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External Beam Radiation Therapy for Prostate Cancer


  • External beam radiation therapy is used to treat prostate cancer. Prostate cancer is a condition where a lump of cancer cells (tumor) grows inside your prostate gland. The prostate is a male sex gland that helps make semen. It wraps around the urethra and the neck of the bladder. With prostate cancer, tumor cells become cancerous and divide without control or order. With prostate cancer, it may be painful to urinate, and it may be hard for you to hold in your urine. You may lose weight and become very weak. You may have trouble getting an erection, or getting your female partner pregnant.
  • During this treatment, x-ray beams are pointed right at your tumor for a short time. A low power beam is often used, and is given every day for up to eight weeks. A wide beam may be used to treat a larger area when there is a high risk of cancer spreading to other body areas. External beam radiation therapy can be used to treat one or more cancer tumors. It can also be used to help stop cancer cells from spreading. This can be done with other treatments such as medicines, chemotherapy, and surgery. With radiation therapy, cancer cells may be killed. These treatments may also make your cancer go away, and increase the years of your life.


Take your medicine as directed.

Call your healthcare provider if you think your medicine is not helping or if you have side effects. Tell him if you are allergic to any medicine. Keep a list of the medicines, vitamins, and herbs you take. Include the amounts, and when and why you take them. Bring the list or the pill bottles to follow-up visits. Carry your medicine list with you in case of an emergency.

Ask for information about where and when to go for follow-up visits:

For continuing care, treatments, or home services, ask for more information.

  • Ask your caregiver when you need to return for other more treatments. You may need daily treatments for several weeks. You may need to have blood tests to check your prostate specific antigen (PSA) level. It will give your caregivers more information about your prostate cancer. PSA tests may be done every six months for five years, and every year after that. Your caregiver will also do yearly prostate exams.

Eating well with cancer and cancer treatment:

Good nutrition can:

  • help you feel better during treatment and decrease treatment side effects
  • decrease your risk of infection
  • help you have more energy and feel stronger
  • help you maintain a healthy weight and heal faster
Eat a variety of healthy foods to get the protein, carbohydrates, and other nutrients that your body needs. You may need to change the foods you eat depending on your treatments and side effects. You also may need to eat more calories than usual. Work with a dietitian to plan the best meals and snacks for you. Ask if you should add vitamins to your diet.

Drinking liquids:

Drink extra liquids to avoid dehydration (loss of body fluid). You will also need to replace fluid if you are vomiting or have diarrhea from cancer treatments. Ask your caregiver which liquids to drink and how much you need each day.

Keep a voiding diary:

Keep track of your signs and symptoms at home using a voiding diary. Take the diary to your appointments. In the diary, write down the date and time that you have any of the following problems:

  • Feeling like you are not completely emptying your bladder after urinating.
  • Having a weak flow of urine.
  • Having to push or strain before your urine comes out.
  • Having to urinate more often than every two hours.
  • Seeing that your urine stream stops and starts when you urinate.
  • Trouble holding in your urine.
  • Waking up during the night to urinate.

Watch for medical problems:

Watch for changes in your health while you are having treatments, and tell your caregiver about any changes that you see or feel. Your caregiver may give you medicines or other treatments for the following problems:

  • Problems that may appear soon after your treatments:
    • Blood in your urine.
    • Dry, red, or broken skin. This makes it easier for you to get infections.
    • Loose watery stools, or blood in your stools.
    • Swelling in your bladder. This may make it hard to empty out all of your urine when you urinate.
    • Trouble sleeping, and feeling very tired.
    • Waking up during the night because you feel like you need to urinate.
  • Problems that may appear months or years after your treatments:
    • Scars (thick patches of healed tissue) may form, and your bladder may get smaller. If this happens, it cannot hold as much urine as it did before, and you may need to urinate more often. Urine may come out when you cough or strain, or before you get to the toilet.
    • New tumors may grow in your body. You may lose a lot of weight and feel very weak.
    • Your urethra may grow scars, and get narrow. If this happens, you may need to strain to let your urine out. Your urine may come out in a weak stream.
    • Swelling or scarring in your bowels. You may have pain in your abdomen (stomach) or blood in your bowel movements.
    • Trouble having an erection or getting your female partner pregnant. You may be given medicines to treat erectile dysfunction (ED). Other treatments such as shots, implants, or vacuum devices may be offered to you. Sexual counseling (talk therapy) may be offered to help you cope with this problem. Ask your caregiver for more information about ED.

Taking care of your skin:

External beam radiation therapy may make your skin red and very dry. Your skin may also get moist. It may begin to bleed, and start to peel off. Ask your caregiver if you should do the following to care for your skin:

  • Wash your skin gently with mild soap. Do not scrub your skin. Pat yourself dry with a towel instead of rubbing your skin.
  • While bathing, do not soak for a long time as this can make your skin drier.
  • Ask your caregiver what type of lotion or cream would be best for you to use on your skin.


  • You cannot make it to your treatment or appointment on time.
  • You feel burning pain while you are urinating.
  • You have a fever.
  • You have problems getting an erection or getting your female partner pregnant.
  • You have trouble holding in your urine.
  • Your urine is red, cloudy, and bad smelling.
  • You have chest pain or trouble breathing that is getting worse over time.


  • You have painful bones, such as those in your hips, legs, or back.
  • Your legs are swollen.
  • Your skin is red and dry, or is moist and peeling off.
  • Your urine is coming out in drops, or no urine is coming out at all.
  • You suddenly feel lightheaded and have trouble breathing.
  • You have new and sudden chest pain. You may have more pain when you take deep breaths or cough. You may cough up blood.
  • Your leg feels warm, tender, and painful. It may look swollen and red.

Learn more about External Beam Radiation Therapy for Prostate Cancer (Aftercare Instructions)

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.