Medically Reviewed by Melinda Ratini, MS, DO on August 31, 2022
6 min read

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.

Anyone can have osteosarcoma, but it’s the most common kind of bone cancer in children and teens. Teenage boys are most likely to get it.

Where does osteosarcoma start?

In children and teens, osteosarcoma often happens at the ends of long bones, where bone grows fastest.

  • Most tumors start 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, including your:

  • Pelvis
  • Shoulder
  • Skull


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
  • Pain at night
  • Pain after exercise
  • Limping

Some limb pain and swelling are common in active, growing children. Talk to your doctor if these signs don’t go away in a couple of weeks or if they get worse.

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. The most common kinds are:
    • Osteoblastic
    • Chondroblastic
    • Fibroblastic
  • Low-grade osteosarcoma. This subtype grows slowly. The cells look more like regular bone.
    • Parosteal (juxtacortical)
    • Intramedullary or intraosseous well-differentiated
  • Intermediate-grade osteosarcoma. This is in between high- and low-grade tumors. It’s rare. The main type is called periosteal or juxtacortical.


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

Some things may make you more likely to get osteosarcoma, including:

  • Age. Teenagers who are having a growth spurt are most likely to get it, especially if the growth is happening quickly.
  • Gender. Osteosarcoma happens more often in males.
  • Height. Taller kids have a higher risk.
  • Treatments like radiation therapy for other types of cancer or cancer medicines called alkylating agents
  • Health conditions tied to your genes, like Paget’s disease of the bone, Li-Fraumeni syndrome, Rothmund-Thomson syndrome, Bloom syndrome, Werner syndrome, Diamond-Blackfan anemia, or a type of eye cancer called hereditary retinoblastoma


Your appointment may include:

  • A medical history and physical exam. Your doctor will ask about your personal and family health histories. They’ll check for unusual lumps around your bones.
  • Imaging tests. X-rays, CT scans, MRIs, bone scans, and PET scans can show unusual changes in bones that may be signs of osteosarcoma. They can also show areas where a tumor may have spread.
  • Biopsy. Your doctor will take a small sample of bone or tissue from a painful or swollen area. They may use a needle or make a cut in your skin, called a surgical or open biopsy. A specialist looks at the sample under a microscope. This test may show cancer cells in your bone or cancer cells that have spread to muscles or other areas.


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 surgery and chemotherapy. Some also get radiation therapy.


The goal of surgery is to remove all the cancer. Even a few cells left behind can grow into a new tumor. Depending on your case, your doctor may do one of these procedures:

  • Limb-sparing surgery. Your doctor takes out the tumor in an arm or leg 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.
  • Amputation. 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 or prosthetic limb.
  • Rotationplasty. If your doctor has to take off your leg above your knee, they can reattach part of your lower leg and foot to your thigh bone. With the help of a prosthesis, your ankle works as a new knee joint.

Osteosarcoma 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 may need to 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 and its treatment can lead to complications including:


According to estimates, more than 76% of people who are diagnosed before the cancer has spread live at least 5 more years. The same is true of 65% of people whose tumors spread to nearby areas and of more than 26% 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.

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.