Cross-Sectional Muscle Area Change in Head and Neck Magnetic Resonance Imaging Defined Sarcopenic State and Survival in Nasopharyngeal Cancer Patients

Abstract

Pre-treatment sarcopenia is associated with worse survival outcomes and severe treatment toxicity in many solid tumors. However, the impact of muscle loss after concurrent chemoradiotherapy and chemotherapy on survival outcomes is unknown in nasopharyngeal cancer. This study aims to investigate the association between muscle loss and survival outcomes of patients with nasopharyngeal cancer (NPC) undergoing concurrent chemoradiotherapy. This is a multi-institute study. There were 976 patients with NPC treated at Taipei Medical University Hospital, Shuang-Ho Hospital and Wan-Fang Hospital between 2002-2019. 504 patients were newly diagnosed with NPC and treated with concurrent chemoradiotherapy. Complete pre- and posttreatment MRI of 292 patients were analyzed. On axial post-contrast T1-WI of MRI, long axis of temporalis muscle thickness (TMT) was measured by using the Sylvian fissure as reference. The outlines of the masseter, pterygoid muscle were delineated in the axial plane at 1-2cm below the zygomatic arch. The cross-sectional areas of the masseter (Me) and masseter+pterygoid (Mt) muscle were then calculated by the imaging software. The averaged values of both sides were used for further analysis. Predictors of overall survival (OS) were then analyzed using Cox regression models. There are 184 male (63%) patients in this cohort. The main age-group at diagnosis is 40-60, which account for 51.2% of this cohort. Most of the patient are stage IV (40.7%) and stage III (25.8%) when they are diagnosed. The median follow-up time is 4.7 years. 93 patients (31.8%) died during the following period. The crude one year-overall survival is 93.2%, and five-year overall survival 68.9%. The average muscle loss of TMT, Me, Mt is 0.012%, 0.029%, 0.026% separately. Among the 3-muscle loss predictor, masseter muscle loss (defined as 20%) is significant related to worse overall survival (p = 0.049 < 0.05) in log-rank test. Muscle loss might not be detected by changes in BMI but can be detected by area changes in MRI captured between pre- and posttreatment. Our data suggest that muscle loss is associated with poor overall survival in patients with Nasopharyngeal cancer.