Background: The aim of this study was to investigate the prognostic impact of sarcopenia and skeletal muscle change in rectal cancer patients who underwent preoperative chemoradiotherapy (preop-CRT).
Material and methods: From April 2004 to June 2013, we identified non-metastatic rectal cancer patients who underwent preop-CRT. Sarcopenia was evaluated according to previous cut-off value by computed tomography measured before starting preop-CRT (sarcopenia_pre) and 4-6 weeks after cessation of preop-CRT (sarcopenia_post). The severe muscle loss was defined as change in muscle mass < -4.2%/100 days. The hazard ratio (HR) and 95% confidence interval (CI) of sarcopenia and muscle change were estimated using a Cox proportional hazards model adjusted for potential confounders.
Results: Among 93 patients who underwent both pre and post-CRT CTs, 48 (51.6%) and 51 (54.8%) were identified as sarcopenia_pre and sarcopenia_post respectively. Twenty-three patients (24.7%) were included in the severe muscle loss group. Multivariable analysis identified sarcopenia_post (HR 2.6, 95% CI 1-6.2, p = 0.023), and severe muscle loss (HR 2.8, 95% CI 1.2-6.2, p = 0.011) along with age and ypStage as independent risk factors for overall survival. Clinical T4 stage was the only factor that can predict severe muscle loss (OR 3.4, 95% CI 1.2-9.4, p = 0.016).
Conclusions: Sarcopenia identified after the completion of preop-CRT and change in muscle mass < -4.2%/100 days during preop-CRT are promising parameters to predict overall survival in patents with locally advanced rectal cancer and should be investigated more rigorously.
Keywords: Preoperative chemoradiotherapy; Rectal cancer; Sarcopenia.
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