Osteosarcoma

Osteosarcoma is a type of bone cancer that most often affects teenagers and young adults, though it can occur at any age. It typically develops in the long bones of the arms and legs, especially near the knee, and can cause pain, swelling, and limited movement.

Table of contents

• What is osteosarcoma?
• Signs and symptoms
• Causes and risk factors
• Diagnosis
• Treatment options
• Outlook and survival
• Coping and support

What is osteosarcoma?

Osteosarcoma is a kind of cancer that begins in the cells that form bones. The cancer cells appear at first to be regular bone cells, but then they create tumors that produce irregular, diseased bone tissue.^[1][2]

This cancer is the most common type of primary bone tumor, which means it starts in the bone itself rather than spreading from another part of the body.^[3] Healthcare providers sometimes call it osteogenic sarcoma. The word “osteo” refers to bones, and “sarcoma” is a type of cancer that develops in connective tissue such as bone, cartilage, or muscle.^[2]

Osteogenic sarcoma

Osteosarcoma most commonly affects the long bones, like those in the arms and legs. It usually develops near the ends of bones around joints, especially near the knees, hips, or shoulders.^[2] The bones most often affected include the shin bone (tibia), thigh bone (femur), and upper arm bone (humerus). Less commonly, it can occur in the jaw, pelvis, skull, or even in soft tissues or organs in the abdomen and chest.^[2][6]

• Tibia (shin bone)
• Femur (thigh bone)
• Humerus (upper arm bone)
• Jaw
• Pelvis
• Skull

Osteosarcoma most often affects teenagers and young adults. In fact, more than three out of every four people with osteosarcoma are younger than 25 years old, with the average age at diagnosis being 15.^[2][5] About 75% of cases occur in patients less than 25 years of age.^[5] However, it can also happen in younger children and older adults. In the United States, fewer than 1,000 people develop osteosarcoma each year, with about 440 cases diagnosed annually in people 19 years and younger.^[2][6]

Signs and symptoms

The most common symptom of osteosarcoma is pain in a bone or joint. This pain might come and go at first and can be mistaken for growing pains or sports injuries, especially in teenagers who are active.^[1] The pain may be worse at night and can vary in intensity. It may have been occurring for a long time before diagnosis.^[3]

Other common symptoms of osteosarcoma include:^[1][2][6]

• Swelling near a bone or over a bony part of the body
• A lump or mass that you can feel (the area around the tumor may feel warm)
• Limited movement in a joint
• Stiffness in a joint
• Discoloration on the skin
• A limp or difficulty walking (if the tumor is in the leg bones)
• Pain when lifting things (if the tumor is in the arm bones)
• A bone that breaks for no clear reason or from minor trauma (called a pathologic fracture)
• Unexplained fever

How painful osteosarcoma is can vary. Some tumors cause intense pain, while others are painless. It depends on where they develop and how fast they grow.^[2] If the tumor is large, it can present as obvious localized swelling. In cases of tumors that are deeper inside the body, such as those in the pelvis, swelling may not be apparent.^[3]

Because these symptoms are similar to many more common conditions, such as sports injuries, it’s important to see a healthcare professional if you or your child has ongoing symptoms that worry you.^[1]

Causes and risk factors

Experts aren’t certain what causes osteosarcoma, but several factors may increase the risk of developing this cancer.^[2]

Rapid bone growth appears to be connected to osteosarcoma risk. The risk increases during growth spurts, which is why this cancer is most common in children and teenagers whose bodies are developing rapidly.^[2]

Exposure to radiation can increase the risk of developing osteosarcoma. This includes exposure to radiation at work, in the environment, or as part of radiation therapy used to treat other types of cancer.^[2][3] Past treatment with chemotherapy can also increase risk.^[6]

Genetic factors play a role in some cases. A genetic change (mutation) that affects the p53 gene may cause some kinds of cancers, including osteosarcoma. The p53 gene is sometimes known as a tumor suppressor gene because it helps the body stop tumors from forming.^[2] Experts also think osteosarcoma may be related to the retinoblastoma (Rb) gene, which can be associated with eye cancers in young children.^[2]

Specific genetic conditions that increase risk include:^[3][6]

• Li-Fraumeni syndrome (germline TP53 mutation)
• Hereditary retinoblastoma
• Rothmund-Thomson syndrome
• Bloom syndrome
• Diamond-Blackfan anemia
• Werner syndrome

Bone conditions can also increase the risk. Certain bone diseases increase the likelihood of developing osteosarcoma, including:^[3][6]

• Paget’s disease of bone
• Fibrous dysplasia
• Enchondromatosis
• Hereditary multiple exostoses

Bone infarction, which happens when something cuts off blood supply to bone tissue, can also increase risk. This lack of blood destroys healthy bone cells and may cause cancerous cells to form.^[2]

Diagnosis

Diagnosing osteosarcoma begins with a physical exam. If a healthcare professional suspects bone cancer based on symptoms, several tests may be ordered.^[1][6]

Imaging tests create pictures of the body to show the location and size of a tumor. These tests might include:^[1][7]

• X-ray
• MRI (magnetic resonance imaging)
• CT scan (computed tomography)
• Bone scan
• PET scan (positron emission tomography scan)

A biopsy is a procedure to remove a sample of tissue for testing in a lab. This is necessary to confirm whether the abnormal growth is cancer. The tissue might be removed using a needle that is put through the skin and into the suspected cancer, or sometimes surgery is needed to get the tissue sample.^[7] The sample is tested in a lab to see if it is cancer, and other special tests give more details about the cancer cells. The healthcare team uses this information to make a treatment plan.^[7]

The biopsy needs to be done carefully so that it won’t interfere with future surgery to remove the cancer. It’s important to have the biopsy performed by a team of experts who have experience treating osteosarcoma.^[7]

After osteosarcoma has been diagnosed, additional imaging tests may be done to find out if cancer cells have spread within the bone or to other parts of the body, particularly the lungs.^[6] Around 10% to 20% of patients present with metastases, which means the cancer has spread, most commonly to the lungs.^[5]

Treatment options

Treatment for osteosarcoma most often involves a combination of surgery and chemotherapy. Rarely, radiation therapy might also be used if the cancer can’t be treated with surgery.^[7]

Surgery

Surgery is the main treatment for osteosarcoma. The goal is to remove all the cancer cells along with some normal tissue around the tumor (called the surgical margin).^[11] Surgery may be the first treatment, or it may be offered after chemotherapy.^[11]

Limb-sparing surgery is often used to remove tumors in an arm or leg. During this procedure, surgeons remove the tumor without amputating the limb. The surgeon does a wide removal (wide resection) to take out the tumor and a small amount of bone and tissue around it.^[11] Bone and tissue grafts may be used to replace tissues removed during surgery, and a joint removed with surgery may be replaced with a metallic artificial joint.^[11]

Amputation removes all or part of the arm or leg with the tumor. It may be done if the cancer has grown into nerves or blood vessels, if the tumor is very big, or if the cancer comes back in the same area after limb-sparing surgery.^[11] Most people who have an amputation will use an artificial limb (prosthesis) after surgery.^[11]

If bone cancer has spread to the lungs, surgery may be used to remove the tumors if doctors think all of the cancer can be removed.^[11]

Chemotherapy

Chemotherapy uses drugs to destroy cancer cells. It is almost always offered for high-grade osteosarcoma.^[11] Chemotherapy is commonly used before surgery to destroy cancer cells and shrink the tumor (called neoadjuvant chemotherapy). It is also given after surgery to destroy any cancer cells that may have been left behind and reduce the risk that the cancer will come back (called adjuvant chemotherapy).^[11]

For young adults, the standard chemotherapy drug combination used for osteosarcoma includes high-dose methotrexate, doxorubicin, and cisplatin (MAP).^[11] This treatment standard has not changed in more than 40 years.^[9] Other chemotherapy drug combinations may include ifosfamide, etoposide, or carboplatin.^[11]

Chemotherapy combinations that use high-dose methotrexate are not usually offered for adults who are 40 or older because older adults are more likely to experience serious side effects.^[11]

Radiation therapy

Radiation therapy may be used occasionally if the cancer can’t be treated with surgery.^[7]

Newer treatment approaches

Researchers are investigating new treatment approaches for osteosarcoma, including:^[13]

• Targeted therapies that attack cancer cells more precisely
• Immunotherapy, including checkpoint inhibitors and CAR-T therapies
• Gene therapy
• Novel drug delivery systems

Outlook and survival

Several factors can affect the outlook (prognosis) for people with osteosarcoma. The most important factor is whether the cancer has spread to other parts of the body.^[6]

Around 7 in 10 people survive if the osteosarcoma doesn’t spread to other parts of their bodies.^[2] For localized disease, the 5-year survival rate is approximately 60-70%.^[13] However, survival rates are much lower for advanced stages when the cancer has spread.^[13]

Advances in chemotherapy have significantly improved survival rates. About two-thirds of children and adolescents with osteosarcoma can achieve long-term cures.^[5]

After treatment for osteosarcoma, people sometimes face late effects from the strong treatments used to control the cancer. Healthcare professionals often suggest lifelong monitoring for side effects after treatment.^[1] Follow-up appointments become a regular part of life after treatment. These check-ups are important for monitoring recovery and watching for any signs that the cancer has returned.^[15]

Coping and support

Coping with a diagnosis of osteosarcoma can be overwhelming. Getting a lot of new information can feel difficult, especially when you have just been diagnosed. It’s normal to experience many different emotions, including feeling shocked, frightened, angry, sad, or numb.^[17]

You may find it helpful to:^[17][14]

• Make a list of questions before you see your doctor
• Take someone with you to appointments to help you remember what you want to ask and the information that was given
• Ask your doctors and nurses to explain things again if you need them to
• Tell your doctor or nurse if you don’t want to know much information right away – you can always ask for more later
• Talk to your friends and relatives about your cancer – this can help and support you
• Make lists and use a calendar to keep track of appointments
• Plan enjoyable activities around difficult times

During treatment, the first couple of weeks after diagnosis are often the hardest because everything is uncertain and you’re still in shock. After that, things typically become more consistent and you’ll get into a rhythm, which makes it less scary.^[14]

Making friends with doctors and nurses can help during treatment. Building these relationships can provide important emotional support during difficult times.^[14] Distraction can also be helpful – activities like putting together puzzles, playing games, doing crafts, or staying connected with friends can help brighten difficult days.^[14]

Support groups and counseling services are available to help you cope with the emotional challenges of cancer. Connecting with other people who have been through similar experiences can provide both emotional support and practical advice.^[17][18]

Remember that you don’t have to sort everything out at once. It may take time to deal with each issue, and it’s okay to ask for help when you need it.^[17]