Acute abnormalities of sensory nerve function associated with oxaliplatin-induced neurotoxicity

Efficacy of a Novel Sigma-1 Receptor Antagonist for Oxaliplatin-Induced Neuropathy: A Randomized, Double-Blind, Placebo-Controlled Phase IIa Clinical Trial

This trial assessed the efficacy of MR309 (a novel selective sigma-1 receptor ligand previously developed as E-52862) in ameliorating oxaliplatin-induced peripheral neuropathy (oxaipn). A discontinuous regimen of MR309 (400 mg/day, 5 days per cycle) was tested in patients with colorectal cancer receiving FOLFOX in a phase II, randomized, double-blind, placebo-controlled, multicenter clinical trial. Outcome measures included changes in 24-week quantitative measures of thermal sensitivity and total neuropathy score. In total, 124 patients were randomized (1:1) to MR309 or placebo. Sixty-three (50.8%) patients withdrew prematurely before completing 12 planned oxaliplatin cycles. Premature withdrawal because of cancer progression was less frequent in the MR309 group (7.4% vs 25.0% with placebo; p = 0.054). MR309 significantly reduced cold pain threshold temperature [mean treatment effect difference (SE) vs placebo: 5.29 (1.60)°C; p = 0.001] and suprathreshold cold stimulus-evoked pain intensity [mean treatment effect difference: 1.24 (0.57) points; p = 0.032]. Total neuropathy score, health-related quality-of-life measures, and nerve-conduction parameters changed similarly in both arms, whereas the proportion of patients with severe chronic neuropathy (National Cancer Institute Common Terminology Criteria for Adverse Events ≥ 3) was significantly lower in the MR309 group (3.0% vs 18.2% with placebo; p = 0.046). The total amount of oxaliplatin delivered was greater in the active arm (1618.9 mg vs 1453.8 mg with placebo; p = 0.049). Overall, 19.0% of patients experienced at least 1 treatment-related adverse event (25.8% and 11.9% with MR309 and placebo, respectively). Intermittent treatment with MR309 was associated with reduced acute oxaipn and higher oxaliplatin exposure, and showed a potential neuroprotective role for chronic cumulative oxaipn. Furthermore, MR309 showed an acceptable safety profile.

Axonal excitability changes and acute symptoms of oxaliplatin treatment: In vivo evidence for slowed sodium channel inactivation

OBJECTIVE

Neurotoxicity is the most frequent dose-limiting side effect of the anti-cancer agent oxaliplatin, but the mechanisms are not well understood. This study used nerve excitability testing to investigate the pathophysiology of the acute neurotoxicity.

METHODS

Questionnaires, quantitative sensory tests, nerve conduction studies and nerve excitability testing were undertaken in 12 patients with high-risk colorectal cancer treated with adjuvant oxaliplatin and in 16 sex- and age-matched healthy controls. Examinations were performed twice for patients: once within 3 days after oxaliplatin treatment (post-infusion examination) and once shortly before the following treatment (recovery examination).

RESULTS

The most frequent post-infusion symptoms were tingling paresthesias and cold allodynia. The most prominent nerve excitability change was decreased superexcitability of motor axons which correlated with the average intensity of abnormal sensations (Spearman Rho = 0.80, p < .01). The motor nerve excitability changes were well modeled by a slowing of sodium channel inactivation, and were proportional to dose/m² with a half-life of about 10d.

CONCLUSIONS

Oxaliplatin induces reversible slowing of sodium channel inactivation in motor axons, and these changes are closely related to the reversible cold allodynia. However, further studies are required due to small sample size in this study.

SIGNIFICANCE

Nerve excitability data provide an index of sodium channel dysfunction: an objective biomarker of acute oxaliplatin neurotoxicity.

Predicting effects on oxaliplatin clearance: in vitro, kinetic and clinical studies of calcium- and magnesium-mediated oxaliplatin degradation

This study evaluated the impact of calcium and magnesium on the in vitro degradation and in vivo clearance of oxaliplatin. Intact oxaliplatin and Pt(DACH)Cl₂ were measured in incubation solutions by HPLC-UV. A clinical study determined changes in plasma concentrations of calcium and magnesium in cancer patients and their impact on oxaliplatin clearance. Kinetic analyses modelled oxaliplatin degradation reactions in vitro and contributions to oxaliplatin clearance in vivo. Calcium and magnesium accelerated oxaliplatin degradation to Pt(DACH)Cl₂ in chloride-containing solutions in vitro. Kinetic models based on calcium and magnesium binding to a monochloro-monooxalato ring-opened anionic oxaliplatin intermediate fitted the in vitro degradation time-course data. In cancer patients, calcium and magnesium plasma concentrations varied and were increased by giving calcium gluconate and magnesium sulfate infusions, but did not alter or correlate with oxaliplatin clearance. The intrinsic in vitro clearance of oxaliplatin attributed to chloride-, calcium- and magnesium-mediated degradation predicted contributions of <2.5% to the total in vivo clearance of oxaliplatin. In conclusion, calcium and magnesium accelerate the in vitro degradation of oxaliplatin by binding to a monochloro-monooxalato ring-opened anionic intermediate. Kinetic analysis of in vitro oxaliplatin stability data can be used for in vitro prediction of potential effects on oxaliplatin clearance in vivo.

Neurophysiological and clinical outcomes in chemotherapy-induced neuropathy in cancer

Chemotherapy induced peripheral neuropathy (CIPN) is a significant toxicity of cancer treatment, with the potential to affect long-term function and quality of life in cancer survivors. There remains a lack of consensus around optimal assessment techniques. While current approaches to CIPN assessment are focused on clinical grading scales, it is becoming increasingly evident that a more comprehensive multimodal assessment package is necessary to accurately characterise the impact of CIPN as well as gauge the utility of neuroprotective mechanisms. Neurophysiological techniques provide objective biomarkers and may enable early detection of toxicity while patient reported outcomes are necessary to determine the significance of symptoms to individual patients. In addition to providing an objective assessment, clinical neurophysiological techniques provide important insights into the contributory pathophysiological mechanisms of CIPN with different chemotherapy agents. There is a paucity of implementation of these techniques in the clinical trial setting. The present Review aims to facilitate the use of neurophysiological studies as part of comprehensive assessment packages for the monitoring of CIPN by summarising current understanding of neurophysiological changes that underlie the development of neuropathy, clinical presentations and patient reported outcomes as well as advantages and limitations of current techniques for the neurophysiological assessment of CIPN.

Aqueous extract of Lithospermi radix attenuates oxaliplatin-induced neurotoxicity in both in vitro and in vivo models

BACKGROUND

Oxaliplatin can induce peripheral neuropathy (OXIPN) as an adverse side effect in cancer patients. Until now, no effective preventive or therapeutic drug has been developed; therefore, the dose-limiting factor of OXIPN is still an obstacle in the use of oxaliplatin to treat cancer patients. In the present study, we report for the first time that the aqueous extract of Lithospermi radix (WLR) can attenuate the OXIPN in both in vitro and in vivo neuropathic models.

METHODS

The protective effect of WLR on OXIPN was evaluated in vitro by quantifying nerve growth factor (NGF)-stimulated neurite outgrowth in PC12 cells treated with a combination of oxaliplatin and WLR. The neuroprotective potential of WLR was further confirmed by measuring the changes in nociceptive sensitivities to external mechanical stimuli in neuropathic animals induced by oxaliplatin. Histological and immunohistochemical studies were further done to examine the effect of WLR in mouse spinal cords and footpads.

RESULTS

Oxaliplatin-induced neurotoxicity in NGF-stimulated PC12 cells. It could reduce the lengths and branching numbers of neuritis in NGF-stimulated PC12 cells. Co-treatment of WLR rescued the differentiated PC12 cells from the neurotoxicity of oxaliplatin. In a chronic OXIPN animal model, administration of oxaliplatin i.p. induced enhanced nociceptive sensitivity to mechanical stimuli (25.0 to 72.5 % of response rate) along with spinal activation of microglias and astrocytes and loss of intraepidermal nerve fibers in footpads, which is remarkably suppressed by oral administration of WLR (67.5 to 35 % of response rate at the end of experiment). Cytotoxicity of oxaliplatin determined in human cancer cells was not affected irrespective of the presence of WLR.

CONCLUSIONS

In conclusion, we demonstrated that WLR can attenuate OXIPN in both in vitro and in vivo experimental models, which may be in part attributed to its anti-inflammatory activity in the spinal cord and its neuroprotective potential in the peripheral nerve system without affecting the anti-tumor potential of oxaliplatin. Therefore, WLR could be considered as a good starting material to develop a novel therapeutic agent targeting OXIPN. However, further studies should be done to elucidate the underlying mechanism such as molecular targets and active constituent(s) in WLR with neuroprotective potential.

Prevalence of Oxaliplatin-induced Chronic Neuropathy and Influencing Factors in Patients with Colorectal Cancer in Iran

BACKGROUND

The chemotherapeutic agent oxaliplatin can cause acute and chronic forms of peripheral neuropathy. The aim of this study was to evaluate the incidence of chronic neuropathy and its risk factors in colorectal cancer (CRC) patients treated with FOLFOX or XELOX regimens in the Oncology Ward of Hazrat-e-Rasoul Hospital in Tehran.

MATERIALS AND METHODS

A total of 130 patients with CRC were entered into our study, aged over 18 years, without history of receiving other neurotoxic agents or other predisposing factors such as diabetes or neurologic diseases and kidney and liver dysfunction. For the FOLFOX regimen, patients received oxaliplatin, 85 mg/m2, every 2 weeks for 12 courses and with the XELOX regimen, oxaliplatin was 130 mg/m(2), every 3 weeks for 8 courses. Based on Common Toxicity Criteria (CTC or NCI-CTC v.3), the patients were divided into 5 groups (grades) based on the severity of their symptoms.

RESULTS

Fifty-seven patients (43.8%) were male and 73(56.2%) female. Some 19 patients (14.7%) had BMI<20, 97(74.6%) were between 20-25 and 14 (10.8%) ≥ 25. In 105 patients (80.7%) neuropathy was found. There was significant correlation between BMI, hypomagnesaemia and especially, severity of anemia in patients with neuropathy compared to those without.

CONCLUSIONS

Oxaliplatin regimens can induce chronic neuropathy in CRC patients, with anemia, high BMI and hypomagnesaemia as risk factors that can predispose to this kind of neurotoxicity.

Comparison of oxaliplatin and paclitaxel-induced neuropathy (Alliance A151505)

PURPOSE

Oxaliplatin and paclitaxel are commonly used chemotherapies associated with acute and chronic neuropathies. There is a need to better understand the similarities and differences of these clinical syndromes.

METHODS

Neuropathy data were pooled from patients receiving adjuvant oxaliplatin and weekly paclitaxel or every 3 weeks of paclitaxel. Patients completed daily questionnaires after each chemotherapy dose and the European Organization for Research and Treatment of Cancer quality-of-life questionnaire for patients with chemotherapy-induced peripheral neuropathy before each chemotherapy cycle and for 12 months post-treatment.

RESULTS

Acute neuropathy symptoms from both drugs peaked around day 3. Acute symptoms experienced in cycle 1 predicted occurrence in subsequent cycles. Paclitaxel-induced acute symptoms were similar in intensity in each cycle and largely resolved between cycles. Oxaliplatin-induced acute symptoms were about half as severe in the first cycle as in later cycles and did not resolve completely between cycles. Both drugs caused a predominantly sensory chronic neuropathy (with numbness and tingling being more common than pain). Oxaliplatin-induced neuropathy worsened after the completion of treatment and began to improve 3 months post-treatment. In contrast, paclitaxel-induced neuropathy began improving immediately after chemotherapy cessation. During treatment, the incidence of paclitaxel sensory symptoms was similar in the hands and feet; with oxaliplatin, the hands were affected more than the feet. Both paclitaxel- and oxaliplatin-induced acute neurotoxicity appeared to predict the severity of chronic neuropathy, more prominently with oxaliplatin.

CONCLUSIONS

Knowledge of the similarities and differences between neuropathy syndromes may provide insight into their underlying pathophysiology and inform future research to identify preventative treatment approaches.

Effect of YH0618 soup on chemotherapy-induced toxicity in patients with cancer who have completed chemotherapy: study protocol for a randomized controlled trial

Background

The incidence of cancer has been staying at a high level worldwide in recent years. With advances in cancer diagnosis and therapy strategy, the survival rate of patients with cancer has been increasing, but the side effects of these treatments, especially chemotherapy, are obvious even when the chemotherapy ceases. YH0618, a prescription, has showed efficacy in reducing chemotherapy-induced toxicity through long clinical practice. However, there is no scientific research exploring the effects of YH0618 in patients with cancer. Therefore, using a randomized controlled trial, this study will explore the efficacy of YH0618 on ameliorating chemotherapy-induced toxicity including dermatologic toxicity, myelosuppression, hepatotoxicity and nephrotoxicity and improving fatigue in cancer patients who have completed chemotherapy.

Methods/design

This is a prospective assessor-blinded, parallel, randomized controlled trial. Patients with cancer at any stage who have completed chemotherapy within two weeks will be randomly divided into group A (YH0618) and group B (wait-list) using a 1:1 allocation ratio. The chemotherapeutic agents include taxanes or anthracyclines. Subjects assigned to group A will receive YH0618 soup 6 days a week for 6 weeks and uncontrolled follow-up for 6 weeks, while group B are required to wait for 6 weeks before receiving YH0618 intervention. The primary outcome of this study is the incidence of protocol-specified grade ≥2 dermatologic toxicities graded by NCI CTCAE Chinese version 4.0 and changes of fingernail color, face skin color and tongue color evaluated by the L*a*b system within 6 weeks. There are some secondary outcomes associated with dermatologic toxicity including fatigue and clinical objective examination.

Discussion

There are few scientific and safe methods in ameliorating chemotherapy-induced toxicity. The proposed study may provide direct and convincing evidence to support YH0618 as an adjuvant treatment for reducing chemotherapy-induced toxicity, which could be introduced into clinical settings.

Trial registration

Chinese Clinical Trial Registry: ChiCTR-IOR-15006486. Registered on 21 May 2015.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-016-1443-9) contains supplementary material, which is available to authorized users.

Electrophysiological and morphological changes in colonic myenteric neurons from chemotherapy-treated patients: a pilot study

BACKGROUND

Patients receiving anticancer chemotherapy experience a multitude of gastrointestinal side-effects. However, the causes of these symptoms are uncertain and whether these therapeutics directly affect the enteric nervous system is unknown. Our aim was to determine whether the function and morphology of myenteric neurons are altered in specimens of the colon from chemotherapy-treated patients.

METHODS

Colon specimens were compared from chemotherapy-treated and non-treated patients following colorectal resections for removal of carcinoma. Intracellular electrophysiological recordings from myenteric neurons and immunohistochemistry were performed in whole mount preparations.

KEY RESULTS

Myenteric S neurons from chemotherapy-treated patients were hyperexcitable; more action potentials (11.4 ± 9.4, p < 0.05) were fired in response to depolarising current pulses than in non-treated patients (1.4 ± 0.5). The rheobase and the threshold to evoke action potentials were significantly lower for neurons from chemotherapy-treated patients compared to neurons from non-treated patients (p < 0.01). Fast excitatory postsynaptic potential reversal potential was more positive in neurons from chemotherapy-treated patients (p < 0.05). An increase in the number of neurons with translocation of Hu protein from the cytoplasm to the nucleus was observed in specimens from chemotherapy-treated patients (103 ± 25 neurons/mm(2) , 37.2 ± 7.0%, n = 8) compared to non-treated (26 ± 5 neurons/mm(2) , 11.9 ± 2.7%, n = 12, p < 0.01). An increase in the soma size of neuronal nitric oxide synthase-immunoreactive neurons was also observed in these specimens.

CONCLUSIONS & INFERENCES

This is the first study suggesting functional and structural changes in human myenteric neurons in specimens of colon from patients receiving anticancer chemotherapy. These changes may contribute to the causation of gastrointestinal symptoms experienced by chemotherapy-treated patients.

Oxaliplatin-Induced Neuropathy: A Long-Term Clinical and Neurophysiologic Follow-Up Study

BACKGROUND

Oxaliplatin is an effective drug used mainly for advanced colorectal cancer. Neurotoxicity is the major side effect of oxaliplatin. The present clinical and neurophysiologic study was conducted to evaluate patients receiving oxaliplatin therapy.

PATIENTS AND METHODS

Thirty-one consecutive patients with colorectal cancer who received oxaliplatin therapy were followed up for more than 3 years. The patients underwent clinical and neurophysiologic tests for large and small fiber function at every visit.

RESULTS

Most of the patients received oxaliplatin-based chemotherapy at the initial dose of 130 mg/m(2) for 6 to 8 cycles, normally every 3 weeks. Acute neurotoxicity with cold and mechanical hyperalgesia was reported by the vast majority of patients after each cycle of therapy and was confirmed by the quantitative sensory, filament, and axon reflex test. Chronic sensory cumulative neuropathy developed in most of the patients after the middle of therapy with numbness and was assessed using clinical scales, nerve conduction studies, and the vibration threshold. Our results support the persistence of the sensory nerve deficits for years after cessation of oxaliplatin therapy.

CONCLUSION

Our study has confirmed the results of a few previous long-term studies concerning the persistence of chronic large sensory fiber neuropathy and the influence of the cumulative dose of oxaliplatin on the development and severity of the chronic neuropathy. Our findings have improved the knowledge about the acute oxaliplatin-induced neurotoxicity using the C-fiber axon reflex response.

Diabetes and Body Mass Index Are Associated with Neuropathy and Prognosis in Colon Cancer Patients Treated with Capecitabine and Oxaliplatin Adjuvant Chemotherapy

BACKGROUND

There are few background data on the impact of clinical factors on neurotoxicity and prognosis in patients treated with adjuvant capecitabine and oxaliplatin (CAPOX) chemotherapy.

METHODS

102 stage II high-risk and stage III colorectal cancer patients were treated for 6 months with adjuvant CAPOX, then they were followed up. Associations between clinical variables, metabolic syndrome components, smoking and neurotoxicity were evaluated by the x03C7;2 test. The Kaplan-Meier product limit method was applied to graph disease-free survival (DFS). Univariate analysis was done with the log-rank test. Cox's proportional hazards regression was used to analyze the effect of several risk factors on DFS.

RESULTS

Significant associations were found between diabetes (p < 0.001), BMI (p = 0.01) and the occurrence of chronic neurotoxicity. After a median follow-up of 46 months, 14 patients (13.7%) had suffered recurrence. An analysis of the prognostic factors for DFS showed that prognosis is unfavorable for patients with high lymph-nodal involvement (HR: 5.23, p = 0.0007), diabetes (HR: 4.86; p = 0.03) and a BMI ≥25 (HR: 3.69, p = 0.002).

DISCUSSION

Common mediators in diabetes and obesity could be involved in peripheral neuropathy and in stimulating micro-metastases. Further studies are necessary to explain this interesting connection between diabetes, obesity and colon cancer.

Effect of Vitamin E on Oxaliplatin-induced Peripheral Neuropathy Prevention: A Randomized Controlled Trial

BACKGROUND

Peripheral neuropathy is one of the most important limitations of oxaliplatin base regimen, which is the standard for the treatment of colorectal cancer. Evidence has shown that Vitamin E may be protective in chemotherapy-induced peripheral neuropathy. The aim of this study is to evaluate the effect of Vitamin E administration on prevention of oxaliplatin-induced peripheral neuropathy in patients with colorectal cancer.

METHODS

This was a prospective randomized, controlled clinical trial. Patients with colorectal cancer and scheduled to receive oxaliplatin-based regimens were enrolled in this study. Enrolled patients were randomized into two groups. The first group received Vitamin E at a dose of 400 mg daily and the second group observed, until after the sixth course of the oxaliplatin regimen. For oxaliplatin-induced peripheral neuropathy assessment, we used the symptom experience diary questionnaire that completed at baseline and after the sixth course of chemotherapy. Only patients with a score of zero at baseline were eligible for this study.

RESULTS

Thirty-two patients were randomized to the Vitamin E group and 33 to the control group. There was no difference in the mean peripheral neuropathy score changes (after - before) between two groups, after sixth course of the oxaliplatin base regimen (mean difference [after - before] of Vitamin E group = 6.37 ± 2.85, control group = 6.57 ± 2.94; P = 0.78). Peripheral neuropathy scores were significantly increased after intervention compared with a base line in each group (P < 0.001).

CONCLUSIONS

The results from this current trial demonstrate a lack of benefit for Vitamin E in preventing oxaliplatin-induced peripheral neuropathy.

Clinical Course of Oxaliplatin-Induced Neuropathy: Results From the Randomized Phase III Trial N08CB (Alliance)

PURPOSE

Given that the clinical course of oxaliplatin-induced neuropathy is not well defined, the current study was performed to better understand clinical parameters associated with its presentation.

METHODS

Acute and chronic neuropathy was evaluated in patients receiving adjuvant FOLFOX (fluorouracil, leucovorin, and oxaliplatin) on study N08CB (North Central Cancer Treatment Group, Alliance). Acute neuropathy was assessed by having patients complete daily questionnaires for 6 days with each cycle of FOLFOX. Before each dose of FOLFOX and as long as 18 months after chemotherapy cessation, chronic neurotoxicity was assessed with use of the 20-item, European Organisation for Research and Treatment of Cancer quality-of-life questionnaire for patients with chemotherapy-induced peripheral neuropathy.

RESULTS

Three hundred eight (89%) of the 346 patients had at least one symptom of acute neuropathy with the first cycle of FOLFOX; these symptoms included sensitivity to touching cold items (71%), sensitivity to swallowing cold items (71%), throat discomfort (63%), or muscle cramps (42%). Acute symptoms peaked at day 3 and improved, although they did not always resolve completely between treatments. These symptoms were about twice as severe in cycles 2 through 12 as they were in cycle 1. For chronic neurotoxicity, tingling was the most severe symptom, followed by numbness and then pain. During chemotherapy, symptoms in the hands were more prominent than they were in the feet; by 18 months, symptoms were more severe in the feet than they were in the hands. Patients with more severe acute neuropathy during the first cycle of therapy experienced more chronic sensory neurotoxicity (P < .0001).

CONCLUSION

Acute oxaliplatin-induced neuropathy symptoms do not always completely resolve between treatment cycles and are only half as severe on the first cycle as compared with subsequent cycles. There is a correlation between the severities of acute and chronic neuropathies.

MC11C4: a pilot randomized, placebo-controlled, double-blind study of venlafaxine to prevent oxaliplatin-induced neuropathy

PURPOSE

Previous pilot data suggested that venlafaxine could prevent acute and chronic oxaliplatin-related neuropathy. The purpose of this randomized, placebo-controlled, double-blinded pilot study was to obtain additional data to support conducting a phase III trial to test the use of venlafaxine to prevent oxaliplatin neurotoxicity.

METHODS

Fifty patients, scheduled to undergo oxaliplatin-based therapy (FOLFOX) for stages II-III (67%) or stage IV (33%) colon cancer, were randomized to receive venlafaxine extended release (37.5 mg) or placebo, twice daily, through their last dose of oxaliplatin and then titrated off. Neurotoxicity was evaluated via several patient- and physician-reported measures, including the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-Chemotherapy-Induced Peripheral Neuropathy 20 (EORTC QLQ-CIPN20) instrument.

RESULTS

Baseline patient characteristics were equivalent for the two arms, with a median age of 60 years. There was a trend toward benefit for the venlafaxine arm, when evaluated by the oxaliplatin-specific neuropathy scale and by acute neuropathy measures of throat discomfort and discomfort swallowing cold liquids, the latter only for the first two oxaliplatin doses. These trends were outweighed by a lack of any such trends in all other measurements including the following: (1) the CIPN20 sensory subscale (P = 0.55, primary endpoint), physician-completed NCI CTCAE assessment, or cumulative administered oxaliplatin doses (median 716 vs 631 mg for placebo and venlafaxine, respectively, P = 0.34).

CONCLUSIONS

The present study neither supports the use of venlafaxine for preventing oxaliplatin-induced neuropathy in clinical practice nor the initiation of a phase III trial to investigate venlafaxine in this setting.

Mechanisms involved in the development of chemotherapy-induced neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating and painful condition seen in patients undergoing treatment with common agents such as vincristine, paclitaxel, oxaliplatin and bortezomib. The mechanisms of this condition are diverse, and include an array of molecular and cellular contributions. Current research implicates genetic predispositions to this condition, which then may influence cellular responses to chemotherapy. Processes found to be influenced during CIPN include increased expression of inflammatory mediators, primarily cytokines, which can create cascading effects in neurons and glia. Changes in ion channels and neurotransmission, as well as changes in intracellular signaling and structures have been implicated in CIPN. This review explores these issues and suggests considerations for future research.

Complex impairment of IA muscle proprioceptors following traumatic or neurotoxic injury

The health of primary sensory afferents supplying muscle has to be a first consideration in assessing deficits in proprioception and related motor functions. Here we discuss the role of a particular proprioceptor, the IA muscle spindle proprioceptor in causing movement disorders in response to either regeneration of a sectioned peripheral nerve or damage from neurotoxic chemotherapy. For each condition, there is a single preferred and widely repeated explanation for disability of movements associated with proprioceptive function. We present a mix of published and preliminary findings from our laboratory, largely from in vivo electrophysiological study of treated rats to demonstrate newly discovered IA afferent defects that seem likely to make important contributions to movement disorders. First, we argue that reconnection of regenerated IA afferents with inappropriate targets, although often repeated as the reason for lost stretch-reflex contraction, is not a complete explanation. We present evidence that despite successful recovery of stretch-evoked sensory signaling, peripherally regenerated IA afferents retract synapses made with motoneurons in the spinal cord. Second, we point to evidence that movement disability suffered by human subjects months after discontinuation of oxaliplatin (OX) chemotherapy for some is not accompanied by peripheral neuropathy, which is the acknowledged primary cause of disability. Our studies of OX-treated rats suggest a novel additional explanation in showing the loss of sustained repetitive firing of IA afferents during static muscle stretch. Newly extended investigation reproduces this effect in normal rats with drugs that block Na(+) channels apparently involved in encoding static IA afferent firing. Overall, these findings highlight multiplicity in IA afferent deficits that must be taken into account in understanding proprioceptive disability, and that present new avenues and possible advantages for developing effective treatment. Extending the study of IA afferent deficits yielded the additional benefit of elucidating normal processes in IA afferent mechanosensory function.

Chemotherapy-induced peripheral neuropathy in patients treated with taxanes and platinum derivatives

BACKGROUND

Chemotherapy with taxanes and platinum compounds has resulted in substantial survival benefits both in adjuvant and metastatic settings. However, as a side effect, such chemotherapy may cause peripheral neuropathy (CIPN) which may result in discontinuation of treatment, and if it persists after treatment completion, has a negative impact on quality of life (QoL).

RESULTS

Symptoms of CIPN are sensory, like pain, numbness, and tingling, typically located in the hands and feet. For oxaliplatin, there is an acute form of CIPN, resulting in paraesthesias in the mouth and throat during or shortly after the infusion triggered by exposure to cold. Risks factors for CIPN include preexisting neuropathy, either from treatment with other neurotoxic agents, or from comorbid conditions. The incidence of CIPN is related to dose per cycle, cumulative dose, and duration of infusion. While cisplatin-induced neuropathy is irreversible, CIPN induced by taxanes may persist for several years in about 30% of patients. Evidence from the literature is suggestive that CIPN is likely to be negatively associated with QoL. No agents have been identified to be recommended for the prevention of CIPN. For treatment of CIPN, the best available data supports a moderate recommendation for treatment with duloxetine and evidence is inconclusive regarding the use of tricyclic antidepressants (such as nortriptyline), gabapentin, and a compounded topical gel containing baclofen, amitriptyline HCL, and ketamine.

CONCLUSION

Research is still needed to predict which patients are at high risk of developing CIPN during treatment and in whom CIPN will persist after completion of chemotherapy.

Reliability and accuracy of quantitative sensory testing for oxaliplatin-induced neurotoxicity

OBJECTIVES

Thermal quantitative sensory testing (QST) is a non-invasive procedure helpful in the assessment of the function of small Aδ and C nerve sensory fibres. Oxaliplatin (OXA) is an effective chemotherapeutic agent, but is frequently associated with neurotoxic dose-limiting side effects. This controlled clinical trial evaluated the reliability and accuracy of thermal QST for assessing the OXA-induced acute neuropathic syndrome, whose clinical hallmark is cold-triggered painful paraesthesia.

MATERIALS & METHODS

A testing protocol with the Thermal Sensory Analyzer (Medoc) was carried out in 20 colorectal cancer patients during the initial four cycles of OXA-based chemotherapy and in 20 age- and sex-matched healthy volunteers. Testing was carried out on the hands and included the determination of thermal detection and pain thresholds and the intensity of pain evoked by cold stimuli. Calculations were made of: coefficients of test-retest and inter-rater reliability, indices of responsiveness and parameters that quantify diagnostic accuracy.

RESULTS

Thermal thresholds showed moderate to good reliability (ρ ≥ 0.383), but were not consistently responsive to the effects of chemotherapy (cold pain thresholds decreased in both groups, although almost twice in patients compared to healthy volunteers). Conversely, the intensity of pain evoked by suprathreshold cold stimuli was reliable (ρ ≥ 0.822), responsive (detected changes over time) and discriminated between patients and healthy volunteers (area under the ROC curve = 0.700).

CONCLUSIONS

The procedure was reliable and accurate to evaluate cold hyperalgesia resulting from OXA administration. The data provided may be used to define efficacy endpoints for future clinical trials of therapies for OXA-induced neuropathies and calculate appropriate sample sizes.

Effects of the compounds resveratrol, rutin, quercetin, and quercetin nanoemulsion on oxaliplatin-induced hepatotoxicity and neurotoxicity in mice

Oxaliplatin (OXA) is a platinum compound widely used in the treatment of some solid tumors, especially colorectal cancer. Despite its usefulness, oxaliplatin-associated neurotoxicity represents the main dose-limiting factor of this drug, and until now, there is no suitable treatment. Chemotherapy with oxaliplatin also increases the rate of developing hepatic damages with inflammatory activity, termed chemotherapy-associated steatohepatitis (CASH). In the present study, we aimed to compare the effects of a series of antioxidant compounds on simultaneous development of oxaliplatin-induced hepato- and neurotoxicity in mice. Mice BALB/c were treated with oxaliplatin for 6 weeks, 10 mg/kg, intraperitoneally, resulting in mechanical allodynia and hepatic steatosis. We administered the following antioxidant compounds--rutin (RT) (20 mg/kg), resveratrol (RVS) (100 mg/kg), quercetin (QT) (20 mg/kg), and quercetin nanoemulsion (NQT) (20 mg/kg)--daily by gavage to BALB/c, and N-acetylcysteine (NAC) was used as positive control. Treatments with RSV, RUT, or NQT were able to prevent mechanical allodynia when compared to the OXA group, and this effect was associated with decreased c-Fos immunopositivity in the lumbar spinal cord. Regarding the effects on steatohepatitis, RVS, QT, and NQT almost completely reversed the mean liver weight increase induced by OXA. In accordance with these previous data, histological evaluation indicated attenuation of all features of hepatic steatosis evaluated in RSV, RUT, QT, and NQT groups. These compounds were able to reduce the immunopositivity for the apoptosis marker caspase-3. On the other hand, only QT and NQT treatments were able to reduce neutrophil migration measured by myeloperoxidase (MPO) activity. These results suggest that the compounds tested, RSV, RUT, QT, and NQT, would be useful for the clinical treatment of neuro- and hepatoxicity induced by oxaliplatin.

Peptidergic intraepidermal nerve fibers in the skin contribute to the neuropathic pain in paclitaxel-induced peripheral neuropathy

Paclitaxel in chemotherapy-induced peripheral neuropathy (CIPN) is predominantly with a dose-limiting effect on neuropathic pain in clinical strategy. In the present study, the relationship between the neuropathic pain and nerve degeneration in paclitaxel CIPN was investigated. Adult male Sprague-Dawley (SD) rats were divided into three paclitaxel groups (0.5, 1.0, 2.0mg/kg) and a vehicle group with four intraperitoneal (i.p.) injections on alternating days. Our results demonstrated that the paclitaxel groups significantly exhibited the reductions of thermal hyperalgesia and mechanical allodynia. The neurotoxicity of paclitaxel conveyed the degeneration of intraepidermal nerve fibers (IENFs) in hindpaw glabrous skin. Nevertheless, the influence of paclitaxel to the peptidergic IENFs are even unknown. The skin innervation of protein gene product 9.5 (PGP 9.5)-immunoreactive (IR) IENFs in paclitaxel groups revealed the decreasing levels of density (73.54±0.72%, 63.17±1.77%, 61.79±2.68%, respectively; vs. vehicle group, p<0.05) throughout the entire experimental period. Additionally, the diminishing levels of density for peptidergic substance P (SP)-IR IENFs in paclitaxel groups were significantly shown (48.84±1.74%, 30.02±1.69%, 30.14±0.37%, respectively; vs. vehicle group, p<0.05). On the contrary, the density for peptidergic calcitonin gene-related peptide (CGRP)-IR IENFs in paclitaxel groups were revealed the similar decreasing levels (82.75±0.91%, 84.34±3.20%, 81.99±0.25%, respectively; vs. vehicle group, p<0.05). Linear regression analyses exhibited that densities of IENFs for PGP 9.5, SP, CGRP were correlated with withdrawal latencies (r(2)=0.77, p<0.0001; r(2)=0.75, p<0.0001; r(2)=0.28, p=0.0001, respectively) and mechanical thresholds (r(2)=0.43, p<0.0001; r(2)=0.73, p<0.0001; r(2)=0.40, p<0.0001, respectively). Therefore, the present results suggested that the development of neuropathic pain following paclitaxel injection induced the progressive degeneration of IENFs in skin and gave the evidence that the peptidergic IENFs may play an important role in therapeutic strategy of paclitaxe CIPN.

Pain in cancer survivors

Pain is a common problem in cancer survivors, especially in the first few years after treatment. In the longer term, approximately 5% to 10% of survivors have chronic severe pain that interferes with functioning. The prevalence is much higher in certain subpopulations, such as breast cancer survivors. All cancer treatment modalities have the potential to cause pain. Currently, the approach to managing pain in cancer survivors is similar to that for chronic cancer-related pain, pharmacotherapy being the principal treatment modality. Although it may be appropriate to continue strong opioids in survivors with moderate to severe pain, most pain problems in cancer survivors will not require them. Moreover, because more than 40% of cancer survivors now live longer than 10 years, there is growing concern about the long-term adverse effects of opioids and the risks of misuse, abuse, and overdose in the nonpatient population. As with chronic nonmalignant pain, multimodal interventions that incorporate nonpharmacologic therapies should be part of the treatment strategy for pain in cancer survivors, prescribed with the aim of restoring functionality, not just providing comfort. For patients with complex pain issues, multidisciplinary programs should be used, if available. New or worsening pain in a cancer survivor must be evaluated to determine whether the cause is recurrent disease or a second malignancy. This article focuses on patients with a history of cancer who are beyond the acute diagnosis and treatment phase and on common treatment-related pain etiologies. The benefits and harms of the various pharmacologic and nonpharmacologic options for pain management in this setting are reviewed.

Treatment of oxaliplatin-induced peripheral neuropathy by intravenous mangafodipir

BACKGROUND

The majority of patients receiving the platinum-based chemotherapy drug oxaliplatin develop peripheral neurotoxicity. Because this neurotoxicity involves ROS production, we investigated the efficacy of mangafodipir, a molecule that has antioxidant properties and is approved for use as an MRI contrast enhancer.

METHODS

The effects of mangafodipir were examined in mice following treatment with oxaliplatin. Neurotoxicity, axon myelination, and advanced oxidized protein products (AOPPs) were monitored. In addition, we enrolled 23 cancer patients with grade ≥ 2 oxaliplatin-induced neuropathy in a phase II study, with 22 patients receiving i.v. mangafodipir following oxaliplatin. Neuropathic effects were monitored for up to 8 cycles of oxaliplatin and mangafodipir.

RESULTS

Mangafodipir prevented motor and sensory dysfunction and demyelinating lesion formation. In mice, serum AOPPs decreased after 4 weeks of mangafodipir treatment. In 77% of patients treated with oxaliplatin and mangafodipir, neuropathy improved or stabilized after 4 cycles. After 8 cycles, neurotoxicity was downgraded to grade ≥ 2 in 6 of 7 patients. Prior to enrollment, patients received an average of 880 ± 239 mg/m2 oxaliplatin. Patients treated with mangafodipir tolerated an additional dose of 458 ± 207 mg/m2 oxaliplatin despite preexisting neuropathy. Mangafodipir responders managed a cumulative dose of 1,426 ± 204 mg/m2 oxaliplatin. Serum AOPPs were lower in responders compared with those in nonresponders.

CONCLUSION

Our study suggests that mangafodipir can prevent and/or relieve oxaliplatin-induced neuropathy in cancer patients. Trial registration. Clinicaltrials.gov NCT00727922. Funding. Université Paris Descartes, Ministère de la Recherche et de l'Enseignement Supérieur, and Assistance Publique-Hôpitaux de Paris.

Oxaliplatin-induced neuropathy in colorectal cancer: many questions with few answers

Oxaliplatin is a chemotherapeutic agent effective against advanced colorectal cancer. Unlike with other platinum-based agents, the main side effect of oxaliplatin is polyneuropathy. Oxaliplatin-induced polyneuropathy (OIPN) has a unique profile, which can be divided into acute and chronic neurotoxicity. Early identification of the neurotoxicity and alterations in dose or schedule for the medication could prevent the development of chronic symptoms, which, once established, may take many months or years to resolve or even persist throughout life with a substantial effect on quality of life. There is no doubt that the use of pharmacogenomic methods to identify genetic bases of interindividual differences in drug response has led to what is called tailoring treatment. Yet there are some challenges regarding the application of these differences. Many efforts have been made to prevent or treat OIPN. Better understanding of the mechanisms underlying the acute and chronic forms of OIPN will be a key component of future advances in the prevention and treatment of OIPN. The aim of this review is to highlight the clinical presentation, assessment, and management of OIPN, as well as the underlying pathophysiologic and pharmacogenomic background.

Efficacy of goshajinkigan for oxaliplatin-induced peripheral neuropathy in colorectal cancer patients

Objective. To evaluate the efficacy of Goshajinkigan for oxaliplatin-induced peripheral neuropathy in colorectal cancer patients. Patients. Colorectal cancer patients (N = 29) who received ≥4 weeks of Goshajinkigan for oxaliplatin-induced peripheral neuropathy during chemotherapy at Kyoto Prefectural University of Medicine were (Goshajinkigan group) compared to 44 patients who had not received Goshajinkigan during the same period (non-Goshajinkigan group). Main Outcome Measures. The effect of Goshajinkigan was graded as curative, effective, stabilizing, or deleterious. The relationships between the grade of peripheral neuropathy and the dose of oxaliplatin in the Goshajinkigan and non-Goshajinkigan groups were evaluated. Results. The effect of Goshajinkigan on peripheral neuropathy in the Goshajinkigan group was curative, effective, stabilizing, and deleterious in 3.4, 20.7, 69.0, and 6.9% of patients, compared to the effect in the non-Goshajinkigan group (4.5, 15.9, 45.5, and 34.1%). The ratio of deleterious effects was significantly different between these two groups (P = 0.04). A Kaplan-Meier analysis in relation to the cumulative dose of oxaliplatin showed that the incidence of grade 3 peripheral neuropathy tended to be less in the Goshajinkigan group (P = 0.05). There were no significant differences in time to treatment failure and severe adverse events between these two groups. Conclusions. Goshajinkigan prevented exacerbation of oxaliplatin-induced peripheral neuropathy. This trial is registered with UMIN000009956

Chemotherapy-induced peripheral neurotoxicity: a critical analysis

With a 3-fold increase in the number of cancer survivors noted since the 1970s, there are now over 28 million cancer survivors worldwide. Accordingly, there is a heightened awareness of long-term toxicities and the impact on quality of life following treatment in cancer survivors. This review will address the increasing importance and challenge of chemotherapy-induced neurotoxicity, with a focus on neuropathy associated with the treatment of breast cancer, colorectal cancer, testicular cancer, and hematological cancers. An overview of the diagnosis, symptomatology, and pathophysiology of chemotherapy-induced peripheral neuropathy will be provided, with a critical analysis of assessment strategies, neuroprotective approaches, and potential treatments. The review will concentrate on neuropathy associated with taxanes, platinum compounds, vinca alkaloids, thalidomide, and bortezomib, providing clinical information specific to these chemotherapies.

Neurological Adverse Effects in Patients of Advanced Colorectal Carcinoma Treated with Different Schedules of FOLFOX

The study is designed to assess the frequency and severity of few dose limiting neurological adverse effects of four different schedules of FOLFOX. Patients with histologically confirmed advanced colorectal carcinoma (CRC) were included in the study. Toxicity was graded according to CTC v 2.0. The frequency of grade 3 and 4 adverse effects was comparatively assessed in each treatment arm. The difference in the pattern of toxicity between the treatment schedule was evaluated. The most frequent adverse symptom of neurological adverse effect was grade 1 paresthesia in the patients treated with FOLFOX4 schedule. Grade 4 peripheral neuropathy was reported in few patients of FOLFOX7 treatment arm. Frequency and onset of neurological adverse effects like paresthesia, dizziness, and hypoesthesia were significantly different (P < 0.05), whereas frequency and onset of peripheral neuropathy were highly significant (P < 0.01) in each treatment arm of FOLFOX. Peripheral neuropathy was associated with electrolyte imbalance and diabetes in few patients. Frequency of symptoms, for example, paresthesia, is associated with increased number of recurrent exposure to oxaliplatin (increased number of cycles) even at low doses (85 mg/m²), whereas severity of symptoms, for example, peripheral neuropathy, is associated with higher dose (130 mg/m²) after few treatment cycles.

Predicting acute and persistent neuropathy associated with oxaliplatin

OBJECTIVES

We sought to predict oxaliplatin-associated peripheral neuropathy during modified FOLFOX6 (mFOLFOX6) therapy.

METHODS

Equal numbers of male and female patients with previously untreated, primary or recurrent colorectal cancer were followed through a first course of mFOLFOX6 with 85 mg/m² oxaliplatin every 2 weeks. Accounting for correlation among a subject's cycle, logistic regression estimated per cycle risk of acute (under 14 d) and persistent (14 d or more) neuropathy. Proportional hazards regression predicted time to persistent neuropathy.

RESULTS

Among mFOLFOX6 recipients (n = 50, age 58.9 ± 10.1 y), 36% received concomitant bevacizumab. Of the total number of cycles, 94.2% (422/448) were evaluable. Most (84%) subjects reported neuropathy at least once; 74% reported acute and 48% reported persistent symptoms. On multivariate analysis, risk factors shared by acute and persistent neuropathy were body surface area >2.0, acute neuropathy in a past cycle, and lower body weight. In addition, risk of acute neuropathy decreased with age (adjusted for renal function and winter season), whereas risk of persistent neuropathy increased with cumulative dose of oxaliplatin and persistent neuropathy in a past cycle. Concomitant bevacizumab was not a risk factor when administered in stage IV disease but was associated with persistent neuropathy when administered experimentally in stage III. Females had no increased risk of either form of neuropathy. After 3 cycles, weight, body surface area, and prior acute neuropathy predicted time to persistent neuropathy.

CONCLUSIONS

Routinely available clinical factors predict acute and persistent neuropathy associated with oxaliplatin. When validated, the proposed prognostic score for persistent neuropathy can help clinicians counsel patients about chemotherapy.

Evidence for a causal relationship between hyperkalaemia and axonal dysfunction in end-stage kidney disease

OBJECTIVE

Potassium (K(+)) has been implicated as a factor in the development of uraemic neuropathy. This study was undertaken to investigate whether hyperkalaemia plays a causal role in axonal dysfunction in end-stage kidney disease (ESKD).

METHODS

Median motor nerve excitability studies were undertaken in four haemodialysis patients during a modified dialysis session. The serum K(+) level was "clamped" (fixed) for the first 3h of dialysis, whilst allowing all other solutes to be removed, this was followed by dialysis against low dialysate K(+) for a further 4 h. Blood chemistry and nerve excitability studies were undertaken prior to, during and following dialysis. Results were compared to results from the same patients during routine dialysis sessions.

RESULTS

All patients demonstrated significant nerve excitability abnormalities reflective of nerve membrane depolarization in pre-dialysis recordings (p<0.01). After the 3 h clamp period, serum K(+) remained elevated (5.0 mmol/L) and nerve excitability remained highly abnormal, despite the significant clearance of other uraemic toxins. In contrast, studies undertaken during routine dialysis sessions demonstrated significant improvement in both serum K(+) and nerve function after 3 h.

CONCLUSIONS

The current study has established a causal relationship between serum K(+) and axonal membrane depolarization in haemodialysis patients.

SIGNIFICANCE

From a clinical perspective, strict K(+) control may help improve nerve function in ESKD.

Oxaliplatin-induced neurotoxicity is dependent on the organic cation transporter OCT2

Oxaliplatin is an integral component of colorectal cancer therapy, but its clinical use is associated with a dose-limiting peripheral neurotoxicity. We found that the organic cation transporter 2 (OCT2) is expressed on dorsal root ganglia cells within the nervous system where oxaliplatin is known to accumulate. Cellular uptake of oxaliplatin was increased by 16- to 35-fold in cells overexpressing mouse Oct2 or human OCT2, and this process was associated with increased DNA platination and oxaliplatin-induced cytotoxicity. Furthermore, genetic or pharmacologic knockout of Oct2 protected mice from hypersensitivity to cold or mechanical-induced allodynia, which are established tests to assess acute oxaliplatin-induced neurotoxicity. These findings provide a rationale for the development of targeted approaches to mitigate this debilitating toxicity.

Effects of hemodiafiltration and high flux hemodialysis on nerve excitability in end-stage kidney disease

OBJECTIVES

Peripheral neuropathy is the most common neurological complication in end-stage kidney disease. While high flux hemodialysis (HFHD) and hemodiafiltration (HDF) have become the preferred options for extracorporeal dialysis therapy, the effects of these treatments on nerve excitability have not yet been examined.

METHODS

An observational proof-of-concept study of nerve excitability and neuropathy was undertaken in an incident dialysis population (n = 17) receiving either HFHD or HDF. Nerve excitability techniques were utilised to assess nerve ion channel function and membrane potential, in conjunction with clinical assessment and standard nerve conduction studies. A mathematical model of axonal excitability was used to investigate the underlying basis of the observed changes. Nerve excitability was recorded from the median nerve, before, during and after a single dialysis session and correlated with corresponding biochemical markers. Differences in nerve excitability were compared to normal controls with longitudinal follow-up over an 18 month period.

RESULTS

Nerve excitability was performed in patient cohorts treated with either HFHD (n = 9) or online HDF (n = 8), with similar neuropathy status. Nerve excitability measures in HDF-treated patients were significantly closer to normal values compared to HFHD patients obtained over the course of a dialysis session (p<0.05). Longitudinal studies revealed stability of nerve excitability findings, and thus maintenance of improved nerve function in the HDF group.

CONCLUSIONS

This study has provided evidence that nerve excitability in HDF-treated patients is significantly closer to normal values prior to dialysis, across a single dialysis session and at longitudinal follow-up. These findings offer promise for the management of neuropathy in ESKD and should be confirmed in randomised trials.

Comparative clinical benefits of systemic adjuvant therapy for paradigm solid tumors

Adjuvant therapy employing cytotoxic chemotherapy, molecularly targeted agents, immunologic, and hormonal agents has shown a significant impact upon a variety of solid tumors. The principles that guide adjuvant therapy differ among various tumor types and specific modalities, but generally indicate a greater impact of therapy in the postsurgical setting of micrometastatic disease, for which adjuvant therapy is commonly pursued, vs. the setting of gross unresectable disease. This review of adjuvant therapies in current use for five major solid tumors highlights the rationale for current effective adjuvant therapy, and draws comparisons between the adjuvant regimens that have found application in solid tumors.

Vitamin E for prevention of oxaliplatin-induced peripheral neuropathy: a pilot randomized clinical trial

CONTEXT AND OBJECTIVE Oxaliplatin is one of the chemotherapy regimens most used for treating colorectal cancer. One of the main limitations to its use is induction of peripheral neuropathy. Previous studies have shown that vitamin E can reduce the incidence of peripheral neuropathy by 50%. This study aimed to assess the effectiveness of vitamin E for prevention of oxaliplatin-induced peripheral neuropathy. DESIGN AND SETTING Prospective, phase II, randomized pilot study developed at a university hospital in the Greater ABC region. METHODS Patients were randomized five days before starting oxaliplatin treatment, to receive either vitamin E or placebo until the end of the chemotherapy regimen. The outcome was evaluated using the Common Terminology Criteria for Adverse Events (CTCAE), version 3, and specific gradation scales for oxaliplatin-induced peripheral neuropathy. Patients with colorectal and gastric cancer who had been scheduled to receive oxaliplatin-based chemotherapy were included. Both groups received calcium and magnesium supplementation before and after oxaliplatin infusions. RESULTS Eighteen patients were randomized to the vitamin E group and 16 to the placebo group. Cumulative incidence of 83% with peripheral neuropathy grades 1/2 was observed in the vitamin E group, versus 68% in the placebo group (P = 0.45). A trend towards more diarrhea was observed among patients who received vitamin E (55.6% vs. 18.8%; P = 0.06). There were no other significant differences in toxicity between the groups. CONCLUSIONS No significant decrease in the incidence of acute oxaliplatin-induced peripheral neuropathy was demonstrated through vitamin E use.

Axonal dysfunction prior to neuropathy onset in type 1 diabetes

BACKGROUND

The present study was undertaken to determine whether there were changes evident in axonal membrane function prior to the onset of neuropathy in patients with type 1 and type 2 diabetes.

METHODS

From a cohort of 110 consecutive referrals, nerve excitability was investigated in 40 diabetic patients without clinical evidence of neuropathy (20 type 1 diabetic patients and 20 type 2 diabetic patients). Groups were matched for gender, disease duration and HbA(1c). Studies were also undertaken in two control groups, younger controls and older controls, matched for age and gender with the diabetic cohorts.

RESULTS

Subjects with type 1 diabetes demonstrated significant nerve excitability abnormalities when compared with younger normal controls. Specifically, type 1 subjects showed a significant reduction at multiple time points in both depolarising and hyperpolarising threshold electrotonus. Additionally, the relative refractory period was prolonged (type 1, 3.19 ms; younger normal controls, 3.0 ms; p < 0.05) and superexcitability was reduced (type 1, -23.12%; younger normal controls, -26.37%; p < 0.05), consistent with axonal membrane depolarisation. Correlations were identified in type 1 patients between disease duration and nerve excitability parameters, including the relative refractory period (r = -0.533, p < 0.05). In contrast, only minor non-specific changes were noted in the type 2 group.

DISCUSSION

This study provides clear evidence of altered axonal function in patients with type 1 diabetes in the absence of clinical neuropathy. These findings suggest that altered axonal membrane potential may precede neuropathy onset in type 1 diabetes and as such may indicate a window of opportunity to intervene and potentially reverse axonal membrane dysfunction before the development of irreversible neuropathy.

Incidence of atypical acute nerve hyperexcitability symptoms in oxaliplatin-treated patients with colorectal cancer

CONTEXT

Peripheral, acute or chronic, neurotoxicity is one of the main dose-limiting adverse effects of oxaliplatin (OXA). Acute neurotoxicity is typically characterized by distal and perioral cold-induced paresthesias and dysesthesias, but other uncommon symptoms might also be present.

OBJECTIVES

The aim of this post hoc analysis of data extracted from a prospective, multicenter study was to assess the incidence of uncommon acute OXA neurotoxicity symptoms in patients undergoing OXA-based chemotherapy.

METHODS

One hundred chemotherapy-naïve patients (62 males, 38 females, aged 64.7 ± 8.7 years) with colorectal cancer scheduled to receive OXA-based therapy (FOLFOX-4, FOLFOX-6, and XELOX) underwent neurologic evaluation after the 1st infusion and then after 3 and 6 months of OXA-based chemotherapy (after 6th or 4th and 12th or 8th cycles, respectively, according to regimen). At evaluation, patients were asked to report the presence and characteristics of acute hyperexcitability symptoms.

RESULTS

Eighty-two patients presented typical symptoms of acute OXA neurotoxicity in the form of cold-induced paresthesias and dysesthesias. In 45/82 (54.9 %) of patients, uncommon symptoms were also present; shortness of breath (32 %), jaw spasm (26 %), fasciculations (25 %), cramps (20 %), and difficulty in swallowing (18 %) were more frequently reported, while voice (4 %) and visual changes, ptosis and pseudolaryngospasm (1 %) occurred rarely. No significant correlation was disclosed between acute OXA neurotoxicity and chemotherapy regimen, cumulative dose of OXA or patients' age.

CONCLUSIONS

A high percentage of patients treated with OXA-based chemotherapy develop acute neurotoxicity also with uncommon manifestations. Since OXA acute neurotoxicity might be related to the onset of chronic neurotoxicity, these patients should be closely monitored to avoid this dose-limiting adverse effect.

Effect of green tea extracts on oxaliplatin-induced peripheral neuropathy in rats

BACKGROUND

A common side effect of oxaliplatin is peripheral neurotoxicity. Oxidative stress to dorsal root ganglion (DRG) may be one of important pathogenic mechanisms. Green tea contains four polyphenol catechins, which are known to be potent antioxidants. The present work is aimed to determine whether green tea extracts have neuroproective or palliative effects on neurotoxicity symptoms induced by oxaliplatin.

METHODS

We conducted behavioral tests including sensory and thermal thresholds, an electrophysiological study, and TUNEL staining to assess neurotoxicity during the experimental period using animal models.

RESULTS

A total of 14 adult rats were randomly allocated into two groups. Oxaliplatin (4 mg/kg) with or without green tea (300 mg/kg orally once daily) was administered intraperitoneally twice per week for 6 weeks. At 4 and 6 weeks after oxaliplatin administration, sensory threshold values were significantly decreased and at 6 weeks after oxaliplatin administration, thermal threshold values were significantly increased in oxaliplatin-treated rats compared with those in rat treated with oxaliplatin and green tea extracts. The electrophysiological assessment, including sensory nerve conduction and H-reflex-related sensory nerve conduction velocity, revealed no significant changes in the two groups. TUNEL staining showed no significant difference in the number of apoptotic-featured cells between the two experimental groups in the DRG or peripheral nerves, but the number of apoptotic-featured cells in DRG was higher than that in sciatic nerves within each group.

CONCLUSIONS

Green tea extracts may be a useful adjuvant to alleviate sensory symptoms after oxaliplatin administration, such as allodynia, but did not prevent morphometric or electrophysiological alterations induced by oxaliplatin.

Differences in tissue degeneration between preoperative chemotherapy and preoperative chemoradiotherapy for colorectal cancer

PURPOSE

Preoperative chemoradiotherapy (CRT) for rectal cancer is administered to improve local control, but can also induce severe anal dysfunction after surgery, while preoperative chemotherapy that significantly reduces the primary lesion in rectal cancer has recently been developed. The aim of the study was to examine differences in the effects of preoperative CRT and chemotherapy on tissue degeneration of patients with colorectal cancer.

METHODS

The subjects were 91 patients, including 68 with rectal cancer who underwent internal sphincteric resection with (n = 47, CRT group) or without (n = 21, control group) preoperative CRT, and 23 with colorectal cancer who received preoperative FOLFOX treatment. Peripheral nerve degeneration was evaluated histopathologically using H&E-stained sections, based on karyopyknosis, disparity of the nucleus, denucleation, vacuolar or acidophilic degeneration of the cytoplasm, and adventitial neuronal changes.

RESULTS

The incidence of neural degeneration was significantly higher in the CRT group than in the control group and FOLFOX group. There were no differences in any items of neural degeneration between the FOLFOX and control groups.

CONCLUSION

CRT induced marked neural degeneration around the rectal tumor. FOLFOX treatment produced mild neural degeneration similar to that in the control group.

Clinical pattern and associations of oxaliplatin acute neurotoxicity: a prospective study in 170 patients with colorectal cancer

BACKGROUND

The objective of the current prospective, multicenter, international study was to trace the incidence and severity of acute oxaliplatin-induced peripheral neuropathy (OXLIPN) and to determine its clinical pattern. The authors also specifically tested whether patients who had more symptoms of acute OXLIPN eventually would develop a more severe chronic, cumulative form of OXLIPN.

METHODS

One hundred seventy patients (mean ± standard deviation age, 63.7 ± 8.7 years) who were scheduled to receive either combined leucovorin, 5-fluoruracil, and oxaliplatin (FOLFOX) or combined capecitabine and oxaliplatin (XELOX) for metastatic colorectal cancer were monitored prospectively at baseline and were followed in 4 European sites. The incidence of hyperexcitability symptoms secondary to acute OXLIPN was assessed by using a descriptive questionnaire (yes/no question) at each clinical evaluation. Motor and neurosensory criteria according to version 3 of the National Cancer Institute's Common Toxicity Criteria were applied to clinically grade the severity of OXLIPN.

RESULTS

Acute OXLIPN was present in 146 of 170 patients (85.9%). The vast majority of these patients manifested cold-induced perioral (95.2%) or pharyngolaryngeal (91.8%) dysesthesias. Severe acute OXLIPN that required prolongation of oxaliplatin infusion from 2 hours to 4 to 6 hours occurred in 32 of 146 patients (21.9%). The increased number of acute OXLIPN symptoms was correlated significantly (Spearman rho correlation coefficient [r]) with both the development (r = 0.602; P < .001) and the degree of the chronic, cumulative form (r = 0.702; P < .001).

CONCLUSIONS

The current results indicated that the vast majority of patients with colorectal cancer who receive oxaliplatin-based chemotherapy will manifest symptoms of a transient acute syndrome soon after oxaliplatin administration. Patients who have a more complex combination of acute phenomena related to axonal hyperexcitability are those who eventually develop more severe OXLIPN. Therefore, it may be advisable to test agents against acute OXLIPN to verify their effects on the chronic form.

Nerve excitability assessment in chemotherapy-induced neurotoxicity

Chemotherapy-induced neurotoxicity is a serious consequence of cancer treatment, which occurs with some of the most commonly used chemotherapies^1,2. Chemotherapy-induced peripheral neuropathy produces symptoms of numbness and paraesthesia in the limbs and may progress to difficulties with fine motor skills and walking, leading to functional impairment. In addition to producing troubling symptoms, chemotherapy-induced neuropathy may limit treatment success leading to dose reduction or early cessation of treatment. Neuropathic symptoms may persist long-term, leaving permanent nerve damage in patients with an otherwise good prognosis³. As chemotherapy is utilised more often as a preventative measure, and survival rates increase, the importance of long-lasting and significant neurotoxicity will increase.

There are no established neuroprotective or treatment options and a lack of sensitive assessment methods. Appropriate assessment of neurotoxicity will be critical as a prognostic factor and as suitable endpoints for future trials of neuroprotective agents. Current methods to assess the severity of chemotherapy-induced neuropathy utilise clinician-based grading scales which have been demonstrated to lack sensitivity to change and inter-observer objectivity⁴. Conventional nerve conduction studies provide information about compound action potential amplitude and conduction velocity, which are relatively non-specific measures and do not provide insight into ion channel function or resting membrane potential. Accordingly, prior studies have demonstrated that conventional nerve conduction studies are not sensitive to early change in chemotherapy-induced neurotoxicity^4-6. In comparison, nerve excitability studies utilize threshold tracking techniques which have been developed to enable assessment of ion channels, pumps and exchangers in vivo in large myelinated human axons^7-9.

Nerve excitability techniques have been established as a tool to examine the development and severity of chemotherapy-induced neurotoxicity^10-13. Comprising a number of excitability parameters, nerve excitability studies can be used to assess acute neurotoxicity arising immediately following infusion and the development of chronic, cumulative neurotoxicity. Nerve excitability techniques are feasible in the clinical setting, with each test requiring only 5 -10 minutes to complete. Nerve excitability equipment is readily commercially available, and a portable system has been devised so that patients can be tested in situ in the infusion centre setting. In addition, these techniques can be adapted for use in multiple chemotherapies.

In patients treated with the chemotherapy oxaliplatin, primarily utilised for colorectal cancer, nerve excitability techniques provide a method to identify patients at-risk for neurotoxicity prior to the onset of chronic neuropathy. Nerve excitability studies have revealed the development of an acute Na⁺ channelopathy in motor and sensory axons^10-13. Importantly, patients who demonstrated changes in excitability in early treatment were subsequently more likely to develop moderate to severe neurotoxicity¹¹. However, across treatment, striking longitudinal changes were identified only in sensory axons which were able to predict clinical neurological outcome in 80% of patients¹⁰. These changes demonstrated a different pattern to those seen acutely following oxaliplatin infusion, and most likely reflect the development of significant axonal damage and membrane potential change in sensory nerves which develops longitudinally during oxaliplatin treatment¹⁰. Significant abnormalities developed during early treatment, prior to any reduction in conventional measures of nerve function, suggesting that excitability parameters may provide a sensitive biomarker.

Impact of oxaliplatin-induced neuropathy: a patient perspective

INTRODUCTION

Dose-limiting neurotoxicity is a major side effect of oxaliplatin treatment, producing initial acute neurotoxicity and chronic neuropathy with increasing exposure. The improvement in survival for patients with early-stage colorectal cancer treated with oxaliplatin has highlighted the need for valid and reliable assessment of peripheral neuropathy.

OBJECTIVES

The objective of this paper was to explore neuropathic symptoms in oxaliplatin-treated patients as assessed using different methods.

METHODS

Consecutive symptomatic patients reporting peripheral neuropathy after oxaliplatin chemotherapy for colorectal cancer were interviewed using a semi-structured clinical interview. Neurotoxicity was also assessed using the National Cancer Institute Common Toxicity Criteria scale (clinician-rated), patient 'self-report' questionnaires (PNQ), nerve conduction and clinical assessment.

RESULTS

Twenty patients were assessed, 12.6 ± 2.8 months after treatment cessation (mean cumulative oxaliplatin dose, 789 mg/m(2)). In 40% of patients, neurotoxicity necessitated early cessation of treatment. Only 10% of patients were designated by clinicians with severe neurotoxicity, whilst, in contrast, patient interviews and self-report questionnaires described significant physical limitations due to neuropathic symptoms in 60% of patients. The majority (85%) of patients had objective evidence of sensory neuropathy with nerve conduction studies. Reports from clinical interviews were strongly correlated with patient self-assessment (Pearson coefficient = 0.790, p < 0.0005).

CONCLUSION

Given the discrepancies in symptom prevalence highlighted by these findings, the monitoring of oxaliplatin-induced neurotoxicity would benefit from more informative clinical assessment, with inclusion of patient-reported outcome measures. Such an approach would be beneficial in a clinical trial setting to monitor the efficacy of interventions and in prospective studies of survivorship to determine the true burden of peripheral neuropathy in oxaliplatin-treated patients.