Purpose: Chemotherapy-induced peripheral neuropathy (CIPN) may negatively influence multiple myeloma (MM) patients' health-related quality of life (HRQOL). Dose modification is the only way to minimize CIPN. To measure CIPN in daily practice, the Indication for Common Toxicity Criteria (CTC) Grading of Peripheral Neuropathy Questionnaire (ICPNQ) was developed which can be completed within five minutes by the patient. The aims of this study were to (1) perform a psychometric evaluation of the ICPNQ and (2) examine the prevalence of CIPN and its influence on HRQOL in population-based MM patients.
Methods: One hundred fifty-six MM patients, diagnosed between 2000 and 2014, completed the ICPNQ, European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Chemotherapy-Induced Peripheral Neuropathy 20 (EORTC QLQ-CIPN20), and EORTC QLQ-C30 (65 % response).
Results: The psychometric analyses showed a Cronbach's alpha of 0.84, 0.74, and 0.61 for, respectively, the sensory, motoric, and autonomic subscales of the ICPNQ. Test-retest reliability and construct validity were good for all subscales. Overall, 65 % of patients reported grade 2-3 neuropathy according to the ICPNQ. Patients with the highest CTC grades (grade 2 with neuropathic pain and grade 3 (38 %)) according to the ICPNQ reported significantly worse scores on all EORTC QLQ-CIPN20 subscales compared to patients with lower CTC grades (p ≤ 0.002). In addition, they reported statistically significant and clinically relevant worse HRQOL scores on almost all EORTC QLQ-C30 subscales.
Conclusions: CIPN is a common side effect in MM patients, which has a negative impact on HRQOL. The ICPNQ is a valid instrument to distinguish the highest CIPN CTC grades from the lower CTC grades necessary to decide on dose modifications of chemotherapy in daily clinical practice.
Keywords: Chemotherapy-induced peripheral neuropathy; Health-related quality of life; Indication for CTC Grading of Peripheral Neuropathy Questionnaire; Multiple myeloma; Patient-reported questionnaire; Validation.