Radiation Therapy for Endometrial Cancer

Radiation therapy uses high-energy radiation (like x-rays) to kill cancer cells. It can be given in 2 ways to treat endometrial cancer:

• By putting radioactive materials inside the body. This is called internal radiation therapy or brachytherapy.
• By using a machine that focuses beams of radiation at the tumor, much like having an x-ray. This is called external beam radiation therapy.

In some cases, both brachytherapy and external beam radiation therapy are used. When that's done, the external beam radiation is usually given first, followed by the brachytherapy. The stage and grade of the cancer are used to help decide what areas need to be treated with radiation therapy and which types of radiation are used.

Radiation is most often used after surgery to treat endometrial cancer. It can kill any cancer cells that may still be in the treated area. If your treatment plan includes radiation after surgery, you will be given time to heal before starting radiation. Often, at least 4 to 6 weeks are needed.

Less often, radiation might be given before surgery to help shrink a tumor so it's easier to remove.

Women who are not healthy enough for surgery may get radiation as their main treatment.

Brachytherapy

Women who have had their uterus (and cervix) removed may have the upper part of the vagina treated with brachytherapy. This is called vaginal brachytherapy. A source of radiation (a radioactive material) is put into a cylinder (called an applicator) and the cylinder is put into the vagina. (It feels a lot like a snug tampon.) The size of the cylinder and how much radiation is in it depend on each case. The upper part of the vagina, closest to the uterus, is always treated. With brachytherapy, the radiation mainly affects the area of the vagina in contact with the cylinder. Nearby structures like the bladder and rectum get less radiation exposure.

This procedure is done in the radiation therapy area of a hospital or a radiation treatment center. There are 2 types of brachytherapy used for endometrial cancer, low-dose rate (LDR) and high-dose rate (HDR).

• In LDR brachytherapy, the applicator with the radiation source in it is left in for about 1 to 4 days. The patient needs to be still to keep the applicator from moving during treatment, so she's usually needs to stay in the hospital during treatment. Because the patient has to stay immobile, this form of brachytherapy carries a risk of serious blood clots in the legs (called deep venous thrombosis or DVT). LDR isn't commonly used in the US.
• In HDR brachytherapy, the radiation is stronger. Each treatment takes a very short time (usually less than an hour), and the radiation is only in for 10 to 20 minutes. The applicator is only in place when the treatment is done. You will be able to go home the same day. For endometrial cancer, HDR brachytherapy might be given weekly or even daily for at least 3 doses.

The most common side effect is changes in the lining of the vagina. (Called radiation vaginitis, this is discussed in more detail below, in the side effects section.) If needed, pain medicines can be used to help you be more comfortable while the applicator is in.

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 tiny tattoos. A special mold of the pelvis and lower back is custom made to make sure you are in the exact same position for each treatment. Each treatment takes less than a half-hour, but daily visits to the radiation center are needed.

Sometimes chemotherapy is given along with the radiation to help it work better. This is called chemoradiation.

Side effects of radiation therapy

Short-term side effects

Common side effects of radiation therapy include tiredness, upset stomach, or loose stools. Severe fatigue, which may not start until about 2 weeks after treatment begins, is also common. Diarrhea is common, but usually can be controlled with over-the-counter medicines. Nausea and vomiting may occur, but can be treated with medicine. These side effects are more common with external beam radiation than with brachytherapy.

Side effects tend to be worse when chemotherapy is given with radiation.

Skin changes, which can range from mild redness to peeling and blistering, are quite common. The skin may release fluid, which can lead to infection, so care must be taken to clean and protect the area exposed to radiation. Sometimes, as it heals, the skin in the treated area becomes darker or less flexible (harder).

Radiation can irritate the bladder, and you might have problems urinating. Irritation to the bladder, called radiation cystitis, can result in discomfort, blood in the urine, and an urge to urinate often.

Radiation can also cause irritation in the intestine. Rectal irritation or bleeding is called radiation proctitis. It's sometimes treated with enemas that contain a steroid (like hydrocortisone) or suppositories that contain an anti-inflammatory.

Radiation can irritate the vagina, leading to discomfort and drainage (a discharge). This is called radiation vaginitis. If it occurs, the doctor may recommend douching with a dilute solution of hydrogen peroxide. When the irritation is severe, open sores can develop in the vagina, which may need to be treated with an estrogen cream.

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.

Long-term side effects

Radiation therapy may cause changes to the lining of the vagina leading to vaginal dryness. This is more common after vaginal brachytherapy than after pelvic radiation therapy. In some cases scar tissue can form in the vagina. The scar tissue can make the vagina shorter or more narrow (called vaginal stenosis), which can make sex (vaginal penetration) 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 sex 3 to 4 times a week or by using a vaginal dilator (a plastic or rubber tube used to stretch out the vagina). Still, vaginal dryness and pain with sex can be long-term side effects of radiation. Some centers have physical therapists who specialize in pelvic floor therapy which can help to treat these vaginal symptoms and sometimes improve sexual function. Ask your doctor about this if you are bothered by these problems. You can also find some helpful information in Sex and the Woman With Cancer.

Pelvic radiation can damage the ovaries, resulting in premature menopause. This is not an issue for most women 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 blockages that keep fluid from draining out of the leg. This can lead to severe swelling, called lymphedema. Lymphedema is a long-term side effect; it doesn't go away after radiation is stopped. In fact it may not start for several months or even years after treatment ends. This side effect is more common if pelvic lymph nodes were removed during surgery to remove the cancer. There are specialized physical therapists who can help treat this. It's important to start treatment right away if you develop it. To learn more, see Lymphedema. 

Radiation to the pelvis can weaken the bones, leading to fractures of the hips or pelvic bones. It's 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 (cancer that's come back after treatment), or other serious conditions.

Pelvic radiation can also lead to long-term problems with the bladder (radiation cystitis) or bowel (radiation proctitis). Rarely, radiation damage to the bowel can cause a blockage (called obstruction) or for an abnormal connection to form between the bowel and the vagina or outside skin (called a fistula). These conditions may need to be treated with surgery.

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.