Statistical Analysis
Descriptive statistics (including mean, standard deviation, median,
interquartile range, frequency, and percent) was calculated to
characterize the study sample (i.e., demographics, tumor profiling,
clinical outcomes, adverse effects, and radiographic factors).
Kaplan-Meier survival analysis was used to descriptively assess PFS and
OS. With a sample size of 21 patients in the study, two-sided 95%
confidence intervals for PFS/OS at defined time points of interest
(i.e., six-months, etc.) were constructed to be within ± 22.8% of the
observed survival proportion estimates. This calculation assumes PFS/OS
proportion estimates of 50% to conservatively maximize the width of the
obtained confidence intervals. Due to the small number of patients with
rHGGs who have completed concurrent ICI+ SBRT, multivariable modeling
was not performed. All p -values were two-sided with statistical
significance evaluated at the 0.05 alpha level. Ninety-five percent
confidence intervals for median PFS/OS survival time and six-month PFS
were calculated to assess the precision of the obtained estimates.
Mann-Whitney U tests were used to identify significant differences
between diffusion and permeability histogram values. All analyses were
performed in R Version 3.6.0 (R Foundation for Statistical Computing,
Vienna, Austria).