Many patients with prostate cancer are eligible for a type of radiation therapy that kills cancer cells while leaving healthy cells essentially unharmed. Treatment sessions are quick, painless and result in minimal side effects for the vast majority of patients. Does this sound too good to be true? Think again.

Proton therapy is the most precise form of radiation therapy and one of the most advanced cancer treatment options — and it's been used to treat prostate cancer for many years. It's a highly targeted treatment that destroys cancer cells in the prostate while reducing the radiation exposure to the bladder, rectum and other gastrointestinal organs.

"Proton therapy allows us to reduce the radiation dose that normal, non-cancerous tissues are exposed to when compared to other forms of radiation," said Arun Goel, MD, a radiation oncologist at Penn Medicine.

Since 2010, the Roberts Proton Therapy Center at Penn's Abramson Cancer Center has treated thousands of patients using proton therapy, including those with prostate cancer.

How does proton therapy treat prostate cancer?

Proton therapy is a type of external beam therapeutic radiation. A beam of charged proton particles is generated by a large machine called a cyclotron and aimed at the prostate tumor. As the beam "deposits" its energy, it destroys the tumor cells.

"We're able to manipulate the energy and the direction of the beam to create a spread of radiation dose that matches the target we want to treat," said Dr. Goel. This accuracy sets proton therapy apart from other radiation techniques that may be used to target prostate cancer cells.

Benefits and side effects of proton radiation for prostate cancer

Studies show that proton therapy is successful in treating and managing prostate cancer. As with all prostate cancer treatments, how well proton therapy works depends on a number of factors, such as how advanced the cancer is and the combination of treatments that it may be used with. "The experts at our center focus on the nuances of a patient's case so that the patient leaves their consultation with a good understanding of the expected outcome," said Dr. Goel.

There are many benefits to proton therapy when treating prostate cancer. Treatments typically last five to ten minutes and are painless. Patients undergo between 28 to 44 treatments depending on the specifics of their case. And remarkably, most people do not experience side effects.

"Only 15 to 20 percent of patients will have a mild side effect that may warrant an over-the-counter or prescription medication to manage," said Dr. Goel.

Potential side effects of proton radiation for prostate cancer vary depending on the patient and may include increased frequency, urgency or discomfort with urination, or side effects affecting the bowel such as frequency, urgency or diarrhea. These side effects typically dissipate within one to two months after treatments are complete.

Am I a good candidate for prostate cancer proton therapy?

The severity of prostate cancer exists on a wide spectrum, and proton therapy can be used to treat patients regardless of where they fall within that spectrum. This includes situations where the cancer has spread from the prostate to the lymph nodes. Proton therapy for prostate cancer can be effective even if the patient has already had a prostatectomy, which is a partial or complete removal of the prostate.

Why choose the Roberts Proton Therapy Center?

Penn Medicine is home to one of the largest and most advanced proton therapy centers in the world: the Roberts Proton Therapy Center, part of Penn's Abramson Cancer Center. It is one of a few proton therapy centers internationally that is fully integrated with a comprehensive cancer center, so even if a patient is not a good candidate for proton therapy, they can receive other types of radiation therapy or cancer treatments for prostate cancer at the Abramson Cancer Center.

The Roberts Proton Therapy Center is the largest center in the world that integrates proton beam therapy with conventional radiation therapy. For patients with prostate cancer, their care is overseen by a team of professionals who specialize in treating and managing the care of patients receiving radiation therapy for prostate cancer. "There's a lot of experience and specialized care," said Dr. Goel

The future of proton therapy for prostate cancer

The use of proton therapy in treating prostate cancer is continuing to evolve at the Roberts Proton Therapy Center, where most patients are effectively treated in only 28 sessions rather than 44. The Center has also begun researching the effectiveness of combining proton therapy with other forms of radiation therapy.

"We're going to explore opportunities to decrease the number of treatments needed to safely and conveniently cure prostate cancer patients," said Dr. Goel.