The goal of this study is to compare the evolution of the density of small nerve fibers assessed with skin biopsies at the foot between two groups of patients with taxane-induced chronic neuropathic pain matched for sex and age: one group treated with applications of capsaicin 8% and a control group who received a systemic treatment. The hypothesis for the capsaicin 8% arm is that in the chronic phase, in the absence in the nervous environment of the toxic agent (in this case taxanes) causing the neuropathy and the functional modifications at the origin of pain, the new small fibers could regenerate without these pathological alterations.
Our analysis will be based on the demonstration of structural abnormalities of small nerve fibers by means of skin biopsy, but also of functional abnormalities using four validated tests commonly used in this field: quantitative sensory testing (QST), laser evoked potential recordings, Sudoscan and confocal corneal microscopy.