Considering benefit and risk before routinely recommending SpaceOAR
William A. Hall, Alison Tree, David P. Dearnaley, Christopher Parker, Vinay Prasad, Mack Roach, C.A. Lawton
Abstract
Localised prostate cancer is a common malignancy with multiple, large, prospective trials reporting a considerable number of patients who can be cured when treated with surgery or radiotherapy. Radiotherapy in this setting is associated with 5% or lower grade 3 toxicity rates, and grade 4 toxicity rates of less than 1%. 1 Michalski JM Moughan J Purdy J et al. Effect of standard vs dose-escalated radiation therapy for patients with intermediate-risk prostate cancer: the NRG oncology RTOG 0126 randomized clinical trial. JAMA Oncol. 2018; 4e180039 Crossref PubMed Scopus (155) Google Scholar , 2 Dearnaley D Syndikus I Mossop H et al. Conventional versus hypofractionated high-dose intensity-modulated radiotherapy for prostate cancer: 5-year outcomes of the randomised, non-inferiority, phase 3 CHHiP trial. Lancet Oncol. 2016; 17: 1047-1060 Summary Full Text Full Text PDF PubMed Scopus (690) Google Scholar In April, 2015, a novel device, SpaceOAR, was given clearance by the US Food and Drug Administration (FDA) to attempt to further reduce toxicity in patients with prostate cancer treated with radiotherapy. 3 Food and Drug AdministrationLetter to Noel Rolon. https://www.accessdata.fda.gov/cdrh_docs/pdf14/DEN140030.pdfDate: 2015 Date accessed: December 2, 2020 Google Scholar The device consists of placement of a hydrogel between the prostate and the rectum to physically separate these two structures, thereby reducing the dose of radiation delivered to the rectum. The biological plausibility of the device relies on the assumption that placement of a foreign body, and displacement of the rectum, does not inherently compromise the normal rectal parenchyma's tolerance to radiotherapy.