Radiation Therapy for Soft Tissue Sarcomas

Radiation therapy uses high-energy rays (such as x-rays) or particles to kill cancer cells. It's a key part of soft tissue sarcoma treatment.

• Most of the time radiation is given after surgery. This is called adjuvant treatment. It's done to kill any cancer cells that may be left behind after surgery. Radiation can affect wound healing, so it may not be started until a month or so after surgery.
• Radiation may also be used before surgery to shrink the tumor and make it easier to remove. This is called neoadjuvant treatment.

Radiation can be the main treatment for sarcoma in someone who isn't healthy enough to have surgery. Radiation therapy can also be used to help ease symptoms of sarcoma when it has spread. This is called palliative treatment.

Types of radiation therapy

• External beam radiation: 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. In most cases, a technique called intensity modulated radiation therapy (IMRT) is used. This better focuses the radiation on the cancer and lessens the damage to healthy tissue.
• Proton beam radiation : This uses streams of protons instead of x-ray beams to treat the cancer. Although this has some advantages over IMRT in theory, it hasn’t been proven to be a better treatment for soft tissue sarcoma. Proton beam therapy is not widely available.
• Intraoperative radiation therapy (IORT): For this treatment, one large dose of radiation is given in the operating room after the tumor is removed but before the wound is closed. Giving radiation this way means that it doesn’t have to travel through healthy tissue to get to the area that needs to be treated. It also allows nearby healthy areas to be shielded more easily from the radiation. Often, IORT is only one part of radiation therapy, and the patient gets some other type of radiation after surgery.
• 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, soft tubes) that have been placed during surgery. 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 part of the body treated and the dose given. Common side effects include:

• Skin changes where the radiation went through the skin, which can range from redness to blistering and peeling
• Fatigue
• Nausea and vomiting (more common with radiation to the belly)
• Diarrhea (most common with radiation to the pelvis and belly)
• Pain with swallowing (from radiation to the head, neck, or chest)
• Lung damage leading to problems breathing (from radiation to the chest)
• Bone weakness, which can lead to fractures or breaks years later

Radiation of large areas of an arm or leg can cause swelling, pain, and weakness in that limb.

Side effects of radiation therapy to the brain for metastatic sarcoma include hair loss (in this case, it can be permanent), headaches, and problems thinking.

If given before surgery, radiation may cause problems with wound healing. If given after surgery, it can cause long-term stiffness and swelling that can affect how well the limb works.

Many side effects improve or even go away after radiation is finished. Some though, like bone weakness and lung damage, can be permanent.

Chemoradiation

After surgery, some high-grade sarcomas may be treated with radiation and chemotherapy at the same time. This is called chemoradiation.

This may also be done before surgery in cases where the sarcoma cannot be removed or removing it would cause major damage. Sometimes, chemoradiation can shrink the tumor enough to take care of these issues so it can be removed.

Chemoradiation can cause major side effects. And not all experts agree on its value in treating sarcoma. Radiation alone after surgery seems to works as well as chemoradiation. Still for some cases, this may be a treatment option to consider.