In an assessment of chemotherapy-induced peripheral neuropathy (CIPN), objectivity may be weak because the evaluation is done by the patient's subjective assessment. Consequently, the management of neuropathy may be delayed, and CIPN symptoms may become severe.

Sato J et al. attempted to evaluate CIPN through this pilot study, using quantitative pain measurement system. For evaluation 41 patients with gynecologic cancer who underwent chemotherapy using taxane and platinum drugs were enrolled. The grading of the peripheral sensory nerve disorder was based on the Common Terminology Criteria for Adverse Events (CTC-AE) version 4.0 and was evaluated before the initiation of therapy for up to six chemotherapy cycles. A symptom scale assessed on the basis of peripheral neuropathy questionnaire (PNQ) was also evaluated. Simultaneously a graded electric current was applied to a fingertip by the probe, and both the lowest current perceived and lowest perceptible current was measured using the quantitative pain measurement system.

From these values, the degree of pain was calculated using the formula: (pain perception current value - lowest perceptible current value) ÷ lowest perceptible current value × 100. The pain degrees were compared by quantitative pain measurement system during CIPN development with the value obtained before chemotherapy initiation.

On evaluation by a medical professional, it was found that 28 (64.3%) patients developed CIPN during 2.5±1.1 chemotherapy cycles. The pain degree by quantitative pain measurement system at grade 1 and 2 CIPN development according to the evaluation (CTC-AE) were significantly decreased as compared to the pain degree before chemotherapy initiation. The pain measurement system also detected changes in the pain degree during scale B and C, D CIPN development in the patient evaluation (PNQ). In 13 patients in whom CIPN did not occur, no significant decrease in the pain degree by this quantitative pain measurement system was detected (p=0.764). The measurements were not discontinued because of adverse events such as discomfort from the electric current.

The study results revealed that a decrease in the pain degree measured by Pain System was associated with the onset of CIPN symptoms. Specifically, detection of CIPN by Pain System was possible, though most of the CIPN exhibited low grade or mild symptoms. Pain System might become a noninvasive and convenient objective CIPN detection tool to supplement subjective CIPN evaluation.