Radiation Therapy for Prostate Cancer: What to Expect

Medically Reviewed by Poonam Sachdev on April 21, 2022
4 min read

Radiation therapy has long been a staple of treatment for many types of cancers. When it comes to prostate cancer, there are two kinds of radiation treatment: external beam radiation and brachytherapy. The kind that your doctor recommends will depend on your particular case.

External beam radiation therapy (EBRT) delivers radiation from a machine called a linear accelerator.

You may get this type of treatment if you have early-stage prostate cancer that hasn’t spread. Doctors also use it along with other treatments for later-stage cancer, after surgery to help prevent your cancer from coming back, after surgery if your cancer has already returned, or to help reduce symptoms of cancer that has spread beyond the prostate.

Brachytherapy works from the inside out. You may hear it called internal radiation therapy. It delivers radiation from small radioactive seeds or pellets, each the size of a grain of rice, that your doctor places directly into your prostate.

This therapy can be used to treat early-stage, slow-growing prostate cancer. It can also be combined with external radiation if there is a high risk that cancer has spread outside your prostate.

Here’s what happens with each type, including how these treatments work and what the side effects may be. Don’t hesitate to ask your doctor any questions that are on your mind.

A planning process makes sure that the amount and location where radiation is delivered are very precise.

Radiation simulation: A few days before this appointment, a radiologist will insert several marker seeds into your prostate to help locate it during treatment. Then, during radiation simulation, the therapy team will make marks on your body to help align the linear accelerator during treatment. The team will use special devices to hold you in place to make sure you don’t move during this process.

Planning scans: A computerized tomography (CT) scan will identify the precise area of your body to be treated. The information gathered during these planning sessions will help determine the type and dose of radiation you receive.

Treatment: Depending on the type of radiation and your specific diagnosis, you will usually get outpatient treatment 5 days a week for 7-9 weeks.

To make sure your prostate is in the same position for each session, an hour before treatment, your doctor may have you follow a few simple steps to make sure your bladder is full and your rectum is empty. This ensures that the radiation can be focused precisely and accurately.

For treatment, you will lie down in the position that was determined during radiation simulation. Then the linear accelerator may rotate around you to deliver radiation from all the planned angles and directions. Your therapy team will be in a different room, but you can talk to each other through audio and video connections.

EBRT treatment is painless and a lot like getting an X-ray. Each session takes less than an hour. Most of the time is spent setting up. The actual treatment lasts just a few minutes.

Imaging tests like ultrasound, CT scans, or MRI help place radioactive pellets in your prostate. The procedure is done in an operating room. You’ll get either spinal anesthesia (that numbs you from the waist down) or general anesthesia.

There are two types of brachytherapy:

Permanent (low dose rate, or LDR): Doctors use needles to place the pellets, which stay there for weeks or months to give off low-dose radiation. This treatment usually uses about 100 pellets that are very small. They are left in place even after their radioactivity wears out.

Temporary (high dose rate): This treatment is less common. It uses higher doses of radiation for shorter time periods. Needles place soft nylon tubes into your prostate. The tubes (or catheters) stay there for 2 days. During that time, radioactive material is placed in them for up to four treatments that each usually last 5 to 15 minutes. You’ll have the catheters removed after your last treatment.

Bowel problems are one possibility. Radiation therapy can irritate the rectum. That can lead to rectal pain, burning, possible diarrhea, and bleeding. These usually don’t last long. You may also have bowel movements more often than usual.

There can also be urinary problems. You may temporarily need to urinate more often than normal, or experience urgency -- feeling that you have to go to the bathroom right away and can’t hold it in. In rare cases, the urethra (the tube that drains urine from your bladder) can close and need to be opened with a catheter or surgery. There is also a chance of urinary incontinence -- not being able to control your urine or having some leaks.

Possible side effects specifically related to external radiation:

  • Blood in your urine
  • Belly cramping
  • Rectal bleeding or leakage
  • Fatigue
  • Skin reactions (similar to a sunburn)
  • Secondary cancers in the radiated area
  • Lymphedema (fluid collects in the legs or genital area)

Possible side effect related to brachytherapy: If you are treated with low dose rate brachytherapy, the seeds will give off low doses of radiation for weeks or months. Your doctor might recommend staying away from pregnant women and very young children during that time. You might also need a doctor’s note to travel since airport security systems can detect low levels of radiation.

There is a small chance that the seeds might move. Your doctor might ask you to strain your urine and wear a condom during sex. Speaking of sex, if you had no erection problems before brachytherapy treatment, the chances are good that will still be true afterward. Other types of prostate cancer treatment may affect this part of your life more than brachytherapy does.