Exploring the reliability and validity of clinically-relevant outcome measures for chemotherapy-induced peripheral neuropathy.

Purpose: To explore the reliability and validity of clinically-relevant outcome measures for balance (i.e., The Short Physical Performance Battery [SPPB] - Balance Subscale) and sensation (i.e., monofilament threshold testing) for use in clinical trials of chemotherapy-induced peripheral neuropathy (CIPN).

Methods: Adult, post-treatment cancer survivors (N = 142) who had reported ≥ 4/10 CIPN symptom severity following neurotoxic chemotherapy were recruited from six National Cancer Institute Community Oncology Research Program (NCORP) sites associated with the University of Rochester Cancer Center NCORP Research Base. Participants completed the monofilament threshold test at the screening and baseline time points (i.e., one week apart), while the Quality of Life Questionnaire-CIPN20, Treatment-Induced Neuropathy Assessment Scale, and SPPB - Balance Subscale were completed at baseline. Test-retest reliability of the monofilament threshold testing scores was assessed using the Intraclass Correlation Coefficient (ICC). The convergent validity among monofilament threshold testing, SPPB - Balance Subscale, and CIPN patient-reported outcome (PRO) scores at baseline was assessed using Spearman's correlation.

Results: Ceiling effects were observed for SPPB-Balance Subscale scores as 113 (79.6%) respondents reported the highest score. Agreement between the screening and baseline monofilament threshold testing scores was moderate (ICC = 0.65). Monofilament threshold testing (r Range: 0.14 - 0.21) and SPPB Balance Subscale scores (r Range: -0.36 - -0.22) showed largely low correlations with all PRO measures.

Conclusions: Monofilament threshold testing demonstrated moderate test-retest reliability, but low convergent validity with CIPN PROs, while the SPPB - Balance Subscale demonstrated low convergent validity with CIPN PROs and ceiling effects (i.e., highest possible score) among post-treatment cancer survivors with CIPN. Future research is needed to identify promising measures of balance and sensation loss for use in clinical trials that complement CIPN PROs to aid in the identification of clinically relevant treatments for CIPN.

Trial Registration: NCT04367490 [April 29, 2020].