Bone Cancer

What bone cancer is

Bone is living tissue made of cells that build and break down bone, cartilage and marrow. Primary bone cancer arises when one of these cells grows out of control, forming a tumor that destroys normal bone and can spread, most often to the lungs.

It is important to separate:

• Primary bone cancer: starts in bone. Rare
• Bone metastases: cancer that started elsewhere (breast, prostate, lung, kidney, thyroid) and spread to bone. Much more common in adults, and treated according to the original cancer
• Blood cancers in bone: multiple myeloma and leukemia start in the bone marrow and are treated differently
• Benign bone tumors: such as osteochondroma and giant cell tumor, which are not cancer but may need treatment

Types of primary bone cancer

Symptoms

• Bone pain: the most common first symptom. It may come and go at first, then becomes constant, worsens with activity, and is often worse at night
• Swelling or a lump over the bone, sometimes tender
• Reduced movement of a nearby joint, or a limp
• Fracture after a minor fall, because the tumor weakens the bone
• General symptoms, more common with Ewing sarcoma: fever, tiredness, weight loss and night sweats
• Back or pelvic tumors can press on nerves, causing numbness, weakness or bladder problems

In teenagers, bone cancer pain is often first blamed on sports injuries or growing pains. Growing pains affect both legs, occur in the evening or night, and are gone by morning, with normal daytime activity. Pain in one place that persists or worsens needs an X-ray.

Causes and risk factors

Most people with bone cancer have no known risk factor. Factors that raise the risk include:

• Rapid bone growth during adolescence
• Previous radiation therapy to the area, years earlier
• Inherited conditions: Li-Fraumeni syndrome, hereditary retinoblastoma, Rothmund-Thomson syndrome and multiple hereditary exostoses
• Paget's disease of bone in older adults, a rare risk for osteosarcoma
• Some benign bone conditions that can rarely turn cancerous, such as osteochondromas (chondrosarcoma)

Injuries do not cause bone cancer, but an injury may draw attention to an existing tumor.

Diagnosis

1. X-ray: usually the first test. Bone cancer often shows bone destruction, new bone formation or a "sunburst" pattern
2. MRI of the whole bone: shows the tumor's size and spread into soft tissue, joints, nerves and vessels
3. CT of the chest: checks for spread to the lungs
4. PET-CT or bone scan: looks for spread to other bones
5. Biopsy: a needle or surgical sample confirms the type. It should be done at a specialist sarcoma center, because a poorly placed biopsy can make limb-sparing surgery harder
6. Blood tests: alkaline phosphatase and LDH can be raised in osteosarcoma

Stage depends on tumor grade (how aggressive the cells look), size and whether it has spread.

Treatment

Bone cancer is treated by a specialist multidisciplinary sarcoma team.

Surgery

• Limb-sparing surgery removes the tumor with a margin of healthy tissue and rebuilds the bone with a metal implant (endoprosthesis) or bone graft. It is possible for most people today
• Amputation is sometimes the best option for tumors involving major nerves and vessels, or when reconstruction is not possible. Modern prosthetics allow good function
• Rotationplasty is an option for some children with tumors around the knee

Chemotherapy

• Osteosarcoma and Ewing sarcoma: chemotherapy is given before surgery to shrink the tumor and treat microscopic spread, then after surgery. How much of the tumor is killed by pre-surgery chemotherapy predicts outcome
• Chondrosarcoma: usually does not respond to chemotherapy, so surgery is the main treatment

Radiation therapy

Ewing sarcoma is sensitive to radiation, which is used when surgery cannot remove the tumor completely or would be too damaging. Proton beam therapy is often used for chordomas and tumors near the spine and skull base.

Targeted therapy

Some rare bone tumors respond to targeted drugs, and clinical trials are recommended for many people with advanced or recurrent disease.

Rehabilitation and follow-up

Physical therapy, prosthetic care and psychological support are part of recovery. Follow-up with scans of the chest and the treated area continues for years to detect recurrence early.

Outlook

For osteosarcoma, about 3 in 4 people whose cancer has not spread are alive 5 years after diagnosis, falling to about 1 in 4 when it has spread to distant sites at diagnosis. Ewing sarcoma has similar or slightly better outcomes when localized. Low-grade chondrosarcoma has an excellent outlook after complete surgical removal. Long-term survivors of childhood bone cancer need follow-up for late effects of chemotherapy and radiation.

Frequently asked questions

What are the first signs of bone cancer?

The most common first sign is bone pain that keeps coming back, becomes constant, and is often worse at night or with activity. Swelling or a lump over the bone may follow. Some people first notice a fracture after a minor fall, a limp, or fever and weight loss.

Is bone cancer pain constant?

It often starts as intermittent pain and becomes constant over weeks. A typical feature is pain at night or at rest that is not explained by an injury. Persistent pain in one bone, especially in a teenager or young adult, should be checked with an X-ray.

What is the survival rate for bone cancer?

It depends on the type and stage. About 3 in 4 people with osteosarcoma that has not spread survive 5 years or more, compared with about 1 in 4 when it has spread widely. Low-grade chondrosarcoma removed completely has an excellent outlook.

How is bone cancer different from cancer that has spread to the bone?

Primary bone cancer starts in bone cells and is rare. Cancer that spreads to the bone from another organ, such as the breast, prostate or lung, is far more common in adults and is treated according to where it started.

Can bone cancer be mistaken for growing pains?

Yes. Growing pains usually affect both legs, come in the evening or at night, and are gone by morning without affecting daytime activity. Pain in one leg or arm that persists, worsens, causes a limp or comes with swelling needs an X-ray.