Decreases in the Psoas Muscle Index Correlate More Strongly with Survival than Other Prognostic Markers in Esophageal Cancer After Neoadjuvant Chemoradiotherapy Plus Esophagectomy

Background Despite wide acknowledgement of the importance of sarcopenia and prognostic markers such as the neutrophil-to-lymphocyte ratio, the impact on cancer patient survival of the timing of sarcopenia's emergence and its severity is not well understood, nor is the association between sarcopenia and prognostic markers. The aim of this study, therefore, was to investigate the effect of the severity and timing of changes in the psoas muscle index (PMI) on survival of advanced esophageal squamous cell carcinoma (ESCC) patients receiving neoadjuvant chemoradiotherapy (NACRT) plus esophagectomy and the association between PMI and known prognostic markers. Methods Included in this study were 113 ESCC patients who underwent NACRT followed by esophagectomy. PMI and prognostic markers were measured at their initial visit, just before surgery (after NACRT), and 3 months postoperatively. Results All patients were classified into four groups according to the percent decrease in PMI after NACRT and after NACRT plus esophagectomy. Patients exhibiting a larger PMI decrease (>= 20%) after NACRT plus esophagectomy had significantly poorer overall survival than those showing a smaller PMI decrease. Furthermore, multivariable analysis showed that a larger decrease in PMI after NACRT plus esophagectomy was a significant risk factor for overall (P < 0.0001) and recurrence-free (P = 0.0097) survival. Neither pretherapeutic PMI nor a decrease in PMI after NACRT significantly affected survival. PMI also showed weak, but significant, correlations with several prognostic markers postoperatively. Conclusions Decreased PMI after NACRT plus esophagectomy is a strong prognostic indicator in ESCC patients.