Ear zaps may soothe painful side effect of breast cancer drugs

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Female participants aged over 18 years; 2. Patients with pathologically confirmed stage I-III primary breast cancer; 3. Patients who have recovered from systemic symptoms related to surgery, radiotherapy, or chemotherapy; 4. Patients with estrogen receptor- and/or progesterone receptor-positive breast cancer who are receiving aromatase inhibitor therapy and have aromatase inhibitor-related musculoskeletal pain, with a score greater than 3 on the Worst Pain item of the Brief Pain Inventory (BPI-WP); 5. Patients who have received aromatase inhibitor therapy for more than 30 days and are expected to continue treatment for more than 1 year; 6. Patients who voluntarily agree to participate in this study and sign the informed consent form. For participants receiving combined IL-2 treatment, the following additional criterion applies: 7. Pain relief rate of less than 50% after taVNS treatment and a lower peripheral blood Treg count than before treatment. Exclusion Criteria: 1. Patients with advanced breast cancer; 2. Patients with other significant organ dysfunction, such as major cardiovascular disease, diabetes mellitus, or hyperthyroidism; 3. Patients with other cancers; 4. Patients with a history of fracture or surgery around the painful joint area within the past 6 months; 5. Patients currently receiving corticosteroids or opioid therapy; 6. Patients with contraindications to vagus nerve stimulation; 7. Patients who are unable to communicate normally, such as those with cognitive impairment or hearing impairment; 8. Patients who have participated in another clinical trial within the past 1 month. For participants receiving combined IL-2 treatment, the following additional exclusion criteria apply: 9. Severe cardiac or renal disease, or hematologic disease; 10. Previous IL-2-related toxic reaction or allergy; 11. Use of other biologic agents or immunosuppressive drugs within the past 1 month; 12. Any other condition that the investigator considers unsuitable for study participation.