Thalidomide-induced neuropathy

Subclinical pretreatment sensory deficits appear to predict the development of pain and numbness in patients with multiple myeloma undergoing chemotherapy

PURPOSE

Chemotherapy-induced peripheral neuropathy is a major complication in the treatment for cancer, including multiple myeloma (MM). Patients may develop painful and non-painful (e.g., numbness) neuropathy symptoms that impair function and often persist after therapy is terminated. This study tested the hypothesis that baseline subclinical neuropathy, as assessed by sensory thresholds, is related to the development of neuropathy symptoms (e.g., pain and numbness) in patients with MM undergoing treatment with chemotherapy.

METHODS

Patients (n = 56) who had undergone two or fewer cycles of induction therapy and who had no evident neuropathy were assessed using quantitative sensory tests to determine multiple-modality sensory thresholds. Patient-reported pain and numbness were assessed through induction therapy (16 weeks) via the MD Anderson Symptom Inventory. A subset of participants (n = 15) continued reporting on their symptoms for an additional 16 weeks ("maintenance phase").

RESULTS

Patients with sharpness detection deficits at baseline (n = 11, 20 % of sample) reported less severe pain and numbness during induction therapy and less numbness during maintenance therapy (P < 0.05). During the maintenance phase, patients with warmth detection deficits (n = 5, 38 % of sample) reported more severe pain and numbness, and those with skin temperature deficits (n = 7, 47 % of maintenance sample) reported more severe pain (P < 0.05). These deficits were related to patient reported difficulty walking, a common symptom of peripheral neuropathy.

CONCLUSION

Our results suggest that baseline subclinical sensory deficits may be related to a patient's risk for developing chemotherapy-induced peripheral neuropathy.

Neurophysiological approach to disorders of peripheral nerve

Disorders of the peripheral nerve system (PNS) are heterogeneous and may involve motor fibers, sensory fibers, small myelinated and unmyelinated fibers and autonomic nerve fibers, with variable anatomical distribution (single nerves, several different nerves, symmetrical affection of all nerves, plexus, or root lesions). Furthermore pathological processes may result in either demyelination, axonal degeneration or both. In order to reach an exact diagnosis of any neuropathy electrophysiological studies are crucial to obtain information about these variables. Conventional electrophysiological methods including nerve conduction studies and electromyography used in the study of patients suspected of having a neuropathy and the significance of the findings are discussed in detail and more novel and experimental methods are mentioned. Diagnostic considerations are based on a flow chart classifying neuropathies into eight categories based on mode of onset, distribution, and electrophysiological findings, and the electrophysiological characteristics in each type of neuropathy are discussed.

Medication, toxic, and vitamin-related neuropathies

PURPOSE OF REVIEW

Although medication, toxic, and vitamin-related neuropathies are rare causes of neuropathy, they are important to recognize because they are treatable and preventable. It is often difficult to conclusively demonstrate that a particular agent is the cause of neuropathy, but understanding the specific electrodiagnostic and clinical patterns produced by these agents is critical for making these assessments.

RECENT FINDINGS

The clinical and electrodiagnostic features for many of these neuropathies have been well established. The exact mechanism by which some of these agents produce neuropathy is only now beginning to be revealed. These mechanisms are critical for both understanding the normal function of nerves as well as eventually devising specific treatments.

SUMMARY

A large number of medications and toxins can produce neuropathy. This article reviews the clinical characteristics, electrodiagnostic features, and mechanism of action (when known) of those agents that produce the most severe, or perhaps the most unique features of, neuropathy.

Management of treatment-emergent peripheral neuropathy in multiple myeloma

Peripheral neuropathy (PN) is one of the most important complications of multiple myeloma (MM) treatment. PN can be caused by MM itself, either by the effects of the monoclonal protein or in the form of radiculopathy from direct compression, and particularly by certain therapies, including bortezomib, thalidomide, vinca alkaloids and cisplatin. Clinical evaluation has shown that up to 20% of MM patients have PN at diagnosis and as many as 75% may experience treatment-emergent PN during therapy. The incidence, symptoms, reversibility, predisposing factors and etiology of treatment-emergent PN vary among MM therapies, with PN incidence also affected by the dose, schedule and combinations of potentially neurotoxic agents. Effective management of treatment-emergent PN is critical to minimize the incidence and severity of this complication, while maintaining therapeutic efficacy. Herein, the state of knowledge regarding treatment-emergent PN in MM patients and current management practices are outlined, and recommendations regarding optimal strategies for PN management during MM treatment are provided. These strategies include early and regular monitoring with neurological evaluation, with dose modification and treatment discontinuation as indicated. Areas requiring further research include the development of MM-specific, patient-focused assessment tools, pharmacogenomic analysis of patient DNA, and trials to assess the efficacy of pharmacological interventions.

The rise, fall and subsequent triumph of thalidomide: lessons learned in drug development

Perhaps no other drug in modern medicine rivals the dramatic revitalization of thalidomide. Originally marketed as a sedative, thalidomide gained immense popularity worldwide among pregnant women because of its effective anti-emetic properties in morning sickness. Mounting evidence of human teratogenicity marked a dramatic fall from grace and led to widespread social, legal and economic ramifications. Despite its tragic past thalidomide emerged several decades later as a novel and highly effective agent in the treatment of various inflammatory and malignant diseases. In 2006 thalidomide completed its remarkable renaissance becoming the first new agent in over a decade to gain approval for the treatment of plasma cell myeloma. The catastrophic collapse yet subsequent revival of thalidomide provides important lessons in drug development. Never entirely abandoned by the medical community, thalidomide resurfaced as an important drug once the mechanisms of action were further studied and better understood. Ongoing research and development of related drugs such as lenalidomide now represent a class of irreplaceable drugs in hematological malignancies. Further, the tragedies associated with this agent stimulated the legislation which revamped the FDA regulatory process, expanded patient informed consent procedures and mandated more transparency from drug manufacturers. Finally, we review recent clinical trials summarizing selected medical indications for thalidomide with an emphasis on hematologic malignancies. Herein, we provide a historic perspective regarding the up-and-down development of thalidomide. Using PubMed databases we conducted searches using thalidomide and associated keywords highlighting pharmacology, mechanisms of action, and clinical uses.

The validity of neuropathy and neuropathic pain measures in patients with cancer receiving taxanes and platinums

PURPOSE/OBJECTIVES

To assess the validity of neuropathy and neuropathic pain-measurement approaches.

DESIGN

Cross-sectional measurement study.

SETTING

Two comprehensive cancer centers in the northeastern United States.

SAMPLE

117 patients with cancer in an outpatient setting.

METHODS

Participants were assessed using the five-component Total Neuropathy Score-reduced (TNSr), the TNSr short form (TNSr-SF), individual TNSr items, the Neuropathic Pain Scale for chemotherapy-induced neuropathy (NPS-CIN), and the National Cancer Institute's Common Toxicity Criteria™, version 3.0 (NCI-CTC).

MAIN RESEARCH VARIABLES

Neuropathy and pain measure scores, cumulative and per M2 chemotherapy dosage, comorbid risk factors, drug class, and the number of neurotoxic drugs received.

FINDINGS

TNSr, TNSr-SF, and tendon reflex scores were greater in patients receiving higher cumulative (z range = -2.2 to -3.6; p range = 0.01 to < 0.001) and per M2 (z range = -1.8 to -2.4; p range = 0.04 to < 0.001) chemotherapy doses. Scores from most neuropathy and pain measures were higher in patients with comorbid illnesses (z range = -1.79 to -3.51; p range = 0.03 to < 0.001). Sensory NCI-CTC scores were higher in patients receiving higher cumulative chemotherapy dosage (z = -2.1; p = 0.02). Only the sensory NCI-CTC correlated with other measures (r range = 0.22-0.63; p range = 0.05 to < 0.001).

CONCLUSIONS

Findings support the validity of the TNSr, TNSr-SF, tendon reflex item, NPS-CIN, and NCI-CTC sensory grading scale when measuring taxane and platinum-induced neuropathy. However, additional validity testing is warranted.

IMPLICATIONS FOR NURSING

Comprehensive neuropathy and pain measures mainly used by researchers and neurologists were simplified to more clinically useful tools for use by nurses when monitoring chemotherapy-induced peripheral neuropathy.

Long-term neuropathy after oxaliplatin treatment: challenging the dictum of reversibility

OBJECTIVES

Oxaliplatin-induced neuropathy is a significant and dose-limiting toxicity that adversely affects quality of life. However, the long-term neurological sequelae have not been adequately described. The present study aimed to describe the natural history of oxaliplatin-induced neuropathy, using subjective and objective assessments.

METHODS

From a population of 108 oxaliplatin-treated patients referred for neurological assessment in 2002-2008, 52.2% of the surviving patient cohort (n = 24) was available for follow-up at a median of 25 months post-oxaliplatin. Patients underwent a protocol that incorporated clinical assessment scales, patient questionnaires, standard electrodiagnostic assessments, and novel nerve excitability studies to precisely assess nerve function.

RESULTS

At follow-up, 79.2% of patients reported residual neuropathic symptoms, with distal loss of pin-prick sensibility in 58.3% of patients and loss of vibration sensibility in 83.3% of patients. Symptom severity scores were significantly correlated with cumulative dose. There was no recovery of sensory action potential amplitudes in upper and lower limbs, consistent with persistent axonal sensory neuropathy. Sensory excitability parameters had not returned to baseline levels, suggesting persisting abnormalities in nerve function. The extent of excitability abnormalities during treatment was significantly correlated with clinical outcomes at follow-up.

CONCLUSIONS

These findings establish the persistence of subjective and objective deficits in oxaliplatin-treated patients post-oxaliplatin, suggesting that sensory neuropathy is a long-term outcome, thereby challenging the literature on the reversibility of oxaliplatin-induced neuropathy.

Genetic factors underlying the risk of thalidomide-related neuropathy in patients with multiple myeloma

PURPOSE

To indentify genetic variation that can modulate and predict the risk of developing thalidomide-related peripheral neuropathy (TrPN).

PATIENTS AND METHODS

We analyzed DNA from 1,495 patients with multiple myeloma. Using a custom-built single nucleotide polymorphism (SNP) array, we tested the association of TrPN with 3,404 SNPs. The SNPs were selected in predicted functional regions within 964 genes spanning 67 molecular pathways thought to be involved in the pathogenesis, treatment response, and adverse effects associated with myeloma and its therapy. Patient cases and controls were derived from two large clinical trials that compared thalidomide with conventional-based treatment in myeloma patients (Medical Research Council Myeloma-IX and HOVON-50/GMMG-HD3).

RESULTS

We report TrPN associations with SNPs-ABCA1 (rs363717), ICAM1 (rs1799969), PPARD (rs2076169), SERPINB2 (rs6103), and SLC12A6 (rs7164902)-where we show cross validation of the associations in both trials. To investigate whether TrPN SNP associations were related to exposure to thalidomide only or general drug-related peripheral neuropathy, we performed a second analysis on patients treated with vincristine. We report SNPs associated with vincristine neuropathy, with a seemingly distinct underlying genetic mechanism.

CONCLUSION

Our results are consistent with the hypothesis that an individual's risk of developing a peripheral neuropathy after thalidomide treatment can be mediated by polymorphisms in genes governing repair mechanisms and inflammation in the peripheral nervous system. These findings will contribute to the development of future neuroprotective strategies with thalidomide therapy and the better use of this important compound.

The reliability and validity of a modified total neuropathy score-reduced and neuropathic pain severity items when used to measure chemotherapy-induced peripheral neuropathy in patients receiving taxanes and platinums

BACKGROUND

Assessment of chemotherapy-induced peripheral neuropathy signs and symptoms has been hampered because of the lack of simple, reliable, and valid measures.

OBJECTIVE

The study objective was to examine the internal consistency and interrater reliability as well as the structural validity of a 5-component total neuropathy score-reduced (TNSr) variant and a chemotherapy-induced neuropathy-specific Neuropathic Pain Scale.

METHODS

One hundred seventeen outpatients receiving taxanes or platinums were assessed by a consistent nurse practitioner using the 2 instruments. Ten subjects participated in interrater reliability testing.

RESULTS

Mean scores and SDs for individual items were low. The strength item was deleted because of low interitem correlations and a floor effect. The reflex item was deleted because of low interitem correlations and its negative influence on Cronbach alpha. Pin sensibility was deleted because of low factor loadings. The TNSr-short form and the chemotherapy-induced neuropathy-specific Neuropathic Pain Scale formed 2 distinct factors, providing evidence of structural validity. Cronbach alpha's for the 2 instruments were .80 and .96, respectively. The TNSr interrater reliability results suggested acceptable rater concordance, but minor revisions could further improve scoring precision.

CONCLUSION

Clinimetric evidence supports the use of 2 new instruments when monitoring taxane- and platinum-related neuropathy and pain. Further instrument modifications are recommended, followed by additional testing in diverse populations.

IMPLICATIONS FOR PRACTICE

With these new instruments, nurses can more easily incorporate prospective neuropathy assessment into daily clinical practice. The outcome will be improved symptom awareness by oncology clinicians and patients, leading to fewer chemotherapy-induced peripheral neuropathy-related devastating effects on functionality and quality of life.

IgD Multiple Myeloma Paraproteinemia as a Cause of Myositis

A 48-years old man was diagnosed an IgD-k multiple myeloma (MM) at age 38 years for which he successfully underwent chemotherapy and bone marrow transplant. He then developed a graft-versus-host disease (GVHD) whose manifestations included, three years later, a polymyositis, diagnosed at muscle biopsy and successfully treated with steroids. Few months after polymyositis remission, myeloma relapsed and the patient was treated with thalidomide for six years with good remission. Soon after thalidomide suspension, MM relapsed again and the patient came to our observation for a new onset of neuromuscular symptoms. He underwent both muscle and peripheral nerve biopsy to discriminate between myositis (paraproteinemia versus GVHD), amyloidosis, and thalidomide toxicity. The first muscle biopsy showed an inflammatory pattern with necrotic fibres, macrophagical invasion (CD68 positive), rare interstitial cellular infiltrates (CD8 positive and CD4 negative), widespread anti-HLA positivity and negative antiMAC. The second muscle biopsy showed the same inflammatory pattern plus an involvement of blood vessels. Direct immunofluorescence for IgD showed diffuse positivity along the sarcolemmal in both muscle biopsies. Sural nerve biopsy demonstrated both demyelinating and axonal aspects with no inflammatory infiltrates, but positivity for HLA and MAC. Congo Red was negative in both skeletal muscle and peripheral nerve.

Peripheral neuropathy and new treatments for multiple myeloma: background and practical recommendations

In multiple myeloma, peripheral neuropathy has for a long time been considered as mainly secondary to the plasma cell dyscrasia itself. With the advent of new targeted drugs such as thalidomide and bortezomib, the iatrogenic neurotoxicity has become the leading cause of peripheral neuropathy. This review discusses the pathogenesis, incidence, risk factors, diagnosis, characteristics, and management of peripheral neuropathy related to new multiple myeloma drugs, mainly bortezomib and thalidomide. The current knowledge of the pathophysiology of the new forms of peripheral neuropathy is still limited. The mechanisms involved depend on the agents used, patient's medical history, and duration of exposure and/or treatment doses or sequence. Diagnosis of such peripheral neuropathy is often easier than treatment. A full anamnesis and regular clinical evaluation are necessary. Electrophysiological assessments may support the diagnosis, although their contribution remains insufficient. Complex clinical features may require a specialized neurological assessment within the context of a multi-disciplinary approach. Finally, early detection of peripheral neuropathy and the use of dose adjustment algorithms as in the case of bortezomib, should help reduce the side effects while maintaining anti-tumor efficacy.

Dealing with neuropathy in plasma-cell dyscrasias

Peripheral neuropathy (PN) is a frequent complication of plasma-cell dyscrasias such as monoclonal gammopathy of undetermined significance, multiple myeloma, Waldenström's disease, POEMS (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) syndrome, Castleman's disease, and light-chain amyloidosis. PN can be associated with the underlying disease or it can related to the treatment. The novel immunomodulatory drugs thalidomide and lenalidomide and the proteasome inhibitor bortezomib have changed the standard treatment of multiple myeloma. Treatment-related PN induced by thalidomide (TiPN) or bortezomib (BiPN) has become the most frequent cause of symptomatic polyneuropathy in multiple myeloma and related diseases. Dealing with PN has become a major challenge in current clinical practice for multiple myeloma patients. This review deals with practical issues such as etiology, incidence, symptoms, and clinical management of treatment-emergent PN. The major focus of the hematologist should be on the prevention of PN, primarily by frequent monitoring of the patient and by timely and adequate dose reduction of thalidomide and bortezomib. Thalidomide should not be given for periods longer than 18 months, and if it is, then patients should be carefully monitored with a low threshold for discontinuation in the face of any emergent neuropathy. In the case of BiPN, the dose of bortezomib should be reduced and/or the administration interval should be prolonged from biweekly to weekly. Adequate pain management and supportive care require a multidisciplinary approach involving the treating physician, expert nursing staff, and a neurologist as clinically indicated.

Multiple myeloma, painful neuropathy, acupuncture?

Thalidomide and bortezomib are remarkably efficacious in the treatment of multiple myeloma. Unfortunately, their use can cause sensory neuropathy, a common and serious adverse event that frequently limits dose and duration of treatment. Although the relationship between peripheral neuropathy and therapeutic dose is controversial, many authors have demonstrated a positive correlation between neuropathy and cumulative dose, dose intensity, and length of therapy. Peripheral neuropathic pain is the most troublesome symptom of neuropathy. Spontaneous pain, allodynia, hyperalgesia, and hyperpathia are often associated with decreased physical activity, increased fatigue, mood, and sleep problems. Symptoms are often difficult to manage, and available treatment options rarely provide total relief. Moreover, the adverse effects of these treatments often limit their use. Several studies have demonstrated the efficacy of acupuncture, with fewer adverse effects than analgesic drugs, in the treatment of painful diabetic and human immunodeficiency virus-related neuropathy. However, the effectiveness of acupuncture in treating toxic neuropathy has not been assessed. Although its putative mechanisms remain elusive, acupuncture has strong potential as an adjunctive therapy in thalidomide- or bortezomib-induced painful neuropathy, and a better understanding might guide its use in the management of chemotherapy-induced neuropathic pain. Well-designed clinical trials with adequate sample size and power are warranted.

Positive and negative effects of thalidomide on refractory cutaneous lupus erythematosus

BACKGROUND

Thalidomide is used in cutaneous lupus erythematosus (CLE) refractory to conventional therapies. Peripheral neuropathy (PN) is the most severe side effect, but the incidence of PN and its relation to thalidomide dose are still unclear.

OBJECTIVE

To prospectively evaluate the efficacy as well as the occurrence of PN in CLE patients treated with thalidomide, and to assess whether PN, when occurs, correlates with thalidomide dose and/or length of treatment.

METHODS

Fourteen female patients with CLE in low-dose thalidomide therapy were followed for up to 24 months. Prior to, and regularly during treatment patients underwent rheumatological, dermatological, neurological and electrophysiological evaluations. A decline in sural SNAP of 50% or more from baseline value was considered as criterion of sensory axonal PN.

RESULTS

All patients showed a dramatic improvement of skin manifestations. Ten patients (71.4%) developed a sensory axonal PN. The median time free from this complication was 14 months. No correlations were found between age of the patients nor thalidomide cumulative dose and occurrence of PN (Mann-Whitney U Test; p>0.16). Other adverse effects were: tremor, paresthesias, somnolence, amenhorrea, constipation and thoracic pain.

CONCLUSIONS

Low does thalidomide is efficacious in treating CLE, but PN is a common complication whose occurrence does not seem to correlate with total thalidomide dose, whereas with the duration of therapy. A closer electrophysiological follow-up is therefore recommended in the long-term treatment.

Chemotherapy-induced peripheral neuropathy

Recent advances in the development and administration of chemotherapy for malignant diseases have led to prolonged survival of patients and the promise of a return to normal lives. This progress comes with a price, however, and the nervous system is frequently the target of therapy-induced toxicity. Unlike more immediate toxicities that affect the gastrointestinal tract and bone marrow, chemotherapy-induced neurotoxicity is frequently delayed in onset and may progress over time. In the peripheral nervous system, the major brunt of the toxic attack is directed against the peripheral nerve, targeting the neuronal cell body, the axonal transport system, the myelin sheath, and glial support structures, resulting in chemotherapy-induced peripheral neuropathy.

Characteristics of bortezomib- and thalidomide-induced peripheral neuropathy

Dose-limiting peripheral neuropathy (PN) is frequently reported with the use of thalidomide and bortezomib, novel proteasome inhibitors. While these two agents have significant activity in multiple myeloma (MM), the combination and the associated PN have not been fully examined in untreated patients. The objective of this study was to report the baseline prevalence and occurrence of PN in newly diagnosed MM patients treated with bortezomib and thalidomide. Twenty-seven patients (11 men and 16 women) with previously untreated MM were prospectively monitored for PN. Total neuropathy score reduced (TNSr) was calculated at baseline and after every two cycles of bortezomib treatment. The median cumulative dose of bortezomib was 35.6 mg/m(2) (median 8 cycles) and of thalidomide was 16.8 g. Only three subjects showed mild PN at baseline (whole group median TNSr 0). At the end of treatment, PN developed in 26 patients (median TNSr 8). PN was of mild to moderate severity (TNSr grade 1 = 11, grade 2 = 10, grade 3 = 5, and grade 4 = 0). Nerve conduction studies showed axonal physiology in all except three subjects in whom demyelinating physiology was noted. The median TNSr was 17 in the demyelinating group and 9 in the axonal group. There was no significant correlation of TNSr with cumulative bortezomib or thalidomide dose. At follow-up, 80% of patients had become asymptomatic after discontinuation of the chemotherapy. We conclude that bortezomib and thalidomide combination chemotherapy induces a reversible length-dependent sensory>motor, predominantly axonal, large-fiber>small-fiber polyneuropathy. In a subset, a more severe demyelinating polyneuropathy may develop.

Bortezomib-induced peripheral neuropathy in multiple myeloma: a comprehensive review of the literature

Bortezomib has demonstrated significant activity in clinical trials, mainly against recurrent or newly diagnosed multiple myeloma (MM). Peripheral neuropathy is a significant toxicity of bortezomib, requiring dose modification and potential changes in the treatment plan when it occurs. The mechanism underlying bortezomib-induced peripheral neuropathy (BIPN) is unknown. Metabolic changes resulting from the accumulation of bortezomib in the dorsal root ganglia cells, mitochondrial-mediated disregulation of Ca(++) homeostasis, and disregulation of neurotrophins may contribute to the pathogenesis of BIPN. It is increasingly recognized that BIPN may be a proteasome inhibitor class effect, producing primarily a small fiber and painful, axonal, sensory distal neuropathy. Incidence of BIPN is mainly related to various risk factors, including cumulative dose and evidence of preexisting neuropathy. Assessment of BIPN is based primarily on neurologic clinical examination and neurophysiologic methods. To date, apart from the use of dose reduction and schedule change algorithm, there is no effective treatment with neuroprotective agents for BIPN. Analgesics, tricyclic antidepressants, anticonvulsants, and vitamin supplements have been used as symptomatic treatment against bortezomib-associated neuropathic pain with some success. This review looks critically at the pathogenesis, incidence, risk factors, diagnosis, characteristics, and management of BIPN, and highlights areas for future research.

Chemotherapy-induced neuropathy

Neurotoxic side effects of cancer therapy are second in frequency to hematological toxicity. Unlike hematological side effects that can be treated with hematopoietic growth factors, neuropathies cannot be treated and protective treatment strategies have not been effective. For the neurologist, the diagnosis of a toxic neuropathy is primarily based on the case history, the clinical and electrophysiological findings, and knowledge of the pattern of neuropathy associated with specific agents. In most cases, toxic neuropathies are length-dependent, sensory, or sensorimotor neuropathies often associated with pain. The platinum compounds are unique in producing a sensory ganglionopathy. Neurotoxicity is usually dependent on cumulative dose. Severity of neuropathy increases with duration of treatment and progression stops once drug treatment is completed. The platinum compounds are an exception where sensory loss may progress for several months after cessation of treatment ("coasting"). As more effective multiple drug combinations are used, patients will be treated with several neurotoxic drugs. Synergistic neurotoxicity has not been extensively investigated. Pre-existent neuropathy may influence the development of a toxic neuropathy. Underlying inherited or inflammatory neuropathies may predispose patients to developing very severe toxic neuropathies. Other factors such as focal radiotherapy or intrathecal administration may enhance neurotoxicity. The neurologist managing the cancer patient who develops neuropathy must answer a series of important questions as follows: (1) Are the symptoms due to peripheral neuropathy? (2) Is the neuropathy due to the underlying disease or the treatment? (3) Should treatment be modified or stopped because of the neuropathy? (4) What is the best supportive care in terms of pain management or physical therapy for each patient? Prevention of toxic neuropathies is most important. In patients with neuropathy, restorative approaches have not been well established. Symptomatic and other management are necessary to maintain and improve quality of life.

Chemotherapy-induced peripheral neuropathy

Recent advances in the development and administration of chemotherapy for malignant diseases have led to prolonged survival of patients and the promise of a return to normal lives. The cost of progress comes with a price, however, and the nervous system is frequently the target of therapy-induced toxicity. Unlike more immediate toxicities that affect the gastrointestinal tract and bone marrow, chemotherapy-induced neurotoxicity is frequently delayed in onset and may progress over time. In the peripheral nervous system, the major brunt of the toxic attack is directed against the peripheral nerve, targeting the neuronal cell body, the axonal transport system, the myelin sheath, and glial support structures, resulting in chemotherapy-induced peripheral neuropathy.

An Overview of Chemotherapy-Induced Peripheral Neuropathy

Peripheral neuropathy remains a major limitation of chemotherapeutic agents used in cancer treatment. This neurologic complication from chemotherapy occurs frequently and can be debilitating. Although difficult to predict, both chemotherapeutic and patient-specific risk factors may contribute to this adverse event. Symptoms of peripheral neuropathy may appear acutely after treatment or persist chronically upon drug discontinuation. The taxanes, vinca alkaloids, and immunomodulatory drugs commonly cause peripheral nervous system toxicity. Prompt recognition and evaluation of this neurological adverse event by those who provide care to patients with cancer can prove to have a positive impact on the quality of life of those patients.

Thalidomide in the treatment of multiple myeloma

Thalidomide--either alone or in combination with dexamethasone or chemotherapy--has shown significant activity in relapsed/refractory disease. When used in the induction regimens in untreated patients, it significantly increases the response rates as well progression-free survival. Moreover, thalidomide as a maintenance therapy has become a very attractive option. However, the toxicity profile of the drug, mainly neurotoxicity and thrombotic events, mandate careful monitoring of patients treated with thalidomide, whether as the first line, in the relapsed setting, or as maintenance. In this chapter we will review the pharmacology, mechanisms of action, and toxicity of the drug, and will focus on available data from clinical experience and randomized trials of thalidomide in the different settings of multiple myeloma: refractory/relapsed disease, upfront treatment in patients who are eligible for high-dose therapy as well as those who are not, and finally the use of thalidomide as a maintenance treatment.

Childhood thalidomide neuropathy: a clinical and neurophysiologic study

Thalidomide was recently reintroduced to treat several immune-mediated pathologies. Peripheral neuropathy is a significant side effect limiting its clinical use. Our aims include: (1) describing and identifying the incidence of clinical or electrophysiologic peripheral neuropathy in children, (2) determining whether peripheral neuropathy correlates with cumulative dose of thalidomide and with age, and (3) defining its reversibility rate. We studied 13 children manifesting immune-mediated pathologies treated with thalidomide at doses ranging from 25-100 mg/day. Clinical and neurophysiologic evaluation was performed before and after starting treatment. Seven children (53.8%) showed neurophysiologic signs of sensory peripheral axonal polyneuropathy. Five presented associated clinical symptoms, while the other two only presented subclinical, neurophysiologic signs of peripheral neuropathy. We found a significant correlation between the incidence of peripheral neuropathy and thalidomide cumulative dose (P = 0.02). We observed a lower incidence of peripheral neuropathy at a cumulative dose <20 gm, and a correlation with age (P < 0.01). The clinical and electrophysiologic recovery rate was 40%, and clinical improvement alone was observed in another 40%. Thalidomide induces dose-dependent and age-dependent peripheral neuropathy at a significant frequency in childhood (53.8%). In our experience a cumulative dosage at >20 gm and long-term administration for >10 months seem to increase the risk of peripheral neuropathy. We propose clinical and neurophysiologic follow-up every 3 months to identify and monitor possible side effects.

Neurotoxicity of bortezomib therapy in multiple myeloma: a single-center experience and review of the literature

BACKGROUND

Bortezomib is active in heavily pretreated multiple myeloma patients; the dose-limiting toxicity is peripheral neuropathy (PN).

METHODS

The authors retrospectively reviewed the incidence, severity, and risk factors for PN in 78 patients who received bortezomib. The median age was 57 years (range, 33-80 years), 62% of patients were men, and 37% of patients were African Americans. Seventeen patients (22%) had diabetes mellitus (DM), and 66 patients (85%) had received thalidomide. Before bortezomib treatment, 37% of the patients reported subjective, grade 1 or 2 PN. Patients received bortezomib alone (n = 10 patients) plus dexamethasone (n = 36 patients) and thalidomide (n = 20 patients) or chemotherapy (n = 12 patients). PN affected 52% of patients, including grade 3 and 4 PN in 15% and 7%, respectively.

RESULTS

Twelve patients stopped bortezomib because of side effects that included PN (n = 9 patients), diarrhea (n = 2 patients) and cytomegalovirus pneumonia (n = 1 patient); 11 patients had dose reductions because of PN. Grade 4 PN affected 6 patients (sensory, n = 4 patients; motor/sensory, n = 2 patients). The onset of grade 4 PN was sudden rather than cumulative. Factors that were predictive of PN grade were baseline PN (P = .002), prior thalidomide use (P = .03), and the presence of DM (P = .03). Multiple myeloma responses included complete, near complete, and partial responses in 5% of patients, 10% of patients, and 27% of patients, respectively. Responses were independent of PN and of whether bortezomib was combined with chemotherapy or thalidomide. Patients remained on therapy longer for a median of 5 cycles (range, 2-36 cycles) when they received bortezomib plus thalidomide versus 3 cycles (range, 1-19 cycles) for the other combinations. PN therapy was mostly supportive. It was noteworthy that 6 of 9 patients with PN who received lenalidomide as salvage therapy after bortezomib had significant improvement in their symptoms.

CONCLUSIONS

The risk of bortezomib-related PN was greater in patients who had PN and DM at baseline. The authors concluded that an unexpected, symptomatic improvement of PN on lenalidomide is worth further investigation.

New therapies in multiple myeloma

The melphalan-prednisone regimen has been considered as standard therapy for patients with multiple myeloma (MM) for many years. Recently, high-dose chemotherapy with stem-cell support has extended progression-free survival and increased overall survival, and it is now considered conventional therapy in younger patients. However, most patients relapse and the salvage treatment is not very effective. New active drugs, including immunomodulatory agents, thalidomide (Thal) and lenalidomide, and the proteasome inhibitor bortezomib, have shown promising anti-myeloma activity. These novel treatments are aimed at overcoming resistance of tumour cells to conventional chemotherapy, acting both directly on myeloma cells and indirectly by blocking the interactions of myeloma cells with their local microenvironment and suppressing growth and survival signals induced by autocrine and paracrine loops in the bone marrow. Thal has been widely studied, mostly in combination regimens in patients with relapsed MM and, more recently, in front-line therapy, showing efficacy in terms of response rate and event-free survival. Bortezomib has been found to possess remarkable activity, especially in combination with other chemotherapeutic agents, in relapsed/refractory and newly diagnosed MM, as well as in patients presenting adverse prognostic factors. Lenalidomide, in combination with dexamethasone, is showing high overall response rates in relapsed and refractory MM and promising results also in first-line therapy. In this paper, the results of the most significant trials with Thal, bortezomib and lenalidomide are reported. Several ongoing clinical studies will hopefully allow the identification of the most active combinations capable of improving survival in patients with MM.

Chemotherapy-induced peripheral neuropathy: a review and implications for oncology nursing practice

Advances in supportive care have increased the likelihood that previously less common adverse effects of chemotherapy will be more evident. The incidence of chemotherapy-induced peripheral neuropathy (CIPN) is increasing because more neurotoxic drugs have been developed and because patients are living longer and receiving multiple chemotherapy regimens. This article reviews the anatomy of the peripheral nervous system, the proposed mechanisms of CIPN, and manifestations of CIPN from vinca alkaloids, taxanes, and platinum analogs. Major topics of this article are evidence-based data regarding symptom management, a review of medical management, and a synthesis of nursing care for patients at risk for or experiencing CIPN.

Neuroprotection during chemotherapy: a systematic review

The development of neurotoxicity during antineoplastic therapy is one of the most common reasons for termination or modification of cancer treatment. A number of different agents have been proposed to provide neuroprotection without affecting antitumor efficacy. This review provides an evidence-based summary of neuroprotective medicines, an overview of the literature relating to neuroprotection during cancer treatment and a Neurologist perspective risk assessment and management. Through a systematic review the authors identified 49 papers published to date that report human clinical trials involving potential neuroprotectants in adults. Case reports and series completed in a prospective fashion were also included. Sensory neuropathies were the most prevalent subtype in the literature, and most were at least partially reversible with or without neuroprotective treatment. The majority of study medications had minimal side effects, though 2 trials were prematurely terminated because of adverse patient outcomes. No study reported an effect on antitumor efficacy. Because of the variability in study design, cancer type, outcome measures, and clinical confirmation of neuropathy, meta-analysis could not be appropriately performed. We highlight risk factors and discuss neuropathy screening. Descriptive analysis is provided which reveals that many of the agents studied were likely to confer some at least some neuroprotective benefit.

Efficacy and safety of thalidomide in children and young adults with intractable inflammatory bowel disease: long-term results

BACKGROUND

Anti-tumour necrosis factor-alpha antibodies are useful for the treatment of refractory Crohn's disease and ulcerative colitis. Thalidomide is another agent with tumour necrosis factor-alpha suppressive properties.

AIM

To investigate the long-term efficacy and safety of thalidomide in a group of children and young adults with refractory inflammatory bowel disease.

METHODS

Twenty-eight patients with refractory moderate-severe inflammatory bowel disease (19 Crohn's disease, 9 ulcerative colitis) received thalidomide 1.5-2.5 mg/kg/day. Patients were assessed at baseline, at weeks 2, 4, 8 and 12, and then every 12 weeks by patient's diary, physical examinations, laboratory analyses and scoring on activity indexes. Primary outcomes were: (i) efficacy in inducing remission; and (ii) efficacy in maintaining remission.

RESULTS

Remission was achieved with thalidomide in 21 of 28 (75%) patients (17 with Crohn's disease, 4 with ulcerative colitis). Mean duration of remission was 34.5 months. Sixteen of 20 (80%) patients suspended steroids. Reversible neuropathy occurred in seven of 28 (25%) patients, but only with cumulative doses over 28 g. Other side effects requiring thalidomide suspension were vertigo/somnolence (one of 28), and agitation/hallucinations (one of 28).

CONCLUSIONS

Thalidomide seems to be effective in inducing long-term remission in children and adolescents with intractable inflammatory bowel disease. Neuropathy is the main adverse effect, but appears to be cumulative dose-dependent, thus allowing long-term remission before drug suspension.

Peripheral nervous system involvement in patients with cancer

Involvement of the peripheral nervous system (PNS) is common in patients with cancer and any part, including motor neurons, sensory ganglia, nerve roots, plexuses, cranial and peripheral nerves, and neuromuscular junctions, can be affected. Different mechanisms can initiate damage associated with cancer-related PNS disorders. These include tumour infiltration, toxicity of treatments, metabolic and nutritional perturbations, cachexia, virus infections, and paraneoplastic neurological syndromes. The type of cancer, lymphoma, or solid tumour is a further determinant of a PNS disorder. In this Review we discuss the different causes and mechanisms of disorders of the PNS in patients with cancer and we will focus on their assessment and diagnosis.

Regional Cancer Pain Syndromes

Cancer pain often presents in a body region. This review summarizes articles from 1999-2004 relevant to cancer pain syndromes in the head and neck, chest, back, abdomen, pelvis, and limbs. Although the evidence is limited, progress is being made in further development of the evidence base to support and guide current practice.

Management of chemotherapy-induced peripheral neuropathy

Recent advances in the development and administration of chemotherapy for malignant diseases have been rewarded with prolonged survival rates. The cost of progress has come at a price and the nervous system is frequently the target of chemotherapy-induced neurotoxicity. Unlike more immediate toxicities that effect the gastrointestinal tract and bone marrow, chemotherapy-induced neurotoxicity is frequently delayed in onset and may progress over time. In the peripheral nervous system, the major brunt of the toxicity is directed against the peripheral nerve, resulting in chemotherapy-induced peripheral neuropathy (CIPN). Chemotherapeutic agents used to treat hematologic and solid tumors target a variety of structures and functions in the peripheral nervous system, including the neuronal cell body, the axonal transport system, the myelin sheath, and glial support structures. Each agent exhibits a spectrum of toxic effects unique to its mechanism of toxic injury, and recent study in this field has yielded clearer ideas on how to mitigate injury. Combined with the call for a greater recognition of the potentially devastating ramifications of CIPN on quality of life, basic and clinical researchers have begun to investigate therapy to prevent neurotoxic injury. Preliminary studies have shown promise for some agents including glutamine, glutathione, vitamin E, acetyl-L-carnitine, calcium, and magnesium infusions, but final recommendations await prospective confirmatory studies.

Preventing paclitaxel-induced peripheral neuropathy: a phase II trial of vitamin E supplementation

A randomized, controlled trial was performed to assess the efficacy and safety of vitamin E supplementation for prophylaxis against paclitaxel-induced peripheral neuropathy (PIPN). Thirty-two patients undergoing six courses of paclitaxel-based chemotherapy were randomly assigned to receive either chemotherapy with vitamin E (300 mg twice a day, Group I) or chemotherapy without vitamin E supplementation (Group II). A detailed neurological examination and electrophysiological study was performed during and 3 months after chemotherapy. The severity of PIPN was summarized by means of a modified Peripheral Neuropathy (PNP) score. The incidence of neurotoxicity differed significantly between groups, occurring in 3/16 (18.7%) patients assigned to the vitamin E supplementation group and in 10/16 (62.5%) controls (P=0.03). The relative risk (RR) of developing PIPN was significantly higher in controls than in vitamin E group patients (RR=0.3, 95% confidence interval (CI)=0.1-0.9). Mean PNP scores were 2.25+/-5.1 (range 0-15) for patients in Group I and 11+/-11.63 (range 0-32) for those in Group II (P=0.01). Vitamin E supplementation was well tolerated and showed an excellent safety profile. This study shows that vitamin E effectively and safely protects patients with cancer from the occurrence of paclitaxel-induced peripheral nerve damage. A double-blind, placebo-controlled trial is needed to confirm these results.

Development of neuropathy in patients with myeloma treated with thalidomide: patterns of occurrence and the role of electrophysiologic monitoring

PURPOSE

Peripheral neuropathy frequently limits the duration of treatment with thalidomide for patients with multiple myeloma. We assessed the time course of occurrence, possible predictive factors, and the utility of serial nerve electrophysiological studies (NES) for detecting onset of neuropathy.

PATIENTS AND METHODS

Seventy-five patients with relapsed/refractory myeloma were enrolled onto a multicenter trial of dose-escalating thalidomide with or without interferon. Patients underwent clinical assessment plus NES at baseline and every 3 months. Time to development of neuropathy according to clinical or NES criteria was compared. Patient and treatment-related factors were compared as predictors of neuropathy.

RESULTS

Thirty-nine percent had some NES abnormalities at baseline. Patients received thalidomide at a median dose-intensity of 373 mg/d. Thirty-one of 75 patients (41%) developed neuropathy during thalidomide treatment; 11 patients (15%) discontinued treatment with thalidomide due to neuropathy. The actuarial incidence of neuropathy increased from 38% at 6 months to 73% at 12 months, with 81% of responding patients developing this complication. Serial NES did not reliably predict the imminent development of clinical neuropathy requiring thalidomide cessation, nor were patient age, sex, or prior therapy predictive. Patients who developed neuropathy had a longer duration of thalidomide exposure (median, 268 v 89 days; P = .0001). Cumulative dose or dose-intensity received was not predictive.

CONCLUSION

The majority of patients will develop peripheral neuropathy given sufficient length of treatment with thalidomide. To minimize the risk of neurotoxicity, therapy should be limited to less than 6 months. Electrophysiologic monitoring provides no clear benefit versus careful clinical evaluation for the development of clinically significant neuropathy.

Neurologic complications of cancer chemotherapy

Neurotoxicity related to cancer therapy is a common problem in oncology practice. Neurologic side effects can be dose-limiting, can inhibit treatment, and can substantially diminish quality of life. Symptoms may appear acutely after treatment, or remotely after therapy has been discontinued. Multiple therapies may share similar toxicities, and certain agents may potentiate symptoms. When faced with the development of neurologic complaints, familiarity with the most common complications is helpful in determining the etiology of these symptoms. This review will discuss the common complications of both established and novel agents used to treat cancer.

Chemotherapy-induced neuropathy

Increasingly, surgeons are becoming aware of the successful treatment of symptomatic peripheral neuropathy by surgical decompression of peripheral nerves. Armed with the knowledge that patients can have underlying neuropathy with overlying anatomic compressions, surgeons have affected improvement in diabetes-induced neuropathy, neuropathy of unknown etiology, and chemotherapy-induced neuropathy. This article details the most well-known culprits in chemotherapy-induced neuropathy and discusses the putative mechanisms of action, medical management, and surgical data.

Multi-center assessment of the Total Neuropathy Score for chemotherapy-induced peripheral neurotoxicity

The aim of this multi-center study was to assess with reduced versions of the Total Neuropathy Score (TNS), the severity of chemotherapy-induced peripheral neurotoxicity (CIPN), and to compare the results with those obtained with common toxicity scales. An unselected population of 428 cancer patients was evaluated at 11 different centers using a composite (clinical + neurophysiological, TNSr) or clinical (TNSc) examination and with the National Cancer Institute - Common Toxicity Criteria (NCI-CTC) 2.0 and Eastern Cooperative Oncology Group (ECOG) scores. A highly significant correlation was demonstrated between the TNSr and the NCI-CTC 2.0 and ECOG scores; but the TNSr evaluation was more accurate in view of the more extended score range. Also, the simpler and faster TNSc (based only on the clinical neurological examination) allowed to grade accurately CIPN and correlated with the common toxicity scores. The correlation tended to be closer when the sensory items were considered, but also the TNSr motor items, which were not specifically investigated in any other previous study, significantly correlated with the results of the common toxicity scales. In conclusion, this study suggests that the TNSr is a reliable tool for accurately grading and reporting CIPN, with the additional and so far unique support of a formal comparison with known and widely used common toxicity scales. The TNSc is a valid alternative if neurophysiological examination is not feasible. The longer time needed to calculate the TNSr and TNSc in comparison to the ECOG or the NCI-CTC 2.0 scales is offset by the more detailed knowledge of the CIPN characteristics.

Thalidomide in multiple myeloma

Multiple myeloma is an incurable bone marrow cancer, the treatment of which is notoriously difficult. Only modest advances have been achieved using complex polychemotherapeutic regimens, transplant strategies and supportive therapy. In 1999, when new drugs for myeloma were urgently needed, thalidomide was introduced and opened up a completely new line of therapy for the disease. Although the mechanism of action is not yet completely understood, thalidomide has demonstrated efficacy in patients with refractory, relapsed myeloma, even in late-stage cases. This article reviews the current knowledge of thalidomide in myeloma treatment, focusing especially on the possible mechanisms of action, clinical results and adverse events of this drug.

Advances in Understanding Drug-Induced Neuropathies

Many commonly used medications have neurotoxic adverse effects; the most common of these is peripheral neuropathy. Neuropathy can be a dose-limiting adverse effect for many medications used in life-threatening conditions, such as malignancy and HIV-related disease. Epidemiological evidence supports previous case reports of HMG-CoA reductase inhibitors (or 'statins') causing an axonal sensorimotor neuropathy or a purely small-fibre neuropathy in some patients. The neuropathy improves when the medication is withdrawn. Despite the association between HMG-CoA reductase inhibitors and neuropathy, the risk is low compared with the significant vascular protective benefits. Oxaliplatin, a new platinum chemotherapy agent designed to have fewer adverse effects than other such agents, has been shown to cause a transient initial dysaesthesia in addition to an axonal polyneuropathy. Thalidomide, an old therapy currently being utilised for new therapeutic indications (e.g. treatment of haematological malignancies), is associated with a painful, axonal sensorimotor neuropathy that does not improve on withdrawal of the drug. Nucleoside reverse transcriptase inhibitors are important components of highly active antiretroviral therapy, but are associated with a sensory neuropathy that is likely to be due to a direct effect of these drugs on mitochondrial DNA replication. New research demonstrates that lactate levels may help discriminate between neuropathy caused by nucleoside analogues and HIV-induced neuropathy. Understanding the mechanism of drug-induced neuropathy has led to advances in preventing this disabling condition.

Therapy Insight: pyoderma gangrenosum—old disease, new management

Well-designed studies that help guide physicians to apply the optimal therapeutic strategy for the management of pyoderma gangrenosum are lacking in the literature. A multidisciplinary approach is paramount for the effective management of this condition, with close involvement of a wound-care specialist and a microbiologist. Treatment should be stepwise in nature. Local wound care, avoidance of trauma and the application of local steroid or tacrolimus ointment are the first-line treatments. Steroid therapy is the most widely published effective therapy for achieving resolution of pyoderma gangrenosum, although there is growing evidence for the efficacy of infliximab in refractory cases. Other therapies such as dapsone and clofazamine should be left as third-line agents for refractory pyoderma gangrenosum, while novel treatments such as granulocyte apheresis should only be used under trial conditions, to gain an objective evaluation of their efficacy. This article reviews the published treatment strategies in current use, and aims to guide the effective management of pyoderma gangrenosum.

Uremic pruritus: a review

Pruritus is a major disorder among the skin derangements in advanced renal failure. Its prevalence seems to be diminishing perhaps because of improvements in dialysis treatment. Recent information suggests that interactions between dermal mast cells and distal ends of nonmyelinated C fibers may be important in the precipitation and regulation of the sensory stimuli. The knowledge as to the control of pruritus transmission to cortex areas is still incomplete but endogenous opioid and opioid receptors may have a role in this regard. A recent classification was proposed for pruritus based on the level of its origin. Uremic pruritus, however, seems to be too complex to fit perfectly in any of the suggested modalities. Inflammation and malnutrition are recognized risk factors for cardiovascular death in end-stage renal disease patients, which may be related to the genesis of pruritus. Consistent with this concept, lower serum levels of albumin and higher serum levels of ferritin were found in pruritic patients when compared to nonpruritic ones. Newer treatments for this difficult clinical problem are being developed and tested.

Toxic neuropathy

PURPOSE OF REVIEW

This paper examines recent research on toxic neuropathy and potential therapeutic developments. It also summarizes reports of new agents reported to cause peripheral neuropathy.

RECENT FINDINGS

Gene therapy with vasoactive endothelial growth factor, neurotrophic substances such as nerve growth factor and neurotrophin-3 are reported to reverse or protect against neurotoxicity in animal models. The neuroprotective effects of more established therapeutic agents like vitamin E, tacrolimus (FK 506) and erythropoietin hold promise for the immediate future. Cisplatin and high-dose pyridoxine are used more frequently to produce robust models of peripheral neuropathy in animals. Statins do appear to cause peripheral neuropathy. The incidence is low, however, and compared to its benefits in terms of cardiovascular protection, relatively innocuous. The profile of thalidomide neuropathy is becoming clearer as the indications for this drug increases. The incidence of thalidomide neuropathy is high, up to three quarters in some series, and although the information on dose dependency is variable, lower cumulative doses appear to be less toxic. Like thalidomide bortezomib, a novel proteosome inhibitor, is reportedly effective in the treatment of multiple myeloma and is associated with peripheral neuropathy. Oxaliplatin and epothilone are emerging anticancer drugs with neurotoxic potential. Similarly, leflunomide, a new disease modifying-agent approved for the treatment of rheumatoid arthritis, is reported to cause neuropathy.

SUMMARY

The study of toxic neuropathy is not only enhancing our knowledge of the mechanisms of neurotoxicity but also the neurobiology of peripheral neuropathy in general; and is likely to reveal avenues for therapeutics.

Thalidomide and immunomodulatory drugs in the treatment of cancer

Thalidomide has antiangiogenic and immunomodulatory properties and has recently been used in the management of human malignancies. Multiple studies have confirmed its activity in multiple myeloma, alone or combined with dexamethasone and/or chemotherapy as first- or second-line treatment. In addition, it may reduce the need for transfusions in patients with myelofibrosis or myelodysplastic syndromes. The activity of thalidomide in solid tumours is less prominent. The most promising results have been reported in Kaposi's sarcoma, malignant melanoma and prostate cancer, especially when it is combined with chemotherapy. Recently, thalidomide analogues (immunomodulatory drugs), with higher immunomodulatory activity and different toxicity profile, have been developed. They have already shown promising activity in multiple myeloma and are currently being evaluated in clinical studies.