Radiation therapy for soft tissue sarcomas

Radiation therapy uses high-energy rays (such as x-rays) or particles to kill cancer cells.

Most of the time radiation is given after surgery as an added measure. This, called adjuvant treatment, is done to kill any cancer cells that may be left behind after surgery.

Radiation may also be used before surgery to shrink the tumor and make the operation easier. This is called neoadjuvant treatment.

Radiation can be the main treatment for sarcoma in people whose general health is too poor to undergo surgery.

Radiation therapy can also be used to help symptoms of sarcoma when it has spread. This is called palliative treatment.

Types of radiation therapy

External beam radiation therapy: For this treatment, radiation delivered from outside the body is focused on the cancer. This is the type of radiation therapy most often used to treat sarcomas. Treatments are often given daily, 5 days a week, usually for several weeks. Newer forms of external beam radiation may be used that can lessen the impact of the radiation on healthy tissue, such as:

• Intensity modulated radiation therapy (IMRT)
• Proton beam radiation

These types of radiation are discussed in more detail in our document, Understanding Radiation Therapy: A Guide for Patients and Families.

Brachytherapy: Brachytherapy (sometimes called internal radiation therapy) is a treatment that places small pellets (or seeds) of radioactive material in or near the cancer. For soft tissue sarcoma, these pellets are put into catheters (very thin tubes) that have been placed during surgery. In high-dose rate (HDR) brachytherapy, the pellets give off a lot of radiation in a short time, and so stay in place for only minutes at a time. In low-dose rate (LDR) brachytherapy, the pellets may stay in place for days at a time, and then removed.

Brachytherapy may be the only form of radiation therapy used or it can be combined with external beam radiation.

Side effects of radiation treatment

Side effects of radiation therapy depend on the area treated and the dose given. Common side effects include mild skin problems and fatigue. These often go away after a short time. If given before surgery, radiation may cause problems with wound healing. Radiation to the abdomen may cause nausea, vomiting, and diarrhea, while radiation to the chest may cause pain with swallowing and lung damage leading to problems breathing. Radiation of large areas of an arm or leg can cause swelling, pain, and weakness. Sometimes the bone that was treated becomes weak, and can fracture years after the treatment. Side effects of radiation therapy to the brain for metastatic sarcoma include hair loss, headaches, and problems thinking.