Osteosarcoma is a primary bone cancer. This means the cancer starts in a bone rather than spreading to bone from another part of the body. Osteosarcoma begins in the cells that form bones. Osteosarcoma tends to happen most often in teenagers and young adults. But it also can happen in younger children and older adults.

Osteosarcoma is rare. Even so, it is the most common primary bone cancer in children, teenagers and young adults.

Osteosarcoma also is called osteogenic sarcoma.

Osteosarcoma can start in any bone. It's most often found in the long bones of the legs and sometimes the arms. Very rarely, osteosarcoma happens in soft tissue outside the bone. This is called extraskeletal osteosarcoma.

Osteosarcoma is different from other primary bone cancers because its cancer cells make immature bone, called osteoid. Ewing sarcoma is another bone cancer seen mostly in children and young people. But it has different tumor biology, and it is treated with a different combination of chemotherapy and local treatment.

Advances in the treatment of osteosarcoma have improved the outlook for this cancer. Children and adolescents treated for osteosarcoma may have side effects that last or develop months or years after treatment. Healthcare professionals often suggest lifelong monitoring for side effects after treatment.

Osteosarcoma signs and symptoms most often start in a bone. The cancer most often affects the long bones of the legs and sometimes the arms. The most common symptoms include:

• Bone or joint pain. Pain might come and go first. It can be mistaken for growing pains.
• Pain related to a bone that breaks for no clear reason.
• Swelling or a growing lump near a bone. The lump may feel firm and may not move easily. It can be painful.

When to see a doctor

Make an appointment with a healthcare professional if you or your child has ongoing symptoms that worry you. Osteosarcoma symptoms are like those of many more common conditions, such as sports injuries. The health professional might check for those causes first.

It's not clear what causes osteosarcoma. Osteosarcoma develops when bone-forming cells undergo genetic changes. The exact changes that lead to the cancer are not fully understood.

As osteosarcoma grows, it can damage nearby tissue and spread to other parts of the body. The lungs are the most common site of distant spread. The cancer also can spread to other bones.

Most people with osteosarcoma don't have any known risk factors for the cancer. But these things can raise the risk of osteosarcoma:

• Certain conditions that run in families. These include hereditary retinoblastoma, Bloom syndrome, Li-Fraumeni syndrome, Rothmund-Thomson syndrome and Werner syndrome.
• Other bone conditions. These include Paget's disease of bone and fibrous dysplasia.
• Prior treatment with radiation therapy.

Osteosarcoma can spread from where it started to other areas. This is called metastatic osteosarcoma. Cancer that has spread can affect treatment options and outlook. Osteosarcoma most often spreads to the lungs, another part of the same bone or to another bone.

Prevention

In general, there is no way to prevent osteosarcoma. People with hereditary conditions should be monitored for the development of osteosarcoma and other cancers. People with Li-Fraumeni syndrome, which raises the risk of many cancers, should avoid radiation for the treatment of other cancers because radiation has a high risk of inducing osteosarcoma. These hereditary conditions are very rare, however.

Osteosarcoma diagnosis may begin with a physical exam. Based on the findings of the exam, there might be other tests and procedures.

Imaging tests

Imaging tests make pictures of your body. They can show the location and size of an osteosarcoma. Tests might include:

• X-ray.
• Magnetic resonance imaging (MRI). MRI shows the tumor's size and extent in the bone and nearby soft tissues. It also helps surgeons plan a biopsy and surgery.
• Computed tomography (CT). A CT scan of the chest looks for osteosarcoma that has spread to the lungs.
• Bone scan. A bone scan can look for osteosarcoma in other bones.
• Positron emission tomography (PET) scan. A PET scan can help look for cancer in other bones, soft tissues and other areas of the body. In most cases, a PET scan is preferred over a bone scan for staging osteosarcoma.

An X-ray often is one of the first imaging tests. Some osteosarcomas may show areas where bone is being destroyed along with areas of new bone formation. Some tumors show a sunburst pattern, in which new bone appears to radiate outward, or a Codman triangle, a small triangle of new bone that can form along the edge of the tumor. These findings can suggest osteosarcoma, but imaging alone cannot confirm the diagnosis.

Removing a sample of cells for testing, called a biopsy

A biopsy is a procedure to remove a sample of tissue for testing in a lab. The tissue might be removed using a needle that is put through the skin and into the cancer. Sometimes surgery is needed to get the tissue sample. The sample is tested in a lab to see if it is cancer. Other special tests give more details about the cancer cells. Your healthcare team uses this information to make a treatment plan.

Determining the type of biopsy needed and how it should be done requires careful planning by the medical team. Biopsy planning is important because a poorly placed biopsy can raise the risk of cancer cells spreading into nearby tissue or make later surgery more difficult.

The biopsy should be carefully planned with the orthopedic cancer surgery team so the area where the biopsy is done can be removed during surgery, if needed. Before having a biopsy, ask your healthcare professional to refer you to or consult with a team of experts who have experience treating osteosarcoma.

Osteosarcoma treatment most often involves surgery and chemotherapy. Rarely, radiation therapy also might be considered if the cancer can't be treated with surgery. Radiation also may be considered in some cases where osteosarcoma happens outside the bone, called extraskeletal osteosarcoma. This is a very rare form of the disease.

Surgery

For most osteosarcoma surgeries, the goal is to completely remove the tumor with clear margins. This means no cancer cells are left at the edges of the tissue that is removed.

In planning the surgery, the healthcare team keeps in mind how the surgery will affect you or your child's daily life. The extent of surgery for osteosarcoma depends on several factors, such as the size of the cancer and where it is located.

Operations used to treat osteosarcoma include:

• Limb-sparing surgery. Most operations for osteosarcoma in an arm or leg can be done in a way that removes the cancer and spares the limb. Whether this type of surgery 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 rebuild the bone. How the bone is rebuilt depends on the situation. Options include metal implants or bone grafts. An important goal of limb-sparing surgery is to preserve as much function as possible while completely removing the cancer. Surgeons consider whether the tumor involves important nerves or blood vessels when deciding whether limb-sparing surgery is an option.
• Surgery to remove the affected arm or leg, called amputation. Rarely, a surgeon might remove the affected leg or arm to get all the cancer. After surgery, an artificial arm or leg can be used. This is called a prosthesis.
• Surgery to remove the part of the leg where the cancer is located, called rotationplasty. Rotationplasty might be an option for osteosarcoma around the knee joint. In this surgery, the surgeon removes the part of the leg containing the cancer, including the knee joint. The foot and ankle are then rotated and put backward on the part of the leg that remains above the knee. The ankle then works as a knee. A prosthesis is used for the lower leg and foot.

Coping after surgery to remove an arm or leg

Surgeons aim to remove the cancer and spare the arm or leg when they can. But sometimes surgeons need to remove part of the affected limb to remove all the cancer. Your healthcare team can help you decide whether a prosthesis is right for you and what may work best for your needs and goals. If you use a prosthesis, ask your healthcare team what to expect as you learn to use it.

Chemotherapy

Chemotherapy treats cancer with strong medicines. The medicines travel through the bloodstream, so they can reach cancer cells throughout the body. This is why chemotherapy is called a systemic treatment.

For osteosarcoma, chemotherapy often is used before surgery. It can shrink the cancer and make it easier to remove. Chemotherapy often continues after surgery to kill any cancer cells that might remain.

A common chemotherapy combination for high-grade osteosarcoma in children and many young people is called MAP. It includes high-dose methotrexate, doxorubicin (Adriamycin) and cisplatin.

When osteosarcoma has spread or comes back after treatment, chemotherapy may be part of treatment. Surgery also may be used to remove the main tumor and other sites of cancer that can be safely removed.

Radiation therapy

Radiation therapy treats cancer with powerful energy beams. The energy can come from X-rays, protons or other sources. During radiation therapy, you lie on a table while a machine moves around your body. The machine directs radiation to precise points in your body.

Radiation is not often used to treat osteosarcoma. Radiation therapy might be considered when surgery isn't possible or can't completely remove the cancer. It also may be used as part of treatment for extraskeletal osteosarcoma.

A diagnosis of osteosarcoma can feel overwhelming. With time, you'll find ways to cope with the distress and uncertainty of cancer. Until then, you might find the following helpful:

Helping children and teens

• Ask the healthcare team to explain osteosarcoma and treatment in a way your child or teen can understand.
• Encourage your child or teen to ask questions and talk about worries or fears.
• Ask whether a child life specialist is available to help your child or teen understand and cope with medical care.

For parents and caregivers

• Ask the healthcare team for help talking with your child about osteosarcoma and treatment in a caring, age-appropriate way.
• Let friends and family help with practical needs, such as caring for your home or other responsibilities, while your child is in the hospital.
• Ask about counseling, social work, or other support for your child and family.

For adults

• Ask how treatment may affect your daily life and the activities that are important to you.
• Talk with your healthcare team about concerns such as fertility before treatment begins.
• Ask about counseling, social work or other support if cancer or treatment is affecting your emotional well-being.

If you or your child has signs and symptoms that worry you, start by making an appointment with a healthcare professional. If the health professional suspects osteosarcoma, ask to be referred as quickly as possible to an experienced specialist.

Osteosarcoma typically is treated by a team of specialists, which may include:

• Orthopedic surgeons who specialize in operating on cancers that affect the bones, called orthopedic oncologists.
• Other surgeons, such as pediatric surgeons. The type of surgeon depends on the site of the cancer and the age of the person with osteosarcoma.
• Doctors who specialize in treating cancer with chemotherapy or other systemic medicines. These might include medical oncologists or, for children, pediatric oncologists.
• Doctors who study tissue to diagnose the specific type of cancer, called pathologists.
• Rehabilitation specialists who can help in recovery after surgery.
• Child life specialists who can provide support for children and teens during cancer care.

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, and when they began.
• Any medicines you or your child takes, as well as vitamins and herbs, and their doses.
• Key personal information, including any major stresses or recent life changes.

Also consider:

• Bringing scans or X-rays, both the images and the reports, and any other medical records that are linked to this condition.
• Making a list of questions to ask the health professional to make sure you get the information you need.
• Taking a relative or friend to the appointment, if you can, to help you remember the information you get.

For you or your child, your questions might include:

• 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 side effects and risks of each treatment option?
• Which treatment do you think is best?
• Will treatment affect being able to have children? If so, do you offer ways to preserve that ability?
• Are there brochures or other printed materials I can have? What websites do you suggest?

What to expect from your doctor

Your healthcare professional will likely ask you questions, such as:

• What are the signs and symptoms that worry you?
• When did you notice these symptoms?
• Do you always have the symptoms, or do they come and go?
• 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?