Radiation Therapy for Prostate Cancer: How It Works, Side Effects, and Success Rates

There are many treatments for prostate cancer. Along with surgery, radiation therapy is a standard treatment for prostate cancer that hasn’t spread to other parts of your body. Radiation therapy may also be an option for people who have more advanced forms of prostate cancer.

To help you navigate the process, we’ll cover how radiation therapy works, and the different types used for prostate cancer. We’ll also look at possible side effects and how well radiation therapy works. Read on to see how radiation therapy might fit into your prostate cancer treatment. 

How does radiation therapy work for prostate cancer?

Radiation therapy uses X-rays, radioactive particles, or radioactive materials to treat cancer. It kills cancer cells by damaging their DNA, or genetic material. When the DNA is damaged, cancer cells can’t divide. If they try to divide, they die.

Radiation therapy can also affect healthy cells nearby. But new technology allows radiation oncologists to deliver radiation therapy with more precision. This helps lower the risk of damage to healthy tissue. 

What are the different types of radiation therapy?

There are many types of radiation therapy that can help treat prostate cancer. But not all treatments work for everyone. The right treatment depends on your specific situation. 

Here are some of the most commonly used radiation treatments for prostate cancer right now.

External beam radiation therapy (EBRT)

In external beam radiation therapy (EBRT), radiation therapy is delivered to the prostate gland from outside of your body. 

There are several types of EBRT, including:

• Intensity-modulated radiation therapy (IMRT): IMRT delivers high doses of radiation to cancer cells while minimizing harm to healthy cells

• Stereotactic body radiation therapy (SBRT): Compared with IMRT, SBRT delivers higher doses of radiation with high precision during each treatment session. Because of this, fewer treatment sessions are needed with SBRT. 

• Proton therapy: Proton therapy uses charged energy particles to treat cancer cells.

Before starting EBRT, radiation oncologists often place metallic markers in the prostate gland. This helps them aim the radiation with more precision. In some cases, a spacer is also placed between the prostate and rectum. This helps to prevent damage to the rectum.

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Brachytherapy

In brachytherapy, radiation therapy is delivered to the prostate cancer from inside your body. A radiation oncologist places radioactive material directly into the prostate gland. There are two main types of brachytherapy: 

• Low-dose rate (LDR) brachytherapy: The radioactive material stays in your body after treatment. 

• High-dose rate (HDR) brachytherapy: The radioactive material stays in your body for only a few minutes during each session and then removed.

Radiopharmaceuticals

Radiopharmaceuticals are medications that deliver radiation directly to cancer cells. 177Lu-PSMA-617 (Pluvicto) is a radiopharmaceutical that is FDA-approved to treat metastatic prostate cancer that no longer responds to hormone therapy (also called metastatic castration-resistant prostate cancer) and whose tumors have enough PSMA protein. 

Radium-223 (Xofigo) is another FDA-approved radiopharmaceutical that treats advanced prostate cancer that has spread to the bones. 

How effective is radiation therapy for prostate cancer?

Radiation therapy’s effectiveness depends on your situation. In general, radiation therapy is a very effective treatment for people with localized prostate cancer. In fact, radiation therapy and surgery have similar results.

A large clinical trial recently looked at different treatments for prostate cancer. People in the study were randomly assigned to surgery, radiation therapy, or active monitoring. After 10 years, survival rates were similar for all three groups. But people in the active monitoring group were more likely to have cancer spread to their bones. Among all groups, fewer than 1 in 50 people died from prostate cancer after 10 years.

After treatment, the healthcare team uses a blood test called prostate-specific antigen (PSA) to make sure people responded to treatment and look for signs that the cancer might come back. If the PSA starts to increase after treatment, it’s called “biochemical recurrence.” 

Studies have shown that the rate of biochemical recurrence is low after radiation therapy:

• Less than 10% for low-risk prostate cancer

• Between 10% and 15% for intermediate-risk prostate cancer

• Between 15% and 20% for high-risk prostate cancer

How many radiation therapy sessions does it take to treat prostate cancer?

There isn’t one standard course of prostate radiation therapy. 

But here’s what it might look like:

• Intensity modulated radiation (IMRT): People usually get treatment 5 days a week for 4 to 6 weeks. Each session lasts up to 30 minutes. 

• Stereotactic body radiation therapy (SBRT): Treatment may be given 3 to 5 times over 1 to 2 weeks. Some people need as few as 5 treatment sessions. Each session can last up to 1 hour.

Most of this time during these sessions is spent making sure your body is in the right position for treatment. The radiation beam is usually on for 3 to 5 minutes.

Brachytherapy usually takes just one or two sessions. Each session is done in an operating room under general anesthesia. Brachytherapy is usually an outpatient procedure, so you can go home the same day. The procedure usually takes 1 to 4 hours.

What are the side effects of prostate radiation therapy?

A radiation beam is invisible, and you won’t feel anything during treatment.

But during a course of prostate radiation, it’s common to have some side effects. These are usually mild, and severe side effects are rare. Common side effects include:

• Fatigue

• Frequent urination

• Burning with urination

• Weaker urinary stream

• Diarrhea

• Rectal irritation

• More frequent bowel movements

• Erectile dysfunction

• Lower sperm production

Some of these side effects happen right away. Others might not show up until after you’ve finished therapy. Some of these side effects will go away over time, but others may be long-lasting. 

It’s not always easy to predict who will have long-term side effects. But if they do happen, they’re usually manageable, and your care team can help.

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Written by:

David Marcus, MD

David Marcus, MD, is a board-certified radiation oncologist with expertise in the management of many types of cancer, including prostate cancer, breast cancer, and several others. He earned his medical degree at Emory University in Atlanta, Georgia, where he also completed residency training in radiation oncology.

Edited by:

Patricia Pinto-Garcia, MD, MPH

Patricia Pinto-Garcia, MD, MPH, is a medical editor at GoodRx. She is a licensed, board-certified pediatrician with more than a decade of experience in academic medicine.

Reviewed by:

Brandon R. Mancini, MD, MBA, FACRO

Brandon R. Mancini, MD, MBA, FACRO, serves as medical director at BAMF Health in Grand Rapids, Michigan in the emerging field of theranostics. His primary clinical focus is on the treatment of people with metastatic prostate and neuroendocrine cancers.

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