Current Perception Threshold Testing (CPT) to Measure Sensory Fiber Changes After Chemotherapy

Abstract

Introduction: Chemotherapy induced peripheral neuropathy (CIPN) remains a significant complication of cancer treatment. For patients receiving taxanes and/or platinum chemotherapy, the incidence is as high as 84-100%. With no existing preventative or curative treatment, patients that develop CIPN report symptoms ranging from constant numbness and tingling of the hands and/or feet to debilitating burning pain. Unfortunately, symptoms often persist for several months or even years after the completion of treatment. As there is no "gold standard" measure to accurately identify CIPN, diagnosis is dependent upon the patient's self report of symptoms, often when long term or permanent neuronal injury has already occurred. When symptoms limit function, current oncologic practice is to limit or discontinue treatment. A definite need exists for a standard measure to accurately identify and more importantly predict the outcome of CIPN, in an effort to limit long-term neuronal damage and improve prognosis. Purpose: The purpose of this study was to determine if CPT measurement could accurately identify patients who develop CIPN and whether this measure could predict CIPN prior to developing symptoms, in patients receiving a taxane and/or a platinum chemotherapy regimen. Methods: This prospective study enrolled 35 chemotherapy naïve participants. Subjective and objective measurements, including CPT were collected during each chemotherapy treatment visit to assess sensory nerve function and the development of CIPN. Results: At 2000 Hz, 250 Hz, and 5 Hz, the CPT identified 78%, 56%, and 33% of participants who developed CIPN, respectively. However, the false-positive rate was 70%, 50%, and 45%, respectively. Generalized linear mixed model analysis determined that CPT measures do not predict the outcome of CIPN. However, the number of treatment visits was predictive of CIPN (OR=1.88, 95% CI=1.10-3.20, p=0.02). This suggests that a one-treatment increase in visits from a mean of 9.4, increases the odds of CIPN development by 88%. Discussion: While this measure accurately identfied a majority of patients with CIPN at 2000 Hz, the false-postive rate was unnacceptibly high. This study demonstrated that CPT measurement did not predict the outcome of CIPN.The lack of predictive significance demonstrated in this investigation is likely attributed to the small sample size.