Serum Cytokines Correlate with Pretreatment Body Mass Index-Adjusted Body Weight Loss Grading and Cancer Progression in Patients with Stage III Esophageal Squamous Cell Carcinoma Undergoing Neoadjuvant Chemoradiotherapy Followed by Surgery. Circulating cytokines have been linked to the development of esophageal squamous cell carcinoma (ESCC) and its associated malnutrition process. Nonetheless, given the varied disease stages and treatment modalities in previous studies, the clinical relevance of their findings is limited. We retrospectively studied 52 patients with stage III ESCC who underwent neoadjuvant chemoradiotherapy and curative-intent surgery. We investigated the association of clinicopathological features, pretreatment laboratory data, and pretreatment inflammatory status, as indicated by the levels of albumin, C-reactive protein, and 10 circulating cytokines, namely tumor necrosis factor-alpha (TNF-α), interferon-gamma, interleukin-1-beta (IL-1β), IL-4, IL-6, IL-8, IL-12, IL-13, IL-17A, and IL-23, with malnutrition, as shown by body mass index-adjusted body weight loss (BMI-BWL) grading, cancer progression. Half the patients showed severe malnutrition and high BMI-BWL grades (3 and 4). Multivariate analysis revealed an independent association between the levels of three cytokines (TNF-α, ≤ 5.8 pg/ml; IL-1β, > 0.4 pg/ml; IL-6, ≤ 12.4 pg/ml) and high BMI-BWL grades and between IL-4 levels > 22.5 pg/ml and cancer progression. All 10 cytokines were closely correlated with each other. In conclusion, TNF-α, IL-1β, and IL-6 were independent markers of malnutrition status and IL-4 was a prognostic factor for cancer progression in this patient population.