Neuromodulation Therapy for Chemotherapy-Induced Peripheral Neuropathy: A Systematic Review

The Efficacy of Neuromodulation Interventions for Chemotherapy-Induced Peripheral Neuropathy: A Systematic Review and Meta-Analysis

Purpose

To determine the efficacy and safety of a neuromodulation intervention regimen in the treatment of chemotherapy-induced peripheral neuropathy (CIPN).

Patients and Methods

Systematic searches were conducted in seven English databases. Randomized controlled trials of all neuromodulation interventions (both invasive and non-invasive) for the treatment of CIPN were selected. Group comparisons of differences between interventions and controls were also made. We divided the outcomes into immediate-term effect (≤3 weeks), short-term effect (3 weeks to ≤3 months), and long-term effect (>3 months).

Results

Sixteen studies and 946 patients with CIPN were included. Among immediate-term effects, neuromodulation interventions were superior to usual care for improving pain (SMD=-0.77, 95% CI -1.07~ 0.47), FACT-Ntx (MD = 5.35, 95% CI 2.84~ 7.87), and QOL (SMD = 0.44, 95% CI 0.09~ 0.79) (moderate certainty); neuromodulation loaded with usual care was superior to usual care for improving pain (SMD=-0.47, 95% CI -0.71 ~ -0.23), and QOL (SMD = 0.40, 95% CI 0.12 ~ 0.69) (moderate certainty). There were no statistically significant differences between the neuromodulation interventions regimen vs usual care in short- and long-term outcomes and neuromodulation vs sham stimulation from any outcome measure. There were mild adverse events such as pain at the site of stimulation and bruising, and no serious adverse events were reported.

Conclusion

Neuromodulation interventions had significant immediate-term efficacy in CIPN but had not been shown to be superior to sham stimulation; short-term and long-term efficacy could not be determined because there were too few original RCTs. Moreover, there are no serious adverse effects of this therapy.

Role of pattern recognition receptors in chemotherapy-induced neuropathic pain

Progress in the development of effective chemotherapy is producing a growing population of patients with acute and chronic painful chemotherapy-induced peripheral neuropathy (CIPN), a serious treatment-limiting side effect for which there is currently no US Food and Drug Administration-approved treatment. CIPNs induced by diverse classes of chemotherapy drugs have remarkably similar clinical presentations, leading to the suggestion they share underlying mechanisms. Sensory neurons share with immune cells the ability to detect damage associated molecular patterns (DAMPs), molecules produced by diverse cell types in response to cellular stress and injury, including by chemotherapy drugs. DAMPs, in turn, are ligands for pattern recognition receptors (PRRs), several of which are found on sensory neurons, as well as satellite cells, and cells of the immune system. In the present experiments, we evaluated the role of two PRRs, TLR4 and RAGE, present in dorsal root ganglion (DRG), in CIPN. Antisense (AS)-oligodeoxynucleotides (ODN) against TLR4 and RAGE mRNA were administered intrathecally before ('prevention protocol') or 3 days after ('reversal protocol') the last administration of each of three chemotherapy drugs that treat cancer by different mechanisms (oxaliplatin, paclitaxel and bortezomib). TLR4 and RAGE AS-ODN prevented the development of CIPN induced by all three chemotherapy drugs. In the reversal protocol, however, while TLR4 AS-ODN completely reversed oxaliplatin- and paclitaxel-induced CIPN, in rats with bortezomib-induced CIPN it only produced a temporary attenuation. RAGE AS-ODN, in contrast, reversed CIPN induced by all three chemotherapy drugs. When a TLR4 antagonist was administered intradermally to the peripheral nociceptor terminal, it did not affect CIPN induced by any of the chemotherapy drugs. However, when administered intrathecally, to the central terminal, it attenuated hyperalgesia induced by all three chemotherapy drugs, compatible with a role of TLR4 in neurotransmission at the central terminal but not sensory transduction at the peripheral terminal. Finally, since it has been established that cultured DRG neurons can be used to study direct effects of chemotherapy on nociceptors, we also evaluated the role of TLR4 in CIPN at the cellular level, using patch-clamp electrophysiology in DRG neurons cultured from control and chemotherapy-treated rats. We found that increased excitability of small-diameter DRG neurons induced by in vivo and in vitro exposure to oxaliplatin is TLR4-dependent. Our findings suggest that in addition to the established contribution of PRR-dependent neuroimmune mechanisms, PRRs in DRG cells also have an important role in CIPN.

Methodological and statistical characteristics of meta-analyses on spinal cord stimulation for chronic pain: a systematic review

BACKGROUND

A growing number of meta-analyses (MA) have investigated the use of spinal cord stimulation (SCS) as a treatment modality for chronic pain. The quality of these MAs has not been assessed by validated appraisal tools.

OBJECTIVE

To examine the methodological characteristics and quality of MAs related to the use of SCS for chronic pain syndromes.

EVIDENCE REVIEW

An online literature search was conducted in Ovid MEDLINE(R), Ovid EMBASE, Ovid Cochrane Database of Systematic Reviews, and Scopus databases (January 1, 2000 through June 30, 2023) to identify MAs that investigated changes in pain intensity, opioid consumption, and/or physical function after SCS for the treatment of chronic pain. MA quality was assessed using A Measurement Tool to Assess Systematic Reviews (AMSTAR-2) critical appraisal tool.

FINDINGS

Twenty-five MAs were appraised in the final analysis. Three were considered "high" quality, three "low" quality, and 19 "critically low" quality, per the AMSTAR-2 criteria. There was no association between the publication year and AMSTAR-2 overall quality (β 0.043; 95% CI -0.008 to 0.095; p=0.097). There was an association between the impact factor and AMSTAR-2 overall quality (β 0.108; 95% CI 0.044 to 0.172; p=0.002), such that studies published in journals with higher impact factors were associated with higher overall quality. There was no association between the effect size and AMSTAR-2 overall quality (β -0.168; 95% CI -0.518 to 0.183; p=0.320).According to our power analysis, three studies were adequately powered (>80%) to reject the null hypothesis, while the remaining studies were underpowered (<80%).

CONCLUSIONS

The study demonstrates a critically low AMSTAR-2 quality for most MAs published on the use of SCS for treating chronic pain. Future MAs should improve study quality by implementing the AMSTAR-2 checklist items.

PROSPERO REGISTRATION NUMBER

CRD42023431155.

The nerve cells in gastrointestinal cancers: from molecular mechanisms to clinical intervention

Gastrointestinal (GI) cancer is a formidable malignancy with significant morbidity and mortality rates. Recent studies have shed light on the complex interplay between the nervous system and the GI system, influencing various aspects of GI tumorigenesis, such as the malignance of cancer cells, the conformation of tumor microenvironment (TME), and the resistance to chemotherapies. The discussion in this review first focused on exploring the intricate details of the biological function of the nervous system in the development of the GI tract and the progression of tumors within it. Meanwhile, the cancer cell-originated feedback regulation on the nervous system is revealed to play a crucial role in the growth and development of nerve cells within tumor tissues. This interaction is vital for understanding the complex relationship between the nervous system and GI oncogenesis. Additionally, the study identified various components within the TME that possess a significant influence on the occurrence and progression of GI cancer, including microbiota, immune cells, and fibroblasts. Moreover, we highlighted the transformation relationship between non-neuronal cells and neuronal cells during GI cancer progression, inspiring the development of strategies for nervous system-guided anti-tumor drugs. By further elucidating the deep mechanism of various neuroregulatory signals and neuronal intervention, we underlined the potential of these targeted drugs translating into effective therapies for GI cancer treatment. In summary, this review provides an overview of the mechanisms of neuromodulation and explores potential therapeutic opportunities, providing insights into the understanding and management of GI cancers.

Chemotherapy-Induced Peripheral Neuropathy: Diagnosis, Agents, General Clinical Presentation, and Treatments

PURPOSE OF REVIEW

This review aims to discuss pathophysiology, diagnosis, clinical presentation, and treatment of chemotherapy-induced peripheral neuropathy. Agent-specific presentation and pathophysiology is also being discussed.

RECENT FINDINGS

As new systemic oncological treatments continue to be developed, the number of cancer survivors continues to grow. Survivors are living longer with the long-term side effects of oncological treatments. We reviewed the pathophysiology of agent-specific chemotherapy-induced peripheral neuropathy and the updates in its treatment and preventative tools. Chemotherapy-induced peripheral neuropathy is a debilitating long-term side effect that often impairs cancer survivors' function and quality of life. The increasing life expectancy of cancer survivors has resulted in increased prevalence of this condition. Understanding its intricacies can provide physicians with better treatment tools and research opportunities to develop or identify new therapeutic agents.

Treatment of pain in length-dependent peripheral neuropathy with the use of spinal cord stimulation: a systematic review

BACKGROUND

Chronic intractable pain from peripheral neuropathy is a debilitating condition that might not respond to conventional medical management and pharmacotherapy. The primary objective of this systematic review was to assess change (or reduction) in pain intensity in patients with length-dependent peripheral neuropathy after spinal cord stimulation (SCS) therapy.

METHODS

This systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The primary outcome was change (or reduction) in pain intensity after 12 months of SCS therapy compared with baseline in participants with length-dependent peripheral neuropathy. Secondary outcomes included change in pain intensity after 6 months and change in opioid consumption after 12 months. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) guidelines were used to appraise the quality of evidence.

RESULTS

Nineteen studies consisting of 376 participants who underwent SCS implantation met the inclusion criteria. Qualitative synthesis revealed that all eligible studies reported a significant improvement in pain intensity after 12 months of SCS therapy as compared with baseline. Mean differences with 95% confidence intervals were calculated for 4 studies, all of which achieved the minimal clinically important difference for change in pain intensity at 12 months. The GRADE quality of evidence for this outcome was appraised as very low quality.

CONCLUSION

This systematic review highlights that SCS could lead to significant improvement in pain intensity for length-dependent peripheral neuropathy, although future well-powered randomized controlled trials are warranted to increase the certainty of evidence in this finding.

STUDY REGISTRATION

PROSPERO (https://www.crd.york.ac.uk/PROSPERO/) ID: CRD42022377572.

Cancer Pain Management: A Narrative Review of Current Concepts, Strategies, and Techniques

Pain is frequently reported during cancer disease, and it still remains poorly controlled in 40% of patients. Recent developments in oncology have helped to better control pain. Targeted treatments may cure cancer disease and significantly increase survival. Therefore, a novel population of patients (cancer survivors) has emerged, also enduring chronic pain (27.6% moderate to severe pain). The present review discusses the different options currently available to manage pain in (former) cancer patients in light of progress made in the last decade. Major progress in the field includes the recent development of a chronic cancer pain taxonomy now included in the International Classification of Diseases (ICD-11) and the update of the WHO analgesic ladder. Until recently, cancer pain management has mostly relied on pharmacotherapy, with opioids being considered as the mainstay. The opioids crisis has prompted the reassessment of opioids use in cancer patients and survivors. This review focuses on the current utilization of opioids, the neuropathic pain component often neglected, and the techniques and non-pharmacological strategies available which help to personalize patient treatment. Cancer pain management is now closer to the management of chronic non-cancer pain, i.e., "an integrative and supportive pain care" aiming to improve patient's quality of life.

Microbiological and Physiological Effects of Pain

Pain is an important innate defense mechanism that can dramatically alter a person's quality of life. Understanding the microbiological and physiological effects of pain may be important in the pursuit of novel pain interventions. The three descriptors of pain recognized by the International Association for the Study of Pain are nociceptive, neuropathic, and nociplastic pain. Our review examined the current understanding of all three pain types, focusing on the key molecules involved in the manifestation of each type as well as physiological effects. Additionally, we compared the differences in painful and painless neuropathies and discussed the neuroimmune interaction involved in the manifestation of 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.

A Review of Chronic Pain and Device Interventions: Benefits and Future Directions

Chronic pain is a debilitating condition with a growing prevalence both in the USA and globally. The complex nature of this condition necessitates a multimodal approach to pain management that extends beyond the established pharmaceutical interventions currently employed. A variety of devices comprising both invasive and noninvasive approaches are available to patients, serving as adjuvants to existing regimens. The benefits of these interventions are notable for their lack of addiction potential, potential for patient autonomy regarding self-administration, minimal to no drug interaction, and overall relative safety. However, there remains a need for further research and more robust clinical trials to assess the true efficacy of these interventions and elucidate if there is an underlying physiological mechanism to their benefit in treating chronic pain or if their effect is predominantly placebo in nature. Regardless, the field of device-based intervention and treatment remains an evolving field with much promise for the future chronic pain management.