Radiation Therapy for Vaginal Cancer

Radiation therapy is the treatment most often used for vaginal cancer. It involves using high-energy rays (such as gamma rays or x-rays) or particles (such as electrons, protons, or neutrons) to kill cancer cells.

How is radiation used to treat vaginal cancer?

There are 2 ways to treat vaginal cancer with radiation:

• External beam radiation therapy
• Intracavity (in the body cavity) brachytherapy (also called internal radiation therapy).

Vaginal cancer is most often treated with acombination of both external and internal radiation with or without low doses of chemotherapy.

External beam radiation therapy/ Intensity-modulated radiation therapy (EBRT/IMRT)

EBRT is radiation delivered from outside the body. It's a lot like getting an x-ray.

IMRT is a type of EBRT, where radiation beams change strength depending on where they hit the tumor; this helps lessen damage to nearby normal body tissues.

EBRT/IMRT can be used for vaginal cancer in a few different ways:

• For Stage I: EBRT/IMRT is commonly given alone, then followed by intracavitary brachytherapy.
• For Stages II through Stage IVA: EBRT/IMRT is commonly given with chemotherapy, then followed by intracavitary brachytherapy.

Intracavitary brachytherapy

Another way to deliver radiation is to place radioactive material inside the vagina. There are 2 main types of intracavitary brachytherapy:

• Low dose rate (LDR) brachytherapy: The radioactive material is inside a cylinder-shaped container that's put in the vagina. It stays in place for a day or 2. Gauze packing helps hold the cylinder in place, but you have to stay in bed in the hospital during the treatment.
• High dose rate (HDR) brachytherapy: The radiation source is in a cylinder, but it doesn’t need to stay in place for long. This means it can be given in an outpatient setting. Typically, 3 or 4 treatments are given 1 or 2 weeks apart.

When given this way, the radiation mainly affects the tissue touching the cylinder. This means the radiation is less likely to cause bladder and bowel side effects.

Another type of brachytherapy, called interstitial radiation, uses radioactive material inside needles that are put right into the tumor and nearby tissues.

Side effects of radiation therapy

Radiation can destroy nearby healthy tissue along with the cancer cells. Side effects depend on the area being treated, the amount of radiation, and the way the radiation is given. Side effects tend to be more severe for external beam radiation than for brachytherapy.

Short-term side effects

Common short-term side effects of radiation therapy include:

• Tiredness, which may get worse about 2 weeks after treatment begins and get better over time after treatment ends
• Nausea and vomiting (more common if radiation is given to the belly or pelvis)
• Diarrhea (more common if radiation is given to the belly or pelvis)
• Skin changes in the area where the radiation is given, which can range from mild redness to blistering and peeling. The skin may become raw and tender.
• Low blood counts

The diarrhea caused by radiation can usually be controlled with over-the-counter medicines. Nausea and vomiting can be treated with medicines from your doctor. Skin that becomes raw and tender needs to be kept clean and protected to prevent infection.

Side effects tend to be worse when chemotherapy is given with radiation.

Long-term side effects

Radiation to treat vaginal cancer can also cause some long-term side effects. Many of them are caused by radiation damage to nearby organs. For instance, pelvic radiation can damage the ovaries, leading to early menopause. It can also weaken bones, making them more likely to break from a fall or other trauma.

Radiation to the pelvis can also severely irritate the intestines and rectum (called radiation colitis), leading to diarrhea and bloody stool. If severe, radiation colitis can cause holes or tears (perforations) to form in the intestines.

Pelvic radiation can cause problems with the bladder (radiation cystitis), leading to discomfort and an urge to urinate often. In rare cases, radiation can cause abnormal connections (called fistulas) to form between the vagina and the bladder, rectum, or uterus.

If the skin is irritated by radiation, when it heals it may be darker and not as soft. The hair may not grow back.

Radiation can cause the normal tissue of the vagina to become irritated and sore. As it heals, scar tissue can form in the vagina. The scar tissue can make the vagina shorter or more narrow (this is called vaginal stenosis). When this happens, vaginal intercourse can become painful. Stretching the walls of the vagina a few times a week can help prevent this problem.

One way to do this is to have vaginal sex at least 3 to 4 times a week. Since this might be uncomfortable while getting cancer treatment (and even after), another option is to use a vaginal dilator. A dilator is a plastic or rubber tube used to stretch out the vagina. It feels much like putting in a large tampon for a few minutes. Even if there is no interest in staying sexually active, keeping the vagina normal in size allows for comfortable gynecologic exams. This is an important part of follow-up after treatment. Vaginal creams may also be used to relieve dryness, prevent painful sex, and help maintain the size of the vagina. Still, vaginal dryness and pain with sex can be long-term side effects from radiation. See Sex and the Woman With Cancer to learn more.