Severe muscle loss during radical chemoradiotherapy for non‐metastatic nasopharyngeal carcinoma predicts poor survival

BACKGROUND: Skeletal muscle loss is a novel imaging biomarker that is considered to be predictive of survival outcomes and toxicity in a variety of solid tumors. This study explored to investigate whether skeletal muscle loss after chemoradiotherapy (CRT) in nasopharyngeal carcinoma (NPC) patients can predict survival. METHODS: A total of 394 non‐metastatic NPC patients were enrolled. The cross‐sectional area of the third lumbar skeletal muscle based on computed tomography (CT) scan was measured and the skeletal muscle index (SMI) was calculated. A cut‐off value suitable for the Chinese population was used to define sarcopenia, and relative changes in skeletal muscle after treatment were analyzed for the confirmation of skeletal muscle tissue loss during treatment and its impact on overall survival (OS). RESULTS: The median follow‐up was 22.7 (range, 2.5‐46.4) months. One hundred and thirty patients (33.0%) were defined sarcopenia at baseline. Two hundred and forty one patients (61.2%) had posttreatment sarcopenia. The mean SMI before and after treatment was 42.8 and 38.1 cm(2)/m(2) (P < .001), and the average SMA loss was 13.1 cm(2). While sarcopenia before or after treatment was not associated with OS, severe muscle loss after CRT was an independent predictor of survival prognosis for NPC (hazard ratio 2.79, 95% confidence interval 1.47‐5.28, P = .002) when adjusted for gender and cancer stage. CONCLUSIONS: During CRT, patients with NPC often experience different levels of muscle loss, and severe skeletal muscle loss may shorten OS.