Radiation Therapy for Endometrial Cancer

Radiation therapy 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.

Sometimes, both brachytherapy and external beam radiation therapy are used. The external beam radiation is usually given first, followed by 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.

When is radiation used to treat endometrial cancer?

Radiation most often is used after surgery to treat uterine cancer. It can kill many 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.

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

Brachytherapy for endometrial cancer

 After the uterus and cervix are removed,  the upper part of the vagina may be treated with brachytherapy. This is called vaginal brachytherapy. A radioactive material is put into a cylinder ( 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 might vary. 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. Two types of brachytherapy are used for endometrial cancer: low-dose rate (LDR) and high-dose rate (HDR).

Low-dose rate brachytherapy

The applicator with the radiation source in it is left in place for up to 4 days. The patient needs to be still to keep the applicator from moving during treatment, so this requires a hospital stay during treatment. Because the patient must not move, 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 United States.

High-dose rate brachytherapy

The radiation given 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 while 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 a change in the lining of the vagina. (Called radiation vaginitis, this is discussed 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 for endometrial cancer

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 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 usually needed.

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

Side effects of radiation therapy for endometrial cancer

Short-term side effects

Severe fatigue, which might 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 be more vulnerable 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).
• Irritation to the bladder, called radiation cystitis, can result in discomfort and problems urinating, blood in the urine, and an urge to urinate often.
• 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.
• Vaginal irritation 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 certain creams.
• 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

Vaginal dryness. Vaginal dryness 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. 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. 

Premature menopause. Pelvic radiation can damage the ovaries, resulting in premature menopause. This is not an issue for most treated for endometrial cancer because they usually have already gone through menopause, either naturally or as a result of surgery to treat the cancer (hysterectomy and removal of the ovaries).

Lymphedema. 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 might 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 (lymph node dissection) to stage 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.

Weakened bones. Radiation to the pelvis can weaken the bones, leading to fractures of the hips or pelvic bones. It's important that those 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.

Bladder and bowel problems. 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 cause an abnormal connection 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, be sure to tell someone on your cancer care team. There are things you can do to get relief from these symptoms or to prevent them from happening. It’s very important to talk about what to expect, and continue to talk about what's changing or has changed in your life as you go through procedures, treatments, and follow-up care. Don't assume your doctor or nurse will ask about any concerns you have about sexuality. Remember, if they don't know you're having a problem, they can't help you manage it.