Osteosarcoma: Symptoms, Causes, Diagnosis, Treatment, and What to Expect
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
Osteosarcoma is a bone cancer that usually starts in the long bones of the legs or arms and most often affects teenagers and young adults. Early signs include bone or joint pain that may mimic growing pains, unexplained bone fractures, and swelling near a bone. Diagnosis involves imaging tests and a carefully planned biopsy, and treatment most often combines surgery with chemotherapy. Because the disease and its treatments can have lasting effects, lifelong follow-up is usually recommended [1] [2].
Quick Answer: What is osteosarcoma?
Osteosarcoma is a bone cancer that begins in the cells that form bone, most often in the long bones of the legs or arms of teenagers and young adults. Symptoms include bone or joint pain, unexplained breaks and swelling. Imaging and a carefully planned biopsy confirm it. Treatment usually combines surgery with chemotherapy, followed by lifelong monitoring for late effects. [1] [2]
What the research says
Survival is good but depends on how the tumor responds. In the EURAMOS-1 cohort of 2,260 registered patients aged 40 or younger, 5-year event-free survival was 54% and 5-year overall survival was 71%; pulmonary metastases at diagnosis (HR 2.34) and, in patients with localized disease, a poor histologic response to preoperative chemotherapy (HR 2.13) were linked to worse outcomes (Smeland et al., Eur J Cancer, 2019).
Adding more chemotherapy did not help poor responders. In a randomized phase 3 trial of 618 patients whose tumors responded poorly to preoperative chemotherapy, adding ifosfamide and etoposide to standard MAP did not improve event-free survival (HR 0.98; 95% CI 0.78 to 1.23) and caused more grade 4 non-hematological toxicity (24% vs 12%) (Marina et al., Lancet Oncol, 2016).
New options are being tested for relapsed disease. In a randomized, double-blind phase 2 trial of 42 patients with progressive metastatic osteosarcoma, regorafenib improved median progression-free survival compared with placebo (3.6 vs 1.7 months; HR 0.42), with no statistically significant difference in overall survival in the context of crossover (Davis et al., J Clin Oncol, 2019).
What Is Osteosarcoma?
Osteosarcoma is a kind of bone cancer. It begins in the cells that form bones. The cancer most often starts in the long bones of the legs or the arms, but it can happen in any bone in the body [1].
Osteosarcoma tends to occur most often in teenagers and young adults. It also can develop in younger children and older adults. In very rare cases, it happens in soft tissue outside the bone [1].
The outlook for this cancer has improved thanks to advances in treatment. However, people who have been treated sometimes face late effects from the strong treatments used to control the cancer. Because of this, healthcare professionals often suggest lifelong monitoring for side effects after treatment [1].
Key fact | Detail |
|---|---|
What it is | A bone cancer that starts in the cells that form bone |
Most common locations | Long bones of the legs, sometimes the arms; any bone can be affected |
Most common age groups | Teenagers and young adults; also younger children and older adults |
Outside the bone | Very rarely occurs in soft tissue |
Outlook | Improved by advances in treatment |
Long-term care | Lifelong monitoring for late effects is often recommended |
Where osteosarcoma most often develops. It typically starts in the long bones of the legs, such as around the knee, and sometimes in the long bones of the arms.
What are the symptoms of osteosarcoma?
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 [1].
Common Signs
Bone or joint pain is one of the most common symptoms. The pain might come and go at first, and it can be mistaken for growing pains. This similarity to normal childhood growing pains is one reason the cancer is sometimes noticed late [1].
Pain related to a bone that breaks for no clear reason is another warning sign. A fracture that occurs without a significant injury may point to a problem inside the bone [1].
Swelling or a growing lump near a bone may also be present. The lump may feel firm and may not move easily, and it can be painful [1].
Symptom | What it feels or looks like |
|---|---|
Bone or joint pain | May come and go at first; can be mistaken for growing pains |
Pain from an unexplained bone break | A bone fractures without a clear cause or significant injury |
Swelling or a growing lump near a bone | Close to the affected bone; may feel firm, may not move easily, and can be painful |
When should you see a doctor about osteosarcoma?
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, so the health professional might check for those causes first. Persistent or worsening symptoms are the reason to keep seeking answers [1].
Symptom situation | Recommended action |
|---|---|
Ongoing bone or joint pain, especially pain that comes and goes | Schedule an appointment with a healthcare professional |
A bone that breaks without a clear cause | Seek medical evaluation |
Unexplained swelling or a lump near a bone | Seek medical evaluation |
Symptoms that seem like a sports injury but do not improve | Return for re-evaluation |
What Causes Osteosarcoma?
The exact cause of osteosarcoma is not clear, though experts understand how it develops at the level of the cells. What is known is that osteosarcoma happens when bone cells develop changes in their DNA. A cell's DNA holds the instructions, called genes, that tell a cell what to do. In healthy cells, the DNA gives instructions to grow and multiply at a set rate, and it tells the cells to die at a set time [1].
In cancer cells, the DNA changes give different instructions. The changes tell the cancer cells to make many more cells quickly, and cancer cells can keep living when healthy cells would die. This produces too many cells that might form a mass called a tumor. As osteosarcoma grows, it can damage nearby tissue, and in time cancer cells can break away and spread to other parts of the body [1].
Step | What happens |
|---|---|
Normal cell behavior | DNA instructs cells to grow and multiply at a set rate and to die at a set time |
DNA changes | Bone cells develop altered instructions in their DNA |
Uncontrolled growth | Cancer cells multiply quickly and outlive healthy cells, creating too many cells |
Tumor formation | The excess cells form a mass that can invade and destroy healthy tissue |
Possible spread | Cells can break away and spread to other parts of the body (metastatic cancer) |
What are the risk factors for osteosarcoma?
Most people with osteosarcoma do not have any known risk factors for the cancer. Still, some factors can increase the risk [1].
Family Conditions
Certain conditions that run in families can raise the risk. These include hereditary retinoblastoma, Bloom syndrome, Li-Fraumeni syndrome, Rothmund-Thomson syndrome, and Werner syndrome [1].
Other Bone Conditions
Other bone conditions also increase risk. These include Paget's disease of bone and fibrous dysplasia [1].
Prior Cancer Treatment
Prior treatment with radiation therapy can increase the risk of developing osteosarcoma later [1].
Risk factor category | Specific factors |
|---|---|
Conditions that run in families | Hereditary retinoblastoma, Bloom syndrome, Li-Fraumeni syndrome, Rothmund-Thomson syndrome, Werner syndrome |
Other bone conditions | Paget's disease of bone, fibrous dysplasia |
Prior treatment history | Prior radiation therapy |
In general, there is no way to prevent osteosarcoma. Risk factors raise the chance of the cancer but do not guarantee it, and most people with the cancer have no known risk factors [1].
What complications can osteosarcoma and its treatment cause?
Cancer That Spreads
Osteosarcoma can spread from where it started to other areas, which makes treatment and recovery harder. It most often spreads to the lungs, another part of the same bone, or another bone [1].
Coping After Limb Surgery
Surgeons aim to remove the cancer and spare the arm or leg whenever they can, and most osteosarcoma operations can be done this way. Rarely, a surgeon needs to remove part of the affected limb to get all the cancer. After surgery, an artificial arm or leg, called a prosthesis, can be used [2].
Long-Term Treatment Side Effects
The strong treatments needed to control osteosarcoma can cause side effects. People treated for osteosarcoma may have side effects that last or develop months or years after treatment, which is why healthcare professionals often suggest lifelong monitoring [1].
Complication | What it involves |
|---|---|
Metastasis | Cancer spreads to the lungs, the same bone, or another bone, making treatment and recovery harder |
Limb surgery recovery | A prosthesis may be used if part of an arm or leg is removed |
Long-term side effects | Strong treatments can cause side effects that last or appear months or years later and need ongoing monitoring |
How Is Osteosarcoma Diagnosed?
An osteosarcoma diagnosis may begin with a physical exam. Based on the findings of the exam, there might be other tests and procedures [2].
Imaging Tests
Imaging tests make pictures of the body. They can show the location and size of an osteosarcoma. Tests might include an X-ray, an MRI, a CT scan, a bone scan, and a positron emission tomography scan, also called a PET scan [2].
The 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, and sometimes surgery is needed to get the tissue sample. The sample is tested in a lab to see if it is cancer, and other special tests give more details about the cancer cells. Your healthcare team uses this information to make a treatment plan [2].
Why Biopsy Planning Matters
Determining the type of biopsy needed and how it should be done requires careful planning by the medical team. The biopsy needs to be done so that it will not get in the way of future surgery to remove the cancer. Before having a biopsy, ask your healthcare professional to refer you to a team of experts who have experience treating osteosarcoma [2].
Diagnostic step | Purpose |
|---|---|
Physical exam | Initial evaluation that guides further testing |
Imaging tests (X-ray, MRI, CT, bone scan, PET scan) | Show the location and size of the osteosarcoma |
Biopsy | Removes a tissue sample so a lab can confirm whether it is cancer |
Special lab tests | Provide details about the cancer cells to shape the treatment plan |
The osteosarcoma diagnosis pathway: a physical exam, then imaging tests to locate and size the tumor, then a carefully planned biopsy to confirm cancer cells in the lab.
What are the treatment options for osteosarcoma?
Osteosarcoma treatment most often involves surgery and chemotherapy. Rarely, radiation therapy also might be an option if the cancer cannot be treated with surgery [2].
Surgery
The goal of surgery is to remove all the cancer cells. In planning the surgery, the healthcare team keeps in mind how the surgery will affect your or your child's daily life. The extent of surgery depends on several factors, such as the size of the cancer and where it is located [2].
Limb-sparing surgery removes the cancer only. Most osteosarcoma operations can be done in a way that removes all the cancer and spares the arm or leg. 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 using options such as metal implants or bone grafts [2].
Amputation removes the affected arm or leg. 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 [2].
Rotationplasty removes the lower portion of the leg. It might be an option for osteosarcoma in and around the knee joint. In this surgery, the surgeon removes the cancer and surrounding area, 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, so the ankle then works as a knee. A prosthesis is used for the lower leg and foot. This surgery is sometimes a good option for children who are still growing, because it allows them to take part in sports and physical activities [2].
Surgical option | How it works | When it is used |
|---|---|---|
Limb-sparing surgery | Removes the cancer while sparing the arm or leg; bone is rebuilt with metal implants or bone grafts | Most common option, when the extent of the cancer and tissue removal allow it |
Amputation | Removes the affected arm or leg entirely | Rarely, when all the cancer cannot be removed otherwise |
Rotationplasty | Removes the cancer and knee joint; the foot and ankle are rotated so the ankle works as a knee, with a prosthesis for the lower leg | Sometimes used for cancers in and around the knee, especially in children who are still growing |
Chemotherapy
Chemotherapy treats cancer with strong medicines. For osteosarcoma, chemotherapy often is used before surgery, when it can shrink the cancer and make it easier to remove. After surgery, chemotherapy treatments might be used to kill any cancer cells that might remain. For osteosarcoma that returns after surgery or spreads to other areas of the body, chemotherapy might help relieve pain and slow the growth of the cancer [2].
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 and directs radiation to precise points on your body. Radiation is not often used to treat osteosarcoma. It might be suggested instead of surgery if surgery cannot remove all the cancer [2].
Clinical Trials
Clinical trials are studies of new treatments. These studies provide a chance to try the latest treatments, though the risk of side effects might not be known. Ask your healthcare team if you or your child might be able to take part in a clinical trial [2].
Treatment | How it works for osteosarcoma |
|---|---|
Surgery | Removes all the cancer cells; may spare the limb, remove it, or use rotationplasty |
Chemotherapy | Strong medicines used before surgery to shrink the cancer, after surgery to kill remaining cells, and to slow or ease returning or spreading cancer |
Radiation therapy | Powerful energy beams (X-rays, protons, or other sources) used rarely, usually when surgery cannot remove all the cancer |
Clinical trials | Studies of new treatments that may offer the latest options with unknown side-effect risks |
The osteosarcoma treatment pathway: treatment most often combines surgery with chemotherapy, while radiation therapy is reserved for rare cases where surgery cannot remove all the cancer.
How can people cope with osteosarcoma?
A diagnosis of osteosarcoma can feel overwhelming. With time, you will find ways to cope with the distress and uncertainty of cancer. Until then, several approaches can help [2].
Learn Enough to Make Care Decisions
Ask your or your child's healthcare professional about osteosarcoma, including treatment options. As you learn more, you may feel better about making choices about treatment options. If your child has cancer, ask the healthcare team to guide you in talking to your child about the cancer in a caring way that your child can understand [2].
Keep Friends and Family Close
Keeping your close relationships strong will help you deal with osteosarcoma. Friends and family can help with daily tasks, such as taking care of your home if your child is in the hospital, and they can serve as emotional support when you feel like you are dealing with more than you can handle [2].
Ask About Mental Health Support
Talking to a counselor, medical social worker, psychologist, or other mental health professional also may help. Ask your healthcare team for options for professional mental health support for you and your child. You also can check online for a cancer organization, such as the American Cancer Society, that lists support services [2].
Coping strategy | What it involves |
|---|---|
Learning about the cancer | Ask about osteosarcoma and treatment options; ask the team to help explain the cancer to your child in an age-appropriate way |
Keeping loved ones close | Friends and family help with daily tasks and provide emotional support |
Mental health support | Counseling, medical social work, psychology, or other professional support; cancer organizations list support services |
How should you prepare for an osteosarcoma appointment?
If there are 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 to an experienced specialist [2].
Osteosarcoma typically needs to be treated by a team of specialists, which may include orthopedic surgeons who specialize in operating on cancers that affect the bones (orthopedic oncologists). Other surgeons, such as pediatric surgeons, may be involved depending on the site of the cancer and the age of the person. Doctors who specialize in treating cancer with chemotherapy or other systemic medicines, such as medical oncologists or pediatric oncologists for children, also may be part of the team, along with pathologists, who study tissue to diagnose the specific type of cancer, and rehabilitation specialists who help in recovery after surgery [2].
What You Can Do
Preparation step | Details |
|---|---|
List symptoms | Include unrelated symptoms and when they began |
List medicines | Include vitamins and herbs, with doses |
Note personal information | Include major stresses or recent life changes |
Bring records | Bring scans or X-rays, the images and reports, and related medical records |
Write questions | Prepare questions to make sure you get the information you need |
Bring support | Take a relative or friend to help remember information |
Questions to Ask
For you or your child, your questions might include [2]:
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, and if so, do you offer ways to preserve that ability?
Are there brochures or other printed material I can have, and what websites do you suggest?
What to Expect From Your Doctor
Your healthcare professional will likely ask you questions such as [2]:
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?
What is the bottom line on osteosarcoma?
Osteosarcoma is a bone cancer that most often starts in the long bones of the legs or arms, and it affects teenagers and young adults most frequently. Its symptoms, such as bone or joint pain and unexplained swelling, can easily be mistaken for growing pains or sports injuries, which makes persistent symptoms worth taking seriously [1].
Diagnosis depends on imaging tests and a carefully planned biopsy, ideally at a center experienced in treating this cancer. Treatment most often combines surgery with chemotherapy, and advances in care have improved outcomes. Because the disease and its treatments can cause lasting side effects, lifelong follow-up is typically recommended [1] [2].
If you or your child has bone or joint pain that lingers, a bone that breaks without a clear cause, or swelling near a bone, do not wait for it to pass. Schedule an appointment with a healthcare professional today so you can get an accurate evaluation, a clear diagnosis, and an expert treatment plan.
Frequently Asked Questions
What is osteosarcoma?
Osteosarcoma is a bone cancer that begins in the cells that form bone. It most often starts in the long bones of the legs or arms, and very rarely occurs in soft tissue outside the bone.
Who is most likely to get osteosarcoma?
Osteosarcoma tends to happen most often in teenagers and young adults. It also can happen in younger children and older adults.
What are the first symptoms of osteosarcoma?
The most common symptoms are bone or joint pain that may come and go and be mistaken for growing pains, pain related to a bone that breaks for no clear reason, and swelling or a growing lump near a bone.
Can osteosarcoma pain feel like growing pains?
Yes. Bone or joint pain from osteosarcoma might come and go at first and can be mistaken for growing pains, which is why ongoing or worsening pain deserves medical attention.
What causes osteosarcoma?
It is not clear what causes osteosarcoma. It happens when bone cells develop changes in their DNA that tell cells to multiply quickly and keep living when healthy cells would die, forming a tumor.
What are the risk factors for osteosarcoma?
Most people with osteosarcoma have no known risk factors. Known factors include certain family conditions (such as hereditary retinoblastoma, Bloom syndrome, Li-Fraumeni syndrome, Rothmund-Thomson syndrome, and Werner syndrome), other bone conditions (Paget's disease and fibrous dysplasia), and prior radiation therapy.
Is there a way to prevent osteosarcoma?
In general, no. There is no known way to prevent osteosarcoma, and most people who develop it have no known risk factors.
How is osteosarcoma diagnosed?
Diagnosis may begin with a physical exam, followed by imaging tests such as X-ray, MRI, CT, bone scan, and PET scan to show the location and size of the cancer. A biopsy then removes a tissue sample for lab testing. The biopsy requires careful planning so it will not interfere with future surgery.
What treatments are used for osteosarcoma?
Treatment most often involves surgery and chemotherapy. Surgery may spare the limb, remove it, or use rotationplasty. Chemotherapy is often given before surgery to shrink the cancer and after surgery to kill remaining cells. Radiation therapy is rarely used.
Where does osteosarcoma spread most often?
Osteosarcoma most often spreads to the lungs, another part of the same bone, or another bone, which makes treatment and recovery harder.
What support is available after an osteosarcoma diagnosis?
Helpful supports include learning enough about the cancer to make care decisions, keeping friends and family close for daily and emotional support, and asking about mental health support such as counselors, medical social workers, or psychologists. Cancer organizations also list support services.
Related Resources
External resources for deeper reading:
National Cancer Institute. Osteosarcoma Treatment (PDQ®)–Patient Version. National Cancer Institute. Updated February 25, 2025. https://www.cancer.gov/types/bone/patient/osteosarcoma-treatment-pdq
National Comprehensive Cancer Network. Bone Cancer – Guidelines Detail. National Comprehensive Cancer Network. NCCN Guidelines Version 1.2027. https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1418
American Cancer Society. Treating Bone Cancer. American Cancer Society. Last revised January 5, 2026. https://www.cancer.org/cancer/types/bone-cancer/treating.html
Children's Oncology Group. Home page. Children's Oncology Group. Accessed October 30, 2026. https://www.childrensoncologygroup.org
Related Reading
References
Mayo Clinic Staff. Osteosarcoma: symptoms and causes. Mayo Clinic. Sept. 18, 2026. https://www.mayoclinic.org/diseases-conditions/osteosarcoma/symptoms-causes/syc-20351052
Mayo Clinic Staff. Osteosarcoma: diagnosis and treatment. Mayo Clinic. Sept. 18, 2026. https://www.mayoclinic.org/diseases-conditions/osteosarcoma/diagnosis-treatment/drc-20351053
Smeland S, Bielack SS, Whelan J, et al. Survival and prognosis with osteosarcoma: outcomes in more than 2000 patients in the EURAMOS-1 (European and American Osteosarcoma Study) cohort. Eur J Cancer. 2019;109:36-50. PMID: 30685685. DOI: 10.1016/j.ejca.2018.11.027
Marina NM, Smeland S, Bielack SS, et al. Comparison of MAPIE versus MAP in patients with a poor response to preoperative chemotherapy for newly diagnosed high-grade osteosarcoma (EURAMOS-1): an open-label, international, randomised controlled trial. Lancet Oncol. 2016;17(10):1396-1408. PMID: 27569442. DOI: 10.1016/S1470-2045(16)30214-5
Davis LE, Bolejack V, Ryan CW, et al. Randomized double-blind phase II study of regorafenib in patients with metastatic osteosarcoma. J Clin Oncol. 2019;37(16):1424-1431. PMID: 31013172. DOI: 10.1200/JCO.18.02374
Medical disclaimer
This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have about a medical condition.
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