Radiation Therapy for Uterine Sarcomas

Radiation therapy uses high-energy x-rays or particles to destroy cancer cells or slow their growth.

Radiation might be used to treat uterine sarcoma in these ways:

• After surgery (adjuvant radiation) it may help lower the chance of the cancer coming back in the pelvis. It might be done for cancers that are high grade or when cancer cells are found in the lymph nodes. The entire pelvis or part of the pelvis may be treated with external beam radiation therapy (see below). Sometimes the radiation field will also include an area of the abdomen (belly) called the para-aortic field. This is the area around the aorta (the main artery). Brachytherapy (internal radiation) may also be used in some cases after surgery (see below). 
• It might be used alone or with chemo as the main treatment if surgery can't be done because of other health problems.
• It might be used to treat problems caused by tumor growth, but is not intended to cure the cancer. For instance, radiation can be used to shrink a tumor that's causing pain and swelling by pressing on nearby nerves and blood vessels. This is called supportive or palliative care.

Radiation therapy seems to help keep some uterine sarcomas from coming back after surgery, but there is not enough information to know if it can help someone live longer. 

Types of radiation therapy

Two types of radiation treatments might used for uterine sarcoma:

• External beam radiation therapy
• Internal radiation therapy or brachytherapy

Sometimes brachytherapy and external beam radiation therapy are used together. How much of the pelvis needs to be exposed to radiation therapy and the type(s) of radiation used depend on the extent of the disease.

External beam radiation therapy

External beam radiation therapy (EBRT) is the more common type of treatment for uterine sarcoma. It focuses radiation from outside the body onto the cancer.

EBRT is much like getting an x-ray, but the radiation is stronger. A machine focuses the radiation on the area with the cancer. The procedure itself is painless, but may cause side effects. Each treatment lasts only a few minutes, but the setup time—getting you into place for treatment—usually takes longer. This therapy is usually given 5 days a week for 4 or 5 weeks. The actual radiation treatment takes less than 30 minutes. Sometimes, a special mold of the pelvis and lower back is custom-made to be sure the person is in the exact same position for each treatment.

Brachytherapy

Brachytherapy, also known as internal radiation, is another way to deliver radiation. Instead of aiming radiation beams from outside the body, a device containing radioactive materials is placed inside the body close to the tumor. People treated with this type of radiation are not radioactive after the implant is removed.

After hysterectomy, the tissues in the upper part of the vagina might need to be treated. In this situation, the radioactive material is put into the vagina. This is called vaginal brachytherapy.

When vaginal brachytherapy is needed, treatment is done in the radiation suite of the hospital or treatment center. About 6 to 8 weeks after the hysterectomy, the surgeon or radiation oncologist puts a special cylinder (applicator) into the vagina. The length of the cylinder (and the amount of the vagina treated) can vary, but the upper part of the vagina is always treated. Pellets of radioactive material are then put into the applicator. With this treatment, nearby structures, like the bladder and rectum, will get less radiation exposure.

There are 2 types of brachytherapy: low-dose rate (LDR) and high-dose rate (HDR).

In LDR brachytherapy, the radiation pellets are usually left in for 1 to 4 days at a time. The patient needs to stay very still to keep the applicator from moving during treatment, so they're usually kept in the hospital on strict bed rest. More than one treatment may be needed.

In HDR brachytherapy, the radiation is more intense. It's given the same way as LDR, but a higher dose of radiation is given over hours instead of days. Because the applicator is in for a shorter period of time, you can usually go home the same day. For uterine cancers, HDR brachytherapy is often given daily or weekly for a total of about 3 doses.

Side effects of radiation therapy

Short-term side effects

Short-term side effects of radiation therapy include:

• Feeling tired (fatigue)
• Nausea and vomiting
• Loose stools or diarrhea
• Bladder irritation
• Skin changes
• Low blood counts

Skin changes in the treated area can look and feeling sunburned. As the radiation passes through the skin to its target, it might damage the skin cells. This can cause irritation that ranges from mild redness to permanent discoloration or skin darkening. The skin might release fluid, which can lead to infection, so care must be taken to clean and protect the area exposed to radiation.

This same kind of damage that can happen to the skin can happen inside the vagina with brachytherapy. As long as there is not a lot of bleeding, a person can continue to have sex during radiation therapy. But the outer genitals and vagina may become sore and tender to touch, and many choose to stop having sex for a while to let the area heal.

Radiation can also irritate the bladder and may cause problems urinating (peeing). Bladder irritation, called radiation cystitis, can cause discomfort and an urge to urinate frequently.

Almost all side effects can be treated with medicines and many go away over time after treatment ends. If you're having any side effects from radiation, discuss them with your cancer care team. There are things you can do to get relief from these symptoms or prevent them.

Long-term side effects of radiation

Radiation can also cause some side effects that can last a long time.

Radiation therapy might also cause scar tissue to form in the vagina. If the scar tissue makes the vagina shorter or more narrow it's called vaginal stenosis. This can make vaginal sex painful. Stretching the walls of the vagina several times a week can help prevent this problem. This can be done by having sex 3 to 4 times a week or by using a vaginal dilator (a plastic or rubber tube used much like a tampon to stretch out the vagina). Still, vaginal dryness and pain with sex can be long-term problems after radiation. Explore how radiation can impact your sex life for more information on this topic.

Pelvic radiation can damage the ovaries, resulting in premature (early) menopause. But most women being treated for uterine sarcoma have already gone through menopause, either naturally or as a result of surgery to treat the cancer.

Radiation to the pelvis can block fluid drainage from the legs, leading to leg swelling. This is called lymphedema. It's more common in those who had lymph nodes removed during surgery.

Pelvic radiation can also weaken bones, leading to fractures of the hips or pelvic bones. If you have had pelvic radiation, contact your doctor right away if you have pelvic pain. Such pain might be caused by a fracture, recurrent cancer, or other serious conditions, such as hemorrhagic cystitis (injury to the bladder with blood in the urine) or radiation proctitis (injury to the rectum with blood in the stool).