Prostate cancer

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Potential side effects of radiation therapy for prostate cancer

Side effects can occur with any type of treatment for prostate cancer, but not everyone has them or experiences them in the same way. Side effects of radiation therapy will depend mainly on the:

  • type of radiation therapy
  • size of the area being treated
  • specific area or organs being treated
  • total dose
  • treatment schedule

Radiation therapy damages cancer cells, but healthy cells in the treatment area can also be damaged, even though steps are taken to protect them as much as possible. Different cells and tissues in the body tolerate radiation differently.

Side effects can happen any time during radiation therapy. Some may happen during, immediately after or a few days or weeks after radiation therapy. Most side effects go away after radiation therapy is completed. Late side effects can occur months or years after radiation therapy. Some side effects may last a long time or be permanent.

It is important to report side effects to the healthcare team. Many side effects can be relieved by medications, a change in diet or other measures.


Fatigue is one of the most common side effects of radiation therapy. Fatigue may be caused by anemiaanemiaA reduction in the number of healthy red blood cells., poor appetite, depression, or it may be related to toxic substances that are produced when cancer cells break down and die. During radiation therapy, the body uses more energy to heal itself, so fatigue will not always be relieved by rest.

Fatigue usually goes away gradually after treatment has ended, but some people continue to feel tired for several weeks or months after radiation therapy.

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Bladder problems

Radiation therapy can irritate the bladder and cause it to become inflamed (called cystitis). Symptoms of bladder irritation or inflammationinflammationThe body’s protective response to injury or infection that includes redness, swelling, pain and warmth of the affected area. include:

  • bladder spasms
  • burning or pain during urination
  • intense need to urinate (urgency)
  • need to urinate often (frequency)
  • blood in the urine (hematuria)
  • bladder infection
  • urinary incontinence (loss of bladder control)

Symptoms usually occur 3 to 5 weeks after radiation therapy is started. They gradually go away 2 to 8 weeks after radiation is completed. Some bladder problems, like cystitis or incontinence, may continue or develop after treatment is over.

Drinking plenty of fluids to ensure a regular flow of urine and emptying the bladder frequently are helpful for preventing bladder problems.

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Bowel problems

Bowel problems that may occur after radiation therapy for prostate cancer include:

  • diarrhea
  • inflammation of the rectum and anus (proctitis)
  • pain
  • itching
  • spasms, cramping
  • rectal bleeding
  • hemorrhoids
  • bowel obstruction or perforation (rare)

Bowel habits usually return to normal after treatment. However, some problems, such as bowel obstruction due to strictures (narrowing due to scars), can occur several months or years after radiation therapy.

The radiation therapy team can suggest ways to help manage diarrhea, itching and hemorrhoids. Treatment options for severe rectal problems may include:

  • anti-inflammatory drugs, corticosteroid drugs or anti-spasm drugs
  • dilation or widening of rectal strictures
  • surgery, if the problem is severe enough

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Erectile dysfunction

Radiation therapy to the pelvic area may cause erectile dysfunction (ED), or impotence. ED means that a man is unable to get or maintain an erection. It happens because radiation can affect the blood vessels that carry blood to the penis, which is necessary to create a firm erection. It also affects the nerves.

Men should talk to the radiation therapy team about treatment options for ED.

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Skin reactions

Skin reactions occur because external beam radiation travels through the skin to reach the area being targeted for treatment. The skin in the treated area may become red, dry or change colour (become darker or tanned looking). Most skin reactions occur within the first 2 weeks of starting radiation treatment. They usually go away a few weeks after treatment, but some skin changes, like skin darkening or scarring, can persist. Some people do not experience any skin reactions with radiation therapy.

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Bruising and bleeding may occur in the area of skin where the brachytherapy needles are inserted.

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Urethral stricture

Radiation may cause the formation of scar tissue that blocks the urethra. This is called a urethral stricture. It blocks the flow of urine. Urethral strictures are treated with dilators or surgery.

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Bone marrow suppression

Low blood cell counts occur because of radiation's damaging effect on the bone marrow, where blood cells are made. Blood counts are more likely to be affected when the pelvic bones (where many of an adult's blood cells are made) lie in the treatment area.

Decreases in blood cell counts are rarely severe enough to cause problems. When there is a break from treatment for a few days, blood cell counts usually recover.

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Bone pain

Radiation therapy to treat bone metastases might cause an increase in bone pain after the first few treatments (called a tumour flare reaction). Radiation triggers an inflammatory response in the cancer cells. The flare-up can be controlled by pain medications.

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Marie Whitehead Catch the cancer early. That’s the number one thing. It could save your life.

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