Electroneurography in Evaluation of Peripheral Neuropathy During Oxaliplatin-Based Chemotherapy for Colorectal Cancer

Abstract

Introduction: Oxaliplatin-based chemotherapy is a standard systemic therapy for colorectal cancer. Cold induced-neuropathy is a typical toxicity during oxaliplatin treatment. Electroneurography is a standard method evaluating condition of peripheral nerves. This neurological examination has not been used in oncological setting so far. Methods: A total of 22 patients enrolled to this study with colorectal cancer treated FOLFOX4 +/- bevacizumab or XELOX chemotherapy in Oncological Department in University Hospital in Cracow, Poland, between February 2013 and January 2014. Chemotherapy regimen FOLFOX4 consisted of intravenous oxaliplatin 85 mg/m2 on day 1, leucovorin 200 mg/m2 on day 1, 2 and 5Fu 400 mg/m2 in bolus on day 1, 2 and 5Fu 600 mg/m2 in 22 hours on day 1, 2. Treatment courses were repeated every 2 weeks until maximum 12 cycles. Bevacizumab 10 mg/ kg was administered intravenously on 1 day every cycle. Chemotherapy regimen XELOX consisted of intravenous oxaliplatin 130 mg/ m2 on day 1 and oral capecitabine 1000 mg/m2 twice daily on days 1-14 followed by 7-days rest. Treatment courses were repeated every 3 weeks until maximum 8 cycles. Electroneurography was performed before starting chemotherapy, after 4 cycles (when peripheral neuropathy risk increases) and after completion of treatment. All patients underwent a complete neurological examination and a semi-structured questionnaire interview. The neurographic examinations were carried out according to the commonly applied routine methods with the use of a Viking Quest (Nicolet Biomedical Incorporated, Madison, USA). In all patients we performed neurographic examinations of motor and sensory fibres of the following nerves: median, ulnar, peroneal, sural and tibial using standard stimulating sites. The results of the examinations were compared with our own standards. Patient characteristics are presented in table number 1. Results: Sixteen patients finished neurological evaluation. Eight patients had performed 3 electroneurography tests. Two patients had only two electroneurography tests due to progression of disease. In 6 cases - treatment is continued. Adverse events were assessed at each cycle according to National Cancer Institute Common Toxicity Criteria (NCI-CTC, version 2.1). Advanced symptoms of neuropathy (G3/G4) were observed only in one case. Despite oxaliplatin dose reduced, symptoms of neuropathy persisted. Oxaliplatin was omitted in the last chemotherapy cycle. Results are presented in table number 2. Neurographic examination revealed the presence of peripheral neuropathy in 4 patients (25%). Sensory neuropathy was diagnosed in 1 patient (6,2%). Sensory and motor neuropathy was diagnosed in 3 patients (18,75%). 3 patients showed clear electrophysiologic signs of axonal neuropathy - 3 patients with motor and sensory neuropathy and in 1 patients with sensory neuropathy. None of the patients showed electrophysiologic features of demyelination. In 1 patient (6,2%) compression mononeuropathies were diagnosed such as carpal tunnel syndrome. The neurographic examination led to results in the normal range in the remaining 11 patients (68,75%). Conclusion: 1. Electroneurography is safe and useful method evaluating status of peripheral nerves in patients treated with oxaliplatin. 2. Electroneurography indicates patients who will have advanced symptoms of neuropathy after completion of oxaliplatin treatment.