Efficacy of Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) in Aromatase Inhibitor-induced Arthralgia (AIA)

Inclusion Criteria:

1. Menopausal women receiving an aromatase inhibitor (AI) as adjuvant treatment for breast cancer (letrozole (Femara), anastrozole (Arimidex) or exemestane (Aromasin)). The same AI must have been the same during the 4 weeks preceding inclusion and not be intended to be changed during the study period;
2. Polyarticular and symmetrical pain that developed or worsened after the initiation of AI therapy and has persisted for at least 1 month;
3. Score greater than 4 within 7 days before randomization (range,0-10; higher scores indicate greater pain) on the average pain item of the Brief Pain Inventory-Short Form (BPI-SF) as reported by patient;
4. Patients receiving stable background analgesic treatment for AIA may be included, provided that this treatment has remained stable and that no new medication has been initiated prior to inclusion, as follows:

   * Analgesic treatment: stable for at least 2 weeks before inclusion, with no initiation of new medication.
   * Antidepressant treatment, including serotonin-norepinephrine reuptake inhibitors (SNRIs) (e.g., duloxetine, venlafaxine): stable for at least 4 weeks before inclusion, with no initiation of new medication."
5. Patients with an Eastern Cooperative Oncology Group performance status of 0 to 2;
6. Patient covered by a social security system;
7. Patient mastering the French language and able to complete the evaluation questionnaires;
8. Signed written informed consent form.

Exclusion Criteria:

1. Patients who have previously used an electrostimulation device for pain management;
2. Use of vagus nerve stimulation prior to the study;
3. Patients who have received auriculotherapy for the same indication within the previous 4 weeks or who plan to initiate such treatment during the study;
4. Symptomatic orthostatic hypotension (according to investigator) or recurrent vasovagal syncope or history of vagotomy;
5. Previously implanted electrically active medical devices (eg, cardiac pacemakers or automatic implantable cardioverter defibrillators), or significant electrocardiogram abnormalities (cardiac rhythm disturbances, atrioventricular block \>first degree or total bundle branch block);
6. Current treatment with beta-blocker drugs;
7. Patient under guardianship or unable to give informed consent;
8. Patient unable to undergo medical follow-up for geographical, social or psychopathological reasons.