Sarcoma is the general term for a broad group of cancers that begin in the bones and soft tissues of the body, including muscle, fat, blood vessels, nerves, tendons and the lining of your joints. There are more than 70 types of sarcoma. 

Bone cancer is a rare disease, accounting for just 0.2% of all cancers. An estimated 3,910 new cases of sarcoma of the bones and joints will be diagnosed in 2022, according to the National Cancer Institute. 

Some types of bone cancer occur primarily in children, while others affect mostly adults. 

"When we think of sarcomas of the bone, the common types are chondrosarcoma, Ewing sarcoma, and osteosarcoma," says Dr. Safia Ahmed, a radiation oncologist at Mayo Clinic. "While sarcoma can happen in any bone in the body, the most common sites include the pelvis, the spine, and the skull base for most of these tumors."

Treatment for sarcoma varies depending on sarcoma type, location and other factors. Treatments can include surgery, chemotherapy and radiation therapy. 

Proton beam therapy is a type of radiation therapy that is more precise than traditional X-ray treatment, which delivers radiation to everything in its path. Proton beam therapy uses positively charged particles in an atom — protons — that release their energy within the tumor. Because proton beams can be much more finely controlled, specialists can use proton beam therapy to safely deliver higher doses of radiation to tumors. This is particularly important for bone cancers.

"When we treat these tumors in the bone with radiation, they need much higher doses of radiation than, say a sarcoma that arises purely in the muscle, what we call a soft tissue sarcoma," explains Dr. Ahmed. "And these high doses of radiation often exceed what the normal tissues around the area can tolerate. So proton therapy allows us to give this high dose of radiation while protecting the normal tissues."

July is Sarcoma Awareness Month. On this Mayo Clinic Q&A podcast, Dr. Ahmed discusses sarcoma diagnoses and treatment options, including proton beam therapy.