Radiation for prostate cancer: how it works, benefits, side effects

last updated: Nov 10, 2021

5 min read

The last thing you want to hear in a doctor’s office is the dreaded ‘C’ word: cancer. Your mind instantly flashes to the worst-case scenarios—understandably. If you or a loved one has been diagnosed with prostate cancer, the good news is there are effective treatments available, one of which is radiation. 

Radiation for prostate cancer is one of the most common options for treatment. 

Understanding how radiation therapy works, along with its risks and benefits, can help you and your healthcare provider when you’re making a plan to manage your condition.


Men’s healthcare, without the waiting room

What is radiation therapy for prostate cancer?

Radiation therapy uses high-energy rays to destroy cancer cells, and it’s highly effective at treating prostate cancer. Prostate cancer is the most commonly diagnosed cancer in males. Fortunately, it’s also usually slow-growing and highly treatable. If your cancer is limited to just your prostate, it’s called “localized prostate cancer,” and it’s potentially curable (Leslie, 2021).

Even if your cancer has spread to other areas of the body, there are still prostate cancer treatments available, one of which is radiation therapy (Gay, 2018).

Radiation therapy can be provided on its own or in combination with surgery or hormone therapy. The benefits of radiation for prostate cancer are that it offers similar success rates to radical prostatectomy surgery (a procedure in which the entire prostate is removed) but with fewer long-term sexual side effects and little risk of urinary incontinence. This can be important for your quality of life after treatment (Gay, 2018).

Radiation therapy can help control any stray cancer cells that may have been missed if you have your prostate gland removed. This can prevent them from traveling to other areas of your body and forming new tumors (called metastases) (Leslie, 2021).

Your provider might also recommend radiation treatment if an enzyme in your blood called the prostate-specific antigen (PSA) starts to rise. This can indicate that there might still be prostate cancer cells in your body that weren’t detected before (Leslie, 2021).

4 types of radiation treatment options for prostate cancer

There are several different types of radiation therapy available to treat prostate cancer. Your provider can help you choose the type of treatment to manage your symptoms best.  

1. External beam radiation therapy

External beam radiation therapy (EBRT) is the most common form of radiotherapy. During treatment, the participant sits or lies on a couch, and an external radiation source is pointed at the part of the body to be treated. The exact area to be treated is calculated using special imaging techniques and can include both the tumor and nearby lymph nodes (Leslie, 2021).

Radiation oncologists often use subtypes of EBRT called intensity-modulated radiation therapy (IMRT) and image-guided radiation therapy (IGRT) to get larger doses of radiation to the tumor while sparing the surrounding tissues. This can help reduce side effects (Leslie, 2021; Rosario, 2021).

Androgen deprivation therapy for six months to three years is often used in combination with external radiation. This can improve your outcome, especially if you have intermediate-risk or high-risk disease. Researchers think that hormone therapy can make cancer cells even more sensitive to radiation, increasing success rates (Leslie, 2021; Rosario, 2021).

External beam radiation therapy usually consists of daily exposures (5 days a week) for up to 8 weeks (Leslie, 2021).

2. Stereotactic body radiation therapy

Stereotactic body radiation therapy (SBRT), also called Stereotactic Ablative Radiation Therapy, is a very precise method for delivering ultra-high doses of radiation to your prostate. SBRT requires just five treatments over the course of one to two weeks (Gay, 2018). Providers aren’t as sure about which patients are good candidates for SBRT as they are for other types of radiation for prostate cancer. They do know that it doesn’t work as well for men with very large prostates or who have had surgery on the urethra (Leslie, 2021). 

3. Brachytherapy

Another type of radiation therapy frequently used for prostate cancer is called brachytherapy. This involves surgically implanting 75 to 125 tiny radioactive seeds directly into your prostate. That may sound frightening, but it allows higher doses of radiation to be delivered to the prostate without exposing nearby organs (Leslie, 2021; Mayer, 2021).

Many men undergo hormone therapy first to shrink the size of their prostate before using brachytherapy. This internal radiation therapy has been shown to improve the therapy outcome, so it’s a standard recommendation from oncologists (Leslie, 2021).

Brachytherapy can be divided into low-dose rate (LDR) and high-dose rate (HDR) therapy. In low-dose brachytherapy, the seeds release their radiation over a few months and then remain in the prostate permanently. In high-dose treatment, a radioactive source is delivered into the prostate during a single visit to the hospital and then removed. This is often combined with other types of radiation therapy (Rosario, 2021).

4. Proton beam radiation therapy

Proton beam therapy (PBT) is a type of radiation therapy that uses protons to deliver the treatment instead of light particles (photons) like external beam therapy. The protons travel through your tissue until they reach a specific depth, and then they release their energy (Gay, 2018). 

The unique properties of protons give oncologists the ability to target the tumor with high doses of radiation while sparing the surrounding healthy tissues and organs. Theoretically, this should lead to fewer side effects (Wisenbaugh, 2014). 

Unfortunately, there aren't any randomized clinical trials that directly compare all of the different types of radiation treatment against each other. So researchers have to use the data from studies looking at each type individually (Wisenbaugh, 2014).

Side effects of radiation for prostate cancer

All medical treatments carry a risk of possible side effects. Your healthcare provider can help you minimize these risks and manage any symptoms that come up.

Some of the more common side effects of radiation therapy include (Leslie, 2021; Mullangi, 2021):

  • Inflammation of the bladder (radiation cystitis)

  • Inflammation of the intestines (radiation proctitis)

  • Blood in your urine

  • Fatigue

  • Greater risk of bone fractures

  • Skin rash

  • Other types of cancer (very rare)

Erectile dysfunction is another relatively common complication of radiation treatment for prostate cancer. Problems with sexual function have been reported in about 30–40% of men who had regular erectile function before being treated (Leslie, 2021).

If you choose to use brachytherapy to treat your cancer, you should know that smoking cigarettes can increase your risk of side effects and decrease how well the treatment works. Also, if any of the implanted radiation sources become dislodged, you must place it into a lead container and keep other people away from it. This will prevent other people from being contaminated by the radiation  (Mayer, 2021).

What is the success rate of radiation treatment for prostate cancer?

Your healthcare provider can give you the most detailed prognosis for your unique condition. There are a lot of factors that go into predicting how well radiation for prostate cancer will help your condition. In general, your prognosis will depend on (Leslie, 2021):

  • Your age

  • Other health conditions you have

  • How far the cancer cells have spread in your body

  • How well you tolerate treatment

The earlier that your prostate cancer is discovered, the more likely it can be successfully treated. However, even if your prostate cancer is advanced when it is found, there are still treatments that can help you live longer and control your symptoms.

The best available data shows that there is no significant advantage of one type of radiation for prostate cancer over another. So your healthcare provider can help you choose a treatment based on your unique condition (Leslie, 2021).


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

November 10, 2021

Written by

Ellyn Vohnoutka, BSN, RN

Fact checked by

Steve Silvestro, MD

About the medical reviewer

Dr. Steve Silvestro is a board-certified pediatrician and Associate Director, Clinical Content & Education at Ro.