Lessons learned from proton vs photon radiation therapy for glioblastoma signal-finding trial

alexandrossfakianakis shared this article with you from Inoreader Lessons learned from proton vs photon radiation therapy for glioblastoma signal-finding trial Via Neuro-Oncology Current Issue We appreciate the astute comments of Drs Vogelius and Bentzen regarding the analyses reported in association with our phase II randomized trial of proton therapy (PT) vs intensity-modulated radiotherapy (IMRT) for patients with newly diagnosed glioblastoma (GBM).1 To address their question about the differences in the reported numbers, the abstract in 2017 reported the intention-to-treat (ITT) analysis of the available patients with completed follow-up whereas the final report presented updated ITT analyses as well as the important per-protocol analysis. The per-protocol analysis included a shift of 2 patients who were assigned to protons but received IMRT due to insurance denial for protons. This raises the learned challenges that were faced within this randomized trial comparing two radiation modalities that relied on insurance approvals eve n within the clinical trial context. We do summarize that although 90 patients consented, the analysis consisted of 67 patients because "the majority of patients were excluded before treatment began due to insurance denial of proton therapy" (p. 1340). There was a further loss of evaluable patients due to loss of follow-up, limiting the evaluable patients who completed neurocognitive function testing, our primary study endpoint. It is possible that further bias may have been introduced in the patients who chose to remain on study vs those who chose to no longer participate or were lost to follow-up. Due to these various competing factors that limited the evaluable patients as well as the primary goal of evaluating the cognitive effects of two treatments, we reported the per-protocol analysis in order to try and associate cognitive toxicity of the treatment received and its related brain dosimetry. When seeking to understand the differences particularly in treatment-related toxic ity between treatments in small phase II signal-finding trials, we argue that there is substantial value to ensuring you are comparing the clinical outcomes relative to delivered treatments, which requires an effective treatment analysis approach. Given the various lessons learned and challenges faced, we congratulate the forethought of the ongoing randomized proton trials that integrated more sophisticated randomization and trial designs to help address some of these challenges. View on the web Inoreader. Take back control of your news feed. Follow us on Twitter and Facebook.