2. Overall study design
Participants were interviewed about their cancer-related PTSS and underwent magnetic resonance imaging (MRI) at baseline. Participants then completed four, 60-minute in-person KKC classes, following the aforementioned standard procedures. KKC is a MAT that has been shown to lower pain and emotional distress in pediatric cancer and other populations, e.g., sickle cell, schoolchildren, adults with opioid use disorder [11,18,19]. PTSS were re-assessed following the completion of the four classes (Figure 1a ).
Cancer-related PTSS
We computed an overall PTSS severity score at baseline and post-intervention, then change scores were computed to indicate response to intervention, i.e., PTSS at baseline minus post-intervention, such that higher scores indicate greater reductions in PTSS over time. PTSS subtypes (i.e., re-experiencing, avoidance, negative affect, hyperarousal) were also examined.
Gray matter volume analysis
See supplemental material.
Statistical Analyses
Related-Samples Wilcoxon Signed Rank Test was used to test for within-subjects significant changes in PTSS over time (baseline vs. follow-up). Regressions were used to examine whether baseline hippocampal volumes were associated with baseline PTSS or PTSS change scores, adjusting for total intracranial volume. Overall PTSS and subtypes were examined. Follow-up analyses were conducted to test for specificity of results to gray matter (GM) vs. white matter (WM). All analyses were performed in SPSS v.27.0 [22] atp <0.05 (two-tailed).