Abstract 3119: Novel measures of somatosensory impairment in chemotherapy-exposed pediatric cancer patients

Introduction: The magnitude and timeline of somatosensory impairments due to chemotherapy-induced peripheral neuropathy are not well understood due to a lack of objective measures with appropriate resolution. Here, we have updated a methodology for measuring proprioceptive acuity and developed a novel measure of haptic function, appropriate for adult and pediatric populations, to measure somatosensory impairment in chemotherapy-exposed pediatric cancer patients and identified relationships between chemotherapy-related somatosensory impairment and cumulative chemotherapy exposure. Methods: To map the development of proprioceptive acuity, 308 typically developing (TD) children (ages 5-17 years) and 26 adults (ages 18-25 years) performed a forearm position matching task with a bimanual manipulandum. Haptic acuity (discrimination) or sensitivity (detection) thresholds were measured using curvature perception assessments in 99 and 56 children respectively (ages 6-17 years). Healthy adults completed both haptic assessments (n = 27, ages 19-25 years). These brief proprioceptive and haptic assessments were utilized to characterize somatosensory impairment in 15 individuals treated with vinca alkaloid-containing chemotherapy regimens for non-central nervous system (CNS) pediatric cancers (ages 6-25 years). Normative quantiles were calculated for the proprioceptive and haptic measures from children and adults in the control group to use as comparison for the individuals exposed to chemotherapy. Regression analysis were used to determine if the somatosensory measures were correlated with treatment variables such as cumulative dosage of chemotherapeutic agents. Results: 7 of 15 cancer survivors exhibited elevated proprioceptive precision measures and 11 of 15 exhibited at least one elevated haptic function measure. Elevated measures are above the 75th percentile of the age matched normative cohort indicating more variability in limb position sense and higher haptic discrimination and detection thresholds. A multiple linear regression model of cumulative dosage of chemotherapeutic agent types predicted 80% of the variability in the haptic discrimination thresholds (adjusted r-squared = 0.80). Greater doses of plant alkaloids and anti-tumor antibiotics were associated with higher haptic discrimination thresholds. Conclusion: This study demonstrated proof-of-concept for identifying somatosensory deficits in individuals treated with chemotherapy for non-CNS pediatric cancers. The haptic assessment has sufficient resolution to correlate with cumulative chemotherapy exposure. These brief, objective, clinically relevant, somatosensory assessments can identify somatosensory deficits in pediatric cancer patients with known or suspected chemotherapy-associated dysfunction and may be used to follow progression and resolution of symptoms over time. Citation Format: Jessica M. Holst-Wolf, Juergen Konczak, Lucie Turcotte. Novel measures of somatosensory impairment in chemotherapy-exposed pediatric cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3119.