A nomogram based on clinical characteristics and nutritional indicators for relative and absolute weight loss during radiotherapy in initially inoperable patients with locally advanced esophageal squamous cell carcinoma

Radiation for locally advanced esophageal squamous cell carcinoma (LAESCC) often comes with radiation esophagitis, interfering with oral intake difficulty. We aimed to compare and develop a nomogram model to identify initial inoperable patients with relative/absolute weight loss who need prophylactic nutritional supplementation. A total of 365 initial inoperable LAESCC patients receiving radiotherapy between January 2018 and December 2022 were included in the study, which was divided into a discovery and validation cohort. ROC analysis and Kaplan-Meier curve were performed to compare the areas under-the-curve (AUC) and survival benefits. 42.2% (154/365) of the patients were diagnosed with cancer cachexia. The malnourished group had higher interruption rate of radiotherapy, and the number of complication diseases (p<0.05). Meanwhile, patients with malnutrition had lower lymphocytes, and PNI index (p<0.05). The combined index showed higher AUC value (0.67, p<0.001) than the number of complication diseases (AUC=0.52) and PNI index (AUC=0.49) for relative weight loss (≥5%). Similarly, the combined index had a higher AUC value (0.79, p< 0.001) than the number of complication diseases (AUC=0.56), treatment regimens (AUC=0.56), subcutaneous fat thickness (AUC=0.60), pretreatment body weight (AUC=0.61), neutrophils (AUC=0.56) and PNI index (AUC=0.50) for absolute weight loss(≥5kg). Patients in the absolute or relative weight loss groups were remained as independent prognostic factors with short overall survival compared to those in the normal group (p<0.05). Patients with high nomogram score supported by nutritional intervention showed less weight loss, better nutrition score and increased plasm CD8+ T cells, IFN-γ. We developed a nomogram model that was intended to estimate relative/absolute weight loss in initial inoperable LAESCC patients during radiotherapy, interfering an objective decision on prophylactic nutritional supplementation.