Endometrial Cancer: Radiation Therapy 

What is radiation therapy?

Radiation therapy is a treatment for cancer that uses strong beams of energy to kill and damage cancer cells. A machine directs the energy rays to the area of cancer. Radiation therapy is also called radiotherapy. Its goal is to kill cancer cells and shrink tumors.

When radiation therapy may be used

Your doctor may suggest radiation therapy in these cases:

  • If you're not able to have surgery, radiation can be used instead.

  • Radiation is often used after surgery to reduce the chance of the cancer coming back later. Radiation after surgery is not started until you've had some time to heal. This is usually about 4 to 6 weeks after surgery.

  • Radiation might be used before surgery to help shrink a tumor so it's easier to remove.

  • Radiation may be given along with chemotherapy. This is called chemoradiation. The chemo helps the radiation work better, but this combination causes more side effects.

How radiation therapy is done

There are 2 main ways to get radiation therapy for endometrial cancer:

  • External radiation. The radiation comes from a machine called a linear accelerator (linac). The beams of energy are aimed at the tumor and go through your skin. The treatment is a lot like getting an X-ray.

  • Internal radiation (brachytherapy). This is the more common type of radiation therapy used for endometrial cancer. Radioactive material is put inside the vagina, near the tumor. This is usually done after surgery to remove the uterus. It treats the upper part of the vagina that was near the uterus.

Some people need both an external radiation treatment (often for a few minutes each day for 4 to 5 weeks) followed by internal radiation (often 2 to 3 sessions).

Which method is used depends on:

  • How much the cancer has spread (the stage). Imaging studies, exams, and looking at the tissue taken out during surgery help make this decision.

  • How fast the cancer is growing (grade), which is based on lab testing of the removed tissue

  • If cancer was found in nearby lymph nodes

Deciding on a radiation treatment plan

You will meet with a radiation oncologist to talk about this treatment. This is a doctor who specializes in treating cancer with radiation. You’ll work with your doctor to decide what your treatment will be and how long it will last. During your visit, ask what you can expect to feel like during and after treatment. 

What to expect during external radiation therapy

This treatment is a lot like getting an X-ray. The radiation comes from a large machine. The machine doesn't touch you during the treatment. The treatments don't hurt and they are quick. Radiation is given once a day, 5 days a week, for 4 to 6 weeks.

Before you start treatment, imaging scans will be done to map out exactly where the cancer is. You may be asked to drink contrast fluid to help better see your bowel and other tissues on the scans. This process is called simulation. It's done to find and measure the tumor so the beams of radiation can be focused there.

Small marks (tiny tattoos) may be put on your skin to mark the treatment area. A special mold may be made to hold you in the exact same position for each treatment. This ensures that the radiation hits the tumor, and limits damage to the healthy parts of your body.

Each treatment will likely take less than an hour. You are carefully put into the right position. A radiation therapist may use special shields to cover parts of your body to protect you from the radiation. Or the machine itself may have built-in shields to protect you. You may see lights from the machine lined up with the marks on your skin.

The therapist will leave the room while the machine sends radiation to the cancer. During this time, he or she can see you, hear you, and talk to you. When the machine sends radiation to the cancer, you'll need to be very still, but you don't have to hold your breath. You may hear whirring or clicking noises from the machine. But you can't feel radiation. You will not be radioactive afterward.

What to expect during internal radiation (brachytherapy)

A plastic device in the shape of a cylinder is used for brachytherapy. This device is called an applicator. It's filled with a radiation source and is put into the vagina during treatment.

Applicators come in different sizes and will fit in your vagina like a tampon. The amount of radioactive material put in the applicator depends on how much of your vagina needs to be treated. The upper part of the vagina, called the cuff, is always treated. This is where the uterus connected to the vagina before it was removed.

The radiation travels only a very short distance to kill the nearby cancer cells. This can help lower the risk of the cancer returning in the vagina. It also helps limit damage to nearby organs, like your bladder and rectum.

This type of radiation may be given in a hospital or in an outpatient radiation clinic. It's given in 2 different ways: 

  • High-dose rate (HDR) brachytherapy. This uses strong radiation that's put in for 10 to 20 minutes at a time. There's no need to stay in the hospital, and you can go home after the applicator is taken out. HDR brachytherapy may be given weekly or daily. It's usually done 2 or 3 times.

  • Low-dose rate (LDR) brachytherapy. This is usually done in the hospital, but it's seldom used in the U.S. The applicator is put in and left in place for 1 to 4 days. During this time you have to stay in the hospital and can’t move very much.

What happens after radiation therapy?

After you finish getting your radiation therapy, your oncologist and other healthcare providers will closely watch you to see how your body responds to the treatment. You will get lab tests and scans on a regular basis. Tell your healthcare providers about any problems or symptoms you have. Go to all of your follow-up appointments.

What are common side effects of radiation therapy?

Talk with your doctor about what you might feel like during and after radiation therapy. Side effects often get worse as treatment goes on. But they can be treated. They often get better or go away over time after treatment ends.

Common side effects of radiation therapy for endometrial cancer include:

  • Skin irritation in the treated area (with external radiation)

  • Vaginal lining becomes irritated, dry, red, and blistered like sunburn from (the most common side effect of brachytherapy)

  • Vaginal pain and discharge

  • Hair loss in the area being treated (including pubic hair)

  • Feeling very tired or weak

  • Nausea

  • Bladder irritation and/or blood in your urine

  • Bowel irritation and diarrhea or rectal bleeding

  • Early menopause (If you still have your ovaries, radiation can damage them so they stop making hormones.)

Side effects depend on the type of radiation therapy used. For instance, brachytherapy mainly affects the lining of the vagina that's in contact with the cylinder, not your skin.

Side effects tend to be worse if you get chemotherapy along with radiation. Talk with your provider about what side effects you should watch for. Talk about what can be done to help prevent or ease them. 

When to call your healthcare provider

Ask your doctor what symptoms to watch out for. Also ask when you should call your healthcare team. Your doctor may want you to call if you have signs of infection, such as fever or pain that gets worse.

Long-term side effects

Some long-term side effects of radiation may not show up for many months or years after you finish treatment. These depend on the dose and type of radiation. Vaginal dryness or scarring may become a life-long problem. Sex can be painful. Bowel and bladder problems can also become life-long issues. There are things you can do to help lessen and manage some of these long-term side effects. Ask your doctor what to expect.

Online Medical Reviewer: Dave Herold MD
Online Medical Reviewer: Kimberly Stump-Sutliff RN MSN AOCNS
Online Medical Reviewer: Louise Cunningham RN BSN
Date Last Reviewed: 2/1/2021
© 2021 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare provider's instructions.