Oxaliplatin is an anticancer agent commonly used in the treatment of colorectal cancer. However, the development of neuropathic pain under treatment limits its use. These are manifested by acute hyperesthesia / distal cold allodynia and chronic course of hypoesthesia.

It is widely reported that these pains are consecutive to hyperexcitability of some ioniques2 channels (mainly sodium and potassium channels). However, the pathophysiological mechanisms of neurotoxicity are multifactorial and still imperfectly described.

Since May 2014, the hospital group Paris Saint Joseph led the pilot study LIPIDOXA whose challenge is to quantify / measure NAION and explained by a biochemical approach, specifically Lipidomics. The CANALOXA study is the logical continuation of LIPIDOXA study insofar design methodology relies heavily on techniques developed for LIPIDOXA study and that the expected results will be complementary to those of LIPIDOXA.

Main objective:

it is, in cancer patients chronically treated with oxaliplatin (over 5 courses) and exhibiting signs of neuropathy, to correlate the quantitative changes in the thermal sensitivity to hot and cold (Thermotest, Quantitative Sensory Testing QST ) with any changes in the ion conductance chlorine measured by electrophysiological technique (SUDOSCAN).

Secondary objectives:

• Correlating the results obtained with both types of techniques and with the descriptive parameters of the population included.
• Understand the importance of regulating the activity of the chloride channel in the development of neuropathy induced by oxaliplatin.

Methodology :

Prospective study, single center, intervention in routine care. Time study: February 2015 - October 2016

1. Evaluation of neuropathy by electrophysiological methods (SUDOSCAN) The SUDOSCAN is a new technology fast and non-invasive to quantify the degree of neuropathy objectively through evaluation of chloride conductance at the skin of the palms and the soles of pieds4,5.

2. Evaluation of neuropathy by devices for quantitative measurement of neuropathic pain

   The pain symptoms was evaluated through various semi-objective neuropathy quantification tools (Quantitative Sensory Testing devices) 6:

   • The Thermotest (Somedic®): medical device that measures the thermal sensitivity thresholds to cold and hot: cold sensitivity threshold, threshold of sensitivity to hot, cold pain threshold, pain threshold warm. These stimuli are transmitted by the fiber Adelta and C. Since dysesthesia to thermal stimuli (allodynia in acute and chronical hypoesthesia) are typical of oxaliplatin, Thermotest is fundamental.
   • Questionnaire NPSI (Neuropathic Pain Symptom Inventory) widely used in the field and validated.

3. Statistical Analysis: Professor Gilles Chatellier, statistician (Clinical Research Unit, Hôpital Européen Georges Pompidou) will bring its expertise in statistical analysis.

NB: For each subject will be awarded an identifier (simple counter: increment as and measurement of inclusions) and the data will be entered on a computer file which will be sent to the statistician in charge of the analysis. There will be no exchange of personal data for this study is single center on the site GHPSJ.

Development of the study:

• Inclusion of patients treated with oxaliplatin from 6th cycle (FOLFOX protocols FOLFIRINOX, EOX, GEMOX, EOF, XELOX).
• Expected duration of patient recruitment: 9 months
• Number of patients to recruit and duration of participation for each patient: Based on 75 patients seen in 9 months in GHSPJ the oncology department for cancer of the digestive tract, and knowing that the prevalence of neuropathic pain in oxaliplatin is 50-70% (Attal 2009), the investigators plan to include at least 36 patients in this period of 9 months.

Inclusion Criteria:

• Patient newly treated with oxaliplatin
• Patient suffering from any type of cancer treated with oxaliplatin
• Man or Woman over 18

Exclusion Criteria:

• Patient with brain or leptomeningeal metastases
• Patient previously treated with cisplatin
• Patient addicted to alcohol
• Diabetic patient with peripheral neurological disorders
• Patient receiving calcium or magnesium salts intravenously
• Patient suffering from peripheral neuropathy
• Patient suffering from psychiatric disorders
• Patient treated with at least one of the following drug: venlafaxine, carbamazepine, gabapentin, pregabalin, clomipramine, amitriptyline, imipramine, duloxetine.