Osteosarcoma is a type of bone cancer that begins in the cells that form bones. Osteosarcoma is most often found in the long bones — more often the legs, but sometimes the arms — but it can start in any bone. In very rare instances, it occurs in soft tissue outside the bone.

Osteosarcoma tends to occur in teenagers and young adults, but it can also occur in younger children and older adults.

Treatment usually involves chemotherapy, surgery and, sometimes, radiation therapy. Doctors select treatment options based on where the osteosarcoma starts, the size of the cancer, the type and grade of the osteosarcoma, and whether the cancer has spread beyond the bone.

Treatment innovations for osteosarcoma have greatly improved the outlook (prognosis) for this cancer over the years. After completion of treatment, lifelong monitoring is recommended to watch for potential late effects of intense treatments.

Signs and symptoms of osteosarcoma may include, among others:

• Swelling near a bone
• Bone or joint pain
• Bone injury or bone break for no clear reason

When to see a doctor

Make an appointment with your child's doctor if your child has any persistent signs and symptoms that worry you. Osteosarcoma symptoms are similar to many more-common conditions, such as sports injuries, so your doctor may investigate those causes first.

It's not clear what causes osteosarcoma. Doctors know this cancer forms when something goes wrong in one of the cells that are responsible for making new bone.

Osteosarcoma begins when a healthy bone cell develops changes in its DNA. A cell's DNA contains the instructions that tell a cell what to do. The changes tell the cell to start making new bone when it isn't needed. The result is a mass (tumor) of poorly formed bone cells that can invade and destroy healthy body tissue. Cells can break away and spread (metastasize) throughout the body.

These factors increase the risk of osteosarcoma:

• Previous treatment with radiation therapy
• Other bone disorders, such as Paget's disease of bone and fibrous dysplasia
• Certain inherited or genetic conditions, including hereditary retinoblastoma, Bloom syndrome, Li-Fraumeni syndrome, Rothmund-Thomson syndrome and Werner syndrome

Complications of osteosarcoma and its treatment include:

• Cancer that spreads (metastasizes). Osteosarcoma can spread from where it started to other areas, making treatment and recovery more difficult. Osteosarcoma that spreads most often spreads to the lungs and to other bones.
• Adapting to limb amputation. Surgery that removes the tumor and spares the limb is used whenever possible. But sometimes it's necessary to remove part of the affected limb in order to remove all of the cancer. Learning to use an artificial limb (prosthesis) will take time, practice and patience. Experts can help you adapt.
• Long-term treatment side effects. The aggressive chemotherapy needed to control osteosarcoma can cause substantial side effects, both in the short and long term. Your health care team can help you manage the side effects that happen during treatment and provide you with a list of side effects to watch for in the years after treatment.

To diagnose osteosarcoma, the doctor may begin with a physical exam to better understand the symptoms.

Imaging tests

Imaging tests help your doctor investigate your bone symptoms, look for cancer and look for signs that the cancer has spread.

Imaging tests may include:

• X-ray
• Computerized tomography (CT)
• Magnetic resonance imaging (MRI)
• Positron emission tomography (PET)
• Bone scan

Removing a sample of cells for testing (biopsy)

A biopsy procedure is used to collect a sample of suspicious cells for laboratory testing. Tests can show whether the cells are cancerous. Lab tests can determine the type of cancer and whether it's aggressive (the grade).

Types of biopsy procedures used to diagnose osteosarcoma include:

• Needle biopsy. The doctor inserts a thin needle through the skin and guides it into the tumor. The needle is used to remove small pieces of tissue from the tumor.
• Surgical biopsy. The doctor makes an incision through the skin and removes either the entire tumor (excisional biopsy) or a portion of the tumor (incisional biopsy).

Determining the type of biopsy needed and the specifics of how it should be performed requires careful planning by the medical team. Doctors need to perform the biopsy in a way that won't interfere with future surgery to remove the cancer. For this reason, ask your doctor for a referral to a team of experts with extensive experience in treating osteosarcoma before the biopsy.

Osteosarcoma treatment typically involves surgery and chemotherapy. Radiation therapy might be an option in certain situations.

Surgery

The goal of surgery is to remove all of the cancer cells. But planning the operation also takes into consideration how it will affect your ability to go about your daily life. The extent of surgery for osteosarcoma depends on several factors, such as the size of the tumor and its location.

Operations used to treat osteosarcoma include:

• Surgery to remove the cancer only (limb-sparing surgery). Most osteosarcoma operations can be done in a way that removes all of the cancer and spares the limb so that function can be maintained. Whether this procedure is an option depends, in part, on the extent of the cancer and how much muscle and tissue need to be removed.

  If a section of bone is removed, the surgeon will reconstruct the bone. The method of reconstruction depends on your particular situation, but options include metal prosthetics or bone grafts.

• Surgery to remove the affected limb (amputation). With advancements in limb-sparing surgery, the need for amputation — removing a limb or part of a limb — has greatly reduced over the years. If amputation is necessary, advances in prosthetic joints can significantly improve outcomes and function.
• Surgery to remove the lower portion of the leg (rotationplasty). In this surgery, sometimes used for children who are still growing, the surgeon removes the cancer and surrounding area, including the knee joint. The foot and ankle are then rotated, and the ankle functions as a knee. A prosthesis is used for the lower leg and foot. Results typically enable the person to function very well in physical activities, sports and daily living.

Chemotherapy

Chemotherapy uses drugs to kill cancer cells. Chemotherapy treatment usually combines two or more drugs that can be administered as an infusion into a vein (IV), in pill form, or through both methods.

For osteosarcoma, chemotherapy is often recommended before surgery (neoadjuvant therapy). Doctors monitor how the cancer cells respond to the chemotherapy in order to plan further treatments.

If the osteosarcoma shrinks in response to the chemotherapy, it may make limb-sparing surgery possible.

If the osteosarcoma doesn't respond to treatment, it may indicate the cancer is very aggressive. Doctors may recommend a different combination of chemotherapy drugs or suggest a more aggressive operation to ensure all the cancer is removed.

Chemotherapy can also be used after surgery to kill any cancer cells that might remain.

If osteosarcoma returns after surgery or spreads to other areas of the body, chemotherapy might be recommended to try to slow the growth of the disease.

Radiation therapy

Radiation therapy uses high-energy beams, such as X-rays and protons, to kill cancer cells. Radiation might be an option in certain situations, such as when surgery isn't possible or if surgeons can't remove all of the cancer during an operation.

During radiation therapy, the beams of energy are delivered from a machine that moves around you as you lie on a table. The beams are carefully directed to the area of the osteosarcoma in order to reduce the risk of damage to surrounding healthy cells.

Clinical trials

Clinical trials are studies to investigate new ways of treating cancer. Ask your doctor or your child's doctor about whether you may be eligible to join a trial.

A diagnosis of osteosarcoma can be frightening. With time you'll find ways to cope with the distress and uncertainty of cancer. Until then, you may find it helps to:

• Learn enough about osteosarcoma to make decisions about care. Ask your doctor about this sarcoma, including treatment options. As you learn more, you may become more confident in understanding and making decisions about treatment options. If your child has cancer, ask the health care team for guidance on sharing this information in a caring and age-appropriate way.
• Keep friends and family close. Keeping your close relationships strong can help you deal with cancer. Friends and relatives can provide the practical and emotional support you'll need, especially when you feel overwhelmed.
• Ask about mental health support. The concern and understanding of a counselor, medical social worker, psychologist or other mental health professional also may help you. If your child has cancer, ask your health care team for advice on providing emotional and social support and options for professional mental health support. You can also check online for a cancer organization, such as the American Cancer Society, that lists support services.

If there are signs and symptoms that worry you, you'll likely start by making an appointment with your primary care doctor — or the pediatrician if the concern is with your child. If your doctor suspects osteosarcoma, ask for a referral to an experienced specialist.

Osteosarcoma typically needs to be treated by a team of specialists, which may include, for example:

• Orthopedic surgeons who specialize in operating on cancers that affect the bones (orthopedic oncologists)
• Other surgeons, depending on patient age (for example, pediatric surgeons)
• Doctors who specialize in treating cancer with chemotherapy or other systemic medications (medical oncologists or, for children, pediatric oncologists)
• Doctors who analyze tissue to diagnose the specific type of cancer (pathologists)
• Rehabilitation specialists who can help in recovery after surgery

What you can do

Before the appointment, make a list of:

• Signs and symptoms, including any that seem unrelated to the reason for the appointment
• Any medications being taken, including vitamins, herbs and over-the-counter medicines, and their dosages
• Key personal information, including any major stresses or recent life changes

Also:

• Bring previous scans or X-rays (both the images and the reports) and any other medical records related to this situation.
• Consider taking a relative or friend along to help you remember all the information provided during the appointment.
• Prepare a list of questions to ask the doctor to make the most of your time.

Whether you're the patient or your child is the patient, your questions might include, for example:

• What type of cancer is this?
• Has the cancer spread?
• Are more tests needed?
• What are the treatment options?
• What are the chances that treatment will cure this cancer?
• What are the potential side effects and risks of each treatment option?
• Which treatment do you think is best?
• Will treatment affect the ability to have children? If so, do you offer fertility preservation evaluations and services?
• Are there any brochures or other printed material that I can have? What websites do you recommend?

What to expect from your doctor

Your doctor will likely ask several questions. Be ready to answer them to allow more time to cover other points you want to address. Whether you're the patient or your child is the patient, the doctor may ask:

• What are the signs and symptoms that you're concerned about?
• When did you first notice these symptoms?
• Have the symptoms been continuous or occasional?
• How severe are the symptoms?
• What, if anything, seems to improve the symptoms?
• What, if anything, appears to worsen the symptoms?
• Is there a personal or family history of cancer?