Radiation therapy uses high-energy radiation (such as x-rays) to kill cancer cells. It can be given in 2 ways to treat endometrial cancer:
- By placing radioactive materials inside the body. This is called internal radiation therapy or brachytherapy.
- By using a machine that focuses a beam 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 given. When that is done, usually the external beam radiation is given first, followed by the brachytherapy. The stage and grade of the cancer help determine what areas need to be exposed to radiation therapy and which methods are used.
If your treatment plan includes radiation after surgery, you will be given time to heal from the operation before starting radiation. Often, at least 4 to 6 weeks are needed.
The guidelines for post-operative radiation therapy were recently revised so be certain to ask if you are being treated according to the latest recommendations.
Patients who have had their uterus (and cervix) removed may have the upper part of the vagina treated with brachytherapy. To do this, called vaginal brachytherapy, a source of radiation is placed into a cylinder and inserted into the vagina. The length of the cylinder (and how much of the vagina is treated) can vary, but the upper part of the vagina is always treated. With this method, the radiation mainly affects the area of the vagina in contact with the cylinder. Nearby structures such as the bladder and rectum get less radiation exposure. The most common side effect is change in the lining of the vagina (discussed in more detail in side effects).
This procedure is done in the radiation suite of the hospital or care center. The 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 radiation devices are usually left in place for about 1 to 4 days. The patient needs to stay immobile to keep the radiation sources from moving during treatment, and so she is usually kept in the hospital overnight. Several treatments may be necessary. 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 is less commonly used now in this country.
- In HDR brachytherapy, the radiation is more intense. Each dose takes a very short time (usually less than an hour), and the patient can go 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.
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 bowels. Serious fatigue, which may not occur until about 2 weeks after treatment begins, is a common side effect. Diarrhea is common, but usually can be controlled with over-the-counter medicines. Nausea and vomiting may also occur, but can be treated with medication. These side effects are more common with pelvic radiation than with vaginal 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 also 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 similar changes in the intestine. When there is rectal irritation or bleeding, it is called radiation proctitis. This is 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 and if it occurs, your radiation 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 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 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 intercourse can be a long-term side effect 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. You should ask your physician about this if you are bothered by these problems. You can also find some helpful information in our booklet Sexuality for the Woman With Cancer.
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. There are specialized physical therapists who can help treat this. It is important to begin treatment early if you develop it. For more on lymphedema, you can read Understanding Lymphedema: For Cancers Other than Breast 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.
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.
For more information, please see the “Radiation Therapy” section of our website.
Last Revised: 02/29/2016