Understanding nasopharyngeal carcinoma

Abstract

An international collaborative project, based at the Chinese University of Hong Kong, seeks to drastically improve the prognosis and quality of life for nasopharyngeal cancer patients. Hong Kong has experienced a rise in the incidence of nasopharyngeal carcinoma (NPC) in an increasingly ageing population. Swallowing disorders and neuropathy are common occurrences in survivors, as a result of continued exposure to chemotherapy. Most of the techniques developed in studying this pathological phenomenon are invasive and impractical and complicate the establishment of clinical correlations between current treatment courses and physiological events. There is therefore a pressing need for better treatment strategies and early diagnostic methods that allow subclinical identification. Professor Michael Chi-Fai Tong, from the Chinese University of Hong Kong's Department of Otorhinolaryngology, is investigating the pathophysiologic mechanisms that lead to methods with novel approaches.During the studies, Tong revamped common evaluation techniques for swallowing motor capacity in order to perfect the assessment of muscle function in irradiated nasopharyngeal cancer patients. During the studies, Tong revamped common evaluation techniques for swallowing motor capacity in order to perfect the assessment of muscle function in irradiated nasopharyngeal cancer patients. While FEES and VFSS were the most explored techniques, Tong also focused on developing a better understanding on results obtained from HD-EMG performed on dysphagia subjects. The chosen parameters were related to SEMG signals that, when brought together provided the opportunity to map out muscular activities involved in the act of swallowing. From all the techniques, high-density electromyography brought forward the highest number of clinical correlations to the physiology behind dysphagia, namely by analysing aspiration rates, penetration, oral and pharyngeal stasis and premature spillage as measures for early diagnosis, early intervention and monitoring treatment progress. After applying the techniques to patients participating in the trial, Tong concluded that dysphagia indeed remained a major clinical problem for surviving patients and a significant number suffered from adverse effects that compromised their quality of life. Nearly 30 percent of the studied population experienced subsequent health burdens as well as higher medical expenses. ‘Values obtained from sEMG reflected actual changes in the geniohyoid muscle during contraction, whilst ultrasound imaging allowed direct visualisation and measurement of the muscle,’ Tong explains. ‘Both are useful techniques in providing supplementary information regarding muscle function, and provide quick tools to monitor treatment progress, but more effort is needed to prevent or delay the occurrence of dysphagia and its related complications.’ Novel methods of swallowing training were tested among survivors. Tong compared the outcomes of conventional training with transcutaneous electrical stimulation (TES) and found that TES had a superior outcome compared to conventional treatments. Despite having obtained positive results, validation of these methods is dependent on the sample size that the team used to execute the studies, as conventional swallowing assessments are subjective and require quantitative parameters to reach an objective evaluation. However, Tong is positive that those results will be attained, especially with the help of the multidisciplinary team gathered through this consortium, from laryngologists, to speech therapists and academic research staff. The methods developed are still in need of optimisation, but with this collaborative endeavour, Tong and his team will surely come up with a new strategy, providing a deeper understanding of neck muscle defects in surviving NPC patients for future applications.