Proton therapy for prostate cancer is a newer type of radiation therapy that can kill cancer cells. Traditional radiation therapy uses X-rays, which can kill healthy cells. Some research suggests that proton therapy may more accurately target cancer, reducing damage to healthy cells.

Some research suggests that proton therapy may cause fewer side effects, potentially reducing the complications of prostate cancer treatment. However, researchers do not yet know the long-term effects of proton therapy, including whether the risks are higher or lower than traditional radiation therapy.

Proton therapy may also be more expensive than radiation therapy, and research does not show that it increases the chances of survival.

Prostate cancer has high survival rates with all available treatments, especially when a doctor diagnoses the disease early.

This article explains how proton therapy for prostate cancer works, including the procedure, benefits, and risks.

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Proton therapy is a type of radiation. Radiation uses energy to kill cancer cells. But radiation can also damage nearby cells, including healthy cells. This can cause a wide range of side effects and increase the long-term risk of developing other types of cancer.

Traditional radiation therapy uses X-rays to produce photons.

Proton therapy uses protons, a type of subatomic particle. Unlike X-rays, proton therapy causes less damage to surrounding tissue. This can reduce treatment side effects and damage to surrounding organs.

A 2020 study that looked at proton therapy as a treatment for a variety of metastasized cancers found significantly fewer side effects with this newer form of radiation. People did not live longer with proton therapy, but prostate cancer survival rates are already very high at 99% over 5 years.

What is prostate cancer?

Prostate cancer is cancer that begins in the prostate. The prostate is a walnut-sized gland. Situated below the bladder and in front of the rectum, it is a part of the male reproductive system that helps produce seminal fluid.

Prostate cancer is the most common form of cancer in males and the sixth leading cause of death.

Proton therapy delivers concentrated radiation to the tumor site. Radiation is a type of energy that can kill cells.

During treatment, a doctor or technician uses a device to concentrate the radiation and deliver it to the site of the cancer. A person has treatment in a hospital or treatment center, not at home. Unlike traditional radiation, proton therapy delivers almost all of its radiation to the cancer site, protecting nearby tissue.


Proton therapy is still a new treatment. Trials into its use for prostate cancer are ongoing. The stages and frequency of treatment depend on many different factors, including:

  • a person’s overall health
  • treatment goals
  • the stage of the cancer

For this reason, there is no standard course of treatment or standard progression of treatment stages. In many cases, though, a person will have proton therapy as part of a treatment course that includes prostatectomy, which is surgery to remove the prostate.

The main benefit of proton therapy for prostate cancer is that it may reduce side effects. In a 2020 study of people with locally advanced cancers — not just prostate cancer — researchers compared 391 people who underwent proton therapy to 1,092 who underwent photon therapy.

Over 90 days, proton therapy recipients had fewer side effects. Just 12% in the proton therapy group had side effects requiring hospitalization, compared with 28% in the photon therapy or traditional radiation group.

Proton therapy was also as effective as traditional radiation. This suggests that proton therapy may be a safer alternative to radiation, with fewer side effects. Proton therapy does not reduce testosterone levels, which may be important to males concerned about sexual functioning and hormone levels.

Proton therapy also reduces radiation to nearby organs, potentially reducing the risk of damage and subsequent cancers.

Proton therapy is a new treatment. Researchers do not yet know its long-term effects.

Additionally, proton therapy is more expensive than traditional treatments.

The research on proton therapy is also not conclusive. While most studies suggest a lower risk of side effects, the data on genitourinary and sexual side effects are contradictory and inconclusive.

Finally, there is no significant evidence to support the claim that people live longer or have higher cure rates with proton therapy. So for some people, the risks of more side effects may be worth it in return for saving money on treatment, especially when financial concerns increase the stress of prostate cancer.

Proton therapy is a promising new treatment for prostate cancer. For many people, the side effects of treatment are significant, potentially affecting their quality of life and long-term health. Proton therapy can reduce these side effects.

However, this is a novel and potentially expensive treatment, and researchers do not fully understand its long-term risks. People may need to seek care at specialized treatment facilities, and proton therapy may not be available to everyone.

People considering proton therapy should discuss the risks and benefits with an oncologist.