A double-blind, placebo-controlled trial of a topical treatment for chemotherapy-induced peripheral neuropathy: NCCTG trial N06CA

Beyond p-values: a cross-sectional umbrella review of chemotherapy-induced peripheral neuropathy treatments

Introduction

Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of neurotoxic chemotherapy agents, significantly impacting the daily lives of many cancer survivors. Despite thousands of articles published on CIPN, we remain no closer to a successful treatment regimen for the condition. In recent years, several new clinical trials and systematic reviews have been published, many exploring nonpharmaceutical interventions, prompting the need for a comprehensive synthesis of this emerging evidence.

Methods

We conducted an umbrella review to identify and appraise the 19 systematic reviews (SRs) published in 2023 that examined randomized controlled trials (RCTs) for established CIPN treatment. We focused our analysis on the three most researched treatment options: oral drugs, exercise, and acupuncture. RCTs not previously synthesized together were reviewed, and effect size analyses were performed to allow readers to interpret the existing literature beyond binary p-values.

Results

Our analysis of RCTs revealed the following key findings. For cancer survivors with CIPN after completing chemotherapy, serotonin-norepinephrine reuptake inhibitors (SNRIs) as well as acupuncture provided at least short-term relief for pain and sensory symptoms. For patients with CIPN who were actively undergoing chemotherapy, home-based balance and strength training exercises appeared to alleviate symptoms. Effect size analyses highlighted variability in treatment responses, underscoring the limitations of relying solely on p-values to assess intervention efficacy.

Discussion

Through an umbrella review approach, we demonstrate that SRs are often less systematic than expected. None of the 19 SRs captured all relevant RCTs within their search timeframe. However, by cross-referencing SRs, we identified 41 RCTs across 42 publications, illustrating the feasibility of an umbrella review approach to uncover relevant trials. Furthermore, many SRs exhibited methodological concerns that limit the interpretability of their findings. Finally, we discuss multiple opportunities for refining methods and reporting in future CIPN treatment trials.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/view/CRD42024508283, PROSPERO (42024508283).

Pharmacological Treatment of Chemotherapy-Induced Neuropathy: A Systematic Review of Randomized Clinical Trials

PURPOSE

Chemotherapy-induced peripheral neuropathy (CIPN) affects up to 80% of patients undergoing cytotoxic chemotherapy. This painful condition significantly impairs quality of life and often necessitates dose reduction or discontinuation of chemotherapy, negatively impacting overall survival. Currently, duloxetine is the only pharmacological treatment recommended by the American Society of Clinical Oncology (ASCO). This systematic review aims to evaluate the efficacy of various pharmacological interventions in CIPN treatment, providing substantial evidence for clinical practice and future research.

DESIGN

This systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to assess the effectiveness of pharmacological treatments for CIPN.

METHODS

Only randomized controlled trials (RCTs) were included. Herbal and phytotherapeutic treatments were excluded. Two independent reviewers performed the study selection, with a third reviewer resolving disagreements. Risk of bias assessment was conducted using the COCHRANE's RoB 2 tool.

RESULTS

Out of 860 screened articles, 17 RCTs met the inclusion criteria, encompassing 15 different pharmacological agents. Duloxetine, pregabalin, and amitriptyline were the most studied. Thirteen studies utilized a placebo as a control. Investigated medications exhibited varied outcomes, with some showing significant benefits in reducing neuropathic pain while others did not demonstrate statistically significant efficacy.

CONCLUSION

Duloxetine is an effective and well-tolerated option, while pregabalin shows promising results but requires further investigation. Other agents, such as venlafaxine and tapentadol, lack strong supporting evidence. Treatments like acetyl-l-carnitine, monosialotetrahexo-sylganglioside 1, and tetrodoxine yield inconsistent results, highlighting the need for additional research. Larger RCTs are recommended for comprehensive evaluation. Nurses are essential in CIPN care by monitoring symptoms, educating patients, and collaborating with the team.

Systemic ketamine toxicity following dermal application of a compounded pain cream

Ketamine is an NMDA receptor antagonist commonly used as a dissociative anesthetic and analgesic. Though it is conventionally administered via the intravenous, intramuscular, or intranasal route, use as a compounded analgesic cream is becoming increasingly common. This is a case report of a 61-year-old man who was detained by the police for erratic driving. He was transported to the emergency department for bizarre behavior and altered mental status. Upon arrival, he was agitated and had torsional nystagmus. He had just applied a large amount of an analgesic cream containing 10 % ketamine, 5 % lidocaine, and 5 % amitriptyline to numerous ulcerations in his perineal and sacral region from pyoderma gangrenosum. His clinical presentation was consistent with ketamine toxicity, and mass spectrometry demonstrated an elevated urine ketamine concentration (32,300 ng/mL). His symptoms resolved spontaneously within a few hours and he was discharged. This is a unique case of systemic toxicity following dermal application of a ketamine pain cream in a patient with impaired skin barrier function due to pyoderma gangrenosum.

The Use of Nerve Conduction Study to Evaluate the Effects of Frozen Sock Treatment on Docetaxel-Induced Peripheral Neuropathy in Breast Cancer Patients: A Prospective Clinical Trial

Background/Objectives: Docetaxel is a cytotoxic agent for the treatment of breast cancer, and its toxicities include peripheral neuropathy (PN). This study evaluated the ability of frozen sock (FS) treatment to prevent docetaxel-induced PN by performing nerve conduction study (NCS). Methods: From October 2017 to October 2018, 48 patients who had invasive carcinoma and were planned for docetaxel treatment every three weeks were evaluated. Patients wore a FS on the right foot, and the left foot was not protected by the FS during docetaxel infusion. Motor and sensory NCS as well as nail and skin toxicities were assessed. Results: The amplitude and velocity of the motor and sensory nerves significantly decreased after three months in both feet. Before and after three months of chemotherapy, the compound motor action potentials (CMAPs) for the right peroneal nerve were 7.64 ± 2.42 and 6.81 ± 2.21 mV, respectively (p < 0.001), and 7.13 ± 2.41 and 5.90 ± 2.24 mV, respectively (p < 0.001), for the left peroneal nerve. Reductions in the CMAP amplitude of the peroneal nerve were significantly lower in the right foot compared to the left foot (-9.58 vs. -16.8, p = 0.043). Application of the FS did not significantly decrease the overall incidence of skin and nail toxicity compared with the left foot during the study period (all p > 0.05). Conclusions: Docetaxel induced motor and sensory PN, but the use of a FS resulted in a smaller reduction in peroneal nerve amplification three months after the end of chemotherapy.

Topical menthol for chemotherapy-induced peripheral neuropathy: a randomised controlled trial in breast cancer

OBJECTIVES

Chemotherapy-induced peripheral neuropathy (CIPN) symptom is one of the side effects of paclitaxel in breast cancer patients. This randomised controlled study was conducted to investigate the effect of topical menthol applied on the hands and feet of breast cancer patients receiving chemotherapy on CIPN symptoms.

METHODS

60 breast cancer patients receiving chemotherapy were randomly assigned to an intervention group (n=30), which received topical menthol treatment, or a control group (n=30), which received standard care. Both groups continued their routine pharmacological treatments throughout the study. The intervention group applied 1% menthol topically to their hands and feet two times a day. The effect of the intervention on CIPN symptoms was evaluated 3 weeks and 6 weeks after the intervention.

RESULTS

The intervention group showed a significantly greater improvement in CIPN symptoms over time compared with the control group, with an effect size of η2=0.214 for the group×time interaction. Additionally, the intervention group exhibited a notable positive change in the exposure subscale of the CIPN rating scale, with an effect size of η2=0.114.

CONCLUSIONS

Topical application of menthol significantly mitigates the symptoms of CIPN in breast cancer patients. This study supports the use of menthol as an effective adjunctive treatment for CIPN.

TRIAL REGISTRATION NUMBER

NCT05429814.

The role of ketamine and its enantiomer in managing depression and pain in cancer patients: A narrative review

Depression and pain are common comorbidities in cancer patients, and ketamine, a dissociative anesthetic, has shown potential in managing both. This review summarizes current literature on ketamine and its enantiomer, esketamine, in managing depression and pain in the oncologic population. Studies indicate that sub-anesthetic doses of intravenous ketamine and esketamine can alleviate postoperative depressive symptoms in cancer patients with a tolerable safety profile. Research into non-intravenous routes for depression management in the oncologic population remains limited. Ketamine has also proven effective in managing acute postoperative pain, particularly through intravenous administration. While alternative administration routes, such as local infiltration and intramuscular methods, show mixed results, they may provide viable options for patients averse to intravenous (IV). However, the effectiveness of ketamine for chronic cancer pain remains inconsistent. Overall, ketamine offers a promising approach for managing depression and pain in oncologic patients.

Chemotherapy-Induced Peripheral Neuropathy: A Recent Update on Pathophysiology and Treatment

Chemotherapy-induced peripheral neuropathy (CIPN) is a major long-lasting side effect of some chemotherapy drugs, which threatens cancer survival rate. CIPN mostly affects sensory neurons and occasionally motor neurons, causing numbness, tingling, discomfort, and burning pain in the upper and lower extremities. The pathophysiology of CIPN is not completely understood; however, it is believed that chemotherapies induce peripheral neuropathy via directly damaging mitochondria, impairing the function of ion channels, triggering immunological mechanisms, and disrupting microtubules. The treatment of CIPN is a medical challenge, and there are no approved pharmacological options. Currently, duloxetine and other antidepressants, antioxidant, anti-inflammatory, and ion-channel targeted therapies are commonly used in clinics to relieve the symptoms of CIPN. Several other types of drugs, such as cannabinoids, sigma-1 receptor antagonists, and nicotinamides ribose, are being evaluated in preclinical and clinical studies. This paper summarizes the information related to the physiology of CIPN and medicines that could be used for treating this condition.

The Efficacy of Ketamine for Acute and Chronic Pain in Patients with Cancer: A Systematic Review of Randomized Controlled Trials

Managing cancer-related pain poses significant challenges, prompting research into alternative approaches such as ketamine. This systematic review aims to analyze and summarize the impact of ketamine as an adjuvant to opioid therapy for cancer-related pain. We conducted a literature review in MEDLINE, EMBASE, and Scopus from 1 January 1982 to 20 October 2023. Abstracts were screened against inclusion criteria, and eligible studies underwent a full-text review. Data was extracted from the included studies, and a framework analysis approach summarized the evidence regarding ketamine's use in patients with cancer. A total of 21 randomized clinical trials were included, and the quality of all the included studies was good or fair. Significant improvements in pain scores and reduced morphine consumption were consistently observed with intravenous ketamine administration for postoperative pain control, particularly when combined with other analgesics such as morphine. Ketamine was less effective when used as an analgesic for chronic pain management, with several studies on neuropathic pain or chemotherapy-induced neuropathy finding minimal significant effect on reduction of pain scores or morphine requirements. The efficacy of ketamine in pain management appears to depend on factors such as dosage, route of administration, and patient population.

Applications of Cannabinoids in Neuropathic Pain: An Updated Review

Neuropathic pain is experienced due to injury to the nerves, underlying disease conditions or toxicity induced by chemotherapeutics. Multiple factors can contribute to neuropathic pain such as central nervous system (CNS)-related autoimmune and metabolic disorders, nerve injury, multiple sclerosis and diabetes. Hence, development of pharmacological interventions to reduce the drawbacks of existing chemotherapeutics and counter neuropathic pain is an urgent unmet clinical need. Cannabinoid treatment has been reported to be beneficial for several disease conditions including neuropathic pain. Cannabinoids act by inhibiting the release of neurotransmitters from presynaptic nerve endings, modulating the excitation of postsynaptic neurons, activating descending inhibitory pain pathways, reducing neural inflammation and oxidative stress and also correcting autophagy defects. This review provides insights on the various preclinical and clinical therapeutic applications of cannabidiol (CBD), cannabigerol (CBG), and cannabinol (CBN) in various diseases and the ongoing clinical trials for the treatment of chronic and acute pain with cannabinoids. Pharmacological and genetic experimental strategies have well demonstrated the potential neuroprotective effects of cannabinoids and also elaborated their mechanism of action for the therapy of neuropathic pain.

Colon Cancer Survivorship in Patients Who Have Received Adjuvant Chemotherapy

The number of colon cancer survivors in the United States is increasing due to improved early detection, better treatments that extend survival, and the growing aging population who are at high risk for cancer. Following initial active treatment, colon cancer survivors experience a wide range of long-term physical, psychological, and socio-economic effects that impact their overall well-being. Healthcare providers caring for survivors need to prioritize not only monitoring for cancer recurrence but also optimizing their overall health through addressing these long-term effects; managing their comorbidities; promoting healthy behaviors (like exercise, nutrition, and weight loss); and screening for a second primary cancer depending on their risk. Personalized survivorship care plans should be formulated clearly outlining the roles of various healthcare providers involved in their care. Our review article focuses on these various aspects of colon cancer survivorship, including surveillance for cancer recurrence specific to those who received adjuvant chemotherapy with curative intent.

Does adding muscle relaxant make post-operative pain better? a narrative review of the literature from US and European studies

Centrally acting skeletal muscle relaxants (CASMR) are widely prescribed as adjuncts for acute and chronic pain. Given the recent interest in multimodal analgesia and reducing opioid consumption, there has been an increase in its use for perioperative/postoperative pain control. The mechanism of action, pharmacodynamics, and pharmacokinetics of these drugs vary. Their use has been studied in a wide range of operative and non-operative settings. The best evidence for the efficacy of CASMRs is in acute, nonoperative musculoskeletal pain and, in the operative setting, in patients undergoing total knee arthroplasty and abdominal surgery, including inguinal herniorrhaphy and hemorrhoidectomy. The risk of complications and side effects, coupled with the limited evidence of efficacy, should prompt careful consideration of individual patient circumstances when prescribing CASMRs as part of perioperative pain management strategies.

Anti-proliferative and anti-inflammatory effects of the application of baclofen cream, a GABAB receptor agonist, on skin inflammation in mice

Previous studies have demonstrated the role of γ-aminobutyric acid type B (GABAB) receptors in skin-related conditions and pain. However, most studies have focused on the main effects of GABAB on the central nervous system. Therefore, this study has aimed to determine the potential topical anti-inflammatory and anti-proliferative effects of baclofen cream in an inflammatory skin disease model. The effects of the baclofen cream were evaluated using acute and chronic models of 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced skin inflammation in mouse ears. Histological and immunohistochemical evaluations were performed using an ear oedema assay. The effect of baclofen on keratinocyte proliferation was assessed in PAM212, the murine keratinocyte cell line. The results demonstrate that a single topical application of 5% baclofen, 7.5% baclofen, and 1% dexamethasone each inhibited acute TPA-induced ear oedema (58.94 ± 6.14%, 47.73 ± 11.26%, and 87.33 ± 4.59%, respectively). These results were confirmed by histological analysis. In the chronic model, baclofen (5%) and dexamethasone (1%) each inhibited ear oedema and the maximum inhibitory effect was reached at the end of the experiment (9th day of TPA application) with a percentage inhibition of 54.60 ± 6.15% for baclofen and 71.68 ± 3.45% for dexamethasone, when compared to the vehicle. These results were confirmed by histological analysis. Baclofen and dexamethasone also reduced proliferating cell nuclear antigen expression by 62.01 ± 6.65% and 70.42 ± 6.11%, respectively. However, baclofen did not inhibit keratinocyte proliferation in PAM212 cells. In conclusion, these results demonstrate that baclofen exhibits notable topical antiproliferative and anti-inflammatory properties and could be a potential therapeutic alternative for treating inflammatory and proliferative skin diseases.

Efficacy of Duloxetine on electrodiagnostic findings of Paclitaxel-induced peripheral neuropathy, does it have a prophylactic effect? A randomized clinical trial

This study aimed to evaluate the efficacy of Duloxetine on electrodiagnostic findings of Paclitaxel-induced peripheral neuropathy in patients with breast cancer. This randomized, double-blind clinical trial was conducted on 40 patients with breast cancer who received Paclitaxel as their first chemotherapy session. All the patients were randomly allocated into two groups, intervention (20 subjects) and placebo (20 subjects). The intervention group received 30 mg duloxetine/day in the first week, followed by 60 mg (twice daily) until 8 weeks. The patient neurotoxicity questionnaire (PNQ) was used to evaluate the severity of neuropathy. Nerve conduction study was also performed. The evaluations were performed at the baseline and 8 weeks after the treatment. Out of 20 subjects in the placebo group, 10 (50%) patients had neurotoxicity (two milds, three moderate, four severe, and one incapacitated), according to PNQ. However, in the duloxetine group, two patients had mild neurotoxicity ( P = 0.03). Significant differences between groups related to the mean of Median Sensory Latency ( P <0.001), Median Motor Latency ( P < 0.001), and Median Motor velocity ( P = 0.001) were reported. However, the relative risk of polyneuropathy between the two groups (relative risk: 1) was not significant. Regarding the results, duloxetine could be an effective treatment for preventing paclitaxel-induced peripheral neuropathy in patients with breast cancer, and an electrodiagnostic study confirmed this effect.

Recent Progress in Gels for Neuropathic Pain

Neuropathic pain is a complex and debilitating condition that affects millions of people worldwide. While several treatment options are available, they often have limited efficacy and are associated with adverse effects. In recent years, gels have emerged as a promising option for the treatment of neuropathic pain. Inclusion of various nanocarriers, such as cubosomes and niosomes, into gels results in pharmaceutical forms with higher drug stability and increased drug penetration into tissues compared to products currently marketed for the treatment of neuropathic pain. Furthermore, these compounds usually provide sustained drug release and are biocompatible and biodegradable, which makes them a safe option for drug delivery. The purpose of this narrative review was to provide a comprehensive analysis of the current state of the field and identify potential directions for future research in the development of effective and safe gels for the treatment of neuropathic pain, ultimately improving the quality of life for patients suffering from neuropathic pain.

Evidence-Based Treatment of Pain in Chemotherapy-Induced Peripheral Neuropathy

PURPOSE OF REVIEW

Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating and often painful condition that occurs after administration of chemotherapeutic agents. The primary objective of this systematic review was to appraise the literature on conservative, pharmacological, and interventional treatment options for CIPN pain.

RECENT FINDINGS

There is level I evidence supporting modest to moderate improvement in CIPN pain from duloxetine treatment, as well as short-term modest improvement from physical therapy and acupuncture. Although opioid and cannabis administration may provide short-term modest improvement, administration is commonly limited by side effects. Generally, most studies reported no clinical benefit from yoga, topical neuropathic agents, gabapentinoids, and tricyclic antidepressants. Evidence is currently equivocal for scrambler therapy and transcutaneous electrical nerve stimulation. Finally, evidence on neuromodulation options is limited to mostly case reports/series and one observational study highlighting moderate improvement with auricular nerve stimulation. This systematic review provides an overview of conservative, pharmacologic, and interventional treatment modalities for CIPN pain. Furthermore, it provides a level of evidence and degree of recommendation based on the United States Preventive Services Task Force (USPSTF) criteria for each specific treatment modality.

Efficacy of ketamine mouthwash in the management of oral and pharyngeal toxicity associated with head and neck chemoradiotherapy: protocol for a phase II, Simon's two-stage trial

INTRODUCTION

Curative intent treatment of head and neck cancer (HNC) is frequently radiation therapy over 7 weeks with concurrent chemotherapy. This regimen is effective but carries a burden of toxicity leading to severe pain and treatment breaks portending inferior outcomes. Conventional palliation methods include opioids, anticonvulsants and local anaesthetics. Breakthrough toxicities are nevertheless ubiquitous and present an urgent unmet need. Ketamine is an inexpensive drug with mechanisms of analgesia outside the opioid pathway including N-methyl-D-aspartate (NMDA) receptor antagonism and a pharmacologically unique property of opioid desensitisation. Systemic ketamine is validated in randomised controlled trials for efficacy in reducing pain and/or opioid burden in the oncologic setting. Literature supports peripherally administered ketamine for pain control without systemic toxicity. These data support our rationale of using ketamine mouthwash to decrease acute toxicity of curative treatment of HNC, the efficacy of which is our aim to elucidate.

METHODS AND ANALYSIS

This is a phase II, Simon's two-stage trial. Patients have pathologically confirmed HNC and an intended regimen of 70 Gy of radiation with concurrent cisplatin. The protocol is initiated on diagnosis of grade 3 mucositis and consists of 2 weeks of 4 times daily (QID) ketamine mouthwash use. The primary endpoint is pain response defined as a combination of pain score and opioid use. 23 subjects will be enrolled in stage 1. If statistical criteria are met, 33 subjects will be enrolled in stage 2. Secondary endpoints include daily pain, daily opioid use, dysphagia at baseline and completion, nightly sleep quality, feeding tube placement and any unscheduled treatment breaks.

ETHICS AND DISSEMINATION

All trial data will be stored in an Institutional Review Board (IRB) approved database. The protocol is registered under Northwell IRB registration number #22-0292 and U.S. Food and Drug Administration (FDA) Investigational New Drug (IND) approval has been granted under IND number 161609. Results are intended to be published in an open-source journal and further data, statistics and source documents are available on request.

TRIAL REGISTRATION NUMBER

NCT05331131.

N-type calcium channel blockers: a new approach towards the treatment of chronic neuropathic pain

Neuropathic pain (NP) remains maltreated for a wide number of patients by the currently available treatments and little research has been done in finding new drugs for treating NP. Ziconotide (PrialtTM) had been developed as the new drug, which belongs to the class of ω-conotoxin MVIIA. It inhibits N-type calcium channels. Ziconotide is under the last phase of the clinical trial, a new non-narcotic drug for the management of NP. Synthetically it has shown the similarities with ω-conotoxin MVIIA, a constituent of poison found in fish hunting snails (Conus magus). Ziconotide acts by selectively blocking neural N-type voltage-sensitized Ca2+ channels (NVSCCs). Certain herbal drugs also have been studied but no clinical result is there and the study is only limited to preclinical data. This review emphasizes the N-type calcium channel inhibitors, and their mechanisms for blocking calcium channels with their remedial prospects for treating chronic NP.

Combination pharmacotherapy for the treatment of neuropathic pain in adults: systematic review and meta-analysis

ABSTRACT

Neuropathic pain causes substantial morbidity and healthcare utilization. Monotherapy with antidepressants or anticonvulsants often fails to provide relief. Combining different drugs sometimes provides improved analgesia and/or tolerability. More than half of patients receive 2 or more analgesics, and combination trials continue to emerge. This review comprehensively searched CENTRAL, MEDLINE, and EMBASE for relevant trials. Included studies are double-blind randomized controlled trials evaluating combinations of 2 or more drugs vs placebo or at least one monotherapy in adults with neuropathic pain. Outcomes included measures of efficacy and adverse effects. Risk of bias was assessed. Meta-analyses compared combination to monotherapy wherever 2 or more similar studies were available. Forty studies (4741 participants) were included. Studies were heterogenous with respect to various characteristics, including dose titration methods and administration (ie, simultaneous vs sequential) of the combination. Few combinations involved a nonsedating drug, and several methodological problems were identified. For opioid-antidepressant, opioid-gabapentinoid, and gabapentinoid-antidepressant combinations, meta-analyses failed to demonstrate superiority over both monotherapies. In general, adverse event profiles were not substantially different for combination therapy compared with monotherapy. Despite widespread use and a growing number of trials, convincing evidence has not yet emerged to suggest superiority of any combination over its respective monotherapies. Therefore, implementing combination therapy-as second- or third-line treatment-in situations where monotherapy is insufficient, should involve closely monitored individual dosing trials to confirm safety and overall added benefit. Further research is needed, including trials of combinations involving nonsedating agents, and to identify clinical settings and specific combinations that safely provide added benefit.

The Ameliorative Effect of Thymoquinone on Vincristine-Induced Peripheral Neuropathy in Mice by Modulating Cellular Oxidative Stress and Cytokine

Thymoquinone (TQ), an active constituent of Nigella sativa, has been reported to exert a broad spectrum of pharmacological effects, including neuroprotective, anticancer, anti-inflammatory, antidiabetic, antiepileptic, antioxidant, and other modulatory roles in inflammation in experimental studies. The present study aims to evaluate the potential effects of TQ on vincristine-induced neuropathy in mice, as well as the possible role of oxidative stress, and pro- and anti-inflammatory cytokine in neuropathy development. A Swiss strain of male albino mice were randomly divided into seven groups, comprising of five animals each. Vincristine sulfate (0.1 mg/kg, i.p.) was administered for 10 consecutive days for the induction of peripheral neuropathy. The animals received their respective treatment of TQ (2.5, 5, and 10 mg/kg, p.o.) and pregabalin (10 mg/kg, p.o.) concurrently with vincristine for 10 days followed by 4 days post treatment. The animals were assessed for pain and related behavior on day 7 and 14 using hot and cold plates, and a rotarod test. TQ preventive treatment attenuated vincristine induced neuropathy in a dose dependent manner evidenced as a significant (p < 0.001) increase in reaction time on the hot plate and the cold plate, and a fall off time on the rotarod test. Further, TQ preventive treatment resulted in a significant (p < 0.001) reduction in the number of flinches and duration of paw elevation in a formalin test. Preventative treatment with TQ abolished the vincristine-induced rise in malondialdehyde and glutathione depletion in sciatic nerve tissue, as well as the blood IL-6 levels. In conclusion, TQ at 2.5, 5, and 10 mg/kg dose produced significant attenuation of neuropathic pain induced by vincristine which may be due to its antinociceptive, antioxidant, and anti-proinflammatory activity.

Treatment for chemotherapy-induced peripheral neuropathy: A systematic review of randomized control trials

Purpose: Treatment of chemotherapy-induced peripheral neuropathy (CIPN) is challenging for clinicians, and many clinical trials and meta-analyses on CIPN are controversial. There are also few comparisons of the efficacy among drugs used to treat CIPN. Therefore, this systematic review aimed to study the efficacy of drugs in treating CIPN using existing randomized controlled trials. Methods: Electronic databases were searched for randomized controlled trials (RCTs) involving any pharmaceutical intervention and/or combination therapy of treating CIPN. Results: Seventeen RCTs investigating 16 drug categories, duloxetine, pregabalin, crocin, tetrodotoxin, venlafaxine, monosialotetrahexosyl ganglioside (GM1), lamotrigine, KA (ketamine and amitriptyline) cream, nortriptyline, amitriptyline, topical Citrullus colocynthis (bitter apple) oil, BAK (baclofen, amitriptyline hydrochloride, and ketamine) pluronic lecithin organogel, gabapentin, and acetyl l-carnitine (ALC), in the treatment of CIPN were retrieved. Many of the included RCTs consisted of small sample sizes and short follow-up periods. It was difficult to quantify due to the highly variable nature of outcome indicators. Conclusion: Duloxetine, venlafaxine, pregabalin, crocin, tetrodotoxin, and monosialotetrahexosyl ganglioside exhibited some beneficial effects in treating CIPN. Duloxetine, GM1, and crocin showed moderate benefits based on the evidence review, while lamotrigine, KA cream, nortriptyline, amitriptyline, and topical Citrullus colocynthis (bitter apple) oil were not beneficial. Further studies were necessary to confirm the efficacy of gabapentin in the treatment of CIPN because of the controversy of efficacy of gabapentin. Furthermore, BAK topicalcompound analgesic gel only had a tendency to improve the CIPN symptoms, but the difference was not statistically significant. ALC might result in worsening CIPN. Most studies were not of good quality because of small sample sizes. Therefore, standardized randomized controlled trials with large samples were needed to critically assess the effectiveness of these drugs in treating CIPN in the future.

Assessing chemotherapy-induced peripheral neuropathy with patient reported outcome measures: a systematic review of measurement properties and considerations for future use

PURPOSE

Chemotherapy-induced peripheral neuropathy (CIPN) is a common toxicity of cancer treatment, with potential to significantly impact cancer survivors' long-term quality of life. Patient reported outcome measures (PROMs) are increasingly utilised to evaluate CIPN. However, guidance remains lacking on how to identify fit for purpose PROMs with considerations necessarily differing when used in various research and in-clinic contexts. This study aimed to evaluate evidence about CIPN PROMs measurement properties and propose considerations to optimize CIPN PROM selection for each purpose.

METHODS

A systematic review was conducted to identify literature assessing measurement properties of CIPN PROMs. These were evaluated against Consensus-based Standards for the selection of health Measurement Instruments (COSMIN) criteria and International Society for Quality of Life minimum standards. Risk of Bias (RoB) was assessed using the COSMIN RoB checklist.

RESULTS

Thirty-nine papers evaluating measurement properties of 13 PROMs were included. The European Organization for Research and Treatment of Cancer Quality of Life Chemotherapy-Induced Peripheral Neuropathy Questionnaire (QLQ-CIPN20) and Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-Ntx) were the most commonly investigated PROMs and had the most measurement properties meeting established criteria.

CONCLUSION

The use of the QLQ-CIPN20 and FACT/GOG-Ntx to assess CIPN in research settings has the most supporting evidence. However other considerations including study aims, endpoints and target population also factor into PROM selection and need to be considered more often when determining the most suitable outcome measure. Evidence of CIPN PROMs use in clinical practice is limited and their adoption to individual-patient level management requires more evaluation.

Chemotherapy-induced peripheral neuropathy in children and adolescent cancer patients

Brain cancer and leukemia are the most common cancers diagnosed in the pediatric population and are often treated with lifesaving chemotherapy. However, chemotherapy causes severe adverse effects and chemotherapy-induced peripheral neuropathy (CIPN) is a major dose-limiting and debilitating side effect. CIPN can greatly impair quality of life and increases morbidity of pediatric patients with cancer, with the accompanying symptoms frequently remaining underdiagnosed. Little is known about the incidence of CIPN, its impact on the pediatric population, and the underlying pathophysiological mechanisms, as most existing information stems from studies in animal models or adult cancer patients. Herein, we aim to provide an understanding of CIPN in the pediatric population and focus on the 6 main substance groups that frequently cause CIPN, namely the vinca alkaloids (vincristine), platinum-based antineoplastics (cisplatin, carboplatin and oxaliplatin), taxanes (paclitaxel and docetaxel), epothilones (ixabepilone), proteasome inhibitors (bortezomib) and immunomodulatory drugs (thalidomide). We discuss the clinical manifestations, assessments and diagnostic tools, as well as risk factors, pathophysiological processes and current pharmacological and non-pharmacological approaches for the prevention and treatment of CIPN.

Antitumoral Effects of Tricyclic Antidepressants: Beyond Neuropathic Pain Treatment

Simple Summary

Tricyclic antidepressants (TCAs) are old and known therapeutic agents whose good safety profile makes them good candidates for drug repurposing. As the relevance of nerves in cancer development and progression is being unveiled, attention now turns to the use of nerve-targeting drugs, such as TCAs, as an interesting approach to combat cancer. In this review, we discuss current evidence about the safety of TCAs, their application to treat neuropathic pain in cancer patients, and in vitro and in vivo demonstrations of the antitumoral effects of TCAs. Finally, the results of ongoing clinical trials and future directions are discussed.

Abstract

Growing evidence shows that nerves play an active role in cancer development and progression by altering crucial molecular pathways and cell functions. Conversely, the use of neurotropic drugs, such as tricyclic antidepressants (TCAs), may modulate these molecular signals with a therapeutic purpose based on a direct antitumoral effect and beyond the TCA use to treat neuropathic pain in oncology patients. In this review, we discuss the TCAs’ safety and their central effects against neuropathic pain in cancer, and the antitumoral effects of TCAs in in vitro and preclinical studies, as well as in the clinical setting. The current evidence points out that TCAs are safe and beneficial to treat neuropathic pain associated with cancer and chemotherapy, and they block different molecular pathways used by cancer cells from different locations for tumor growth and promotion. Likewise, ongoing clinical trials evaluating the antineoplastic effects of TCAs are discussed. TCAs are very biologically active compounds, and their repurposing as antitumoral drugs is a promising and straightforward approach to treat specific cancer subtypes and to further define their molecular targets, as well as an interesting starting point to design analogues with increased antitumoral activity.

Treatment and diagnosis of chemotherapy-induced peripheral neuropathy: An update

When peripheral neuropathy occurs due to chemotherapy treatment, it is referred to as chemotherapy-induced peripheral neuropathy (CIPN). Typically, symptoms are sensory rather than motor and include reduced feeling and heightened sensitivity to pressure, pain, temperature, and touch. The pathophysiology of CIPN is very complex, and it involves multiple mechanisms leading to its development which will be described specifically for each chemotherapeutic class. There are currently no approved or effective agents for CIPN prevention, and Duloxetine is the only medication that is an effective treatment against CIPN. There is an unavoidable necessity to develop preventative and treatment approaches for CIPN due to its detrimental impact on patients' lives. The purpose of this review is to examine CIPN, innovative pharmacological and nonpharmacological therapy and preventive strategies for this illness, and future perspectives for this condition and its therapies.

Updates in the Treatment of Chemotherapy-Induced Peripheral Neuropathy

OPINION STATEMENT

Chemotherapy-induced peripheral neuropathy (CIPN) is a common toxicity associated with treatment with platinum-based agents, taxanes, vinca alkaloids, and other specific agents. The long-term consequences of this condition can result in decreased patient quality of life and can lead to reduced dose intensity, which can negatively impact disease outcomes. There are currently no evidence-based preventative strategies for CIPN and only limited options for treatment. However, there are several strategies that can be utilized to improve patient experience and outcomes as more data are gathered in the prevention and treatment setting. Before treatment, patient education on the potential side effects of chemotherapy is key, and although trials have been limited, recommending exercise and a healthy lifestyle before and while undergoing chemotherapy may provide some overall benefit. In patients who develop painful CIPN, our approach is to offer duloxetine and titrate up to 60 mg daily. Chemotherapy doses may also need to be reduced if intolerable symptoms develop during treatment. Some patients may also try acupuncture and physical therapy to help address their symptoms, although this can be limited by cost, time commitment, and patient motivation. Additionally, data on these modalities are currently limited, as studies are ongoing. Overall, approaching each patient on an individual level and tailoring treatment options for them based on overall physical condition, their disease burden, goals of care and co-morbid health conditions, and willingness to trial different approaches is necessary when addressing CIPN.

Chemotherapy-Induced Peripheral Neuropathy: Epidemiology, Pathomechanisms and Treatment

PURPOSE

This review provides an update on the current clinical, epidemiological and pathophysiological evidence alongside the diagnostic, prevention and treatment approach to chemotherapy-induced peripheral neuropathy (CIPN).

FINDINGS

The incidence of cancer and long-term survival after treatment is increasing. CIPN affects sensory, motor and autonomic nerves and is one of the most common adverse events caused by chemotherapeutic agents, which in severe cases leads to dose reduction or treatment cessation, with increased mortality. The primary classes of chemotherapeutic agents associated with CIPN are platinum-based drugs, taxanes, vinca alkaloids, bortezomib and thalidomide. Platinum agents are the most neurotoxic, with oxaliplatin causing the highest prevalence of CIPN. CIPN can progress from acute to chronic, may deteriorate even after treatment cessation (a phenomenon known as coasting) or only partially attenuate. Different chemotherapeutic agents share both similarities and key differences in pathophysiology and clinical presentation. The diagnosis of CIPN relies heavily on identifying symptoms, with limited objective diagnostic approaches targeting the class of affected nerve fibres. Studies have consistently failed to identify at-risk cohorts, and there are no proven strategies or interventions to prevent or limit the development of CIPN. Furthermore, multiple treatments developed to relieve symptoms and to modify the underlying disease in CIPN have failed.

IMPLICATIONS

The increasing prevalence of CIPN demands an objective approach to identify at-risk patients in order to prevent or limit progression and effectively alleviate the symptoms associated with CIPN. An evidence base for novel targets and both pharmacological and non-pharmacological treatments is beginning to emerge and has been recognised recently in publications by the American Society of Clinical Oncology and analgesic trial design expert groups such as ACTTION.

Chemotherapy-induced peripheral neuropathy and rehabilitation: A review

Chemotherapy-induced peripheral neuropathy (CIPN) is a common complication after chemotherapy that can damage the sensory, motor, autonomic, or cranial nerves in approximately 30%-60% of patients with cancer. CIPN can lead to detrimental dose modifications and/or premature chemotherapy discontinuation due to patient intolerance. The long-term impact of CIPN is particularly challenging and can have a profound impact on the quality of life (QoL) and survivorship. However, this condition is often underdiagnosed. No agents have been established to prevent CIPN. Pre-chemotherapy testing is recommended for high-risk patients. Duloxetine is considered a first-line treatment, whereas gabapentin, pregabalin, tricyclic antidepressants, and topical compounding creams may be used for neuropathic pain control. Home-based, low-to-moderate walking, and resistance exercise during chemotherapy can reduce the severity and prevalence of CIPN symptoms, especially in older patients. Pre-habilitation and rehabilitation should be recommended for all patients receiving cytotoxic chemotherapies. The purpose of this article is to review common chemotherapeutic drugs causing CIPN, risk factors, diagnosis and treatment of CIPN, and evidence of the benefits of rehabilitation.

Chemotherapy-Induced Peripheral Neuropathy: Mechanisms and Therapeutic Avenues

Chemotherapy-induced peripheral neuropathy (CIPN) is a serious and often persistent adverse consequence of certain chemotherapeutic agents. It is a major dose-limiting factor of many first-line chemotherapies, affecting 20-50% of patients at standard doses and nearly all patients at high doses. As cancer survivorship continues to increase with improvements in early diagnosis and treatment, more patients will experience CIPN despite completing cancer treatment, which interferes with recovery, leading to chronic pain and worsening quality of life. The National Cancer Institute has identified CIPN as a priority in translational research. To date, there are no FDA-approved drugs for preventing or treating CIPN, with emerging debate on mechanisms and promising new targets. This review highlights current literature and suggests novel approaches to CIPN based on proposed mechanisms of action that aim either to confer neuroprotection against chemotherapy-induced neurotoxicity or reverse the downstream effects of painful neuropathy.

Usefulness of cyclic thermal therapy and red blood cell scintigraphy in patients with chemotherapy-induced peripheral neuropathy

Background

Pharmacological and non-pharmacological therapies have been used to treat patients with chemotherapy-induced peripheral neuropathy (CIPN). However, the effect of therapies in cancer patients has yet to be investigated comprehensively. We hypothesized that cyclic thermal therapy would improve blood flow and microcirculation and improve the symptoms driven by CIPN.

Methods

The criteria of assessment were blood volume in region of interest (ROI) in the images, and European Organization for Research and Treatment of Cancer-Quality of Life Questionnaire-Chemotherapy-Induced Peripheral Neuropathy 20 questionnaire scores. The blood volume was quantified by using red blood cell (RBC) scintigraphy. All patients were treated 10 times during 10 days. The thermal stimulations, between 15° and 41°, were repeatedly delivered to the patient's hands.

Results

The total score of the questionnaires, the score of questions related to the upper limbs, the score of questions closely related to the upper limbs, and the score excluding the upper limbs questions was decreased. The blood volume was decreased, and the variance of blood volume was decreased. During cooling stimulation, the blood volume was decreased, and its variance was decreased. During warming stimulation, the blood volume was decreased, and its variance was decreased.

Conclusions

We suggest that cyclic thermal therapy is useful to alleviate CIPN symptoms by blood circulation improvement. RBC scintigraphy can provide the quantitative information on blood volume under certain conditions such as stress, as well as rest, in peripheral tissue.

Innovative Approach for the Prevention of Chemotherapy-Induced Peripheral Neuropathy in Cancer Patients: A Pilot Study With the Hilotherm Device, the Poliambulanza Hospital Experience

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) is an adverse event of taxanes, with no effective prevention or treatment available and a highly negative impact on patient quality of life. The aim of this study is to asses that the constant application of cooled cuffs on the hands and feet prevent and mitigate CIPN.

METHODS

Patients with breast, gynecologic, and pancreatic cancer who received weekly paclitaxel (PTX), PTX/carboplatin, and nab-paclitaxel (nab-PTX)/gemcitabine for any indication at the therapeutic scheduled dosage were included in this prospective study. Hilotherm Chemo care device forms a closed-loop system with cuffs and tubes through which a coolant flows at a temperature of 10 °C. CIPN was monitored using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (edition 3.0), and the tolerability and side effects were scored by using the Common Terminology Criteria for Adverse Events (T4.03 2017).

RESULTS

To date, we have enrolled 64 patients. Of these, 54 (84%) completed all cooling cycles. Continuous cooling was well tolerated by all patients. No patients had grade >2 CIPN or had serious or lasting adverse events as a result of Hilotherapy. The median time to CIPN onset was 77 days for the entire population.

CONCLUSION

Hilotherapy has good effectiveness and tolerability and seems to be able to prevent or reduce the symptoms of CIPN. We are still recruiting patients to obtain more data and to collect data at 3 months after the end of chemotherapy. Prospective studies seem to be warranted.

Drug-Induced Peripheral Neuropathy: Diagnosis and Management

Peripheral neuropathy comes in all shapes and forms and is a disorder which is found in the peripheral nervous system. It can have an acute or chronic onset depending on the multitude of pathophysiologic mechanisms involving different parts of nerve fibers. A systematic approach is highly beneficial when it comes to cost-effective diagnosis. More than 30 causes of peripheral neuropathy exist ranging from systemic and auto-immune diseases, vitamin deficiencies, viral infections, diabetes, etc. One of the major causes of peripheral neuropathy is drug induced disease, which can be split into peripheral neuropathy caused by chemotherapy or by other medications. This review deals with the latest causes of drug induced peripheral neuropathy, the population involved, the findings on physical examination and various workups needed and how to manage each case.

Chemotherapy-induced neurotoxicity in the treatment of gynecological cancers: State of art and an innovative approach for prevention

Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect that occurs in 20% of ovarian cancer patients treated with the combination of carboplatin/paclitaxel (CP). This toxicity is directly correlated with the dose of paclitaxel administered. Several studies have investigated whether different formulations of taxane can induce this side effect at a lower rate, but, unfortunately, no significant improvement was obtained. CIPN can be disabling in the daily lives of patients and can cause dose reduction or early termination of the treatment. Neuropathy can last for months and even years after its onset. Moreover, patients responsive to CP treatment are candidates for a reintroduction of the same drugs when disease relapse occurs, and residual neuropathy can affect the continuation of treatment. There are no approved drugs that mitigate or prevent the onset of CIPN. In this review, we summarize the evidence regarding the incidence of CIPN with different taxane formulations, regimen schedules and prevention systems. In particular, the Hilotherm® Chemo care device is a regional cooling system that lowers the temperature of the hands and feet to reduce the flow of chemotherapy into the capillaries. We used hilotherapy during chemotherapy infusion to prevent the onset of CIPN. Updated data from 44 ovarian cancer patients treated with 6 cycle of CP show that hilotherapy was well tolerated; only two patients (4.5%) stopped hilotherapy because of cold intolerance, and only one patient (2.2%) experienced grade ≥ 2 CIPN.

Dermal delivery of amitriptyline for topical analgesia

Abstract

Amitriptyline, administered orally, is currently one of the treatment options for the management of neuropathic pain and migraine. Because of the physicochemical properties of the molecule, amitriptyline is also a promising candidate for delivery as a topical analgesic. Here we report the dermal delivery of amitriptyline from a range of simple formulations. The first stage of the work required the conversion of amitriptyline hydrochloride to the free base form as confirmed by nuclear magnetic resonance (NMR). Distribution coefficient values were measured at pH 6, 6.5, 7, and 7.4. Solubility and stability of amitriptyline were assessed prior to conducting in vitro permeation and mass balance studies. The compound demonstrated instability in phosphate-buffered saline (PBS) dependent on pH. Volatile formulations comprising of isopropyl alcohol (IPA) and isopropyl myristate (IPM) or propylene glycol (PG) were evaluated in porcine skin under finite dose conditions. Compared with neat IPM, the IPM:IPA vehicles promoted 8-fold and 5-fold increases in the amount of amitriptyline that permeated at 24 h. Formulations containing PG also appear to be promising vehicles for dermal delivery of amitriptyline, typically delivering higher amounts of amitriptyline than the IPM:IPA vehicles. The results reported here suggest that further optimization of topical amitriptyline formulations should be pursued towards development of a product for clinical investigational studies.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s13346-021-00982-x.

Melittin, a honeybee venom derived peptide for the treatment of chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is the most prevalent neurological complication of cancer treatment which involves sensory and motor nerve dysfunction. Severe CIPN has been reported in around 5% of patients treated with single and up to 38% of patients treated with multiple chemotherapeutic agents. Present medications available for CIPN are the use of opioids, nonsteroidal anti-inflammatory agents, and tricyclic antidepressants, which are only marginally effective in treating neuropathic symptoms. In reality, symptom reappears after these drugs are discontinued. The pathogenesis of CIPN has not been sufficiently recognized and methods for the prevention and treatment of CIPN remain vulnerable to therapeutic problems. It has witnessed that the present medicines available for the disease offer only symptomatic relief for the short term and have severe adverse side effects. There is no standard treatment protocol for preventing, reducing, and treating CIPN. Therefore, there is a need to develop curative therapy that can be used to treat this complication. Melittin is the main pharmacological active constituent of honeybee venom and has therapeutic values including in chemotherapeutic-induced peripheral neuropathy. It has been shown that melittin and whole honey bee venom are effective in treating paclitaxel and oxaliplatin-induced peripheral neuropathy. The use of melittin against peripheral neuropathy caused by chemotherapy has been limited despite having strong therapeutic efficacy against the disease. Melittin mediated haemolysis is the key reason to restrict its use. In our study, it is found that α-Crystallin (an eye lens protein) is capable of inhibiting melittin-induced haemolysis which gives hope of using an appropriate combination of melittin and α-Crystallin in the treatment of CIPN. The review summarizes the efforts made by different research groups to address the concern with melittin in the treatment of chemotherapeutic-induced neuropathy. It also focuses on the possible approaches to overcome melittin-induced haemolysis.

Topical Treatments and Their Molecular/Cellular Mechanisms in Patients with Peripheral Neuropathic Pain-Narrative Review

Neuropathic pain in humans results from an injury or disease of the somatosensory nervous system at the peripheral or central level. Despite the considerable progress in pain management methods made to date, peripheral neuropathic pain significantly impacts patients' quality of life, as pharmacological and non-pharmacological methods often fail or induce side effects. Topical treatments are gaining popularity in the management of peripheral neuropathic pain, due to excellent safety profiles and preferences. Moreover, topical treatments applied locally may target the underlying mechanisms of peripheral sensitization and pain. Recent studies showed that peripheral sensitization results from interactions between neuronal and non-neuronal cells, with numerous signaling molecules and molecular/cellular targets involved. This narrative review discusses the molecular/cellular mechanisms of drugs available in topical formulations utilized in clinical practice and their effectiveness in clinical studies in patients with peripheral neuropathic pain. We searched PubMed for papers published from 1 January 1995 to 30 November 2020. The key search phrases for identifying potentially relevant articles were "topical AND pain", "topical AND neuropathic", "topical AND treatment", "topical AND mechanism", "peripheral neuropathic", and "mechanism". The result of our search was 23 randomized controlled trials (RCT), 9 open-label studies, 16 retrospective studies, 20 case (series) reports, 8 systematic reviews, 66 narrative reviews, and 140 experimental studies. The data from preclinical studies revealed that active compounds of topical treatments exert multiple mechanisms of action, directly or indirectly modulating ion channels, receptors, proteins, and enzymes expressed by neuronal and non-neuronal cells, and thus contributing to antinociception. However, which mechanisms and the extent to which the mechanisms contribute to pain relief observed in humans remain unclear. The evidence from RCTs and reviews supports 5% lidocaine patches, 8% capsaicin patches, and botulinum toxin A injections as effective treatments in patients with peripheral neuropathic pain. In turn, single RCTs support evidence of doxepin, funapide, diclofenac, baclofen, clonidine, loperamide, and cannabidiol in neuropathic pain states. Topical administration of phenytoin, ambroxol, and prazosin is supported by observational clinical studies. For topical amitriptyline, menthol, and gabapentin, evidence comes from case reports and case series. For topical ketamine and baclofen, data supporting their effectiveness are provided by both single RCTs and case series. The discussed data from clinical studies and observations support the usefulness of topical treatments in neuropathic pain management. This review may help clinicians in making decisions regarding whether and which topical treatment may be a beneficial option, particularly in frail patients not tolerating systemic pharmacotherapy.

Capsaicin 8% patch Qutenza and other current treatments for neuropathic pain in chemotherapy-induced peripheral neuropathy (CIPN)

PURPOSE OF REVIEW

Current oral treatments for neuropathic pain associated with chemotherapy-induced peripheral neuropathy (CIPN) have limited clinical efficacy, and undesirable side-effects. Topically delivered treatments have the advantage of avoiding CNS side-effects, while relieving pain. We have reviewed treatments of neuropathic pain associated with CIPN, focusing on the Capsaicin 8% patch, which can provide pain relief for up to 3 months or longer after a single 30-60-min application.

RECENT FINDINGS

Capsaicin 8% patch is a licensed treatment in the EU/UK for neuropathic pain and shown to be safe and effective in providing pain relief for patients with CIPN. Repeated daily oral or topical administrations are not required, as with other current treatments. The side-effects are transient and restricted to the time around patch application. New evidence suggests the Capsaicin 8% patch can promote the regeneration and restoration of skin nerve fibres in CIPN, in addition to the pain relief.

SUMMARY

The Capsaicin 8% patch is now often a preferred a treatment option for localised neuropathic pain conditions, including the feet and hands in patients with CIPN. Capsaicin 8% patch can be repeated three-monthly, if needed, for a year. In addition to pain relief, it may have a disease-modifying effect.

Chemotherapy-induced peripheral neuropathy (CIPN): current therapies and topical treatment option with high-concentration capsaicin

Cancer diagnosis and treatment are drastic events for patients and their families. Besides psychological aspects of the disease, patients are often affected by severe side effects related to the cancer itself or as a result of therapeutic interventions. Particularly, chemotherapy-induced peripheral neuropathy (CIPN) is the most prevalent neurological complication of oral or intravenous chemotherapy. The disorder may require dose reduction of chemotherapy and is accompanied by multiple symptoms with long-term functional impairment affecting quality of life (QoL), e.g., sensory and functional deteriorations as well as severe pain. Although CIPN may reverse or improve after termination of the causative chemotherapy, approximately 30–40% of patients are faced with chronicity of the symptoms. Due to the advantages in cancer diagnosis and treatments, survival rates of cancer patients rise and CIPN may occur even more frequently in the future. In this review, we summarize current recommendations of leading national and international societies regarding prevention and treatment options in CIPN. A special focus will be placed on current evidence for topical treatment of CIPN with high-dose capsaicin. Finally, an algorithm for CIPN treatment in clinical practice is provided, including both pharmacologic and non-pharmacologic modalities based on the clinical presentation.

[Rehabilitation methods for cancer patients with peripheral polyneuropathy induced by cytostatics]

An analytical review of the methods of cancer patients' rehabilitation with peripheral polyneuropathy induced by cytostatics (PNPIC) was carried out. Studies from electronic databases were investigated: Scopus, Web of Science, MedLine, World Health Organization, The Cochrane Central Register of Controlled Trials, ScienceDirect, US National Library of Medicine National Institutes of Health, PubMed Cancer, eLIBRARY, CyberLeninka. Despite the improvement of anticancer therapy and an increase in patients' life expectancy, the emerging peripheral polyneuropathy remains an urgent problem, since it significantly affects both the patients' life quality and the selection of adequate therapy. The frequency of detection of PNPIC is 90%, after discontinuation of treatment; symptoms of damaged peripheral nerve fibers remain in 30% of patients. The clinical symptoms of PNPIC are varied and most often include numbness in the extremities and / or increased sensitivity to thermal or mechanical stimuli, neuropathic pain. Currently, to prevent PNPIC, treatment is being modified with a reduction in the duration of courses and doses of cytostatics, and interruption of treatment. Official guidelines do not recommend any prophylaxis other than the possible use of duloxetine or a topical gel containing baclofen, amitriptyline, and ketamine. Over the past few years, there has been no significant progress in the prevention and treatment of PNPIC. The most common drug treatment method in clinical practice is the prescription of vitamins B. Among the non-drug treatment methods of PNPIC, the authors used acupuncture, electro-acupuncture, manual therapy, massage, gymnastics, yoga, sensorimotor training, general vibration therapy, percutaneous electro-neuro-stimulation, electro-analgesia, local cryotherapy, hydrotherapy, low-intensity alternating magnetic radiation. The studies included in the review are heterogeneous in design and protocol, number of patients, and time points for assessing outcomes. In connection with the existing differences, it is not possible to carry out a comparative analysis of the results of these rehabilitation types and to give an unambiguous answer about their effectiveness. As the analysis has shown, peripheral PNPIC is well known all over the world, however, the search for methods of its treatment is far from complete.

Peripheral Neuropathy under Oncologic Therapies: A Literature Review on Pathogenetic Mechanisms

Peripheral neurologic complications are frequent adverse events during oncologic treatments and often lead to dose reduction, administration delays with time elongation of the therapeutic plan and, not least, worsening of patients' quality of life. Experience skills are required to recognize symptoms and clinical evidences and the collaboration between different health professionals, in particular oncologists and hospital pharmacists, grants a correct management of this undesirable occurrence. Some classes of drugs (platinates, vinca alkaloids, taxanes) typically develop this kind of side effect, but the genesis of chemotherapy-induced peripheral neuropathy is not linked to a single mechanism. This paper aims from one side at summarizing and explaining all the scattering mechanisms of chemotherapy-induced peripheral neuropathy through a detailed literature revision, on the other side at finding new approaches to possible treatments, in order to facilitate the collaboration between oncologists, hematologists and hospital pharmacists.

Chemotherapy-Induced Peripheral Neuropathy: Nursing Implications

Chemotherapy-induced peripheral neuropathy (CIPN) is an unsolved and potentially life-compromising problem for most patients receiving neurotoxic chemotherapy. It manifests with numbness, tingling, and possibly neuropathic pain and motor and autonomic symptoms. This review aims to provide an evidence synthesis that prepares nurses to comprehensively assess, provide supportive care for, and critically evaluate the literature on CIPN. The prevalence, significance, characteristics, mechanisms, and risk factors of CIPN will be discussed, as well as nursing-relevant evidence on the assessment, prevention, and management of CIPN. The importance of critical literature evaluation before clinical implementation to reduce physical and financial harms to patients will also be highlighted.

Comprehensive Review of Topical Analgesics for Chronic Pain

PURPOSE OF REVIEW

Topical analgesics are a non-opioid option for the treatment of chronic pain conditions including neuropathic pain, musculoskeletal pain, and osteoarthritis. There are many topical medications available; however their efficacy is variable. This article reviews the various topical analgesics, their mechanisms of action, and their efficacy.

RECENT FINDINGS

Studies have found topical NSAIDs are useful in treating acute musculoskeletal pain syndromes (strains and sprains) and show some efficacy in treating hand and knee osteoarthritis (Derry et al. Cochrane Database Syst Rev 5:CD008609, 2017). Topical capsaicin 8% has been shown to be efficacious in the treatment of postherpetic neuralgia, painful diabetic peripheral neuropathy, and HIV-neuropathy (Derry et al. Cochrane Database Syst Rev 1:CD007393, 2017). Topical lidocaine has been widely studied and found to reduce pain in patients with postherpetic neuralgia (Knezevic et al. Pain Manag 7:537-58, 2017). Although many other topical analgesics are available, there is limited data to support the efficacy of other agents. Topical analgesics are a relatively benign treatment for chronic pain conditions including neuropathic pain, musculoskeletal, and myofascial pain. There is evidence to support the use of topical NSAIDs, high concentration topical capsaicin, and topical lidocaine for various painful conditions.

Peripheral Mechanisms of Neuropathic Pain-the Role of Neuronal and Non-Neuronal Interactions and Their Implications for Topical Treatment of Neuropathic Pain

Neuropathic pain in humans arises as a consequence of injury or disease of somatosensory nervous system at peripheral or central level. Peripheral neuropathic pain is more common than central neuropathic pain, and is supposed to result from peripheral mechanisms, following nerve injury. The animal models of neuropathic pain show extensive functional and structural changes occurring in neuronal and non-neuronal cells in response to peripheral nerve injury. These pathological changes following damage lead to peripheral sensitization development, and subsequently to central sensitization initiation with spinal and supraspinal mechanism involved. The aim of this narrative review paper is to discuss the mechanisms engaged in peripheral neuropathic pain generation and maintenance, with special focus on the role of glial, immune, and epithelial cells in peripheral nociception. Based on the preclinical and clinical studies, interactions between neuronal and non-neuronal cells have been described, pointing out at the molecular/cellular underlying mechanisms of neuropathic pain, which might be potentially targeted by topical treatments in clinical practice. The modulation of the complex neuro-immuno-cutaneous interactions in the periphery represents a strategy for the development of new topical analgesics and their utilization in clinical settings.

Analgesic Effects of Topical Amitriptyline in Patients With Chemotherapy-Induced Peripheral Neuropathy: Mechanistic Insights From Studies in Mice

Oral amitriptyline hydrochloride (amitriptyline) is ineffective against some forms of chronic pain and is often associated with dose-limiting adverse events. We evaluated the potential effectiveness of high-dose topical amitriptyline in a preliminary case series of chemotherapy-induced peripheral neuropathy patients and investigated whether local or systemic adverse events associated with the use of amitriptyline were present in these patients. We also investigated the mechanism of action of topically administered amitriptyline in mice. Our case series suggested that topical 10% amitriptyline treatment was associated with pain relief in chemotherapy-induced peripheral neuropathy patients, without the side effects associated with systemic absorption. Topical amitriptyline significantly increased mechanical withdrawal thresholds when applied to the hind paw of mice, and inhibited the firing responses of C-, Aβ- and Aδ-type peripheral nerve fibers in ex vivo skin-saphenous nerve preparations. Whole-cell patch-clamp recordings on cultured sensory neurons revealed that amitriptyline was a potent inhibitor of the main voltage-gated sodium channels (Nav1.7, Nav1.8, and Nav1.9) found in nociceptors. Calcium imaging showed that amitriptyline activated the transient receptor potential cation channel, TRPA1. Our case series indicated that high-dose 10% topical amitriptyline could alleviate neuropathic pain without adverse local or systemic effects. This analgesic action appeared to be mediated through local inhibition of voltage-gated sodium channels. PERSPECTIVE: Our preliminary case series suggested that topical amitriptyline could provide effective pain relief for chemotherapy-induced peripheral neuropathy patients without any systemic or local adverse events. Investigation of the mechanism of this analgesic action in mice revealed that this activity was mediated through local inhibition of nociceptor Nav channels.

High-Dose 8% Capsaicin Patch in Treatment of Chemotherapy-Induced Peripheral Neuropathy. A Systematic Review

INTRODUCTION

This is a review of the evidence from studies of the efficacy and tolerability of topically applied and high-concentration (8%) capsaicin in chemotherapy-induced peripheral neuropathy.

METHODS

For this review, we searched EMBASE and MEDLINE to June 20, 2020. The terms used in the search included capsaicin, capsaicin 8% patch, chemotherapy-induced peripheral neuropathy, and cancer.

RESULTS

A total of 98 studies were obtained, but only five were selected for the final analysis, with a total of 95 patients included. Three of the studies are prospective and two retrospective, including less than 30 patients per study. Capsaicin 8% patch provides significant pain relief in chemotherapy-induced peripheral neuropathy in all of them. However, the small number of studies (and patients) evaluated require caution with these results.

CONCLUSION

Additional clinical trials are required to establish the definitive role of the capsaicin patch in the future.

Neurotoxicity of antineoplastic drugs: Mechanisms, susceptibility, and neuroprotective strategies

This review summarizes the adverse effects on the central and/or peripheral nervous systems that may occur in response to antineoplastic drugs. In particular, we describe the neurotoxic side effects of the most commonly used drugs, such as platinum compounds, doxorubicin, ifosfamide, 5-fluorouracil, vinca alkaloids, taxanes, methotrexate, bortezomib and thalidomide. Neurotoxicity may result from direct action of compounds on the nervous system or from metabolic alterations produced indirectly by these drugs, and either the central nervous system or the peripheral nervous system, or both, may be affected. The incidence and severity of neurotoxicity are principally related to the dose, to the duration of treatment, and to the dose intensity, though other factors, such as age, concurrent pathologies, and genetic predisposition may enhance the occurrence of side effects. To avoid or reduce the onset and severity of these neurotoxic effects, the use of neuroprotective compounds and/or strategies may be helpful, thereby enhancing the therapeutic effectiveness of antineoplastic drug.

Emerging pharmacological strategies for the management of chemotherapy-induced peripheral neurotoxicity (CIPN), based on novel CIPN mechanisms

INTRODUCTION

Based on results of available clinical trials, the treatment and prevention of chemotherapy-induced peripheral neurotoxicity (CIPN) largely remains an unmet clinical need. However, new approaches have emerged in the last few years, attempting to modify the natural history of acute and late CIPN effects through a better knowledge of the pathogenic process on the molecular level.

AREAS COVERED

Clinical results of recently published (last 5 years) or ongoing emerging therapeutic/preventive pharmacological approaches based on novel CIPN mechanisms have been identified from Pubmed and ClinicalTrials.gov. Results are reviewed and discussed, in order to assess the trend of new clinical studies but also to infer the role novel approaches may have in the future.

EXPERT OPINION

The large heterogeneity of disease-causing mechanisms prevents researchers from identifying a reliable approach to effectively and safely treat or prevent CIPN. Understanding of novel pathophysiologic processes is leading the way to novel therapies, which, through targeting the sphingosine 1-phosphate receptor or pharmacologically inhibiting axonal degeneration might achieve in the future both treatment and prevention of CIPN. Toward this end, a multi-targeting approach, combining drugs to target different CIPN pathomechanisms seems to be a rational approach that warrants testing.

Topical agents: a thoughtful choice for multimodal analgesia

For over a thousand years, various substances have been applied to the skin to treat pain. Some of these substances have active ingredients that we still use today. However, some have been discontinued due to their harmful effect, while others have been long forgotten. Recent concerns regarding the cardiovascular and renal risk from nonsteroidal anti-inflammatory drugs, and issues with opioids, have resulted in increasing demand and attention to non-systemic topical alternatives. There is increasing evidence of the efficacy and safety of topical agents in pain control. Topical analgesics are great alternatives for pain management and are an essential part of multimodal analgesia. This review aims to describe essential aspects of topical drugs that physicians should consider in their practice as part of multimodal analgesia. This review describes the mechanism of popular topical analgesics and also introduces the most recently released and experimental topical medications.

Meet the expert: How I treat chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a frequent, often irreversible and disabling adverse effect of many commonly used chemotherapeutic agents. Older patients are at particular risk of developing CIPN due to comorbid conditions affecting the health of peripheral nerves. Symptoms of CIPN include paresthesias, dysesthesias, sensory loss, motor weakness, dysautonomia, and falls. Pharmacologic management of CIPN involves use of medications including antidepressants, anticonvulsants, and topical treatments for modulation of neuropathic pain. These medications should be used and monitored carefully in older patients as they may increase the risk of confusion, falls, and drug-drug interactions. Patients with CIPN are at an increased risk of falls and should be considered for supportive care interventions including physical and occupational therapy, assistive devices, and safety evaluations. Surveillance of CIPN during and following treatment is essential. The development of neuropathic symptoms may require dose reduction, drug holiday, or transitioning to another chemotherapeutic agent. Symptoms of CIPN typically improve following exposure to neurotoxic therapy, although in older adults the rate of improvement may be slow, and recovery is often incomplete. Early involvement of a neurologist should be considered in patients with atypical, progressive, motor- or autonomic- predominant presentations of neuropathy. Patients with refractory neuropathic pain or those who cannot tolerate standard symptomatic treatment should be referred to a pain specialist or palliative care.