The rationale for intensification strategies is that more frequent exposure to chemotherapeutics could enhance antitumor activity. Several trials investigated weekly paclitaxel administration, but there are no clear data concerning peripheral neurotoxicity. The aim of this study was to assess the incidence of peripheral neurotoxicity in patients affected by advanced breast cancer treated with weekly paclitaxel.Neurotoxicity was assessed with neurologic and neurophysiologic evaluation before treatment and after 12 weeks and 24 weeks. A total neurotoxicity score was assigned to each patient on the basis of neurophysiologic and neuropathic signs and symptom changes. Seventeen patients entered the study.After 12 weeks of treatment, 71% showed moderate clinical and/or neurophysiologic signs of neurotoxicity; after 24 weeks, the incidence of neurotoxicity increased to 96%. Sural amplitude at the 24-weeks examination significantly decreased from basal mean value (13.5 microv, standard deviation [SD] 6 microv vs. 7 microv, SD 5.9 microv, respectively; P = 0.01), whereas median sensory amplitude decreased after 24 weeks from 10.3 microv, SD 6.2 microv to 4.9 microv, SD 3.8 microv (P = 0.001). In a subset of 11 patients, we obtained a follow-up examination after 6 months from the end of treatment. In all patients, examined signs and symptoms of neurotoxicity improved with recovery of subjective neuropathic symptoms and neurophysiologic findings.Our results demonstrate, in a little population of patients evaluated with a comprehensive neurologic assessment, that weekly paclitaxel is related to a very high incidence of peripheral neurotoxicity. Follow-up data obtained in a subset of patients indicate that peripheral neurotoxicity is reversible.