RESUMO
PURPOSE: The purpose of this study was to assess whether the infrahyoid skeletal muscle index (IHSMI) can be used instead of the L3 skeletal muscle index (L3SMI) to define sarcopenia and predict prognosis in patients with locally advanced head and neck squamous cell carcinoma (LHNSCC). METHODS: Patients treated for LHNSCC between January 2009 and April 2018 were assessed. The muscular area at the L3 transverse process and infrahyoid was contoured on absorption-corrected computed tomography prior to treatment. Sarcopenia based on L3SMI (S-L) was defined as values of < 52.4 cm2/m2 for men and < 38.5 cm2/m2 for women. Sarcopenia based on IHSMI (S-I) was determined via receiver operating curve analysis. Overall survival (OS) and cause-specific survival (CSS) curves were constructed using the Kaplan-Meier method. RESULTS: In total, 101 patients were analyzed. The median follow-up period was 19 months (range 3-101 month). S-L and S-I were identified in 74 (73.3%) and 56 patients (55.4%), respectively. The 5-year OS rate did not differ between patients with and without S-L (64.9% vs. 79.2%, p = 0.635), whereas the rate was lower in patients with S-I than without S-I (57.1% vs. 93.0%, p = 0.006). Similarly, the 5-year CSS rate did not differ between patients with and without S-L (77.0% vs. 82.3%, p = 0.523), but the rate was lower in patients with S-I (61.2% vs. 93.0%, p = 0.02). CONCLUSION: Pretreatment S-I, but not S-L, was a good predictor of OS and CSS in patients with LHNSCC.