What is osteosarcoma?
Osteosarcoma is the most common type of bone cancer, and the sixth most common type of cancer in children. Although many types of cancers can spread to other parts of the skeleton, osteosarcoma is one of the few that begins in bones and sometimes spreads elsewhere.
Because osteosarcoma usually develops from osteoblasts (the cells that manufacture growing bone), it most commonly develops in teenagers going through their growth spurt. Boys are twice as likely to have osteosarcoma as girls, and most cases involve bones around the knee.
Who can be effected?
Although osteosarcoma is most often seen in teenage boys, there is evidence that teens who are taller than average are at special risk.
Children who've inherited one of the rare cancer syndromes (inherited genetic mutations or changes that predispose them to certain types of cancer) are also at greater risk. This may include Li-Fraumeni Syndrome or Retinoblastoma - a non-cancerous tumor that develops in the retina of the eye, usually in children younger than two.
Exposure to radiation is another trigger for mutations in people's DNA, so children who have already had bone radiation treatments for cancer are at an increased risk of osteosarcoma.
Most osteosarcomas grow from non-inherited errors in the DNA of growing bone cells. Because these issues occur randomly during intense bone growth, there's currently no effective way to prevent this type of tumor.
What are the symptoms?
The most common symptoms are pain and swelling in an leg or arm. This happens most often in longer bones, like above or below the knee or in the upper arm near the shoulder.
Pain may be worse during exercise or at night, and a lump or swelling may develop in the affected area some time (even several weeks) after the pain starts. In osteosarcoma of the leg, the child may develop a limp.
In some cases, osteosarcoma may weaken the bone of an arm or leg, leading to a broken bone. In some children, this may be the first sign of cancer.
Osteosarcoma typically develops during teenage adolescence. If your child or teen has any of these symptoms, it's important their seen by a doctor.
Diagnosis
As well as a physical examination, the doctor will ask about any concerns and symptoms. They'll ask about the child's past health, the family's health, medications being taken, any allergies and other issues. The examination will check for tenderness and swelling and the doctor will order X-rays of the affected area.
Changes in bone structure that are typical of osteosarcoma can be seen in standard bone X-rays, although a bone biopsy (the removal and examination of tissue, cells, or fluids from the body) will also be needed. And before a bone biopsy, a computed tomography (CT) scan may be done to help understand the best area to biopsy. This scan will show if the cancer has spread from the bone into nearby muscles and fat. Magnetic resonance imaging (an MRI scan) is also often used to help understand what's going on.
A type of bone biopsy that may be performed under local anesthesia (when the patient is awake) is a needle biopsy. This is when a long hollow needle is used to take a sample of the tumor. Otherwise, an open biopsy may be done under general anesthesia (when the patient is asleep), where a bit of the tumor is removed. In both types of biopsy, the goal is to get a sample for laboratory examination.
Of all the children who develop osteosarcoma, about 20% of them are diagnosed with advanced stage osteosarcoma. This means the disease has spread to other parts of the body. Cancer cells that have spread from the original tumor to other places are called metastases. Most patients with metastases from osteosarcoma have cancer cells that have spread to their lungs, brain or other bones.
If a diagnosis of osteosarcoma is made, the doctor will order CT scans of the chest as well as a bone scan and sometimes MRI studies. These will show if there has been any spread of cancer in the body beyond the original bone tumour. These tests will also be repeated after treatment starts to see how treatment is working.
Treatment
Treatment of osteosarcoma in children includes chemotherapy drugs and surgery to remove to kill cancer cells. Surgery can often effectively remove bone cancer, and chemotherapy is used as a secondary tool to get rid of any remaining cancer cells.
Surgical treatment
Surgical treatments consists of either amputation or limb-salvage surgery. Currently, most teens with osteosarcomas involving an arm or leg, can be treated with limb-salvage surgery rather than amputation.
In limb-salvage surgery, only the osteosarcoma is removed, leaving a gap in the bone that is filled by a bone graft, usually from the patient's own body, taken from the hip bone. Amputation means removing part of a limb along with the cancer and it's often the only choice when the tumor has spread beyond the bone to important surrounding nerves and blood vessels.
Chemotherapy
Chemotherapy is usually given both before and after surgery. A child or teen with osteosarcoma is given the chemotherapy drugs intravenously (through a vein) or by mouth. The drugs enter the bloodstream and work to kill cancer in parts of the body to which the cancer has spread, such as the lungs or other organs.
Short term and long term side effects
Unfortunately there are side effects to the treatment. After amputation it usually takes at least 3 - 6 months for a young person to learn to use a prosthetic (artificial) leg or arm. And this is just one aspect of rehabilitation and getting used to their new way of life.
Many chemotherapy medications also carry the risk of short-term and long-term problems. Short-term effects include: anemia, abnormal bleeding, increased risk of infection due to destruction of the bone marrow, kidney damage and menstrual (period) irregularities. Some drugs also carry a risk of bladder inflammation and bleeding into the urine, hearing loss, and liver damage. Others may cause heart and skin problems. Years after chemotherapy, patients have increased risk of developing other cancers. The doctor will discuss the side effects so they are understood.
Chances of a cure
Recent studies have shown that survival rates between 60% to 80% are possible for osteosarcoma that hasn't metastasized, depending on the success of chemotherapy.
In cases where the osteosarcoma has metastasized, it is not always possible to treat it as successfully. The outcome (prognosis) for people with osteosarcoma in an arm or leg is generally better than people with the cancer in the ribs, shoulder blades, spine, or hip bones.
New treatments
New treatment plans are being developed and researched with new drugs and technologies.
Some research is looking at the role certain growth factors may play in the development of osteosarcoma. This may be used to develop new medications that may slow the growth factors down and offer a way of treating the cancer.
And for osteosarcomas that cannot be removed with surgery, studies are underway to test treatments involving new combinations of chemotherapy drugs and localised high-dose radiation.
The Tom Prince Osteosarcoma Research Project
All the funds raised by the Tom Prince Cancer Trust have created the Tom Prince Osteosarcoma Research Project which is dedicated specifically to researching osteosarcoma. It's the first UK-wide osteosarcoma research project and is working to improve the survival rates and treatment of patients.
The research is currently focused in three areas: building a collection of samples, analysing epigenetics to understand how each patient will respond to chemotherapy, and looking at if the immune system can be used to help develop new treatments (immunotherapy). You can find out more about the project here.
More information and support sources
There's lots of sources of information and support organisations that can help if your child is diagnosed with osetosarcoma. And your doctor will be able to let you know about local cancer support groups.