Bone Cancer

Most bone cancers start with a mutation in the bone cell DNA.

• Bone cancer is a malignant tumor of the bone that destroys normal bone cells.
• You should seek medical care for new bone pain that worsens over time or if you feel a mass over your bones.
• Treatment of bone cancer depends on the cancer type, tumor location, and cancer stage.
• Primary bone cancer is rare. The majority of people who have cancer in their bones have secondary bone cancer. This means that cancer in their bones develops from the spread, also known as metastasis, from another cancer that developed elsewhere in their body. Bone cancer refers to the cases in which cancer starts in the bone cells and does not include cancers that have spread to the bones. Secondary or metastatic bone cancer may be properly referred to as a carcinoma based on where it first arose. Primary bone cancers are called sarcomas.
• Bone cancer is most common in children and adolescents. It is less common in older adults. There are several different types of bone cancer, and they can occur in any of the bones.

Osteosarcoma is the most common bone cancer type. It is most common in males between 10-25 years of age, but it can also occur in older adults. The most likely locations for developing osteosarcoma are in the long bones of the arms and legs near the growth regions of the knees and shoulders. This is often a very aggressive cancer, and it can spread (metastasize) to other parts of the body like the lungs. Other types are as follows:

• Ewing's sarcoma is a very aggressive bone cancer. It is more common in younger children between 4-15 years old. It is more common in boys and very rarely seen in those over 30 years of age. It is most commonly found in the middle portions of the long bones in the arms and legs. It can also spread to the lungs and other body tissues.
• Chondrosarcoma is the second most common bone cancer. In contrast to the previously described tumors, chondrosarcoma develops from the cartilage cells, not from the bone cells themselves. The pelvis and the hip and shoulder bones are most commonly affected. It is most common in people over 40 years of age. It can also spread to the lungs and lymphatic system.
• Malignant fibrous histiocytoma (MFH) is a rare type of cancer that more commonly arises from soft tissues than from bone. When it arises in bone, it is treated as though it was osteosarcoma. It is most common in people 50-60 years old. It is most common in the arms and legs and is more common in males.
• Fibrosarcoma is a rare soft tissue tumor that most commonly occurs around the knee. It usually affects people 35-55 years old and is more common in males.
• Chordoma is a very rare tumor usually seen in people over 30 years old. It is most commonly found in either the lower or upper ends of the spinal column.

There are also benign bone tumors termed enchondroma or benign tumors of the bone that are made up of cartilage. Osteochondroma (the most common type of benign tumor or osteoma) is similar in that the bony projections capped by cartilage develop. Another rare bone tumor is termed an osteoblastoma, similar to an osteoma. These benign tumors are non-cancerous.

In addition, multiple myeloma and leukemia are types of cancers that arise from cells (not bone-forming cells) in the bone marrow.

In most cases, the cause of bone cancer is unknown. Most cancers begin with an error or mutation in the bone cell DNA, the control region, and the building blocks of the cells. Changes in the cellular DNA can lead to problems with the bone tissue cells dividing and multiplying into new cells, potentially causing uncontrolled growth of abnormal bone cells.

There are certain known risk factors for developing some types of bone cancer:

• Osteosarcoma is more common in people who have received radiation therapy or treatment with certain chemotherapy medications.
• Osteosarcoma is also more common in children who have had hereditary retinoblastoma, which is a rare cancer of the eye.
• Ewing's sarcoma is more common in children with hereditary cancer syndromes, including Li-Fraumeni syndrome or Rothmund-Thomson syndrome, multiple exostoses, or other bone conditions, including Paget's disease of bone.

The most common symptom of bone cancer is pain. The pain often starts off as a dull ache that gradually worsens over time. The pain may initially only occur at night or with specific activities. If the tumor weakens the bone, it may lead to a fracture that can cause more sudden and severe pain. A lump or mass over the surface of the bone may be felt or seen through the patient's skin.

Other less common bone cancer symptoms and signs include:

• Fevers
• Chills
• Anemia
• Weight loss

You should seek medical care if you have a new pain in your bones that does not resolve or worsens over time, if you have a sudden and more severe pain in your bones, or if you see or feel a mass over your bones.

Your physician will likely begin with a complete medical history, family history, and physical examination. The purpose of the medical and family history is to determine how your symptoms developed and how they have changed over time. These clues can help your physician diagnose bone cancer versus some other potential cause of your symptoms. The physical examination will evaluate the area of pain or mass, and check your strength, sensation, and reflexes.

Certain blood tests may be ordered that can help with the diagnosis. Alkaline phosphatase and lactate dehydrogenase are often elevated in the blood of patients with osteosarcoma and Ewing's sarcoma.

Next, the physician will likely order some imaging study of the affected bone. Plain X-rays or radiographs can often identify abnormalities in the bones and provide information on the shape, size, and location of the tumor.

• X-rays can also look for possible fractures and assess the risk of future fractures. A bone scan involves injecting a small amount of radioactive material into the blood that collects in the bones.
• Bone scans can identify areas of increased bone activity that can occur with fracture, growth, and tumors. It can be used to localize bone cancer and look for other areas of involvement.
• Computed tomography (CT) scans can provide a three-dimensional picture of the bones that can provide a better view of cancer.
• Magnetic resonance imaging (MRI) scans may be ordered to evaluate the soft tissues or bones involved.
• Positron emission tomography (PET) scans involve injecting a small amount of radioactive glucose into the bloodstream and scanning the entire body to look for other areas of increased bone activity. This scan can often be combined with the CT scan for improved detail.

After an abnormality has been identified in the bone, your physician may want to obtain a biopsy of the bone. This involves taking a small piece of the bone that can be studied by a pathologist to determine what type of cancer is present. Depending on the location of cancer, the biopsy may be obtained in the office with a small needle or may need to be obtained in the operating room by a surgeon.

The stage of cancer refers to the extent of the spread of the cancer. Based on the various imaging studies and biopsies, your physician can determine how aggressive the cancer is and whether or not it has spread from its initial location to other locations in the body.

• Stage I: Cancer is all contained within the bone and has not spread to other areas of the body.
• Stage II: Cancer is contained within the bone and has not spread, but the biopsy shows the cancer is more aggressive.
• Stage III: Cancer has spread to more than one area within the bone, but it has not spread outside of the bone.
• Stage IV: Cancer has spread outside of the bone to other areas of the body.

Treatment for bone cancer depends on the type of cancer, the location of the tumor, and the stage of cancer. The main types of treatment include surgery, chemotherapy, and radiation therapy. In some cases, a combination of one or more of these treatments may be recommended.

Surgery

Surgery is the most common treatment for bone cancer. The goal of surgery is to remove the entire area of cancer and a surrounding layer of normal bone to help prevent the recurrence of cancer. Depending on the amount of bone removed, the surgeon may replace some of the bone with other normal bone grafts, bone cement, or artificial joints. The specimen that is removed during surgery is studied by the pathologist to verify that a complete layer of normal bone cells surrounds cancer.

If the cancer is not completely removed with a layer of normal cells surrounding it, there is a higher risk of leaving behind some cancer cells that can continue to grow in the body. In this case, your physician may recommend an additional surgery or another treatment. In some cases, the surgery cannot remove entire cancer with a surrounding layer of normal tissue. This may be due to surrounding nerves or blood vessels that cannot be removed. In some of these cases, amputation of the involved limb may be necessary to completely remove cancer, but limb-sparing surgery is possible.

Chemotherapy

Chemotherapy may be used in some cases of bone cancer. The medications are used to help kill cancer cells. It may be used to help shrink the cancer cells prior to surgery to allow for less extensive surgery. It may be used after surgery to help kill any remaining cancer cells left behind following surgery. Research is defining roles for both immune system-based treatments as well as molecularly targeted therapies in the treatment of even advanced metastatic cases of bone cancer.

Radiation Therapy

Radiation therapy involves using high-dose energy X-ray beams to help kill cancer cells. This is often given through a series of treatments over weeks or months. As with chemotherapy, radiation therapy can be used either before or after surgery.

Follow-up with your physician following a diagnosis and treatment of bone cancer is very important. You will likely have routine appointments and imaging and laboratory studies to look for any recurrence of the cancer. Any change in your symptoms should prompt a visit with your physician for evaluation.

At this time, there are no specific methods of prevention of bone cancer.

The outlook for patients with bone cancer is improving. Many recent advancements in early diagnosis and treatment options are improving the survival rates of these cancers. Improved surgical options have decreased the need for amputation in some cases. Improved chemotherapy agents and radiation therapy have also decreased the related side effects of these treatments.

Occasionally, clinical trials are available to selected patients. Your treatment team can provide additional information.

Cancer Survivors Network
http://www.acscsn.org