Radiation therapy is the use of high-energy radiation (such asx-rays) to kill cancer cells. Radiation therapy may be given by placing radioactive materials inside the body near the tumor. This is called internal radiation therapy or brachytherapy. Another option is to give radiation from a machine outside the body in a procedure that is much like having an x-ray. This is called external beam radiation therapy. In some cases, both brachytherapy and external beam radiation therapy are given. The stage and grade of the cancer help determine what areas need to be exposed to radiation therapy and which methods are used.

Brachytherapy

For vaginal brachytherapy, a cylinder containing a source of radiation is inserted into the vagina. With this method, the radiation mainly affects the area in contact with the cylinder, such as the vaginal cuff (the upper third of the vagina). Nearby structures such as the bladder and rectum get less radiation exposure than the area in contact with the cylinder.

This procedure is done in the radiation suite of the hospital or care center. About 4 to 6 weeks after the hysterectomy, the surgeon or radiation oncologist inserts a special applicator into the woman's vagina, and pellets of radioactive material are inserted into the applicator. There are 2 types of brachytherapy used for endometrial cancer, low-dose rate (LDR) and high-dose rate (HDR).

In LDR brachytherapy, the pellets are usually left in place for about a day at a time. The patient needs to stay immobile to keep the pellets from moving during treatment, and so she is usually kept in the hospital overnight. Several treatments may be necessary.

In HDR brachytherapy, the radiation is more intense. Each dose takes a very short period of time (usually less than an hour), and the patient can return home the same day. For endometrial cancer, HDR brachytherapy is often given weekly or even daily for at least 3 doses.

External beam radiation therapy

In this type of treatment the radiation is delivered from a source outside of the body.

External beam radiation therapy is often given 5-days-a-week for 4 to 6 weeks. The skin covering the treatment area is carefully marked with permanent ink or injected dye similar to a tattoo. A special mold of the pelvis and lower back is custom made to ensure that the woman is placed in the exact same position for each treatment.  Each treatment takes less than a half-hour, but the daily visits to the radiation center may be tiring and inconvenient.

Side effects of radiation therapy

Common side effects of radiation therapy include tiredness, upset stomach, or loose bowels. Serious fatigue, which may not occur until about 2 weeks after treatment begins, is a common side effect. Diarrhea is common, but can usually be controlled with over-the-counter medicines. Nausea and vomiting may also occur, but can be treated with medication. Side effects tend to be worse when chemotherapy is given with radiation.

Skin changes are also common, with the skin in the treated area looking and feeling sunburned. As the radiation passes through the skin to the cancer, it may damage the skin cells. This can cause irritation ranging from mild temporary redness to permanent discoloration. The skin may release fluid, which can lead to infection, so care must be taken to clean and protect the area exposed to radiation.

Radiation can irritate the bladder and problems with urination may occur. Irritation to the bladder, called radiation cystitis, can result in discomfort and an urge to urinate often.

Radiation can also lead to low blood counts, causing anemia (low red blood cells) and leukopenia (low white blood cells). The blood counts usually return to normal within a few weeks after radiation is stopped.

Pelvic radiation therapy may cause scar tissue to form in the vagina. The scar tissue can make the vagina shorter or more narrow (called vaginal stenosis), which can make sex (vaginal intercourse) painful. A woman can help prevent this problem by stretching the walls of her vagina several times a week. This can be done by having sexual intercourse 3 to 4 times per week or by using a vaginal dilator (a plastic or rubber tube used to stretch out the vagina). Still, vaginal dryness and pain with intercourse can be long-term side effects from radiation. Pelvic radiation can damage the ovaries, resulting in premature menopause. However, this is not an issue for most women who are being treated for endometrial cancer, because they have already gone through menopause, either naturally or as a result of surgery to treat the cancer (hysterectomy and removal of the ovaries).

Pelvic radiation therapy can also lead to a blockage of the fluid draining from the leg. This can lead to severe swelling, known as lymphedema. Lymphedema is a long-term side effect - it doesn't go away after radiation is stopped. In fact it may not appear for several months after treatment ends. This side effect is more common if pelvic lymph nodes were removed during surgery to remove the cancer.

Radiation to the pelvis can also weaken the bones, leading to fractures of the hips or pelvic bones. It is important that women who have had endometrial cancer contact their doctor right away if they have pelvic pain. Such pain might be caused by a fracture, recurrent cancer, or other serious conditions.

If you are having side effects from radiation, discuss them with your doctor. There are things you can do to get relief from these symptoms or to prevent them from happening.

Last Medical Review: 10/22/2009
Last Revised: 10/22/2009