Proton therapy as effective as standard radiation with fewer side effects

Cancer patients who receive high-tech proton therapy experience similar cure rates and fewer serious side effects compared with those who undergo traditional X-ray radiation therapy, according to a study led by Washington University School of Medicine in St. Louis and the Perelman School of Medicine at the University of Pennsylvania.

The reduction in side effects, particularly lower hospitalisation rates and fewer emergency room visits, could offset the higher initial cost of proton therapy, according to the researchers.

"We observed significantly fewer unplanned hospitalisations in the proton therapy group, which suggests the treatment may be better for patients and, perhaps, less taxing on the healthcare system," said first author Brian C. Baumann, MD, an assistant professor of radiation oncology at Washington University and an adjunct assistant professor of radiation oncology at Penn. "If proton therapy can reduce hospitalisations, that has a real impact on improving quality of life for both patients and caregivers."

While radiation therapy can be curative for certain cancers, it also causes severe side effects that reduce quality of life and can, in some cases, require hospitalisation, said Baumann, who treats patients at Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine.

The study, which included almost 1,500 patients from Penn Medicine, is the first large review of data across several cancer types, including lung, brain, head and neck, gastrointestinal and gynaecologic cancers, to show a reduced side effect profile for proton therapy compared with X-ray radiation therapy for patients receiving combined chemotherapy and radiation. None of the patients had metastatic cancer.

The researchers found no differences between the two groups in survival and cancer control, suggesting that proton therapy is just as effective in treating the cancer. Overall survival at one year for the proton therapy group was 83 percent versus 81 percent for the X-ray radiation therapy group. This difference tipped slightly in favour of proton therapy, but was not statistically significant.

The difference in side effects was more pronounced. Forty-five of 391 patients receiving proton therapy experienced a severe side effect in the 90-day time frame (11.5 percent). In the X-ray radiation therapy group, 301 of 1,092 patients experienced a severe side effect in the same period (27.6 percent). 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. After taking steps to control for these differences, the researchers found that patients receiving proton therapy experienced a two-thirds reduction in the relative risk of severe side effects within the first 90 days of treatment, compared with patients receiving X-ray radiation therapy.

The study was supported by research funds from the University of Pennsylvania.

Reference

Baumann BC, Mitra N, Harton JG, Xiao Y, Wojcieszynski AP, Gabriel PE, Zhong H, Geng H, Doucette A, Wei J, O'Dwyer PJ, Bekelman JE, Metz JM. Comparative effectiveness of proton therapy versus photon therapy as part of concurrent chemo-radiotherapy for locally advanced cancer. JAMA Oncology. Dec. 26, 2019.