Chondrosarcoma is a type of sarcoma that affects the bones and joints. It is a rare cancer that accounts for about 20% of bone tumors and is diagnosed in approximately 600 patients each year in the United States.1Chondrosarcoma typically affects adults between the age of 20 and 60 years old, and it is more common in men. The disease usually starts in the bones of the arms, legs or pelvis, but it can be found in any part of the body that contains cartilage. Sometimes chondrosarcoma grows on an otherwise healthy bone, and sometimes it grows on a benign bone tumor (an enchondroma or osteochondroma).
There are several types of chondrosarcoma that are named based on the way that they appear under the microscope. These include:
Clear cell chondrosarcoma
What causes chondrosarcoma?
As with many cancers, the cause of chondrosarcoma is not clear. However, people with certain medical conditions have an increased risk for developing chondrosarcoma. These conditions include:
Diseases in children that required previous treatment with chemotherapy or radiation therapy
How aggressive is chondrosarcoma?
Chondrosarcomas behave in different ways, but many are low grade tumors. The cells in these tumors look and behave like normal cartilage with only a small amount of abnormality. In intermediate grade tumors, cells still look like cartilage cells, but they show more malignant changes. In high grade tumors, cells look much less like normal cartilage, and they grow and change rapidly.
Conventional chondrosarcoma and clear cell chondrosarcoma are often low to intermediate grade tumors that are not very aggressive and tend to stay in one place. Dedifferentiated and mesenchymal chondrosarcoma are high grade tumors that behave aggressively and tend to spread. [See the page devoted to mesenchymal chondrosarcoma for more information.]
De-differentiated chondrosarcoma occurs in less than 10% of cases, and it is usually found in the arm, leg or pelvis bones. This tumor is a very different kind of chondrosarcoma that is especially difficult to treat. A part of the tumor appears to be a low to intermediate grade cartilage tumor, and it is located close to a high grade non-cartilage kind of sarcoma.
What are the symptoms of chondrosarcoma?
People with chondrosarcoma usually do not feel sick. They may be able to feel a boney bump, and most patients ultimately will have pain, swelling, or limited movement that is caused by the tumor.
How is chondrosarcoma diagnosed?
A bone tumor is often first discovered on x-ray after a physical exam. It can be difficult to tell the difference between a benign bone tumor and chondrosarcoma on x-ray. Additional tests, including a bone scan, CT scan, MRI and PET scan, can provide more information about the tumor. Ultimately, biopsy of the tumor is the only way to make a definite diagnosis of chondrosarcoma. After the biopsy procedure, a pathologist looks at the tumor’s cells under the microscope to make a diagnosis.
Doctors use the results of the biopsy and imaging studies to develop a patient’s treatment plan.
How is chondrosarcoma treated?
Complete surgical removal of the tumor, along with a wide margin of healthy tissue, has historically been the preferred treatment of chondrosarcoma. Limb salvage surgery is a common treatment technique, and amputation is only used occasionally for advanced or recurrent disease.
Studies have been done and are underway to measure the effectiveness of intralesional curettage surgery, which is a less aggressive surgery that removes less tissue, on low grade chondrosarcomas. These studies show that certain low grade tumors respond well to this type of surgery, which has excellent functional results for patients. The issue of how to best deal with low grade chondrosarcoma is controversial and is covered in depth in this article.
Most chondrosarcomas (with the exception of mesenchymal chondrosarcoma) do not respond to chemotherapy or radiation therapy. This makes surgical management crucial in the treatment of chondrosarcoma. In rare situations where the skull is involved, proton radiation therapy may be helpful.
Chemotherapy or radiation therapy is sometimes considered for patients with recurrent, metastatic or dedifferentiated disease. Unfortunately, these treatments have not been proven to be effective, and there is no standard protocol to follow.
Prognosis for chondrosarcoma patients
Prognosis statistics are based on the study of groups of chondrosarcoma patients. These statistics cannot predict the future of an individual patient, but they can be useful in considering the most appropriate treatment and follow-up for a patient.
The prognosis for chondrosarcoma patients varies by the grade of the tumor and the extent of surgery. In general, low grade tumors have an excellent prognosis, with a small chance of recurrence and virtually no chance of disease spread. Risks increase as the grade of the tumor increases, with de-differentiated tumors having the highest risk of recurrence and metastasis and a poor survival rate.