Proton Therapy: The New Weapon to Fight Cancer

Despite there being only 26 proton therapy centers in the United States, this precise radiation is providing many oncology patients with a new weapon in their fight. Primarily used in pediatric oncology for brain and central nervous system (CNS) tumors, solid tumors, such as Ewing’s sarcoma, may also benefit from proton therapy. The therapy has a wide range of uses in adults, including treatment of tumors in the CNS, head and neck, eye and orbit, abdomen, thorax, and pelvis, thus becoming a potential treatment option for many patients with cancers ranging from pancreatic to prostate, non—small cell lung to lymphoma, and more.

WHAT IS PROTON THERAPY?

Proton therapy, also called proton beam therapy, is a type of radiation therapy. Protons are positively charged particles and can be created and supercharged by separating hydrogen atoms. Therapy involves use of the ionization process and energy release at a specific point. According to the Proton Therapy Center, “The main benefit of the proton beam is the fact that the absolute greatest part of its energy is transferred to the area of the so-called Bragg peak (ie, directly to the tumor) where it has maximum destructive effect.”

HOW IS IT DIFFERENT FROM OTHER TYPES OF RADIATION THERAPY?

This type of treatment allows for precise delivery of radiation and energy release directly at the tumor site, allowing higher doses to be given without intense effects on surrounding tissue. Physicians can prescribe higher doses of radiation with less risk of injury to surrounding tissue because of the precision control that proton beam therapy offers. The protons come into the body at low energy, release almost all of that energy directly to the tumor, and then have little to no energy left, massively decreasing the exit dose of radiation that exists with traditional radiation treatment. This can not only reduce surrounding tissue injury, but can also decrease the number of long term adverse effects (AEs), which is especially important in pediatric cases where the tumor may be located in a sensitive area such as the brain.

WHAT ARE THE MOST COMMON AES?

Although proton therapy has less potential for AEs than traditional radiation therapy, due to its delivery method, it is still possible for the patient to experience any of the following:

• An increase in fatigue

• Skin breakdown and/or redness

• Hair loss at the site being treated

• Digestion issues, including oral ulcers or nausea

WHAT PATIENT EDUCATION IS NEEDED?

Instructing patients on the importance of arriving to their proton therapy appointment on time can ensure that the tight schedule of patients, providers, and radiation therapists moves forward as planned, allowing for discussion of AEs and progress. Encourage patients to keep the lines of communication open with their physicians and nurses regarding AEs they may be experiencing. Discuss particulars surrounding their specific treatment plan; for example, some treatments may require a full bladder or withholding food or fluids for sedation, if a pediatric case. Also, ensure proper hygiene is discussed. Daily bathing can prevent skin infections, especially when breakdown is a factor.

WHAT NURSING CARE IS REQUIRED POST TREATMENT?

Many pediatric patients require sedation in order to lie still enough for the proton therapy to be properly delivered to the desired site. In this case, close 1:1 monitoring of the patient’s vital signs and orientation are required until discharge. Sedation recovery is a great time to change dressings, assess central venous catheter line care needs, and treat skin issues, all while the child is sleeping.

Assessing for skin breakdown and redness immediately post treatment is important for patients of any age and can identify areas of concern that may need topical treatment, such as Medihoney or Aquaphor. Patients are typically seen daily for the desired length of treatment. Keeping track of symptoms consistently over time is crucial for early intervention. Asking the same set of daily questions related to fatigue, appetite, skin changes, and bowel/bladder habits can prove to be a useful tracking system for symptom management over the course of treatment.

WHERE CAN I LEARN MORE?

• Principles of proton therapy. Proton Therapy Center website www.proton-cancer-treatment.com/protontherapy/ principles-of-proton-therapy/

• How it works. The National Association for Proton Therapy website www.proton-therapy.org/howit.htm • What is proton therapy?

MD Anderson website www.mdanderson.org/

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