Background Clown intervention has been shown to enhance emotional and behavioral processes, but few studies have comprehensively examined the effectiveness of this practice using biomarkers. Objective The aim of this study was to evaluate the effect of a clown intervention on the levels of psychological stress and cancer-related fatigue in pediatric patients with cancer undergoing chemotherapy. Methods Sixteen patients who met all criteria from a pediatric oncology inpatient unit in a Brazilian comprehensive cancer care hospital participated in this quasi-experimental study. Eight saliva samples were collected, comprising 4 at baseline and 4 after clown intervention (+1, +4, +9, and +13 hours after awakening). Salivary cortisol and α-amylase levels were determined using high-sensitivity enzyme-linked immunosorbent assay kits. Stress and fatigue were measured by the Child Stress Scale-ESI and the PedsQL Multidimensional Fatigue Scale, respectively. Relationships among stress, fatigue, and biomarker levels were investigated using nonparametric statistics. Results In comparison with baseline measurements, the total psychological stress and fatigue levels improved after the clown intervention at the collection time point +4 hours (P = .003 and P = .04, respectively). Salivary cortisol showed a significant decrease after clown intervention at the collection time points +1, +9, and +13 hours (P < .05); however, α-amylase levels remained unchanged. Conclusion These findings provide preliminary evidence that clown intervention merits further study as a way to reduce stress and fatigue in pediatric cancer inpatients, and that self-report and biomarker measures are feasible to collect in this patient group. Implications for Practice Clown intervention as a nonpharmacological intervention may improve stress and fatigue levels in pediatric inpatients with cancer undergoing chemotherapy.

Background: Pediatric cancer patients experience different psychological processes during hospitalization that may regulate the immune response and affect recovery and response to cancer treatment. In this study, we aimed to examine the feasibility of longitudinal testing of psychophysiological parameters of stress and fatigue in pediatric osteosarcoma patients hospitalized for chemotherapy submitted to clown intervention; and to investigate whether changes in the levels of biomarkers are associated with psychological stress and fatigue levels in these patients after the clown intervention. Methods: A pretest-posttest quasi-experimental pilot study was conducted at the pediatric oncology inpatient unit in a comprehensive cancer care center in Brazil including children and adolescents with osteosarcoma hospitalized for chemotherapy. Eight saliva samples were collected, comprising 4 at baseline (pre-intervention) and 4 after the clown intervention (+1, +4, +9, and +13 hours post-awakening). Salivary cortisol, α-amylase (sAA), cytokines, and matrix metalloproteinase-9 (MMP-9) levels were determined using high-sensitivity enzyme-linked immunosorbent assay (ELISA) kits. Stress and fatigue were measured by Child Stress Scale–ESI and PedsQL Multidimensional Fatigue Scale respectively. Bivariate association analysis between stress and fatigue scores and biomarker levels were investigated using nonparametric statistics. Effect sizes were calculated for each outcome variable. Results: Six pediatric osteosarcoma patients were enrolled with no missing data. No significant effects sizes were observed for psychophysiological outcomes. Effect sizes ranged from 0.54 (cortisol) to 0 (interleukin-1β [IL-1β]). Decreasing overall trends were observed for cortisol levels for all 6 pediatric osteosarcoma patients over time. In addition, a similar pattern of tumor necrosis factor–α (TNF-α) levels over time was found for all 6 patients. Patients with metastatic osteosarcoma showed a linear trend for a decrease in MMP-9 levels between 1 and 9 hours after the clown intervention and restoration to basal levels after 13 hours. Conclusions: The results of this pilot study suggest that it is feasible longitudinally measure psychophysiological outcomes in the pediatric osteosarcoma inpatients for chemotherapy. Clown intervention merits further study as a way to reduce stress as well as fatigue, since that the stress and cytokines measurements are feasible based on our work.