Proton Therapy as Effective as Standard Radiation Therapy

Researchers at the University of Pennsylvania (Penn; Philadelphia, USA), Washington University School of Medicine (WUSTL; St. Louis, MO, USA), and other institutions conducted a study involving 1,483 cancer patients, 391 of whom received proton therapy and 1,092 that underwent photon treatment. The patients suffered from non-metastatic brain cancer, head and neck cancer, lung cancer, gastrointestinal cancer, and gynecologic cancer, and were treated with concurrent chemotherapy and radiation. The primary outcome was grade-three or higher radiation side effects within 90 days of treatment.

The results revealed that 11.5% of proton patients experienced a grade three or higher side effect in the 90-day time frame, compared to 27.6% in the conventional photon group. The patients receiving proton therapy experienced fewer side effects despite the fact that they were, on average, older and had more medical problems than those receiving standard X-ray radiation therapy. A weighted analysis found that the relative risk of a severe toxicity was two-thirds lower for proton RT patients, but overall survival and disease-free survival were similar between the two groups. The study was published on December 26, 219, in JAMA Oncology.

“While radiation therapy can be curative for certain cancers, it also causes severe side effects -- such as difficulty swallowing, nausea and diarrhea -- that reduce quality of life and can, in some cases, require hospitalization,” said lead author Brian Baumann, MD, assistant professor of radiation oncology at WUSTL and adjunct professor at Penn. “We observed significantly fewer unplanned hospitalizations in the proton therapy group, which suggests the treatment may be better for patients and, perhaps, less taxing on the health-care system.”

Photon radiation typically uses multiple X-ray beams to attack a tumor target, but unavoidably deposits radiation in the normal tissues beyond the target, potentially damaging those tissues as the beam exits the body. Proton therapy, an alternative radiation, works differently, by directing positively charged protons at the tumor target, where they deposit the bulk of the radiation dose, with minimal residual radiation delivered beyond the target, potentially reducing side effects and damage to surrounding tissue

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Washington University School of Medicine