Pain Control Using Neuromodulation in Patients Undergoing Definitive Chemoradiotherapy or Radiation Therapy for Locally Advanced Head and Neck Cancer
Cancer pain represents a clinical problem in which our empirical conventional treatments offer uncertain relief for a large number of patients. Many therapies for cancer pain that focus on mechanical and peripheral factors are short-lasting or ineffectual, leading to persistent treatment failure and/or poor iatrogenic-induced results, including multiple surgeries. For instance chemo-radiotherapy-induced pain and dysphagia in head and neck cancer are major causes of morbidity and reduced quality of life for those patients. Those symptoms usually appear or augment from the second/third week into treatment, and may persist thereafter. Although neuro-imaging techniques have provided insights into some brain mechanisms of acute pain and related dysfunction in humans, many questions regarding their persistence and modulation are still unanswered. Recent reports from our group and others suggest that cause for chronicity in pain may be due in great part to functional and structural map-adaptive neural changes in endogenous analgesic central mechanisms. A novel treatment modality that could potentially have significant impact would directly modulate such mechanisms in the brain. New non-invasive methods, especially as transcranial direct current stimulation (tDCS), can now safely and directly modulate brain function in chronic pain patients. If appropriate stimulation parameters and cortical targets are defined and used, repetitive tDCS has the potential to provide relatively lasting relief by increasing or decreasing activity of key sensory and motor cortical structures. Hence, our primary and secondary focuses are to investigate the clinical efficacy, and the neuromodulatory mechanism involved, by targeting cortical dysfunction in cancer pain patients using tDCS during chemo-radiotherapy.