Prospective evaluation of neurotoxicity in breast cancer patients treated with adjuvant paclitaxel

Abstract #1115

Background: Taxanes are increasingly used in the treatment of early stage breast cancer (BC). Up to 30% of patients develop moderate-severe neurotoxicity during treatment. We recently reported that about 60% of BC patients complain of some neuropathy up to 2 years after completing adjuvant paclitaxel (T) treatment. The prevalence, severity, and natural history of this syndrome have not been well described.
 Methods: Using a prospective cohort study design, women with stage I-III breast cancer undergoing adjuvant paclitaxel were enrolled. At baseline, 4 weeks, 8 weeks, 3 months, and 6 months, all patients completed the Functional Assessment of Cancer Therapy-Taxane (FACT-Tax) and quantitative sensory testing (touch perception and vibration threshold) was conducted. The FACT-Tax includes a 16-item subscale which measures the severity of neurotoxicity, where lower scores represent worsening symptoms. Blood was obtained at baseline and 2 weeks post-treatment to measure serum nerve growth factor (NGF) levels.
 Results: A total of 34 out of a target of 50 patients have been enrolled to date; median age: 48 (32-77); White/Hispanic/Black/Other: 10/17/4/1; median body mass index (kg/m2): 28 (21-44); stage I/II/III: 4/19/8; paclitaxel regimen T q2wks x4/T q2wks x6/T qwk x12: 19/8/5. Compared to baseline, there was a significant decrease in vibration sense at 8 weeks during active treatment. Mean scores on the Neurotoxicity subscale of the FACT-Tax decreased from 37.3 at baseline to 30.7 at week 4 (p=0.009) and 29.7 at week 8 (p=0.006). These scores remained lower than baseline at 3 months and 6 months after completing paclitaxel treatment (33.7 and 33.2, respectively). At 6 months, up to 50% of patients reported persistent numbness or discomfort in the hands and feet. Serum NGF analyses are underway to determine whether this biomarker correlates with neuropathy symptoms.
 Discussion: To our knowledge, this is one of the first studies to prospectively evaluate persistent neuropathy in women prior to, during and following adjuvant paclitaxel therapy. Over 50% of patients developed moderate to severe neuropathy during active treatment, which persisted 6 months post-treatment. Taxane-based chemotherapy has been shown to improve survival, however, neurotoxicity is the main long-term side effect. Understanding the natural history of this toxicity and validating appropriate measures to be used in interventions to prevent and treat taxane-induced neuropathy are critical.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 1115.

Randomized controlled phase II trial of glatiramer acetate in ALS

The authors conducted a randomized controlled trial to test the safety and immunology of glatiramer acetate in ALS. Twenty treated patients were randomly assigned to daily or biweekly injections. Ten control patients were selected from another trial and followed up concurrently. Injection reactions were the only common adverse event (p = 0.01). Treated patients showed enhanced lymphocyte proliferation (p = 0.02). The safety profile and immune effects support conducting larger trials of dose selection and efficacy.

Quantitative sensory testing: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology

OBJECTIVE

This assessment evaluates the clinical utility, efficacy, and safety of quantitative sensory testing (QST).

METHODS

By searching MEDLINE, Current Contents, and their personal files, the authors identified 350 articles. Selected articles utilized computer operated threshold systems, manually operated threshold systems, and electrical threshold devices. The authors evaluated the use of normal values and the degree of reproducibility between the same and different systems. Articles were rated using a standard classification of evidence scheme.

RESULTS

Because of differences between systems, normal values from one system cannot be transposed to others. Reproducibility of results was also an important concern, and there is no consensus on how it should be defined. The authors identified no adequately powered class I studies demonstrating the effectiveness of QST in evaluating any particular disorder. A number of class II and III studies demonstrated that QST is probably or possibly useful in identifying small or large fiber sensory abnormalities in patients with diabetic neuropathy, small fiber neuropathies, uremic neuropathies, and demyelinating neuropathy.

CONCLUSIONS

QST is a potentially useful tool for measuring sensory impairment for clinical and research studies. However, QST results should not be the sole criteria used to diagnose pathology. Because malingering and other nonorganic factors can influence the test results, QST is not currently useful for the purpose of resolving medicolegal matters. Well-designed studies comparing different QST devices and methodologies are needed and should include patients with abnormalities detected solely by QST.

Electrophysiologic studies in critical illness associated weakness: myopathy or neuropathy--a reappraisal

OBJECTIVE

Unexplained weakness in critically ill patients is recognized with increasing frequency. However, it is debated whether the condition is a peripheral neuropathy or a myopathy. Diagnostic difficulties can arise from multiple sources that are not generally a factor in other neuromuscular conditions. Conventional electrodiagnostic techniques may provide only non-specific data, clinical examination is often hampered, and muscle biopsy is not a practical screening tool.

METHOD

To improve diagnostic yield, we studied 22 consecutive patients with critical illness associated weakness with additional electrodiagnostic techniques, including direct muscle stimulation, quantitative electromyography, and motor unit number estimation.

RESULTS

The applied techniques supported an underlying myopathy in all the patients examined. The diagnosis was confirmed by muscle biopsy in 9 patients. Additional lesser features of neuropathy were concomitantly present in one patient who also underwent sural nerve biopsy.

CONCLUSIONS

The study suggests that myopathy is much more common than polyneuropathy in critical illness. Suspicion of this entity should be high in this setting even without exposure to corticosteroids or non-depolarizing blocking agents.

Antisulfatide antibodies in neuropathy: clinical and electrophysiologic correlates

OBJECTIVE

To investigate the clinical and electrophysiologic characteristics of the neuropathy associated with elevated serum antisulfatide antibodies.

METHODS

Clinical, electrophysiologic, morphologic, and laboratory data of 25 patients with significantly elevated (>25,600) antisulfatide antibodies were reviewed.

RESULTS

Four groups were distinguished based on clinical and electrophysiologic data: Group 1, eight patients with predominantly small fiber sensory neuropathy (32%); Group 2, five patients with mixed large and small fiber sensory neuropathy (20%); Group 3, seven patients with axonal sensorimotor neuropathy (28%); and Group 4, three patients with demyelinating sensorimotor neuropathy (12%). One additional patient had mononeuritis multiplex and one had ALS. An immunoglobulin M (IgM) monoclonal gammopathy was found in 30% of the patients tested, but not in any of the Group 1 patients with small fiber sensory neuropathy. Serum IgM level was elevated in 12 patients, of whom six had a concomitant monoclonal gammopathy. Morphologic studies in five patients showed predominantly axonal degeneration, with three of the patients also exhibiting additional features of demyelination.

CONCLUSIONS

Antisulfatide antibodies are associated with several subtypes of peripheral neuropathy. Predominantly sensory or sensorimotor axonal neuropathies are most common in this series, with the sensory component either small fiber or mixed fiber type. A smaller demyelinating group indistinguishable from patients with chronic inflammatory demyelinating polyradiculopathy was also seen. One third of patients had a concomitant IgM monoclonal gammopathy, and approximately one half had elevated serum IgM.