As more and more health care institutions consider the viability of providing proton therapy to their patients, new research has emerged to further cement the notion that, where young lives are concerned, there is no better option currently available.

Owing to the diminished frequency and severity of side effects from treatment, a new study published in the journal Lancet Oncology has determined that outcomes from medulloblastoma — the most common malignant brain tumor in children — are best when proton therapy is used.

The research, conducted by a Massachusetts General Hospital (MGH) team led by Dr. Torunn Yock, the facility's director of Pediatric Radiology, illustrated that proton therapy enables comparable survival rates to conventional radiation therapy while exposing the child's healthy tissue to a lower dose of toxicity and improving the patient's chances of living a long life unhampered by complications and side effects.

A three-room ProteusPLUS proton therapy system from IBA was installed at MGH in 2001 at the Francis H. Burr Proton Center, (and an additional system from ProTom International is under construction).

Medulloblastoma develops at the rear and base of the brain, near the bottom of the skull. They are rapidly growing tumors that spread through the cerebrospinal fluid to different locations along the surface of the brain and spinal cord. In order to shed light on the clinical value of proton therapy in treating the disease, Dr. Yock and her team enrolled 59 patients between ages 3 and 21 into a clinical study between 2003 and 2009. Of those 59 patients, 55 had their medulloblastoma tumors partially removed through surgery and all 59 received proton therapy and chemotherapy.

Conventionally, these cases are treated with a combination of surgery, radiation therapy and chemotherapy — while that recipe is often sufficient for resolving the mortal threat of the brain tumor, it can also pave the way to myriad side effects that can compromise the patient's quality of life. The younger they are, according to the researchers, the worse the long-term effects can be.

The more common treatment side effects include hearing loss and effects on cognition and hormone function, as well as toxic effects on the heart, lungs, thyroid, vertebra and reproductive organs.

After three years, 12 percent of patients reported serious hearing loss and 83 percent reported progression-free survival. Patients also displayed problems with processing speed and verbal comprehension, but perceptual reasoning and working memory were not significantly affected.

After five years, hearing loss impacted 16 percent of participants, and 80 percent have progression-free survival. More than half of the patients were having trouble related to hormones but there were no reports of cardiac, pulmonary, or gastrointestinal toxic effects — which are common after conventional radiation therapy.

While the authors acknowledge their lack of a control group as a study limitation, they noted that randomized trials comparing conventional radiation therapy and proton therapy in children have been deemed unethical in the U.S. and abroad. "Our findings suggest that proton radiotherapy seems to result in an acceptable degree of toxicity and had similar survival outcomes to those achieved with photon-based radiotherapy," said the authors, who emphasized the importance of eliminating the toxic effects on the body's cardiac, pulmonary, and gastrointestinal systems that arise frequently from conventional care.

Proton radiotherapy resulted in acceptable toxicity and had similar survival outcomes to those noted with conventional radiotherapy, suggesting that the use of the treatment may be an alternative to photon-based treatments, they concluded.

The value of proton therapy for treating head and neck tumors in pediatric patients has long been recognized by advocates of the treatment, but illustrating those benefits in clinical trials is a vital step in the scientific process, and establishing the treatment's efficacy responsibly. Still, the prohibitive costs associated with proton therapy have caused some health professionals to question its value — particularly in cases when the facilities are predominately treating seniors with prostate cancer who may have less to gain from the treatment relative to conventional therapy.

"I believe that radiation oncologists have always understood that our treatments are associated with the potential for severe adverse effects. I also believe that many in radiation oncology embrace new technology, not simply to have the latest and greatest innovations, but rather to reduce the effect of radiation therapy on patients' quality of life. Nowhere in oncology is this more important than for paediatric cancers," wrote Dr. David R. Grosshans, department of Radiation Oncology, University of Texas MD Anderson Cancer Center, in a comment linked to the research.

"This study sets a new benchmark for the treatment of paediatric medulloblastoma and alludes to the clinical benefits of advanced radiation therapies," he concluded.