What Is Osteosarcoma?

Osteosarcoma, also called osteogenic sarcoma, is a kind of bone cancer. It happens when the cells that grow new bone form a cancerous tumor. Treatment -- chemotherapy and surgery to take out the tumor -- is usually successful when the disease is diagnosed early, before it can spread.

It’s the most common kind of bone cancer in children and teens. It can affect adults, too. But teenage boys are most likely to get it.

In children and teens, osteosarcoma often happens at the ends of long bones, where bone grows fastest. Most tumors develop around the knee, in either the lower part of the thighbone or the upper part of the shinbone. They also may grow in the upper arm bone close to the shoulder. But osteosarcoma can happen in any bone, especially in older adults.

Osteosarcoma Subtypes

Doctors divide osteosarcoma into three subtypes, based on what the cells look like under a microscope:

  • High-grade osteosarcoma. This is the fastest-growing type, with cells that look unusual. Most osteosarcomas in children and teens are high-grade.
  • Low-grade osteosarcomas. These grow slowly. The cells look more like regular bone.
  • Intermediate-grade osteosarcoma. This is in between high- and low-grade tumors. It’s rare.

Osteosarcoma Causes

An error in your DNA, or your genetic code, causes osteosarcoma. Bone-growing cells make tumors by mistake.

Teenagers who are having a “growth spurt” are most likely to get it, and taller kids may be at higher risk. There may also be a link between the speed of a growth spurt and tumor development.

Treatments like radiation therapy for other types of cancer or cancer medicines called alkylating agents can raise your risk of osteosarcoma. Some illnesses, like Paget’s disease of the bone or a type of eye cancer called hereditary retinoblastoma, may also make it more likely.

Osteosarcoma Symptoms

Warning signs include:

  • Swelling or lumps around bones or the ends of bones
  • Bone or joint pain or soreness. This pain may come and go for months.
  • Broken bones without a clear reason

You may also have pain at night or after you exercise. You might have a limp if osteosarcoma affects your legs.


Osteosarcoma Diagnosis

The doctor will ask about your personal and family medical history. They’ll check for unusual lumps around your bones.

You might have imaging tests like X-rays, CT scans, MRIs, or bone scans. These can show unusual changes in bones that may be signs of osteosarcoma. They can also show areas where a tumor may have spread.

If your doctor sees signs of a problem on the imaging tests, you may need a biopsy. A surgeon will take a small sample of bone or tissue from a painful or swollen area. A specialist looks at it under a microscope. This test may show cancer cells in your bone or cancer cells that have spread to muscles or other areas.

Osteosarcoma Treatment

Treatment depends on several things, including where the tumor is, how fast it's growing, and whether it’s spread. Your age and overall health will also factor in.

Treatment works best when you start before the cancer spreads beyond your bones to other tissues or organs.

Most people find tumors early because they cause pain, swelling, or a limp. Let your doctor know about warning signs like these so you can start treatment as soon as possible.

Most people with osteosarcoma need both surgery and chemotherapy. Some also get radiation therapy.


The goal of surgery is to remove all the cancer. If even a small number of cancer cells are left behind, they can grow into a new tumor.

For tumors in your arms and legs: In most cases, your surgeon will be able to take out the tumor and some of the tissue around it. A medical device, or prosthesis, will fill in part or all of the gap left in the bone. You might also have a bone graft, which uses a piece of bone from another part of your body or from a donor.

If the tumor is large and has gotten into nerves or blood vessels, your doctor may have to amputate, or remove, all or part of your leg or arm. You might choose to get fitted for an artificial limb, or prosthetic.


For tumors in other areas: Osteosarcoma that forms in your pelvis, jawbone, spine, or skull may be harder to remove completely with surgery. You might also need radiation therapy. If the cancer spreads to your lungs or other parts of your body, your doctor will take out those tumors.


“Chemo” uses strong medications to kill cancer cells or stop them from growing. You usually get them in your vein through an IV.

Doctors treat most osteosarcomas with chemo. The drugs may shrink the tumor, which can make surgery easier. They also get rid of small clusters of cancer cells that doctors may not be able to see on medical scans.

Side effects include nausea and vomiting, diarrhea, and a loss of appetite. Children tend to have less severe side effects from chemo than adults, so they might get higher doses of medication.

Radiation therapy

High-energy X-rays can kill cancer cells.

Radiation doesn't work as well on osteosarcoma cells as it may with other cancers. But your doctor might use a procedure called external beam radiation therapy if they can’t take out all of the cancer through surgery. That often happens when a tumor is in your hip or jawbone.

This type of therapy uses a machine to focus high-energy beams on the tumor to kill the remaining cancer cells.

New therapies

Scientists are studying the best mix of chemo medications to treat osteosarcoma and testing newer types of drugs. They’re also working on stronger and more targeted radiation therapies.

You may want to ask your doctor about clinical trials. These are how experts test new treatments before they’re made widely available. Your doctor can help you find one that might be a good match and help you understand what’s involved.

Osteosarcoma Prognosis

According to estimates, more than 75% of people who are diagnosed before the cancer has spread live at least 5 more years. The same is true of 64% of people whose tumors spread to nearby areas and of more than 25% of those whose cancer has spread farther.

After treatment, you’ll need regular checkups with your doctor to watch for any long-term side effects and make sure the cancer doesn’t come back.


Osteosarcoma Support

A cancer diagnosis can be hard to handle, especially if it affects your child. You may want to consider joining a support group. Counseling is also a good option if the emotions are taking a toll.

Let your family and friends know how they can support you. Chances are, they want to help but may not know how.

WebMD Medical Reference Reviewed by Laura J. Martin, MD on February 15, 2020



American Cancer Society: “What Is Osteosarcoma?” “Treating Osteosarcoma,” “What Are the Risk Factors for Osteosarcoma?” “Can Osteosarcoma Be Found Early?” “Survival Rates for Osteosarcoma.”

Cancer.Net: “Osteosarcoma - Childhood and Adolescence: Risk Factors.”

KidsHealth: “Childhood Cancer: Osteosarcoma.”

MayoClinic.org: “Paget’s disease of bone.”

National Cancer Institute, National Institutes of Health: “Osteosarcoma and Malignant Histiocytoma of Bone Treatment.”

St. Jude Children’s Research Hospital: “Disease Information.”

American Society for Clinical Oncology: “Osteosarcoma -- Childhood and Adolescence: Follow-Up Care.”

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