What is Bone cancer?
Cancer begins in cells, the building blocks that form tissues. Tissues make up the organs of the body.
Normally, cells grow and divide to form new cells as the body needs them. When cells grow old, they die, and new cells take their place.
Sometimes, this orderly process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. These extra cells can form a mass of tissue called a growth or tumor. The cells also become abnormal and have altered functions in patients with cancer.
What causes Bone Cancer?
Bone cancer is caused by a problem with the cells that make bone. It is estimated that around 9,500 people are diagnosed in the India 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.
Common types of bone cancer
There are many different types of bone cancer. The most common bone tumors include
- 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.
- 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 old. It most commonly occurs in the middle of the long bones of the arms and legs.
- 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 old. It is slightly more common in males and can potentially spread to the lungs and lymph nodes. Chondrosracoma most commonly affects the bones of the pelvis and hips.
- 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.
- Fibrosarcoma is much more rare 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.
There are many types of benign bone tumors. The more common types include
- Non-ossifying fibroma unicameral (simple) bone cyst
- Giant cell tumor
What are the symptoms/effects?
The most common symptom of bone tumors is pain. In most cases, the symptoms become gradually more severe with time. 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. The bones can become weakened by the tumor and lead to a fracture after little or no trauma. 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 it diagnosed?
The first thing we do is to take a complete medical history. This will give us clues as to your diagnosis. A description of your symptoms can help us 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 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..
A CT scan (CAT scan or computed tomography) 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.
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).
Blood tests and/or urine tests may be done. A biopsy is another test. A biopsy removes a sample of tissue from the tumor. The tissue sample is examined under a microscope.
There are two basic methods of doing a biopsy.
The doctor inserts a needle into the tumor to remove some tissue. This may be done in the doctor’s office using local anesthesia. A radiologist may do a needle biopsy, using some type of imaging, such as an X-ray, CT, or MRI to help direct the needle to the tumor.
The doctor surgically removes tissue. This is generally done in an operating room. The patient is given general anesthesia and a small incision is made and the tissue is removed.
What are the treatment options?
There are many different methods available for us 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:
- 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.. Historically, amputations were frequently used to remove bone cancer. Newer techniques have decreased the need for amputation.
Limb Salvage Surgery
This surgery removes the cancerous section of bone but keeps nearby muscles, tendons, nerves, and blood vessels. If possible, the surgeon will take out the tumor and a margin of healthy tissue around it. The excised bone is replaced with a metallic implant (prosthesis) or bone transplant.
Amputation removes all or part of an arm or leg when the tumor is large and/or nerves and blood vessels are involved.
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.