DIAGNOSIS OF TAXAN-INDUCED PERIPHERAL NEUROPATHY IN ONCOLOGICAL PATIENTS

Анотація

There is currently no standardized approach to the clinical evaluation of chemotherapy-induced neuropathy. However, there is consensus that the diagnosis of chemotherapy-induced peripheral neuropathy should include both objective signs of neurological disorders and assessment of symptoms from the patient's point of view. The reason for this approach is the discrepancy in the results of the clinical examination and the patients' self-assessment of the severity of their condition. Usually, clinical examination of patients underestimate the severity of adverse reactions during chemotherapy. Diagnosis of chemotherapy-induced peripheral neuropathy includes questionnaires, rating scales, and objective methods for studying of neurophysiological changes in the peripheral nervous system, such as electromyography and quantitative sensory testing. The rating scale should have a wide range of indicators, including clinical symptoms, objective signs of loss of sensitivity and neurophysiological parameters. A key characteristic of the rating scale is high sensitivity to changes in parameters. Not less relevant is the questionnaire with self-assessment of neuropathy by patients in a clinical trial. The inclusion of assessments obtained directly from patients allows for a more comprehensive and detailed study of chemotherapy-induced peripheral neuropathy, improves understanding of the effects of neuropathy on patients, and improves the consistency of objective examination data with the assessment of functional changes.

Chemotherapy-induced peripheral neuropathy should be differentiated from neuropathies of other genesis, in particular diabetic and paraneoplastic neuropathies. The key of differential diagnosis is a thorough examination of patients before chemotherapy with neurotoxic drugs, in order to identify pre-existing neuropathy. In some cases, paraneoplastic neuropathies, in which onconeuronal antibodies affect antigenic determinants of the peripheral nervous system, cause neurological symptoms, which in some cases resemble chemotherapy-induced peripheral neuropathy. Paraneoplastic neuropathies can be manifested both before the diagnosis of a malignant neoplasm, and vice versa, can occur against the background of anticancer therapy. As a result, the differential diagnosis between chemotherapy-induced and paraneoplastic neuropathies may be difficult. Paraneoplastic neuropathies can occur during chemotherapy, however, in contrast to chemotherapy-induced, they are characterized by a different clinical picture, such as loss of proprioceptive sensitivity in the proximal areas and others.

The main method of objective assessment of chemotherapy-induced peripheral neuropathy is electromyography, which allows to measure the amplitude and conduction velocity of the total sensory and motor action potentials. Quantitative sensory testing is also an objective method of assessing chemotherapy-induced peripheral neuropathy. The essence of this method can be defined as the analysis of the patient's sensations that arise in response to external pathogens of a certain intensity. The effect of the irritant on the skin of increasing and decreasing intensity allows to determine the threshold of pain, vibration, temperature, tactile sensitivity and sensory symptoms.