee) and upper arm, and it grows quickly. It is most common in teenagers and young adults during periods of rapid bone growth.

Ewing sarcoma is the second most common type and accounts for about 25% of primary bone cancers. It usually develops in the shaft (middle section) of long bones, particularly in the legs and pelvis. Ewing sarcoma also grows rapidly and is most common in children and young adults under 30.

Chondrosarcoma develops from cartilage cells and is the most common type in adults over 40. It typically grows more slowly than osteosarcoma or Ewing sarcoma and often occurs in the pelvis, upper leg, or shoulder. There are also rarer types like fibrosarcoma and giant cell tumor of bone, but these account for a small percentage of cases.

Where bone cancer most often develops

Bone cancer can occur in any bone, but certain locations are more common. The distal femur (lower end of the thighbone) and proximal tibia (upper end of the shinbone) together account for about half of all osteosarcomas. The proximal humerus (upper arm bone) is another frequent site. In Ewing sarcoma, the femur and pelvis are the most common locations.

The reason certain bones are affected more often relates to growth rate. Bone cancer tends to develop in areas where bones grow fastest, which is why it is more common in children and adolescents during growth spurts. Once a person reaches full skeletal maturity, the risk of developing osteosarcoma or Ewing sarcoma drops significantly.

Signs and symptoms to watch for

Bone pain is the most common early symptom. This pain is often persistent, worsens over time, and may be worse at night or during physical activity. The pain may start mild and gradually become severe. Some people notice the pain comes and goes at first, then becomes constant.

Swelling and a lump near the affected bone are also common signs. You may notice the area feels warm to the touch or appears red. Some people develop a limp if the cancer is in a leg bone, or have difficulty moving an arm if it is in the shoulder or upper arm. In some cases, a fracture occurs in the weakened bone even without a fall or injury.

Other symptoms can include fatigue, weight loss, and fever, though these are less specific to bone cancer. If bone pain lasts more than a few weeks, does not improve with rest, or is accompanied by swelling, it is important to see a doctor for evaluation.

How bone cancer is diagnosed

Diagnosis begins with imaging tests. An X-ray is usually the first step and can show whether a bone has an abnormal area. If the X-ray suggests cancer, your doctor will order an MRI (magnetic resonance imaging) to get detailed images of the bone and surrounding soft tissue. An MRI helps determine how large the tumor is and whether it has spread to nearby muscles or blood vessels.

A biopsy is the only way to confirm bone cancer. During a biopsy, a small sample of tissue is removed from the suspicious area and examined under a microscope by a pathologist. The pathologist looks for cancer cells and determines the specific type of bone cancer. A biopsy can be done with a needle (less invasive) or through a small surgical incision.

Once cancer is confirmed, additional tests determine whether it has spread. A CT scan of the chest is standard because bone cancer often spreads to the lungs first. A PET scan may also be used to detect cancer in other bones or organs. Blood tests can measure alkaline phosphatase and lactate dehydrogenase, enzymes that are often elevated in bone cancer.

Risk factors and causes

The exact cause of bone cancer is not fully understood, but several factors increase the risk. Age is significant — osteosarcoma and Ewing sarcoma are most common in children and young adults. Males are slightly more likely to develop bone cancer than females. Rapid bone growth during adolescence is a major risk factor, which is why bone cancer peaks during the teenage years.

Certain genetic conditions increase risk. People with hereditary retinoblastoma (a rare eye cancer caused by a mutation in the RB gene) have a higher risk of developing osteosarcoma. Li-Fraumeni syndrome, caused by a mutation in the p53 gene, also increases bone cancer risk. Previous radiation therapy to the bone, whether for treatment of another cancer or for other medical reasons, can increase the risk of developing bone cancer years later.

Benign bone conditions like Paget's disease of bone (more common in older adults) can occasionally become cancerous. However, most people with these conditions never develop cancer. Having a family history of bone cancer does not mean you will develop it, but it may warrant closer monitoring if you have symptoms.

Treatment approaches

Surgery is the primary treatment for bone cancer. The goal is to remove the entire tumor along with a margin of healthy tissue around it. In many cases, surgeons can preserve the limb by removing only the affected portion of bone and reconstructing it with a metal implant, bone graft, or rotationplasty (rotating the lower leg and ankle to function as a knee). Amputation is considered when the tumor is very large, involves major blood vessels or nerves, or when limb-sparing surgery is not possible.

Chemotherapy is used before and after surgery for most types of bone cancer. Preoperative chemotherapy (given before surgery) shrinks the tumor and makes it easier to remove. Postoperative chemotherapy destroys any cancer cells that may remain. For osteosarcoma and Ewing sarcoma, chemotherapy significantly improves outcomes. Chondrosarcoma is less responsive to chemotherapy, so surgery is the main treatment.

Radiation therapy uses high-energy beams to kill cancer cells. It may be used when surgery is not possible, when the tumor cannot be completely removed, or when cancer returns. Radiation is also sometimes used for pain management in advanced cases. The specific combination of treatments depends on the type and stage of cancer, the patient's age and overall health, and other individual factors.

Frequently Asked Questions

Is bone cancer hereditary?

Most bone cancers are not inherited, but certain genetic mutations increase risk. If you have a family history of bone cancer or hereditary cancer syndromes like Li-Fraumeni syndrome, talk to your doctor about monitoring. Genetic testing may be recommended depending on your family history and the type of cancer.

Can bone cancer be prevented?

There is no proven way to prevent bone cancer since the exact causes are not fully understood. If you have had radiation therapy for another condition, discuss long-term monitoring with your doctor. Maintaining overall health through exercise and nutrition supports bone health, but does not prevent cancer.

What is the difference between bone cancer and cancer that spreads to bone?

Primary bone cancer originates in bone tissue itself. Secondary bone cancer (metastatic cancer) starts elsewhere in the body — such as the breast, lung, or prostate — and spreads to bone. They are treated differently, so accurate diagnosis is important.

Can a bone fracture cause bone cancer?

A fracture does not cause bone cancer. However, bone cancer can weaken a bone and make it more likely to fracture. If you have a fracture that seems unusual or a bone that breaks without significant injury, mention this to your doctor.

What happens if bone cancer spreads to the lungs?

If cancer spreads to the lungs, it is considered metastatic disease and treatment becomes more complex. Lung nodules may be monitored with imaging or removed surgically if there are only a few. Additional chemotherapy or other treatments may be recommended. Your doctor will discuss options based on the extent of spread.