Effects of repetitive transcranial magnetic stimulation on fear of cancer recurrence and its underlying neuromechanism.

Introduction: Many breast cancer patients suffer from fear of cancer recurrence (FCR). However, effective physical intervention for FCR has been scarce. Previous studies have confirmed that repetitive transcranial magnetic stimulation (rTMS) can help improve patients' anxiety, depression, fear, and stress level. Therefore, this study aims to assess the efficacy of rTMS in the treatment of FCR in breast cancer patients and explore its underlying neural mechanism. Methods and analysis: and analysis: Fifty breast cancer patients with high FCR (FCR total score >27), and fifty age- and gender-matched patients with low FCR (FCR total score <7) will be recruited to participate in this study. Patients in the high FCR group will be randomly assigned to receive 4-week low-frequency rTMS targeting the right dorsolateral prefrontal cortex (rDLPFC) + treatment as usual (TAU) (n = 25), or to receive sham stimulation + TAU (n = 25). Patients in the low FCR group will only receive TAU. All participants will take a baseline fMRI scan to examine the local activities and interactions of brain activity between the prefrontal cortex (DLPFC), amygdala and hippocampus. Fear of Cancer Recurrence Questionnaire (FCRQ7), Patient Health Questionnaire (PHQ9), Generalize Anxiety Disorder (GAD7), Numeric Rating Scale (NRS), and Insomnia Severity Index (ISI7) will be used to measure an individual's FCR, depression, anxiety, pain, and insomnia symptoms at week 0 (baseline), week 4 (the end of intervention), week 5 (1 week post-treatment), week 8 (1 month post-treatment), and week 16 (3 months post-treatment). Participants in the high FCR group will receive a post-treatment fMRI scan within 24 h after intervention to explore the neural mechanisms of rTMS treatment. The primary outcome of the study, whether the rTMS intervention is sufficient in relieving FCR in breast cancer patients, is measured by FCRQ7. Additionally, task activation, local activity and functional connectivity of the DLPFC, amygdala and hippocampus will be compared, between high and low FCR group, and before and after treatment. Discussion: Studies have shown that low-frequency rTMS can be used to treat patient's FCR. However, there is a lack of relevant evidence to support the efficacy of rTMS on FCR in cancer patients, and the neural mechanisms underlying the effects of rTMS on FCR need to be further investigated. Ethics and dissemination: Ethical approval for the study has been obtained from the Ethics Committee of Guangdong Provincial People's Hospital (reference number: KY-N-2022-136-01). The results of the investigation will be published in scientific papers. The data from the investigation will be made available online if necessary. Trial registration: NCT05881889 (ClinicalTrials.gov). Date of registration: May 31, 2023.