Bone Cancer

Bone cancer facts

• The majority of cancer involving the bones is metastatic disease from other remote cancers. Primary bone cancer is much rarer.
• Not all bone tumors are cancerous.
• The most common symptom of bone cancer is pain. The pain is usually mild initially and gradually becomes more intense.
• Treatment of bone cancer includes a combination of surgery, chemotherapy, and radiation therapy.
• Treatment is based on the size and location of the cancer and whether or not the cancer has spread from the bone to surrounding tissues.

What are bones for?

Your body has 206 bones. These bones serve many different functions. First, your bones provide structure to your body and help provide its shape. Muscles attach to the bones and allow you to move. Without the bones, your body would be an unstructured pile of soft tissues and you would be unable to stand, walk, or move. Second, the bones help to protect the more fragile organs of the body. For example, the bones of the skull protect the brain, the vertebrae of the spine protect the spinal cord, and the ribs protect the heart and lungs. Third, the bones contain bone marrow, which produces and stores new blood cells. Finally, the bones help control your body's collection of various proteins and nutrients including calcium and phosphorus.

What is cancer?

Your body is made up of many small structures called cells. There are many different types of cells that grow to form the different parts of your body. During normal growth and development, these cells continuously grow, divide, and make new cells. This process continues throughout life even after you are no longer growing. The cells continue to divide and make new cells to replace old and damaged cells. In a healthy person, the body is able to control the growth and division of cells according to the needs of the body. Cancer is when this normal control of cells is lost and the cells begin to grow and divide in an uncontrolled manner. The cells also become abnormal and have altered functions in patients with cancer. The cancer cells can become very destructive to the surrounding cells and can invade normal organs and tissues, disrupting their function.
There are many different type of cancer. The cancer is usually named based on the type of cell from which the cancer initially grows. For example, lung cancer is caused by uncontrolled cells that form the lungs and breast cancer by cells that form the breast. A tumor is a collection of abnormal cells grouped together. However, not all tumors are cancerous. A tumor can be benign (not cancerous) or malignant (cancerous). Benign tumors are usually less dangerous and are not able to spread to other parts of the body. Benign tumors can still be dangerous. They can continue to grow and expand locally. This can lead to compression and damage to the surrounding structures. Malignant tumors are usually more serious and can spread to other areas in the body. The ability of cancer cells to leave their initial location and move to another location in the body is called metastasis. Metastasis can occur by the cancer cells entering the body's bloodstream or lymphatic system to travel to other sites in the body. When cancer cells metastasize to other parts of the body, they are still named by the original type of abnormal cell. For example, if a group of breast cells becomes cancerous and metastasizes to the bones or liver, it is called metastatic breast cancer instead of bone cancer or liver cancer. Many different types of cancer are able to metastasize to the bones. The most common types of cancer that spread to the bones are cancers of the lung, breast, prostate, thyroid, and kidney. Cancers arising from lymphatic or blood cells, including lymphoma and multiple myeloma, can also frequently affect the bones.
Most of the time, when people have cancer in their bones, it is caused by cancer that has spread from elsewhere in the body to the bones. It is much less common to have a true bone cancer, a cancer that arises from cells that make up the bone. It is important to determine whether the cancer in the bone is from another site or is from a cancer of the bone cells themselves. The treatments for cancers that have metastasized to the bone are often based on the initial type of cancer.

What causes bone cancer?

Bone cancer is caused by a problem with the cells that make bone. More than 2,000 people are diagnosed in the United States each year with a bone tumor. Bone tumors occur most commonly in children and adolescents and are less common in older adults. Cancer involving the bone in older adults is most commonly the result of metastatic spread from another tumor.
There are many different types of bone cancer. The most common primary bone tumors include osteosarcoma, Ewing's sarcoma, chondrosarcoma, malignant fibrous histiocytoma, fibrosarcoma, and chordoma.

• Osteosarcoma is the most common primary malignant bone cancer. It most commonly affects males between 10 and 25 years old but can less commonly affect older adults. It often occurs in the long bones of the arms and legs at areas of rapid growth around the knees and shoulders of children. This type of cancer is often very aggressive with risk of spread to the lungs. The five-year survival rate is about 65%.
• Ewing's sarcoma is the most aggressive bone tumor and affects younger people between 4-15 years of age. It is more common in males and is very rare in people over 30 years of age. It most commonly occurs in the middle of the long bones of the arms and legs. The three-year survival rate is about 65%, but this rate is much lower if there has been spread to the lungs or other tissues of the body.
• Chondrosarcoma is the second most common bone tumor and accounts for about 25% of all malignant bone tumors. These tumors arise from the cartilage cells and can either be very aggressive or relatively slow growing. Unlike many other bone tumors, chondrosarcoma is most common in people over 40 years of age. It is slightly more common in males and can potentially spread to the lungs and lymph nodes. Chondrosarcoma most commonly affects the bones of the pelvis and hips. The five-year survival for the aggressive form is about 30%, but the survival rate for slow-growing tumors is 90%.
• Malignant fibrous histiocytoma (MFH) affects the soft tissues, including muscle, ligaments, tendons, and fat. It is the most common soft-tissue malignancy in later adult life, usually occurring in people 50-60 years of age. It most commonly affects the extremities and is about twice as common in males as females. MFH also has a wide range of severity. The overall five-year survival rate is about 35%-60%.
• Fibrosarcoma is much rarer than the other bone tumors. It is most common in people 35-55 years of age. It most commonly affects the soft tissues of the leg behind the knee. It is slightly more common in males than females.
• Chordoma is a very rare tumor with an average survival of about six years after diagnosis. It occurs in adults over 30 years of age and is about twice as common in males as females. It most commonly affects either the lower or upper end of the spinal column.

In addition to bone cancer, there are various types of benign bone tumors. These include osteoid osteoma, osteoblastoma, osteochondroma, enchondroma, chondromyxoid fibroma, aneurysmal bone cyst, unicameral bone cyst, and giant cell tumor (which has the potential to become malignant). As with other types of benign tumors, these are not cancerous.
There are two other relatively common types of cancer that develop in the bones: lymphoma and multiple myeloma. Lymphoma, a cancer arising from the cells of the immune system, usually begins in the lymph nodes but can begin in the bone. Multiple myeloma begins in the bones, but it is not usually considered a bone tumor because it is a tumor of the bone marrow cells and not of the bone cells.

What are bone cancer symptoms and signs?

The most common symptom of bone tumors is pain. In most cases, the symptoms become gradually more severe with time, including bone pain. Initially, the pain may only be present either at night or with activity. Depending on the growth of the tumor, those affected may have symptoms for weeks, months, or years before seeking medical advice. In some cases, a mass or lump may be felt either on the bone or in the tissues surrounding the bone. This is most common with MFH or fibrosarcoma but can occur with other bone tumors. The bones can become weakened by the tumor and lead to a fracture after little or no trauma or just from standing on the affected bone. This can occur with both benign and malignant tumors. Even benign tumors can spread locally and weaken the surrounding bone. If the tumor compresses the surrounding nerve it can cause pain, numbness, or tingling in the extremities. If the surrounding blood vessels are compressed, it can affect the blood flow to the extremities. Fever, chills, night sweats, and weight loss can occur but are less common. These symptoms are more common after spread of the tumor to other tissues in the body.

How is bone cancer diagnosed?

The first thing your doctor will do is to take a complete medical history. This will include a review of your past health issues as well as early symptoms and the progression of symptoms currently. It will give your doctor clues as to your diagnosis. Some types of cancer are more common in people if they have close family members who have had that type of cancer. Some types of cancer, specifically lung cancer, are more common in people with a history of smoking. A description of your symptoms can help your doctor identify the possibility of bone cancer from other possible causes. Next, a complete physical examination can help find the cause of your symptoms. This may include testing your muscle strength, sensation to touch, and reflexes. Certain blood tests can be ordered that can help to identify a possible cancer.
Next, your doctor will likely order some imaging studies. Plain X-rays are often ordered first. In some cases, if the cancer is identified very early, it may not show up on plain X-rays. The appearance of a tumor on the X-ray can help determine the type of cancer and whether or not it is benign or malignant. Benign tumors are more likely to have a smooth border while malignant tumors are more likely to have a ragged border on X-ray images. This is because the benign tumors typically grow more slowly and the bone has time to try to surround the tumor with normal bone. Malignant tumors are more likely to grow more quickly, not giving the normal bone a chance to surround the tumor. The X-rays can also be used to identify if a fracture has occurred or if the bone has been weakened and is at risk for a potential fracture.
A CT scan (CAT scan or computed tomography) scan is a more advanced test that can give a cross-sectional picture of your bones. This test gives very good detail of your bones and is better able to identify a possible tumor. It also gives additional information on the size and location of the tumor.
An MRI (magnetic resonance imaging) is another advanced test that can also provide cross sectional imaging of your body. The MRI provides better detail of the soft tissues, including muscles, tendons, ligaments, nerves, and blood vessels than a CT scan. This test can give better detail on whether or not the bone tumor has broken through the bone and involved the surrounding soft tissues.
A bone scan is a test that identifies areas of rapidly growing or remodeling bone. The bone scan is often taken of the entire body. This test may be ordered to see if there are any other areas of bone involvement throughout the body. This test is not specific for any specific type of tumor and can be positive with many other conditions including infection, fracture, and arthritis.
If a tumor is identified, your doctor will use all of the information from the history and physical examination along with the laboratory and imaging studies to put together a list of possible causes (differential diagnosis).
Your doctor may then obtain a biopsy sample of the tumor. This involves taking a small sample of the tumor that can be examined in the laboratory by a pathologist (a physician with special training in tissue diagnosis) to determine what kind of tumor it is. The biopsy can be obtained either through a small needle (needle biopsy) or through a small incision (incisional biopsy). The various imaging studies will be used to determine the safest and easiest location from which to obtain the biopsy sample.

What is the treatment for bone cancer?

There are many different methods available for your doctor to treat bone cancer. The best treatment is based on the type of bone cancer, the location of the cancer, how aggressive the cancer is, and whether or not the cancer has invaded surrounding or distant tissues (metastasized). There are three main types of treatment for bone cancer: surgery, chemotherapy, and radiation therapy. These can be used either individually or combined with each other.
Surgery is often used to treat bone cancer. The goal of surgery is usually to remove the entire tumor and a surrounding area of normal bone. After the tumor has been removed, a pathologist examines it to determine if there is normal bone completely surrounding the tumor. If a portion of the cancer is left behind, it can continue to grow and spread, requiring further treatment. If the tumor specimen has normal cells completely surrounding it, there is a much better chance that the entire tumor has been removed and less chance for recurrence. Historically, amputations were frequently used to remove bone cancer. Newer techniques have decreased the need for amputation. In many cases, the tumor can be removed with a rim of normal bone without the need for an amputation. Depending on the amount of bone removed, the surgeon will replace something in its location. For smaller areas, this may be either bone cement or a bone graft from another place in your body or from the bone bank. For larger areas, the surgeon may place larger grafts from the bone bank or metal implants. Some of these metal implants have the ability to lengthen when used in growing children.
You may be referred to a medical oncologist for chemotherapy. This is the use of various medications used to try to stop the growth of the cancer cells. Chemotherapy can be used prior to surgery to try to shrink the bone tumor to make surgery easier. It can also be used after surgery to try to kill any remaining cancer cells left following surgery.
You could also be referred to a radiation oncologist for radiation therapy. The radiation therapy uses high-energy X-ray aimed at the site of the cancer to try to kill the cancer cells. This treatment is given in small doses daily over a period of days to months. As with chemotherapy, radiation therapy can be used either before or after a potential surgery, depending on the specific type of cancer.

What are the side effects of treatment for bone cancer?

Unfortunately, there are risks and side effects with each of the treatments for bone cancer. The main risks associated with surgery include infection, recurrence of the cancer, and injury to the surrounding tissues. In order to remove the entire cancer and reduce the risk of recurrence, some surrounding normal tissue must also be removed. Depending on the location of the cancer, this may require the removal of portions of bone, muscle, nerves, or blood vessels. This could cause weakness, loss of sensation, and the risk of fracture of the remaining bone. You could be referred to a rehabilitation specialist for physical and occupational therapy after surgery to try to improve your strength and function.
Chemotherapy uses very powerful medication to try to kill cancer cells. Unfortunately, some normal cells are also killed in the process. The medications are designed to kill rapidly dividing or growing cells. The normal cells that are affected often include hair, blood-forming cells, and cells lining the digestive system. Side effects include nausea and vomiting, loss of hair, infection, and fatigue. Fortunately, these side effects usually resolve after the chemotherapy is over. Good nutrition is important for your body to fight the cancer. You may be referred to nutrition specialist to help with this, especially if you experience nausea and loss of appetite.
The main side effects from radiation therapy include fatigue, loss of appetite, and damage to the surrounding skin and soft tissues. Prior radiation therapy can also increase the risk of wound problems from surgery in the same area

What does the future hold for patients with bone cancer?

There has been much recent advancement in the understanding and treatment of bone cancer. These developments have led to more focused radiation therapy techniques to reduce the risk to surrounding tissues, better combinations of chemotherapy with less risk and side effects, and improved treatment options, including limb-salvaging surgery, that decrease the need for amputation.
There is currently much work being conducted in each of these areas as well as investigations into the causes of cancer. It is hoped that a better understanding of the specific causes of cancer will lead to gene-therapy techniques to target specific cancer cells with limited risk to other normal cells.

Can bone cancer be prevented?

No. There is no method of preventing bone cancer.
source:medicinenet.com