The Association Between Computed Tomography–Defined Sarcopenia and Outcomes in Adult Patients Undergoing Radiotherapy of Curative Intent for Head and Neck Cancer: A Systematic Review

Abstract

BackgroundComputed tomography (CT)-defined sarcopenia is a demonstrated poor prognostic factor in patients with cancer; however, its influence on outcomes for patients with head and neck cancer (HNC) has not been established. ObjectiveThis review synthesizes current knowledge regarding the association between CT-defined sarcopenia and outcomes for adult patients undergoing radiotherapy with or without other treatment modalities of curative intent for HNC. MethodsA systematic review of the literature published between January 2004 and June 2019 was conducted in Medline, Embase, Cumulative Index of Nursing and Allied Health Literature, Allied and Complementary Medicine Database, and PubMed. Empirical studies of CT-defined sarcopenia in adult patients (≥18 years) with HNC who had completed radiotherapy of curative intent with or without other treatment modalities were included. Outcomes reported included survival, prolonged radiotherapy breaks, and chemotherapy toxicity. Study quality was assessed using the American Academy of Nutrition and Dietetics Quality Criteria Checklist. Synthesis of outcomes and clinical relevance was performed using the Grading of Recommendations Assessment, Development, and Evaluation system. ResultsOf 11 studies (n = 3,461) identified, 3 were positive and 8 were neutral quality. Studies were heterogeneous in HNC diagnosis, ethnicity, definition of sarcopenia, CT level of evaluation, and skeletal muscle index threshold value. Eight definitions for sarcopenia were identified with pretreatment prevalence of 6.6% to 70.9% and posttreatment prevalence of 12.4% to 65.8%. Pretreatment sarcopenia was independently associated with reduced: overall survival (OS), 3-year OS, disease-free survival, prolonged radiotherapy breaks, and chemotherapy-related toxicities. Posttreatment sarcopenia was independently associated with reduced OS and 5-year OS. The overall certainty of evidence according to Grading of Recommendations Assessment, Development and Evaluation criteria was low for OS; 3-year, 5-year, and 10-year OS; locoregional control; locoregional failure; progression-free survival; metastasis-free survival, disease-specific survival; and disease-free survival and very low for distant metastasis, prolonged radiotherapy breaks, and chemotherapy toxicity-related outcomes. ConclusionsCT-defined sarcopenia is independently associated with reduced OS and treatment completion in patients with HNC and holds a clinically meaningful prognostic value. The certainty of the evidence requires strengthening with further research. Understanding the impact sarcopenia has on outcomes for these patients has implications for informing potential nutrition interventions and facilitating individualized care.