Radiation therapy can be an effective treatment for prostate cancer. It can shrink a tumor, relieve symptoms, and delay or halt the growth of cancer cells.

A therapist may target a tumor with an intense beam of radiation from an external machine, or they may implant or inject radioactive materials into the body.

Radiation treatment has benefits, but it can also have risks and side effects.

Learn more about what radiation therapy means for someone who is undergoing treatment for prostate cancer.

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Radiation works by disrupting the DNA in cancer cells so that they are unable to continue multiplying.

The radiation particles can disrupt the DNA in cancer cells. This disruption stops the cells from multiplying and can also kill them.

In some cases, radiation can remove all traces of cancer and is then known as a curative treatment. A doctor may use radiation alone or alongside other treatments.

If it is not possible to eliminate prostate cancer completely, radiation therapy can help control it.

It can also relieve symptoms in the later stages of the disease when it is called metastatic prostate cancer. Doctors then refer to this as palliative treatment.

Prostate cancer is a common type of cancer that affects men. Learn more here.

Several types of radiation treatment are possible for prostate cancer.

These include:

  • external beam radiation
  • internal radiation
  • systemic radiation

External beam radiation

In external beam radiation therapy (EBRT), a large machine will direct X-ray beams onto the prostate gland from outside of the body.

The medical team will prepare for the therapy by:

  • taking measurements and marking the treatment area
  • using MRI or CT scans to identify the target area
  • calculating the correct dose to use

Several sessions are necessary because the body can only tolerate small amounts of radiation at one time. Spreading delivery over several sessions reduces the risk of adverse effects.

There are several ways to deliver EBRT:

Conventional therapy: A person receives 35–45 doses over 7–9 weeks, from Monday to Friday. This allows a 2-day recovery period each week.

Moderate hypofraction: The dose is higher, and there are fewer sessions. The person may have to attend only 20 sessions over 4 weeks for the same benefit.

Ultra-hypofraction: The person receives high doses over five sessions. For some people, this can mean more rapid treatment with fewer side effects. It can be as effective as having lower doses over a longer period, but it may not suit everyone. It is also called stereotactic body radiation therapy (SBRT).

Three-dimensional conformal radiation therapy (3D–CRT): Special computers provide an exact image of the prostate gland. They also shape the beams so that they only affect the area that needs treatment. This can reduce the risk to surrounding tissues.

Intensity modulated radiation therapy (IMRT): In this more advanced version of 3D–CRT, a computer-driven machine moves around the person during treatment. It adjusts both the shape of the beams and their intensity. This makes it possible to deliver a higher dose without increasing the risk to healthy tissues.

Volumetric modulated arc therapy (VMAT): This version of IMRT delivers treatment rapidly so that each session is shorter. It is not clear whether it has additional benefits, apart from saving time.

Proton beam radiation therapy: Proton therapy delivers beams of protons instead of radiation. In theory, it causes less damage to healthy tissues. However, this treatment is expensive and not widely available. It is not yet clear whether it is more effective than radiation therapy.

Internal radiation

Internal radiation therapy (IRT), or brachytherapy, involves placing radioactive pellets inside the body, on the prostate gland. The pellets are around the size of a grain of rice, according to the American Cancer Society.

The implant may be temporary or permanent:

Temporary: The doctor inserts the pellets for a short time. This can vary from a few minutes to 2 days.

Permanent: The doctor will remove the pellets only when they are no longer radioactive.

Before inserting the pellet, the doctor will give the patient either a general or local anesthetic. Imaging technology ensures they position the pellet accurately.

Systemic radiation

In systematic radiation therapy, a doctor gives the person a liquid composed of radioactive substances, either by mouth or injected into a vein. The liquid will move around the body, through the blood, to the cancer site.

Combining treatment

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A doctor can advise on the best course of radiation therapy.

Sometimes, a doctor will recommend more than one type of radiation therapy. They may combine internal and external radiation therapy, or they may change the method if one approach has not been effective.

Another option is to combine radiation therapy and chemotherapy. Chemotherapy can make cancer cells more receptive to radiation. Combining the two may lead to better results.

Learn more here about chemotherapy.

Surgery may help in the early stages when cancer has not spread beyond the prostate. If it has spread to other tissues, the risks often exceed the benefits.

Sometimes, a doctor will recommend both radiation therapy and surgery.

What does surgery for prostate cancer involve? Find out here.

Other options

Other treatments options include high-intensity focus ultrasound (HIFU) and hormone treatment.

Learn more about the stages of prostate cancer and the outlook.

Radiation therapy can have some adverse effects.

Damage to healthy cells

Radiation therapy kills cancer cells, but it can also damage healthy cells.

However, unlike cancer cells, healthy cells can often repair themselves after treatment. This means that most of the adverse effects will be short term; they will go away after treatment finishes.

Bowel and bladder problems

Radiation therapy for prostate cancer can irritate the bowel, the bladder, or both.

A person can develop:

Radiation proctitis: Symptoms include diarrhea and blood in the stool.

Radiation cystitis: Symptoms include a need to urinate more often, a burning sensation when urinating, and blood in the urine.

Bladder problems may improve after treatment, but they may not go away completely.

Erectile dysfunction

Problems with achieving an erection may not appear at once, but they can develop over time, especially in older people. Medication may help.


Damage to the lymph nodes can cause fluid to build up over time in the genital area or the legs. An individual may notice swelling and pain. Symptoms may improve after treatment finishes, but they might not go away completely.

Other effects

Radiation therapy can cause a person to feel generally unwell.

They may experience:

  • skin soreness and sensitivity
  • physical fatigue
  • nausea
  • a loss of appetite
  • a sore mouth

Rest can help conserve energy and ensure that the body and mind can continue with the course of treatment.

Cancer and its treatment can be emotionally draining. A doctor may be able to recommend a counselor who can help.

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There is a risk that radiation therapy may lead to another type of cancer later on.

High doses of radiation can lead to long term, irreversible side effects. In some cases, radiation may lead to another type of cancer later on. The doctor will consider this possibility when they recommend treatment options.

If prostate cancer returns after a person has previously had radiation therapy, the doctor may not recommend it again. Doing so may expose the body to more radiation than it can safely withstand.

A person who has internal radiation treatment may give off a small amount of radioactivity afterward. The doctor may recommend staying away from pregnant women and young children for a while.

Pregnancy and fertility

Doctors do not advise having radiation therapy during pregnancy, as it may harm the unborn child. Anyone who becomes pregnant during treatment should tell their doctor at once.

Experts do not yet know how radiation therapy affects a man’s sperm, or if it causes damage if a child is conceived during treatment. However, they recommend using birth control to prevent pregnancy during the treatment time and for some weeks after, as a precaution.

A doctor will only recommend radiation treatment for prostate cancer if they believe the benefits outweigh any risks and side effects.

Anyone with prostate cancer should speak to their doctor about the available treatment options and the possible adverse effects. The individual should decide with their doctor what the best treatment course is for them.