Radiation therapy is a treatment for cancer that uses high-energy X-rays. 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.

Your doctor may advise radiation therapy for you in any of these cases: 

• You’re not able to have surgery. In rare cases, you may have only radiation. This may destroy all the cancer if the tumor is small.

• You’re getting ready to have surgery for uterine sarcoma. Radiation before surgery may help shrink the tumor. This makes it easier to remove. Having radiation before surgery is called neoadjuvant therapy.

• You recently had surgery for uterine sarcoma. Having radiation after surgery is called adjuvant therapy. This can help lower the chance of the cancer coming back.

• You’re having chemotherapy or hormone therapy to treat uterine sarcoma. In this case, radiation destroys cancer cells to ease symptoms.

• You have a large tumor, or the cancer has spread. In this case, radiation may ease your symptoms.

There are 2 main types of 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). Radioactive material is placed in or near the area of cancer. 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 material will be left in for anywhere from a few minutes up to a few days, depending on the method used. Then it's removed. More than 1 treatment may be needed.

You may be treated with one or both types of radiation therapy. Radiation therapy may also be used along with other cancer treatments, such as surgery or chemotherapy. 

Which method 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

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. 

If you’re having external radiation therapy, you’ll have an appointment before treatment starts to learn exactly where on your body the radiation beam needs to be directed. This is a process called simulation. This appointment may take up to 2 hours. Here's what you can expect to happen during the simulation process: 

• You'll lie still on a table while a radiation therapist uses a machine to identify your treatment field, also called your treatment port. The field is the exact area on your body where the radiation will be aimed. You may have more than 1 treatment field if you have cancer in more than 1 place. The therapist will mark your skin with tiny dots of colored semi-permanent ink or permanent tattoos. This helps the therapist aim the radiation at the same place each time and limit damage to nearby healthy tissues.

• You may also have imaging scans, such as CT scans. These help doctors know the exact location of your tumor to better determine the treatment area.

• You may also have body molds made. Molds are used to hold you in the best position. They also help keep you from moving during the treatments.

Internal radiation also requires imaging scans that help the radiation therapy team plan the treatment. But it does not require a simulation.

You can get external radiation as an outpatient at a hospital or clinic. That means you don't need to stay the night. External beam radiation is given in divided doses. You'll receive a schedule for radiation therapy. The schedule usually is for 5 days a week for 4 to 6 weeks. Spreading out the radiation dose helps protect your healthy tissue. On the days you get radiation, you’ll lie on a table while the machine is placed over you. You may have to wear a hospital gown. The experience is a lot like getting an X-ray, but it lasts longer. The whole process lasts about 15 to 30 minutes, with about 1 to 5 minutes spent actually getting the radiation. 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. The therapist will line up the machine with the areas that were marked during the simulation.

The therapist will leave the room to turn on and run the machine. You’ll be able to talk to the therapist over an intercom, and the therapist can see you the whole time. 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.

You will most likely have radiation treatments every day for 5 days in a row, Monday through Friday, for about 4 to 6 weeks.

Internal radiation may be given as an outpatient in an outpatient surgery suite or in the hospital. The radiation only travels a short distance from the source. So it needs to be placed close to the tumor. Many times more than 1 brachytherapy treatment is needed. There are 2 ways this type of radiation is done:  

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. Make sure you tell your healthcare providers about any problems or symptoms you have. Make sure to go to all of your follow-up appointments.

Radiation can hurt normal cells as well as cancer cells. This can lead to side effects.  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 you have depend on these factors: 

• Whether you have internal or external radiation

• How much radiation you get

• Which normal tissues are affected by the radiation, such as your skin, bladder, rectum, vagina, lymph system, or blood cells

Some side effects may occur during treatment. Others may occur in the weeks or months after treatment.

Short-term side effects of radiation therapy for uterine sarcoma may include: 

• Tiredness

• Redness, flaking, or fluid on the skin near the treatment area

• Nausea

• Bloating

• Loss of hair, especially pubic hair

• Genital and vaginal soreness

• Diarrhea or intestinal cramping, from radiation irritation to the intestines

• Feeling the need to urinate often or a burning feeling when you urinate, from radiation irritation to the bladder

• Infections from low white blood cell levels

• Easy bruising or bleeding from low blood platelet levels

• Tiredness from low red blood cell levels

Long-term side effects are also possible and can include:

• Bladder problems

• Scar tissue in the vagina and dryness that can make vaginal sex painful

• Ovary damage that can lead to early menopause

• Lymph node damage that causes leg swelling (lymphedema)

• Hip and pelvic bone weakness that can lead to bone breaks

• Bowel problems. These may include long-lasting (chronic) diarrhea or even blockages.

Ask your doctor which side effects you are most likely to have. Be sure you know which short- and long-term side effects to watch for and tell your healthcare team about.  Most side effects can be treated. In most cases they will go away or get better within a few weeks after your treatments end. 

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.