What is osteosarcoma?
Osteosarcoma is a type of malignant (cancerous) bone tumor that forms from the cells that make up bones. These bone sarcomas most often occur at the ends of longer bones in body, in locations such as the knees and toward the shoulders. These tumors may also occur in the jaw and pelvis.
Osteosarcoma is the most common childhood cancer starting in bones, but is still fairly rare. Each year, doctors diagnose just 1,000 cases in the U.S. It’s found most often in children and teens between the ages of 10 and 19. When it does occur in adults, people are usually in their 60s, 70s, or 80s.
While highly treatable, osteosarcoma is often aggressive and can metastasize (spread), typically to the lungs or other bones.
The Sarcoma Program at Penn Medicine’s Abramson Cancer Center is home to one of the nation’s most experienced osteosarcoma care teams. Our specialists work closely with the sarcoma program at the Children’s Hospital of Philadelphia to bring children the most effective treatment for osteosarcoma.
Types of osteosarcoma
Osteosarcoma is categorized by grade, based on how the cells appear and how the cancer is likely to behave. Low-grade tumors typically grow slowly, while high-grade tumors act more aggressively. Intermediate-grade tumors fall in between and usually get treated like high-grade tumors. The vast majority of osteosarcoma are high grade.
Doctors also group osteosarcomas by where in the bone they form:
- Medullary (central) osteosarcoma: Most osteosarcomas are this type of tumor, which forms deeper inside bones. Medullary osteosarcomas tend to be aggressive.
- Peripheral (surface) osteosarcoma: Much less often, osteosarcoma forms near the surface of bones. Some of these tumors are high grade. However, one form, parosteal osteosarcoma, is low grade. Another form, periosteal osteosarcoma, is either low grade or intermediate grade.
How osteosarcoma can affect the body
Osteosarcoma often causes unusual, weak bone growth. It can also destroy existing bone. Sometimes, these tumors form a noticeable lump along the bone. You may also experience:
- Pain in a bone or near a joint that comes and goes, getting worse and more consistent as the tumor grows
- Harder time moving with osteosarcoma in a leg
- Loss of bladder or bowel control, for an osteosarcoma in the pelvis
- Swelling near the tumor
- Broken bone from the cancer causing damage
Risk factors for osteosarcoma
Researchers don’t always know what causes osteosarcomas. Certain medical treatments and conditions can raise your risk of developing one of these bone cancers.
For example, previous radiation therapy and some chemotherapy drugs can increase the chance of developing an osteosarcoma. Two noncancerous bone diseases, Paget disease and fibrous dysplasia, can also rarely increase risk for osteosarcoma because these conditions change the makeup of bones.
Additionally, people with certain rare, inherited syndromes face a higher risk of developing osteosarcoma. These syndromes include:
- Bloom syndrome: People with this condition often have limited growth and develop skin rashes from the sun. They also face a higher cancer risk, including for osteosarcoma.
- Hereditary retinoblastoma: This condition can cause cancer to develop in both eyes. It also raises the risk for cancers such as osteosarcoma, melanoma, a brain cancer called pineoblastoma, and soft tissue sarcomas such as fibrosarcoma, liposarcoma, and leiomyosarcoma.
- Li-Fraumeni syndrome: This condition raises the risk for a range of cancers. These cancers include osteosarcoma and soft tissue sarcomas—rhabdomyosarcoma and, much less frequently, fibrosarcoma, leiomyosarcoma, orbital (near the eyes) liposarcoma, and undifferentiated pleomorphic sarcoma (UPS).
- Rothmund-Thomson syndrome II: People with this condition are usually shorter, with less hair on their head and face. They can develop a particular kind of rash and often have dental and bone problems. They face a higher risk for certain cancers, including osteosarcoma.
- Werner syndrome: This condition causes premature aging and raises the risk of developing osteosarcoma, skin cancer, and thyroid cancer.
Testing for osteosarcoma
If our team suspects osteosarcoma, we’ll do a thorough evaluation to rule out other reasons for the bone growth. These other potential diagnoses can include osteomyelitis, (a bone infection), a benign (noncancerous) tumor, or another type of bone sarcoma.
We start with a discussion of your symptoms and a physical exam. Your care provider will check for any lump or bump and look for tenderness, pain, swelling, or loss of joint motion.
Imaging tests allow us to examine the area of concern and identify bone lesions that need a closer look. If we suspect a tumor, we may recommend additional imaging to gather more information.
In addition to scans, we typically remove a small sample of the tumor during an image-guided biopsy. Examining the sample helps us confirm the diagnosis and identify characteristics of the tumor that may help guide treatment decisions.
Together, the exam, imaging, and biopsy help us better understand a tumor and determine its stage. This process helps us plan the most appropriate and effective treatment.
Your options for osteosarcoma care
The outlook for osteosarcoma depends on the location of the tumor, its size, its grade, and whether the cancer has spread. For older adults, overall health is also an important consideration. Because osteosarcoma is rare, it's important to receive sarcoma treatment from a team with extensive experience caring for these tumors.
Whenever possible, the goal is to remove the tumor while preserving function and mobility. Our surgeons have extensive experience removing bone sarcomas in one piece, which is considered the most effective surgical approach. When tumors occur in the arms or legs, limb preservation is often possible. We also work closely with plastic surgeons to help restore tissue, support healing, and preserve function.
Some osteosarcomas can be treated with surgery alone, while others require additional therapies before and after surgery. If the tumor cannot be completely removed, we may recommend treatments to help control cancer growth and manage symptoms.
Even after successful treatment, osteosarcoma can return. Regular follow-up visits help us monitor your recovery, watch for signs of recurrence, and begin treatment quickly if needed.
Why specialized osteosarcoma care matters
The best treatment results come from teams that handle a high volume of these rare bone cancers. As home to the most comprehensive sarcoma program in the region, Penn Medicine routinely cares for complex tumors that other centers might only see once or twice a year.
Our program also offers access to sarcoma clinical trials evaluating promising new therapies. By combining extensive experience treating bone sarcomas with ongoing research, we continue to advance care for children, teens, and adults with osteosarcoma.
Rated “exceptional” by The National Cancer Institute
Penn Medicine’s Abramson Cancer Center is a world leader in cancer research, patient care, and education. Our status as a national leader in cancer care is reflected in our continuous designation as a Comprehensive Cancer Center by the National Cancer Institute (NCI) since 1973, one of 7 such centers in the United States. The ACC is also a member of the National Comprehensive Cancer Network, one of a select few cancer centers in the U.S., that are working to promote equitable access to high-quality, advanced cancer care.