Endometrial Cancer: Radiation Therapy 

What is radiation therapy?

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

When radiation therapy may be used

Your doctor may advise radiation therapy if one or more of the below applies to you:

• You are not able to have surgery.

• You had surgery for endometrial cancer but the doctor believes you are at a high risk of the cancer returning. Having radiation after surgery can help lower the chances of the cancer coming back. It’s the most common reason to have radiation for endometrial cancer. Radiation after surgery is not started until you've had some time to heal. This is usually about 4 to 6 weeks after surgery.

• You are having chemotherapy or hormone therapy, and radiation may help ease symptoms such as excess bleeding.

How radiation therapy is done

There are two main ways to get radiation therapy:

• External radiation. The radiation comes from a machine called a linear accelerator (linac) and is pointed at the skin over the tumor. The treatment is a lot like getting an X-ray. The machine doesn't touch you during the treatment. The treatments don't hurt and they are quick.

• Internal radiation (brachytherapy). This is the most common type of radiation therapy for endometrial cancer. It is usually done after surgery. Radioactive material is placed inside the vagina, near the tumor. The radiation material may be in flexible tubes, called catheters, or metal rods. The radiation only travels a very short distance to kill the nearby cancer cells. This can help lower the risk of the cancer returning in the vagina.

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 (stage)

• How fast the cancer is growing (grade)

• If it was found in nearby lymph nodes

Deciding on a radiation treatment plan

You will talk with a radiation oncologist. This is a doctor who specializes in both cancer and 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 during and after the treatment. 

What to expect during external radiation therapy

The 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 often given once a day, 5 days a week, for about 5 to 6 weeks.

Before you start treatment, imaging scans will be done in the area of your cancer. Your doctor may have you drink contrast fluid to help better see the bowel and other tissues. This process is called simulation. It is done to measure the exact location of the tumor so the beams of radiation can be focused there. Small marks (tiny permanent 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 reaches the tumor, and not healthy parts of your body.

On the day of treatment, the process 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 it 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 will need to be very still, but you do not have to hold your breath. You can't feel radiation. It's painless. You may hear whirring or clicking noises from the machine. The machine may move around you but it will not touch you. You will not be radioactive afterward.

What to expect during internal radiation (brachytherapy)

For brachytherapy, a cylinder filled with a radiation source is put into the vagina so that the upper part of the vagina closest to the uterus is treated. This part of the vagina is called the cuff.  This type of radiation may be given in a hospital or in an outpatient radiation clinic. Brachytherapy is given in 2 different ways: 

• High-dose rate (HDR) brachytherapy. This uses more intense doses of radiation that are put in for less than an hour at a time. There's no need to stay in the hospital, and you can go home after the source is taken out. HDR brachytherapy may be given weekly or daily, most often for about 2 to 3 doses total.

• Low-dose rate (LDR) brachytherapy. This is usually done in the hospital, but it's not often used in the U.S. The radiation source is put in and left in place for about 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 can be treated. They often get better or go away over time after treatment ends. The side effects of radiation therapy include:

• Skin irritation in the treated area

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

• Vaginal pain and discharge

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

• Feeling tired or weak

• Nausea

• Bladder irritation

• Bowel irritation and diarrhea

Side effects depend on the type of radiation therapy used. For example, with brachytherapy the radiation mainly affects the parts of the vagina in contact with the cylinder. This means there are fewer side effects. 

Side effects tend to be worse if you're having chemo along with the radiation. Talk with your doctor about what side effects you can expect. Talk about what can be done to prevent or ease them. 

When to call your healthcare provider

Ask your doctor what symptoms to watch out for. In some cases, 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 years after you finish treatment. These depend on the dose and type of radiation. These also depend on how many times you had the treatment. Vaginal dryness or scarring may become a life-long problem. Bowel and bladder problems can also become life-long issues. Ask your doctor what to expect.