Long-term Effects of Methadone for Cancer Pain

The methadone is an useful opioid for the cancer pain treatment, mostly used in second or last line during the opioid rotation. The Methadone had an anti-MNDA effect, and clinicians agree that the methadone could have an effect in neuropathic cancer pain. During a previous study the investigators find that the pain was still improving after the week 2, but they had only a small number of patients still included at this stage and they cannot conclude.

The investigators decide to follow up systematically all the patients undergoing a methadone treatment for cancer pain, at day 28, to study the hypothesis about the long-term pain improvement.