No abstract

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. CLINICAL TRIAL REGISTRATION: NCT01523574. RESUMO CONTEXTO E OBJETIVO:A oxaliplatina é um dos quimioterápicos mais utilizados no tratamento do cân-cer colorretal, sendo a indução da neuropatia periférica (NP) uma das principais limitações para o seu uso. Trabalhos anteriores demonstraram que a vitamina E poderia reduzir a incidência dessa neuropatia em 50%. Este estudo teve como objetivo avaliar a efetividade da vitamina E na prevenção da NP induzida pela oxaliplatina. TIPO DE ESTUDO E LOCAL:Estudo piloto prospectivo e randomizado de fase II desenvolvido em hospital universitário do Grande ABC. MÉTODOS: Os pacientes foram randomizados para receber vitamina E ou placebo por cinco dias antes do início do tratamento com oxaliplatina e até o término do regime quimioterápico. O desfecho foi avaliado através dos Critérios Comuns de Toxicidade do Câncer versão 3 (CTCAE) e escalas específicas de gradação da NP induzida por oxaliplatina. Foram incluídos pacientes com câncer colorretal e gástrico programado para receber quimioterapia baseada em oxaliplatina. Ambos os grupos receberam suplementação de cál-cio e magnésio antes e depois das infusões de oxaliplatina. RESULTADOS: Dezoito pacientes foram randomizados para grupo da vitamina E e 16 para o grupo placebo. Observou-se incidência cumulativa de 83% das classes I/II de neuropatia periférica no grupo da vitamina E, ...

Alpha-tocopherol augmentation in human neutrophils was investigated for effects on neutrophil activation and tyrosine phosphorylation of proteins, through its modulation of protein kinase C (PKC) and tyrosine phosphatase activities. Incubation of neutrophils with alpha-tocopherol succinate (TS) resulted in a dose-dependent incorporation into cell membranes, up to 2.5 nmol/2x10(6) cells. A saturating dose of TS (40 micromol/l) inhibited oxidant production by neutrophils stimulated with phorbol myristate acetate (PMA) or opsonized zymosan (OZ) by 86 and 57%, as measured by luminol-amplified chemiluminescence (CL). With PMA, TS inhibited CL generation to a similar extent to staurosporine (10 nmol/l) or genistein (100 micromol/l), and much more than Trolox (40 micromol/l). With OZ, TS inhibited CL to a similar extent to Trolox. Neutrophil PKC activity was inhibited 50% or more by TS or staurosporine. The enzyme activity was unaffected by genistein or Trolox, indicating a specific interaction of alpha-tocopherol. TS or Trolox increased protein tyrosine phosphorylation in resting neutrophils, and as with staurosporine further increased tyrosine phosphorylation in PMA-stimulated neutrophils, while the tyrosine kinase (TK) inhibitor genistein diminished phosphorylation. These effects in resting or PMA-stimulated neutrophils were unrelated to protein tyrosine phosphatase (PTP) activities, which were maintained or increased by TS or Trolox. In OZ-stimulated neutrophils, on the other hand, all four compounds inhibited the increase in tyrosine-phosphorylated proteins. In this case, the effects of pre-incubation with TS or Trolox corresponded with partial inhibition of the marked (85%) decrease in PTP activity induced by OZ. These results indicate that alpha-tocopherol inhibits PMA-activation of human neutrophils by inhibition of PKC activity, and inhibits tyrosine phosphorylation and activation of OZ-stimulated neutrophils also through inhibition of phosphatase inactivation.

Gabapentin is a low-cost strategy to improve complete control of CINV, specially delayed CINV control.