Proton Therapy

Proton therapy — also called proton treatment therapy or proton beam therapy — is a very precise type of external beam radiation therapy. Protons are particles that kill cancer cells. With proton therapy, a machine called a cyclotron sends positively charged, high-energy particles (proton beams) to destroy tumors.

This treatment is an option when a cancerous tumor is close to critical or sensitive areas of your body, like your:

• Brain
• Eye
• Liver
• Lung
• Prostate
• Spinal cord

It’s also a treatment for several childhood cancers. Radiation therapy for cancer may affect how your child’s body develops. They may have health issues that develop years after treatment ends. Proton therapy reduces that risk.

Proton therapy is specialized cancer treatment. Researchers continue to evaluate situations where proton therapy is appropriate.

Benefits and risks

One main benefit is that proton therapy limits the amount of radiation that passes through healthy tissues. Your healthcare provider may call this the exit dose. A small exit dose causes less damage to healthy tissue.

Proton therapy may:

• Deliver higher doses: Providers may use higher doses since proton therapy directly hits tumors.
• Limit side effects: Less exposure to radiation means fewer or less severe side effects.
• Reduce second cancer risk: You may avoid a new cancer after completing treatment.
• Treat recurrent cancer: Cancer can come back after treatment. Proton therapy may be a follow-up treatment.

Proton therapy may still cause side effects, like fatigue and skin changes. Specific side effects vary depending on the type of cancer. For example, proton therapy for brain cancer may cause headaches or memory loss.

Your healthcare provider will discuss possible side effects and offer ways to manage them.

What happens during proton therapy?

Proton therapy begins with a planning session. Your care team will explain what happens during treatment.

You’ll receive proton therapy in a special treatment room. Here’s what you may expect:

1. You’ll get into position for treatment.
2. Your care team will do imaging scans. The scans help them direct the radiation beams.
3. Your team will leave the treatment room. But they’ll be able to see and hear you.
4. A device attached to a mechanical arm called a gantry delivers the protons. The gantry will rotate around the table or chair to deliver treatment from the best possible angles.

A proton therapy session may take about 30 minutes to complete.

How long will I need this treatment?

You may have daily sessions over several weeks. Your treatment depends on the type of cancer, the tumor size and how well proton therapy works to destroy the tumor.

How long will it take for me to feel better?

It may take a few weeks to recover from proton therapy. Your healthcare provider will review your recovery timeline with you.

Is there anything I can do to make this treatment easier on me?

Ask your healthcare provider about cancer rehabilitation, which includes services to help you prepare for cancer treatment. For example, a physical therapist may suggest activities to boost your strength before you start radiation therapy. Palliative care is another option. This specialized form of care helps you manage disease symptoms and treatment side effects.

What’s the difference between proton therapy and photon therapy?

The difference is in the delivery. Photon (traditional radiation) therapy moves through your body. It hits the tumor. But it also hits healthy tissue as it moves through your body. Proton therapy stops delivering radiation as soon as it reaches the tumor.

What’s the success rate of proton therapy?

Proton therapy is a treatment for several kinds of cancer, so there’s no single success rate. But some studies look at survival rates for specific types of cancer. For example, one study compared treatments for children with neuroblastoma. Children who had proton therapy had a higher two-year survival rate compared with children who had photon radiotherapy.