Efficacy of Repetitive Transcranial Magnetic Stimulation Over the Primary Cortex in Patients With Neuropathic Pain and Cancer

Efficacy of Repetitive Transcranial Magnetic Stimulation Over the Primary Cortex in Patients With Neuropathic Pain and Cancer: Cross-over and Placebo-control Study

High-frequency repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex (M1) has shown its efficacy to alleviate pain in patients suffering from refractory neuropathic pain. rTMS is now considered as 3rd-line therapy (by the French Society for the Study and Treatment of Pain) for patient's refractory to drug therapy.

However, its efficacy in chronic neuropathic pain related to cancer has not yet been specifically studied, and it therefore remains relatively inaccessible for these patients. This project is a cross-over, double-blinded, and placebo-control study, including 5 sessions of either M1 or "sham" rTMS, a wash-out period (8 weeks), followed by 5 sessions of the other stimulation option (I.e., two arms: M1-sham or sham-M1; order randomized between patients). Treatment efficacy will be assessed in comparison to the placebo condition. Primary outcome is the percentage of pain relief between active and sham rTMS. Other variables to describe quality of life, sensory, neuropathic, and mood states as well as resting-state fMRI will be collected before and after treatment.

Inclusion Criteria:

• Patient affiliated to or entitled under a social security scheme
• Patient who has received informed information about the study and who has co-signed, with the investigator, a consent form to participate in the study.
• Patient aged 18 to 85 (male or female),
• Central or peripheral neuropathic pain related to cancer and/or its treatment;
• Chronic pain (present for more than 4 months) whose intensity is greater than or equal to 4/10 on a VAS (Visual Analogue Scale) numerical scale.
• Pain present on a daily or almost daily basis (at least 4 days a week)
• Patient not completely relieved by recommended first- and second-line drug treatments for neuropathic pain
• Stable analgesic treatment (no new treatment or dosage adjustment) for at least one month and will not need to be modified for the duration of the study.
• Patient can be followed throughout the study.
• Indication for rTMS of the motor cortex by a neurologist.

Exclusion Criteria:

• Accident at work or litigation,
• Contraindication to rTMS or MRI (treatment with seismotherapy during the previous month; history of cranial trauma; intracranial hypertension; intracerebral metal clip; piercing; pacemaker; insulin pump; metal prosthesis; pregnant or breast-feeding woman; claustrophobia).
• Chronic alcoholism
• Abuse of drugs or psychoactive substances
• Neuropathic pain as part of a progressive pathology (e.g. HIV),
• Presence of other pain of greater intensity than the neuropathic pain leading to inclusion
• Acute stroke (< 3 months)
• Patient with brain tumour lesions
• Patient with infectious or metabolic brain lesions
• Patients with severe or recent cardiac disorders
• Patients with cognitive impairment
• Patient unable to understand informed consent,
• Patients refusing to stop or unable to stop treatments prohibited during the study, such as morphine.
• Patients participating in another research protocol involving a medicinal product within 30 days prior to inclusion.
• Patients deprived of their liberty or under legal protection (guardianship, curatorship, safeguard of justice, family habilitation).