SEATTLE -- In many ways Sophia Thompson of Burien is a typical 7 year old; she is in the second grade, takes gymnastic and swimming lessons, and dreams of becoming a meteorologist.
None of this seems remarkable, unless you know that less than a year ago doctors found a brain tumor dangerously close to Thompson's eye. But, thanks to proton therapy, a precise form of radiation, the young girl survived cancer with no brain damage and her vision intact.
Thompson had to travel across the country for her treatment, but now ProCure has opened a proton therapy center within Seattle Cancer Care Alliance, making this unique treatment method available in the Pacific Northwest for the first time.
Still, proton therapy is often twice as expensive as convention radiation and researchers disagree on whether the treatment is worth it.
A more precise treatment
Proton therapy has been practiced in hospital settings since 1990. Still, there are few proton facilities around the country because they are so expensive to build - typically costing between $100 million and $200 million. The ProCure center in North Seattle is the 12th proton therapy center to open in the United States; and at least 12 more are being developed, according to the National Association for Proton Therapy.
Proton and conventional x-ray therapies both deliver radiation to the body to destroy cancerous tumors and prevent them from coming back. But, proton therapy uses atomic particles to deliver radiation more precisely, allowing patients to receive higher doses with less damage to nearby healthy tissue.
Dr. Ralph Ermoian, a radiation oncologist at Seattle Children's Hospital, said x-ray therapy passes through healthy tissue on the way to the tumor and on the way out of the body. With proton therapy, the radiation is concentrated on the tumor, so while healthy tissue could be affected on the way in, there is no exit radiation.
Ermoian said proton therapy patients are less likely to experience side effects from radiation, including secondary cancers.
Despite support from some experts, research has not yet proven that proton therapy causes less long-term side effects than x-ray radiation.
In fact, a study by the Yale University School of Medicine found that prostate cancer patients treated with conventional radiation had no greater toxicity 12 months after treatment. These researchers questioned whether proton therapy - which can cost twice as much as conventional radiation - is worth the price.
Who could benefit
Still, radiation oncologists argue that more precise radiation can be beneficial in certain cases.
Ermoian argued that proton therapy is advantageous to children fighting cancer because their developing bodies are more susceptible to the negative impacts of radiation.
Thompson would likely have survived with conventional radiation, Ermoian said, but she might have suffered damage to her pituitary gland, skull and eye. Seattle's proton therapy center was still being built when Thompson needed treatment, so Ermoian recommended her family travel to the ProCure center in Oklahoma City.
Over six weeks, Thompson had 28 proton sessions. Before long, her parents said she was playing pranks on the radiation therapists and giving them nicknames. The biggest challenge was getting her to stop giggling and stay still during each 30 minute treatment.
During the therapy Thompson's only side effects were redness and blistering around her eye. Since she finished, Thompson has experienced no long-term side effects.
"She's back to her old self, bursting full of energy," Thompson's mother Ingrid said.
Proton therapy is also used to treat patients with tumors in delicate areas such as the brain, spine, lungs or prostate.
"Protons, in some cases, allow you to deliver life-saving radiation to places you wouldn't be able to otherwise," Ermoian said.
Pat Purcell of Seattle was treated with proton therapy after he was diagnosed with prostate cancer in 2011.
Doctors offered Purcell several treatment options. He spent weeks researching each one until another patient urged him to consider proton therapy. Purcell was told he could survive cancer with little or no side effects, but he was skeptical.
"I thought 'There's no way they can cure my cancer with no impact to my quality of life,'" he said.
Still, Purcell and his wife traveled to Loma Linda Medical Center in Southern California for 9 weeks of proton therapy.
The treatment lasted 30 minutes each day, five days a week. Throughout the process Purcell felt well enough to continue working and exercising. In fact, two weeks into his treatment, Purcell competed in a triathlon. Six months after completing the therapy, he participated in his first Ironman race.
Purcell said proton therapy would have hardly impacted his life at all if he had been treated in Seattle.
"Proton therapy is so convenient," Purcell said. "I could have driven over during my lunch hour and gone back to work in the afternoon."
Not for everybody
While it might seem like all cancer patients would benefit from more precisely delivered radiation, Ermoian said proton therapy is not the best option for all patients. Some patients with fast-growing tumors may need more immediate treatment and conventional radiation can be started quicker, he said. In addition, Ermoian said if a patient's cancer is widespread, doctors may advise radiation be delivered more broadly.
Still, Ermoian said he is glad more of his patients will have the opportunity to receive proton therapy now that there is a center in this part of the country. He believes more area doctors will begin recommending the treatment.
"It's not always possible for families to travel across the country," Ermoian said. "I will be delighted that more of my patients can get [proton therapy] when it makes sense for their disease."