Stereotactic body radiotherapy (SBRT) for prostate cancer delivers focused radiation in fewer sessions. Find out how it works and compare its effectiveness and side effects.

If you have cancer that is only in the prostate, your healthcare team may offer several treatment options. Choosing a treatment can feel overwhelming. There are many treatment options to consider and compare.

One newer option is stereotactic body radiotherapy (SBRT), which is a kind of radiation therapy. SBRT for prostate cancer uses highly focused beams of energy that deliver stronger doses of radiation to the prostate than other types of radiation therapy. It's a noninvasive treatment that can often be completed in about two weeks.

If you're considering SBRT for prostate cancer, here's what to know about its benefits and side effects and how it compares to other treatments. Use this information to help you feel more comfortable talking about your treatment options with your healthcare team.

SBRT for prostate cancer works in the same way as other types of radiation therapy. It aims beams of radiation at the prostate. The radiation damages the DNA inside the cancer cells, causing the cells to die over time. Most SBRT treatments use the energy from X-rays, also called photons. Some medical centers offer SBRT using protons, which uses the energy from positively charged particles.

What makes SBRT different is how the radiation is delivered. It uses many radiation beams aimed at the prostate from different angles. The place where the beams meet gets a large dose of radiation. Nearby healthy tissue is less likely to be hurt by the radiation.

SBRT uses advanced technology to carefully plan, shape and deliver the radiation beams. This precise targeting lets healthcare teams give higher doses of radiation in each treatment session, so fewer treatments are needed. For prostate cancer that is only in the prostate, treatment typically takes about two weeks.

SBRT for prostate cancer also is called stereotactic ablative radiotherapy and ultrahypofractionated radiation therapy. Sometimes it's called by the name of the machine that gives the radiation, such as CyberKnife, TrueBeam and other brand names.

SBRT is one treatment option for cancer that's only in the prostate. This cancer also is called localized prostate cancer and early-stage prostate cancer. SBRT also can help treat prostate cancer that comes back after treatment, called prostate cancer recurrence. And it can help treat cancer that spreads, called metastatic prostate cancer.

During SBRT for prostate cancer, you lie on a table in a treatment room. A machine moves around you and gives the radiation from different angles. Each session may take an hour or more. Some of that time is spent preparing. Your healthcare team may use cushions to position you. You might have imaging tests to make sure you're in the right position for treatment.

SBRT for early-stage prostate cancer often takes five treatment sessions over two weeks. Your schedule may vary depending on your treatment plan.

SBRT typically doesn't cause pain or other side effects during a treatment session. You don't feel the radiation going into your body. You might feel discomfort from having to lie still during the treatment. Your care team can see and hear you, so tell them if you're not comfortable.

Side effects of SBRT for prostate cancer may include:

  • More frequent urination.
  • Feeling an urgent need to urinate.
  • Difficulty emptying the bladder completely when urinating.
  • Weaker stream when urinating.
  • More frequent bowel movements.

Symptoms often are mild and may be managed with medicines or other treatments.

SBRT is a highly effective treatment for early-stage prostate cancer. Studies show that about 95% of men stay free of cancer at least five years after treatment. SBRT is especially effective for those who have a low or intermediate risk that the cancer will spread.

SBRT is one of many treatment options for cancer that's only in the prostate. Other treatments might include surgery to remove the prostate, called prostatectomy, and other kinds of radiation therapy. As you and your healthcare team talk about your treatment options, here are some things to consider:

SBRT compared with surgery. SBRT doesn't involve surgery, as prostatectomy does. Recovering from surgery can take a few weeks or more. Surgery is more likely to cause loss of bladder control and erectile dysfunction. SBRT and other forms of radiation are more likely to cause bowel symptoms.

Few studies have compared SBRT and surgery. In general, studies show surgery and radiation therapy have similar long-term success rates.

SBRT compared with IMRT. Intensity-modulated radiation therapy (IMRT) is a way of doing radiation therapy that carefully shapes the energy beams to match the shape of the cancer. It's typically given in daily treatments over several weeks. This longer treatment schedule may interfere with work or other commitments.

Compared with doing radiation treatments in smaller doses over a longer period of time, such as with IMRT, SBRT is slightly more likely to cause urinary and bowel side effects during and soon after treatment. But these usually get better. Two years after treatment, side effects are about the same.

Studies show IMRT and SBRT have similar success rates.

SBRT compared with proton therapy. Proton therapy is a radiation treatment that uses energy from positively charged particles, called protons. It's typically given in daily treatments over several weeks. Some medical centers also offer SBRT using proton therapy. Proton therapy isn't available at all medical centers, so it may require traveling farther from home.

The energy from protons allows healthcare professionals to better control where the radiation goes. In theory, this should lead to fewer side effects. But research on this has had mixed results. The side effects from proton therapy are about the same as with other kinds of radiation therapy.

Proton therapy and other forms of radiation therapy are thought to have similar success rates.

If you're interested in SBRT for prostate cancer treatment, talk with your healthcare team. They can explain whether you're a good candidate and review the possible benefits and disadvantages. Together, you can consider whether SBRT fits with your treatment goals.

You might consider SBRT if:

  • You have good bowel, bladder and sexual function.
  • You prefer to avoid surgery.
  • You want to finish treatment in less time.

More people with early-stage prostate cancer are choosing SBRT for its convenience. Early research shows that it works as well as other radiation treatments. More research is needed to confirm that these results hold up over time, but current findings are encouraging.

Dec. 12, 2025