Material Provided by the Radiation Oncologist

● Journal of the American Medical Association, 2012, 307(15)

Intensity-Modulated Radiation Therapy, Proton Therapy, or Conformal Radiation Therapy and Morbidity and Disease Control in Localized Prostate Cancer. Nathan C. Sheets, MD, et al

My comment: The authors of this four-year-old paper are all based at the University of North Carolina. They include four radiation oncologists, 3 epidemiologists, two statistical analysts, and two specialists in health policy and management. UNC does not have any proton beam equipment, and the author profiles do not show any personal experience with proton beam therapy. The study did not examine long-term survival or short-term side effects (less than one year). The worst thing they could say about proton therapy is “…proton therapy-related patients were more likely to receive a diagnosis of gastrointestinal morbidity and undergo gastrointestinal procedures.” They do not address the severity of the “gastrointestinal morbidity” nor do they mention the percentage of patients affected.

● Journal of Applied Clinical Medical Physics, 2015, 16(3)

Proton-beam therapy: are physicists ignoring clinical realities? R. J. Schulz, PhD

My comment: This study is mostly theoretical and focused on economics. They do say that “…the clinical outcomes of PBT [proton beam treatment] are no better—nor any worse—than those achieved by IMRT [intensity modulated radiation treatment] or SBRT [stereotactic body radiation treatment]. “Of four retrospective studies that compared toxicities following PBT or IMRT, three showed but minor differences between the two modalities, while the study by Sheets et al showed significantly higher GU toxicity following PBT.” The Sheets study is the one described above, and this paper does not address that paper’s deficiencies. 

● NCCN [National Comprehensive Cancer Network] Clinical Practice Guidelines in Oncology

Prostate Cancer, Version 3.2016

This group does not find any increase in any side effects for PBT compared to radiation. “The NCCN panel believes no clear evidence supports a benefit or decrement to proton therapy over IMRT for either treatment efficacy or long-term toxicity. Conventionally fractionated prostate proton therapy can be considered a reasonable alternative to x-ray-based regimens at clinics with appropriate technology, physics, and clinical expertise.”

My summary: The proton beam therapy is just as effective as radiation (which is about as effective as surgery), but it’s more expensive. It might be a little worse for gastrointestinal side effects (the least severe of all the possible side effects), but that has not been shown definitively.