Accelerated transcranial magnetic stimulation for psychological distress in advanced cancer: A phase 2a feasibility and preliminary efficacy clinical trial

Background: Psychological and existential suffering affects many people with advanced illness, and current therapeutic options have limited effectiveness. Repetitive transcranial magnetic stimulation (rTMS) is a safe and effective therapy for refractory depression, but no previous study has used rTMS to treat psychological or existential distress in the palliative setting. Aim: To determine whether a 5-day course of "accelerated" rTMS is feasible and can improve psychological and/or existential distress in a palliative care setting. Design: Open-label, single arm, feasibility, and preliminary efficacy study of intermittent theta-burst stimulation to the left dorsolateral prefrontal cortex, 600 pulses/session, 8 sessions/day (once per hour) for 5 days. The outcomes were the rates of recruitment, completion of intervention, and follow-up (Feasibility); and the proportion of participants achieving 50% improvement on the Hamilton Depression Rating Scale (HDRS) or Hospital Anxiety and Depression Scale (HADS) 2 weeks post-treatment (Preliminary Efficacy). Setting/participants: Adults admitted to our academic Palliative Care Unit with advanced illness, life expectancy >1 month and psychological distress. Results: Due to COVID-19 pandemic-related interruptions, a total of nine participants were enrolled between August 2021 and April 2023. Two withdrew before starting rTMS, one stopped due to clinical deterioration unrelated to rTMS, and six completed the rTMS treatment. Five of six participants had a >50% improvement in HDRS, HADS-Anxiety, or both between baseline and the 2 week follow up; the sixth died prior to the 2-week follow-up. In this small sample, mean depression scores decreased from baseline to 2 weeks post-treatment (HDRS 18 vs 7, p = 0.03). Side effects of rTMS included transient mild scalp discomfort. Conclusions: Accelerated rTMS improved symptoms of depression, anxiety, or both in this small feasibility and preliminary efficacy study. A larger, sham-controlled study is warranted to determine whether rTMS could be an effective, acceptable, and scalable treatment in the palliative setting. Trial registration: NCT04257227