Proton therapy, a form of radiation therapy without many of the short- and long-term side effects, is an advanced cancer treatment for specific types of tumors.

Studies have shown proton therapy to be effective in treating brain, head and neck, pediatric, colorectal and prostate tumors as well as cancers that cannot be removed completely by surgery. Research is showing promising results in the treatment of some breast and lung tumors. Proton therapy is particularly appropriate for treating tumors in children, who can experience serious short-term and long-term side effects from radiation treatments.

Like traditional radiation therapy (which uses photons, or X-rays), proton therapy kills cancer cells by preventing them from dividing and growing. The difference is that in traditional radiation therapy, the X-ray beam spreads radiation to healthy tissue as it travels through the patient's body on its way to (and beyond) the tumor. Proton therapy can be precisely targeted to the tumor, allowing patients to receive higher, more effective doses, and greatly reducing damage to healthy tissue near the tumor. Research shows proton therapy causes fewer side effects than traditional radiation therapy, reduces the chances of secondary tumors and improves patients’ quality of life.

Protons are large particles that can be manipulated to release their energy. The more energy, the deeper the protons can penetrate into the body. Doctors can calculate the precise amount of proton energy needed to release the radiation exactly at the tumor site. The peak of this proton radiation dose (called the Bragg Peak) is set so it releases the radiation when it hits the tumor; immediately after that point, the radiation dose falls to zero. Less of the radiation reaches the healthy tissue in front of the tumor, and almost none of it reaches the healthy tissue behind the tumor. That results in much less damage to healthy tissue and, therefore, fewer short-term and long-term side effects. It also means that a higher dose often can be delivered, leading to more effective treatment.

Proton therapy is most effective on solid tumors that are well-defined and localized, such as those found in the head, brain, neck and prostate. If the tumor has spread (metastasized), a combination of therapies (chemotherapy, traditional radiation and proton therapy) might be a better option to make sure the less-defined tumors are also destroyed.

Yes. Children with a need for radiation therapy can benefit tremendously from proton therapy. Because their bodies are still growing, traditional radiation can be very harmful to children, causing serious growth problems and other complications. In addition, the traditional radiation may cause new tumors to develop at any time throughout the child’s life.

Because of the limited number of proton treatment facilities worldwide, physicians have focused on using the therapy for only a small number of diagnoses that have had positive outcomes, especially in children and for tumors near critical organs. Treatment protocols will continue to expand as more treatment centers become involved in clinical research.

X-rays and protons can be equally effective in destroying cancerous tumors. The difference is that X-ray treatments damage or destroy some healthy tissue in the process of irradiating cancerous tumors. X-rays release much of their energy quickly after penetrating the skin, damaging healthy tissue and organs on their way to the tumor and, again, as they leave the body. Protons can be precisely directed to release most of their energy only when they reach the tumor. Unlike X-rays, which pass completely through the body, protons speed directly to the tumor site and stop there so healthy tissue in front of and behind the tumor is spared.

Yes. Proton therapy has been used in combination with traditional radiation treatment or chemotherapy, and after surgery as a follow-up treatment. Your doctor can help you determine the best treatment option.

Yes. Proton therapy can be used to treat recurrent cancers while standard radiation therapy cannot.

Proton therapy is non-invasive (which means it does not require an injection or involve tools that enter the body), painless, typically takes about 15 to 20 minutes per session and can be performed without an overnight stay in the hospital. Treatments are usually given five days a week, for a period of four to eight weeks. The actual treatment lasts about one minute, but each session can range from 15 to 30 minutes due to time spent positioning the patient for this precise treatment.

Once physicians determine a patient is a candidate for proton therapy, there are several general steps in the process. The following example illustrates the steps for a treatment that would require a patient to lie down (e.g. prostate cancer):

Pre-treatment stage
First, the patient is fitted with a whole-body mold (sometimes called a pod) that he will lie in during treatment to make sure he will be in exactly the same position for each session. Next, a CT scan (multiple X-rays of the body) is taken to give the physician and specialists (medical physicist, dosimetrist) more information about the patient’s body structure and tissue. The treatment team then studies the patient information to determine the best treatment plan.

Treatment stage

After equipment settings are precisely determined and tested for the patient, radiation therapists perform a simulation, or “practice run,” with the patient to make sure the patient information exactly matches the images created in the pre-treatment phase. The proton treatment is delivered in a “gantry” room. A gantry is a large, three-story wheel that rotates 360 degrees around the patient lying in his pod to deliver the proton beam with the utmost precision. The beam may be used several times during the procedure, but the patient feels nothing.

No, treatment is quick and painless. The life of proton radiation in the body is very short and allows the patient to leave the treatment room immediately after treatment. Most patients are able to resume normal daily activities.

It depends on a patient’s condition, age and medical history. Some patients experience minor side effects such as tiredness, skin irritation or slight hair loss. Most patients report no side effects at all.

Proton therapy has been offered for more than 50 years and is not considered experimental. About 55,000 people worldwide have received proton therapy at centers in Europe, Asia and the United States. It was first used to treat patients in 1955 in a research setting, but its use was limited because diagnostic imaging techniques could not accurately pinpoint tumors. Following advances made in imaging technology such as CT, MRI, and PET scans, the first hospital-based proton treatment center opened in California in 1990 at Loma Linda University Medical Center. Since then, nearly 15,000 people have received proton therapy in the United States.

Proton therapy was first used to treat patients in 1955 in a research setting, but its use was limited because diagnostic imaging techniques could not accurately pinpoint tumors. Following advances made in imaging technology such as CT, MRI, and PET scans, the first hospital-based proton treatment center opened in California in 1990 at Loma Linda University Medical Center.

Since the first hospital-based proton treatment center opened in California in 1990, nearly 15,000 people have received proton therapy in the United States, and about 55,000 people worldwide.

Of the 1.4 million people diagnosed with cancer every year in the United States, close to 60 percent (840,000) get treated with radiation. Experts estimate that approximately 30 percent (250,000) of those cancer patients could benefit from proton therapy, yet there is only capacity to treat about 6,000 patients per year in centers in the United States at this time.

Advances and improvements in proton therapy and diagnostic imaging technology have made it an important option in the treatment of cancer.  Most existing facilities have waiting lists, however, and in many cases, patients are forced to choose other forms of treatment because of the limited number of proton treatment slots.

Building a proton center is costly and time intensive. Most proton therapy centers cost around $150 million to build (primarily due to high equipment costs), and take more than two years to complete. Currently, the ProCure Proton Therapy Center in Oklahoma City is on record-breaking pace to open in 27 months from groundbreaking.

The effectiveness of proton therapy has been studied by physicians and physicists around the world and research continues. To see a bibliography of studies, click here.

Studies are currently under way to determine the best proton dosages for specific cancers, including prostate and brain cancer, and to investigate the use of protons in treating various types of cancer, including lung, breast and pancreatic cancers.

Proton therapy is not always the most appropriate cancer treatment. Learn as much as possible about proton therapy in relation to you or your loved one’s condition before you make any decisions. Discuss all of your options with your doctor to see if proton therapy is the best choice.

As with most cancer cases, long-term success means there are no signs of cancer coming back after treatment has been completed. Most patients are monitored by their doctors for at least five years.

Treatment with protons is currently more expensive than traditional X-ray radiation therapy. However, because patients experience fewer long- and short-term side effects and have fewer hospital stays after receiving proton therapy, total costs can be less in the long run. Proton therapy is covered by more than 180 insurance companies and Medicare, and by many Medicaid programs.

If we can give cancer patients better treatment, we should. Curing cancer patients more quickly with reduced side effects can be less expensive in the long-run than having patients with long-term side effects or reoccurring cancer.

It is approved and covered by Medicare, many Medicaid programs and more than 180 private insurance carriers.

Currently, there are five proton therapy treatment centers in the United States. They are located at: Indiana University in Bloomington; Loma Linda University Medical Center in Loma Linda, Calif.; Massachusetts General Hospital in Boston (affiliated with Harvard Medical School); M.D. Anderson Cancer Treatment Center in Houston and the University of Florida in Jacksonville.

Several more treatment centers are currently under construction in the United States including:

• In Philadelphia, the University of Pennsylvania Health System plans to open the Roberts Proton Therapy Center in 2009;
• In Oklahoma City, the ProCure Proton Therapy Center is scheduled to open in 2009;
• In Hampton, Va., Hampton University plans to open a proton therapy center in 2010.
• In Chicago, the ProCure Proton Therapy Center of Central DuPage Hospital is scheduled to open in early 2011.

A number of other hospitals and academic institutions have announced plans for proton therapy centers. Some are projected to open as early as 2011.

Yes, absolutely. The radiation in a proton center is electronically “turned on” when the proton beam is created.  The radiation travels with the beam to the patient where it targets and kills the cancer cells.  When the proton beam is turned off, the radiation disappears instantly.

Yes, it is very safe. We have more than 50 years experience operating proton centers and they have a demonstrated record of safe operations in the U.S. and abroad. They are so safe that Massachusetts General Hospital built its center in downtown Boston; and the proton center at the University of Florida is on the hospital campus right next to an apartment complex.

A proton treatment system does not produce radiation beyond that which is delivered to the patient’s tumor to kill the cancer cells. That happens in treatment rooms where there is significant structural shielding and controls in place to ensure that people working inside the facility, patients and people outside the facility are safe. When the beam is turned off, the radiation disappears instantly. 

Proton centers do not have any type of portable or unsealed radioactive material and there is no “loose” radiation – meaning that nothing can spread or become a contamination hazard inside or in the vicinity of the proton center.

Absolutely. We have more than 50 years experience operating proton centers and they have a demonstrated safety record. Staff are well trained and there are monitoring devices in place to ensure that there are no safety concerns.  The radiation exposure that personnel are exposed to is very low.  In fact, the exposure rates inside the clinic are often lower than the amount of radiation you receive outside, simply by being out in the sun.

Any radiation oncologist can be trained to administer proton therapy. Currently, the ProCure Training and Development Center (TDC), located in Bloomington, Ind., is the first and only facility in the world dedicated to proton therapy training. It offers clinical, technical, interpersonal and administrative training that pertains to all aspects of proton therapy treatment.