Chemotherapy-Induced Peripheral Neuropathy in Pediatric Cancer Patients

Without ENMG, detecting pediatric vincristine neuropathy is a challenge

Objective

Vincristine, a widely used anticancer chemotherapy drug, may cause polyneuropathy (PNP), potentially resulting in permanent functional impairment. We characterized the occurrence and development of vincristine-induced neuropathy (VIPN) in early treatment of childhood leukemia.

Methods

This prospective study of 35 pediatric acute lymphoblastic leukemia (ALL) patients comprised systematic clinical and electrophysiological studies at both the time of diagnosis and at least one time point during the first months of treatment.

Results

After vincristine treatment, all patients had axonal sensorimotor PNP on electroneuromyography (ENMG) In 34/35 patients, the motor and in 24/35 the sensory responses were decreased. Interestingly, in 3 patients PNP was most prominent in the upper limb. However, some children had no PNP symptoms despite moderate ENMG findings, and not all clinical symptoms were correlated with abnormal ENMG.

Conclusions

Pediatric VIPN is a sensorimotor, predominantly motor axonal neuropathy. VIPN can be detected even in its early phase by ENMG, but it is difficult to detect by symptoms and clinical examination only.

Significance

Pediatric ALL patients treated with vincristine are at risk of developing VIPN. Since the clinical signs of PNP in acutely ill children are difficult to identify, VIPN can easily be overlooked if ENMG is not performed.

Exercise and Neuropathy: Systematic Review with Meta-Analysis

INTRODUCTION

Peripheral neuropathies are a prevalent, heterogeneous group of diseases of the peripheral nervous system. Symptoms are often debilitating, difficult to treat, and usually become chronic. Not only do they diminish patients' quality of life, but they can also affect medical therapy and lead to complications. To date, for most conditions there are no evidence-based causal treatment options available. Research has increased considerably since the last review in 2014 regarding the therapeutic potential of exercise interventions for patients with polyneuropathy.

OBJECTIVE

Our objective in this systematic review with meta-analysis was to analyze exercise interventions for neuropathic patients in order to update a systematic review from 2014 and to evaluate the potential benefits of exercise on neuropathies of different origin that can then be translated into practice.

METHODS

Two independent reviewers performed a systematic review with meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Inclusion criteria according to the PICOS approach were: neuropathic patients, exercise interventions only, an inactive or non-exercising control group, and solely randomized controlled trials with the following outcome parameters: neuropathic symptoms, balance parameters, functional mobility, gait, health-related quality of life, and HbA1c (glycated hemoglobin).

RESULTS

A total of 41 randomized, controlled trials met all inclusion criteria, 20 of which could be included in the quantitative analysis. Study quality varied from moderate to high. Current data further support the hypothesis that exercise is beneficial for neuropathic patients. This is best documented for patients with diabetic peripheral neuropathy (DPN) (27 studies) as well as for chemotherapy-induced peripheral neuropathy (CIPN) (nine studies), while there are only few studies (five) on all other causes of neuropathy. We found standardized mean differences in favor of the exercise group of 0.27-2.00 for static balance, Berg Balance Scale, Timed-up-and-go-test, nerve conduction velocity of peroneal and sural nerve as well as for HbA1c in patients with DPN, and standardized mean differences of 0.43-0.75 for static balance, quality of life, and neuropathy-induced symptoms in patients with CIPN.

CONCLUSION

For DPN, evidence-based recommendations can now be made, suggesting a combination of endurance and sensorimotor training to be most beneficial. For patients with CIPN, sensorimotor training remains the most crucial component. For all other neuropathies, more high-quality research is needed to derive evidence-based recommendations. Overall, it seems that sensorimotor training has great potential to target most neuropathies and combined with endurance training is therefore currently the best treatment option for neuropathies. REGISTRATION NUMBER: (PROSPERO 2019 CRD42019124583)/16.04.2019.

Peripheral Nervous System Involvement in Non-Primary Pediatric Cancer: From Neurotoxicity to Possible Etiologies

Peripheral neuropathy is a well described complication in children with cancer. Oncologists are generally well aware of the toxicity of the main agents, but fear the side effects of new drugs. As chemotherapeutic agents have been correlated with the activation of the immune system such as in Chemotherapy Induced Peripheral Neuropathy (CIPN), an abnormal response can lead to Autoimmune Peripheral Neuropathy (APN). Although less frequent but more severe, Radiation Induced Peripheral Neuropathy may be related to irreversible peripheral nervous system (PNS). Pediatric cancer patients also have a higher risk of entering a Pediatric Intensive Care Unit for complications related to therapy and disease. Injury to peripheral nerves is cumulative, and frequently, the additional stress of a malignancy and its therapy can unmask a subclinical neuropathy. Emerging risk factors for CIPN include treatment factors such as dose, duration and concurrent medication along with patient factors, namely age and inherited susceptibilities. The recent identification of individual genetic variations has advanced the understanding of physiopathological mechanisms and may direct future treatment approaches. More research is needed on pharmacological agents for the prevention or treatment of the condition as well as rehabilitation interventions, in order to allow for the simultaneous delivery of optimal cancer therapy and the mitigation of toxicity associated with pain and functional impairment. The aim of this paper is to review literature data regarding PNS complications in non-primary pediatric cancer.

The Antiallodynic Effect of Nefopam on Vincristine-Induced Neuropathy in Mice

Background

Chemotherapy-induced neuropathic pain is a disabling condition following cancer treatment. Vincristine has more neurotoxicity than other vinca alkaloid agents. This study evaluated the correlation of different doses of nefopam with antiallodynic effects in a mouse vincristine neuropathy model.

Methods

A peripheral neuropathic mouse model was made by intraperitoneal injection of vincristine (0.1 mg/kg/day; 5-day-on, 2-day-off schedule over 12 days). After the development of allodynia, mice were injected intraperitoneally with 0.9% normal saline (NS group) or various doses (10, 30, 60 mg/kg) of nefopam (Nefopam group). We examined allodynia using von Frey hairs pre-administration and at 30, 60, 90, 120, 180, 240 mins, and 24 hrs after drug administration. We also measured the neurokinin-1 receptor concentrations in the spinal cord to confirm the antiallodynic effect of nefopam after drug administration.

Results

The peripheral neuropathic mouse model showed prominent mechanical allodynia. Intraperitoneal nefopam produced a clear dose-dependent increase in paw withdrawal threshold compared with pre-administration values and versus the NS group. The concentration of neurokinin-1 receptor was significantly decreased in the Nefopam group (P<0.05).

Conclusion

Intraperitoneally administered nefopam yielded a dose-dependent attenuation of mechanical allodynia and decreased neurokinin-1 receptor concentration, suggesting that the neurokinin-1 receptor is involved in the antiallodynic effects of nefopam in vincristine neuropathy.

The Minnesota Haptic Function Test

Haptic loss severely compromises the fine motor control of many daily manual tasks. Today, no widely accepted assessment protocols of haptic function are in clinical use. This is primarily due to the scarcity of fast, objective measures capable of characterizing mild to severe forms of haptic dysfunction with appropriate resolution. This study introduces a novel curvature-perception assessment system called the Minnesota Haptic Function Test™ that seeks to overcome the shortcomings of current clinical assessments.

Aims: The purpose of this study was threefold: (1) apply the test to a sample of young healthy adults to establish test-specific adult norms for haptic sensitivity and acuity; (2) establish the reliability of this instrument; (3) demonstrate clinical efficacy in a limited sample of cancer survivors who may exhibit haptic dysfunction due to chemotherapy-induced peripheral neuropathy.

Method: Participants manually explored two curved surfaces successively and made verbal judgments about their curvature. A Bayesian-based adaptive algorithm selected presented stimulus pairs based on a subject’s previous responses, which ensured fast convergence toward a threshold. Haptic sensitivity was assessed by obtaining detection thresholds in 26 adults (19–34 years). Haptic acuity was assessed by obtaining just-noticeable-difference thresholds in a second sample of 28 adults (19–25 years). Nine cancer survivors (18–25 years) with suspected peripheral neuropathy completed the acuity assessment. Test-retest reliability of the algorithm was calculated.

Results: First, the test yielded values that are consistent with those reported in the literature. Mean detection threshold for curvature of the healthy adults was 0.782 (SD ± 0.320 m⁻¹). The corresponding mean discrimination threshold was 1.030 (SD ± 0.462 m⁻¹). Second, test-retest reliability of the algorithm was assessed in a simulation, yielding an average correlation between repeated simulated thresholds of r = 0.93. Third, the test documented that 86% of the cancer survivors had acuity thresholds above the 75th percentile of the normative cohort, and 29% had thresholds above the normal range, indicating that the instrument can detect and differentiate between unaffected perception, and mild or more severe forms of haptic loss.

Conclusion: We here provide evidence that this new method to assess haptic perception of curvature is valid, reliable, and clinically practicable.

Measuring Therapy-Induced Peripheral Neuropathy: Preliminary Development and Validation of the Treatment-Induced Neuropathy Assessment Scale

Various sensory and motor effects are associated with cancer treatment-induced peripheral neuropathy. The current method for capturing the multifaceted nature of neuropathy includes a combination of objective tests, clinician evaluation, and subjective patient report, an approach that is often not logistically feasible, especially for multisite trials. We report the performance of a brief yet comprehensive, easily administered measure, the Treatment-Induced Neuropathy Assessment Scale (TNAS), for assessing the severity and course of neuropathy across various cancer treatments. Data were derived from 4 longitudinal or cross-sectional patient cohorts (N = 573). Patients with multiple myeloma treated primarily with bortezomib and patients with colorectal cancer receiving oxaliplatin evaluated candidate items. Cognitive debriefing showed that all items were easy to understand, and this preliminary TNAS demonstrated reliability, validity, and sensitivity. Numbness/tingling was the most severe item, regardless of therapeutic agent. Although numbness and general pain were moderately correlated, patients perceived them as distinct. Most TNAS items were more severe at follow-up, demonstrating the sensitivity of the instrument to accumulating dose. The TNAS will be refined with further patient input, with final psychometric evaluation conducted in a new patient sample receiving treatments known to be associated with peripheral neuropathy. The nonpainful component of neuropathy may be more disabling than the pain component.

PERSPECTIVE

Our data suggest that the nonpainful components of neuropathy may be more disabling than the pain component during cancer treatment. Here we report data on sensory and motor symptoms reported by patients receiving neurotoxic cancer therapy, and we detail the development of a neuropathy assessment scale that follows regulatory guidance for patient-reported outcomes.