When cells divide abnormally and uncontrollably, they can form a mass or lump of tissue. This lump is called a tumor. Bone tumors form in your bones. As the tumor grows, abnormal tissue can displace healthy tissue.
Some tumors are benign, meaning they are not cancerous. While benign bone tumors won’t spread to other parts of the body and are unlikely to cause death, they can still be dangerous and may require treatment. Benign tumors can grow and could compress your healthy bone tissue.
Other tumors are malignant, meaning they are cancerous. Malignant bone tumors can cause cancer to spread throughout the body.
Benign tumors are more common than malignant ones. According to the American Academy of Orthopaedic Surgeons, the most common type is osteochondroma. This type accounts for between 35 and 40 percent of all benign bone tumors (AAOS). Osteochondromas develop in adolescents and teenagers.
The tumors form near the ends of long bones, such as the arm or leg bones. Specifically, these tumors tend to affect the lower end of the thighbone (femur), the upper end of the lower leg bone (tibia) and the upper end of the upper arm bone (humerus). Basically, they are usually found at the actively growing ends of long bones.
These tumors are formed of a combination of bone and cartilage. The osteochondroma has been considered to be an abnormality of growth. A child may develop a single osteochondroma or many.
Non-Ossifying Fibroma Unicameral
Non-ossifying fibroma unicameral is a simple solitary bone cyst. It is the only true cyst of bone. It is usually found in the leg and occurs most often in children and adolescents.
Giant Cell Tumors
Giant cell tumors grow aggressively. They occur in adults and in the rounded end of the bone, not in the growth plate. These are very rare.
An enchondroma is a cartilage cyst that grows inside the bone marrow. When they occur, they begin in children and persist as adults. They tend to be part of syndromes called Ollier’s and Mafucci’s syndrome. Enchondromas occur in the hands and feet as well as the long bones of the arm and thigh.
Fibrous dysplasia is a gene mutation that makes bones fibrous and vulnerable to fracture.
Aneurysmal Bone Cyst
An aneurysmal bone cyst is an abnormality of blood vessels that begins in the bone marrow. It can grow rapidly and can be particularly destructive because it affects growth plates.
There are also several types of cancer that produce malignant bone tumors. Primary bone cancer means that the cancer originated in the bones. According to the National Cancer Institute, primary bone cancer accounts for less than one percent of all types of cancer (NCI). The three most common forms of primary bone cancers are osteosarcoma, Ewing sarcoma family of tumors, and chondrosarcoma.
Osteosarcoma, which occurs mostly in children and adolescents, is the second most common type of bone cancer. This usually develops around the hip, shoulder, or knee. This tumor is fast growing and likely to spread to other parts of the body. The most common sites are the areas where the bones are most actively growing (the growth plates), the lower end of the thighbone, and the upper end of the lower leg bone. Osteosarcoma is also sometimes known as osteogenic sarcoma.
Ewing sarcoma family of tumors (ESFTs) strikes adolescents and young adults, but can sometimes affect children as young as 5 years old. This type of bone cancer usually shows up in the legs (long bones), pelvis, backbone, ribs, and upper arms and in the skull. It begins in the cavities of the bones where the bone marrow is produced(the medullary cavities) In addition to thriving in bone, ESFTs can also grow in soft tissue, such as fat, muscle, and blood vessels. African American children seldom develop Ewings sarcoma. Boys are more likely to be victims than girls. It is a rapidly growing and rapidly spreading tumor.
Middle-aged people and seniors are more likely than other age groups to develop chondrosarcoma. The hips, shoulders, and pelvis are the usual areas for this type of bone cancer.
Secondary Bone Cancer
Secondary bone cancer means that the cancer started somewhere else in the body and then spread to the bone. It usually affects older people. The types of cancer most likely to spread to your bones are:
- lung (particularly osteosarcoma)
- thyroid gland
The most common type of secondary bone cancer is called multiple myeloma. This shows up as tumors in the bone marrow. People between the ages of 50 and 70 are most commonly affected by multiple myeloma.
The cause of bone tumors is not known. Often the tumors occur when parts of the body are growing rapidly. A few possible causes are genetics, radiation treatment, and injuries to the bones. Osteosarcoma has been linked to radiation treatment (particularly high doses of radiation) and other anticancer drugs, especially in children. However, a direct cause has not been identified. People who have had bone fractures repaired with metal implants are also likelier to later develop osteosarcoma.
A dull ache in the affected bone is the most common symptom of bone cancer. The pain starts off as occasional and then becomes severe and constant. The pain may be severe enough to wake you up in the night. Sometimes, when people have an undiscovered bone tumor, what seems like an insignificant injury breaks the already-weakened bone, leading to severe pain. This is known as a pathologic fracture. Sometimes there may be swelling at the site of the tumor.
People with benign tumors might not have any symptoms, and the tumor might not be detected until an imaging scan reveals it while receiving other medical testing. A benign bone tumor (such as an osteochondroma) may not require treatment unless it starts to interfere with function and movement.
Some other conditions, such as fractures and infections, might resemble tumors. To be sure you have a bone tumor, your doctor might order a variety of tests.
First, your doctor will examine you physically, focusing on the area of your suspected tumor. He or she will check for tenderness in your bone and test your range of motion. Your doctor will also ask questions about your family medical history.
Blood and Urine Tests
Your doctor might order tests, including blood or urine samples. These fluids will be analyzed at a lab to detect different proteins that may indicate the presence of a tumor or other medical problems.
An alkaline phosphatase test is one common tool used in diagnosing bone tumors. When your bone tissue is especially active in forming cells, large quantities of this enzyme show up in your blood. This could be because a bone is growing, such as in young people, or it could mean a tumor is producing abnormal bone tissue. This test is more reliable in adults who have stopped growing.
Your doctor will probably order X-rays to determine the size and exact location of the tumor. Depending upon the X-ray results, other imaging tests might be necessary, including:
- CT or CAT scan, also known as computed tomography: This test produces a series of detailed images of your insides, taken from several angles.
- MRI, or magnetic resonance imaging: This test takes detailed pictures of the area in question.
- PET scan, or positron emission tomography: The doctor injects a little radioactive sugar in your vein. Since cancer cells use more glucose than regular cells, this activity helps to locate the site of the tumor.
- Angiogram: This is an X-ray of your blood vessels.
Your doctor might want to perform a biopsy. In this test, a sample of the tissue that makes up your tumor will be removed. The sample is examined in a laboratory under a microscope. The main types of biopsies are a needle biopsy and an incisional biopsy.
A needle biopsy may be done in your doctor’s office or by a radiologist in conjunction with one of the above imaging tests. Either way, you’ll have local anesthetic to block the pain. The doctor will insert a needle into your bone, using it to remove a small bit of tumor tissue. If your needle biopsy is done by a radiologist, he or she will use the image from the X-ray, MRI, or CT scan to help find the tumor and know where to insert the needle.
An incisional biopsy, also called an open biopsy, is done in an operating room under general anesthesia so you will sleep through this procedure. The doctor cuts an incision and removes your tissue through it.
The bone biopsy is important to make a definite determination of the condition.
If your tumor is benign, it may or may not require action. Sometimes doctors just watch benign bone tumors to see if they change. This requires coming back periodically for follow-up X-rays. Bone tumors can grow, stay the same, or eventually disappear. Children have a higher likelihood of having their bone tumors disappear as they mature.
Sometimes benign tumors spread or transform into malignant tumors. Since bone tumors can also lead to fractures, your doctor might want to surgically remove even a benign tumor.
If your tumor is malignant, you will work closely with a team of doctors to try to cure your cancer and maintain your maximum functioning. Although malignant tumors are a cause of concern, the outlook is improving daily as treatments are developed and improved.
Your treatment will depend on what type of bone cancer you have and whether it has spread. If your cancer cells are confined to the tumor and its immediate environs, this is called the localized stage. In the metastatic stage, cancerous cells have already spread to other parts of the body. This makes curing your cancer more difficult.
Surgery, radiation, and chemotherapy are the main strategies for treating cancer.
Bone cancer is usually treated with surgery. Your entire tumor is removed. The surgeon carefully examines the margins of your tumor to make sure no cancer cells are left after surgery. If your bone cancer is in an arm or leg, your doctor may use what is known as limb salvage surgery. This means that while the cancerous cells are removed, your tendons, muscles, blood vessels, and nerves are spared. Your surgeon will replace the cancerous bone with a metal implant. Advances in chemotherapy have greatly improved recovery and survival. New drugs are being introduced on an ongoing basis.
Surgical techniques have improved greatly, making it much more likely that doctors can spare your limbs. According to the National Cancer Institute, nine out of 10 people with bone cancer in a limb can have it removed without amputation (NCI). However, you might need reconstructive surgery to retain as much limb function as possible.
Radiation is often used in conjunction with surgery. High-dose X-rays are used to shrink tumors before surgery and kill cancer cells. Radiation can also reduce pain and decrease the chance of bone fractures.
If your doctor thinks your cancer cells are likely to spread (or if they already have) he or she might recommend chemotherapy. This therapy uses anticancer drugs to kill the rapidly-growing cancer cells.
Chemotherapy does have unpleasant side effects, including nausea, irritablity, hair loss, and extreme fatigue.
Cryosurgery is another possibility. This treatment involves killing cancer cells by freezing them with liquid nitrogen. A hollow tube is inserted into your tumor, and liquid nitrogen or argon gas is pumped in. In some cases, cryosurgery can be used against bone tumors instead of regular surgery.
Your doctor will want you to stay in close contact while you recover. Follow-up X-rays and blood tests will be necessary to make sure the whole tumor is gone and that it does not return. Your doctor might want to run tests on you every few months.
Your rate of recovery will depend on what type of bone tumor you had, its size, and its whereabouts.
If your tumor was benign, your long-term outcome will probably be good. However, benign bone tumors can grow, reoccur, or turn into cancer, so you will still benefit from regular check-ups.
Your prognosis is also good if you had a localized bone tumor. This will vary according to the type of cancer, size, location, and your general health. Again, bone tumors can reoccur, whether malignant or benign. People who have had bone cancer, especially at an early age, are at higher risk of developing other types of cancer. So if you have any symptoms or health concerns, report promptly to your doctor.
The outlook is poorer if your bone cancer has spread. But there are treatments, and technology continues to advance. Many people with bone cancer join clinical trials of new drugs and therapies. This benefits both current cancer patients and those who will be diagnosed and treated in the future. If you’re interested in participating in clinical trials, talk to your doctor or call the National Cancer Institute at 1–800–422–6237.