RESULTS
±, ARC, prostate cancer
PROSTATE CANCER, PROSTATE CANCER
Fifty‐nine men with prostate cancer received VMAT following balloon spacer and SpaceOAR placement. Patient characteristics are described in Table Patient characteristics at baseline.Abbreviations: PSA, prostate‐specific antigen; SD, standard deviation.
Anonymized CTs were uploaded to the central core lab (ARC, New York). Figure Prostate cancer VMAT treatment plan depicting simulated dose distribution in axial (a) and sagittal (b) views after balloon spacer implantation and in axial (c) and sagittal (d) views after SpaceOAR implantation. Colorwash for dose scaling was set in the range 89.0‐110%.Individual rectal dose‐volume histogram (DVH) curves for hypofractionation radiation treatment at V22.6 , V27.1 , V31.7, and V36.25 Gy.With UH analysis, the mean rectal dose reduction for the balloon spacer compared to the SpaceOAR was 72.3% and 39.2% for V22.6 Gy (Difference, in sparing of the rectum with hypofractionation radiation treatment at V22.6 , V27.1 , V31.7, and V36.25 Gy (presented as the % relative reduction ± Standard dev.).When simulated with CF for comparison (Figure Difference in sparing of the rectum with VMAT radiation treatment at V50, V60, V70, and V80Gy (presented as the % relative reduction ± Standard dev.).Table Mean ± SD rectal dose volume histogram (DVH) comparing pre and post implantation DVHs between the balloon spacer and the SpaceOAR, when applying Ultra Hypofractionation and VMAT.% Pre spacer(Mean± SD, p‐value% Post Spacer(Mean± SD, p‐value% of Relative Reduction(Mean± SD, p‐value% of Relative Reduction(Median [range])% Pre spacer(Mean± SD, p‐value% Post Spacer(Mean± SD, p‐value% of Relative Reduction(Mean± SD, p‐value% of Relative Reduction(Median, [Range])Abbreviations: rV = rectal volume; SD = standard deviation.p‐values are calculated using Wilcoxon matched‐paired signed‐rank test.The difference between the balloon spacer and SpaceOAR pre implantation rectal dose values.The difference between the balloon spacer and SpaceOAR post implantation rectal dose values.The difference between balloon spacer and SpaceOAR relative rectal dose reduction.