Osteosarcoma

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at April 24, 2016
StartDiseasesOsteosarcoma

Osteosarcoma is the most common type of cancer that starts in the bones. It can affect people at any age, but teens are most commonly affected by it.

Contents

Definition & Facts

Two of the main types of cells within bones are osteoblasts and osteoclasts. Osteoblasts are the cells that build up the bones, giving them their shape and making them hard. Osteoclasts are the cells that keep the bones in the proper shape by breaking down some of the bone when there is too much being created. The cancerous cells that arise from osteosarcoma are similar to osteoblasts in that they help form bones.

There are three different sub-types that osteosarcoma can be classified as: high-grade, intermediate-grade, or low-grade. High-grade is the fastest growing type of osteosarcoma. In these cases the bone does not look like a normal bone should and the cells divide and form new cells rapidly. The most common high-grade osteosarcomas are osteoblastic, fibroblastic, chondroblastic.

Intermediate-grade is an uncommon form of osteosarcoma and is often treated like low-grade. Low-grade is the slowest growing form. The bone looks normal and has only a few cells that are dividing abnormally.

Symptoms & Complaints

Common symptoms include pain in the bone that is affected and swelling in the same area. The pain will likely not be a consistent pain but will worsen at night and during activity. Swelling of the same area is common but may not appear for several weeks after the pain begins. A lump may be felt depending on where the tumor is located.

It is common for children and teens that are active to feel pain due to normal bumps and bruises which can delay the diagnosis of osteosarcoma. If a child has these symptoms and they do not go away in several weeks or the pain and swelling worsen, it is important to make a doctor's appointment. Bone fractures or breaks of the bone are another symptom of osteosarcoma but are less common. The bones becomes weaker, making fracture more likely.

Causes

Osteosarcoma is caused by genetic mutations that are either acquired or inherited. The reason why these genetic changes occur isn't understood in most cases but there are a number of risk factors that can increase a person's chance of having osteosarcoma.

  • Age- Although osteosarcoma can develop at any age, it is most common in people between the ages of 10 and 30. Those that are under the age of the 10 and over the age of 30 are less likely to develop this type of cancer. Scientists believe that there could be a connection to the rapid growth that happens during this time and the development of this cancer. The risk is also greater in those that are over the age of 60 as well, but this is typically linked to a different cause, such as a bone disease.
  • Height - Children that are taller for their age are more likely to develop osteosarcoma. This is another factor that has suggested to scientists that there is a connection between rapid growth and osteosarcoma.
  • Ethnicity/Race - Osteosarcoma is more commonly found in African-Americans than in other races/ethnic groups.
  • Gender - Osteosarcoma is more commonly found in males than in females.
  • Radiation used on bones - Those that have had another form of cancer and had radiation treatments are more likely to develop osteosarcoma in the same treatment area. Those that have had high doses of radiation at a younger age are even more likely to develop it.

Diagnosis & Tests

When someone goes in to the doctor for the symptoms they have been having, the doctor will do a physical examination and go over their medical history. During the physical exam, they will feel for lumps or masses. They will also look at other parts of the body. If someone has cancer in another area of their body, it could spread to the bones. If osteosarcoma is suspected, other tests may be completed to verify.

Imaging tests that may be used include bone and chest X-rays, an MRI scan, CT scan, bone scan, or PET scans may be used in order to create a picture of the inside of a person's body. The doctor can then look at the picture that was created to look for any abnormalities.

If any of these tests suggest that a person has osteosarcoma, a biopsy will be done. A biopsy is done by taking a small sample of the tumor in order to look at it under a microscope. This will show the doctor whether or not there are any abnormalities in the sample.

Treatment & Therapy

When the diagnosis is osteosarcoma, there are a few treatment options available. Surgery is one of the first options that are used. When having surgery for treatment, the tumor is located and all of it is removed. It is important to remove all of the cells of the tumor. If there are even just a few cells left behind, they can multiply and cause a recurrence.

Sometimes, removing the tumor may not be an option. In some cases where the osteosarcoma is located in a limb, the tumor may be in the nerves or the blood vessels, so amputating the limb would be the best solution to remove all of the cancer.

Chemotherapy is a treatment that includes using drugs that have been designed to kill cancer cells. For a patient with osteosarcoma, this is often used before and after surgery to ensure that all cancer cells have been removed or are dead.

Radiation therapy is another type of treatment that is often used in treating cancer. It uses high-energy radiation rays to target and kill cancer cells and may be used to kill remaining cells after surgery has removed the majority of the tumor.

Prevention & Prophylaxis

There is currently no known way to prevent osteosarcoma except to avoid excessive exposure to radiation.