# Describing the minimally clinically important difference of a chemotherapy-induced peripheral neuropathy patient-reported outcome measure in young adults

## TL;DR

This study evaluates a questionnaire to measure chemotherapy-induced neuropathy in young adults, determining the smallest meaningful change in symptoms over time.

## Contribution

The paper provides the first minimally clinically important difference (MCID) values for the QLQ-CIPN20 in young adults.

## Key findings

- 50% and 52% of participants reached the floor for sensory and motor subscales by the final time point.
- MCID values for worsening sensory and motor scores were 14.37 and 9.57, respectively.
- Internal consistency reliability was strong for both sensory and motor subscales.

## Abstract

The purpose of this secondary analysis was to characterize the reliability, validity, and minimally clinically important difference (MCID) of change scores over time of the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-CIPN-20 item (QLQ-CIPN20) in young adults receiving paclitaxel or vincristine.

Fifty young adults receiving vincristine or paclitaxel for the treatment of cancer completed the QLQ-CIPN20 at three time points associated with increasing cumulative chemotherapy dose. The Subject Significance Questionnaire was completed at T3. The analyses were focused on the calculation of floor and ceiling effects, internal consistency reliability, longitudinal validity, construct validity, and the MCID using an anchor-based approach for the QLQ-CIPN20 sensory and motor subscales.

By T3, 50% and 52% of participants reported QLQ-CIPN20 sensory and motor subscale scores at the floor, respectively. The internal consistency reliability of the sensory (α ​= ​0.83) and motor (α ​= ​0.89) subscales was strong. The Cohen’s d from T1 to T3 for the QLQ-CIPN20 sensory (d ​= ​−0.57) and motor (d ​= ​−0.47) subscales were small to moderate. There were low to moderate correlations between QLQ-CIPN20 sensory (r ​= ​0.45) and motor (r ​= ​0.27) subscale scores and vincristine cumulative dose. The MCID for worsening QLQ-CIPN20 sensory and motor subscale scores was 14.37 and 9.57, respectively (P ​< ​0.01).

Study results provided preliminary evidence surrounding the MCID for worsening of QLQ-CIPN20 scores using an anchor based on young adults' perceived change in CIPN severity. Further research is needed to develop psychometrically sound CIPN patient-reported outcome measures to effectively evaluate the impact of CIPN interventions among young adults.