Patients may have more power than they think when it comes to cancer treatment options. A breakthrough clinical trial studying the side effects and outcomes of proton therapy and photon therapy in non-metastatic breast cancer patients is ongoing until November 2022. Sponsored by the Abramson Cancer Center at Penn Medicine, the Radiotherapy Comparative Effectiveness (RadComp) research study intends on drawing in 1,278 patients and is patient-powered.
How The Proton Therapy vs. Photon Therapy Trial Can Help Breast Cancer Patients and Their Doctors
For many patients with breast cancer, radiation therapy is a life-saving treatment option. However, the benefits of one type of radiation over another are not always clear. The goal of the RadComp clinical trial is to help patients and their doctors make better informed decisions about which radiation treatment may be best for them. The trial will measure the effectiveness of proton therapy versus photon therapy over the time frame of 10 years.
The trial is being conducted like a coin flip. If a patient decides to take part in this study, then they will be randomly assigned to one of two treatment groups: photon therapy or proton therapy.
What Is the Difference Between Proton and Photon Therapy?
Recently, there have been several advances in radiation therapy including conventional therapy, 3D therapy, IMRT, and beyond. While photon therapy is the most common type of radiation treatment for cancer, proton therapy is a more recent advancement.
The main difference between photon therapy and proton therapy has to do with their makeup and how they are used. Photons are bundles of electromagnetic energy. They are a basic unit of nature that makes up all light. Like light, photons do not have physical mass, so they can pass through the body and not stop inside the tumor.
Photon beam therapy is the standard radiation treatment worldwide. It uses x-rays or gamma rays that come from a special machine called a linear accelerator (LINAC) to eradicate cancer cells. The radiation dose is delivered at the surface of the body and goes into the tumor and through the body.
Proton therapy, on the other hand, uses protons to destroy cancer cells. Protons are positively charged subatomic particles found in the nuclei of all atoms. Protons have physical mass and can be stopped before they hit certain tissues and organs. For this reason, proton therapy is considered more targeted.
Benefits of Proton Therapy for Patients with Breast Cancer
"There are possible advantages with protons in beam shaping and reduced scatter to heart or lung due to the different physics properties," explains Gary Freedman, MD, radiation oncologist at Penn Medicine, and one of the researchers for the RadComp clinical trial.
With proton therapy, up to 60 percent less radiation can be delivered to the healthy tissues around the tumor. For this reason, doctors and researchers suspect proton therapy may offer more benefits to breast cancer patients, such as improving outcomes, fewer side effects, the ability to treat cancerous tumors close to the critical organs such as the heart or lung, and a greater quality of life during treatment.
However, not enough breast cancer patients have received proton therapy to know if proton therapy is better than other treatments or not.
"Protons are currently under active investigation on whether it can improve these endpoints measurably for the average woman and not just special challenging cases," said Dr. Freedman. "There are no clinical data yet to show reduced long-term complications or better outcomes - there could be unforeseen downsides too."
Who is a Good Candidate for Proton Therapy or Photon Therapy?
Although radiation for breast cancer is a life-saving treatment, it also poses its challenges. Radiation can increase the risk of developing heart problems. According to the study, certain criteria have to be met to be considered eligible to participate in the RadComp clinical trial. Patients must be 21 years or older, have been diagnosed with non-metastatic breast cancer, and will be having radiation therapy.
Empowering Breast Cancer Patients
The RadComp trial is meant to shed light on the effectiveness of proton versus photon therapy and how treatment affects someone's quality of life, including any financial burden, mental health, and other factors. The objectives were designed by breast cancer patients and for breast cancer patients with the mission of empowering patients to be their own health advocates.
"If the study is positive, showing improvements in these endpoints with protons, it could change national practice. If protons are shown on this study to have less heart or lung effects, then it may become more often approved for use in more routine cases," Dr. Freedman said.
For more information on how to participate in the trial, talk to your doctor.