摘要Background:Cachexia is a metabolic state with weight and muscle mass loss as its basic characteristics.This study aims to reveal the influ-ence of weight loss on the progression of cancer cachexia,and to determine its impact on the patient prognosis.Methods:A total of 2990 cancer patients were enrolled in this retrospective study.Demographic information,clinical materials,and follow-up data were collected for all patients.A receiver operating characteristic curve was used to determine threshold values for weight loss within the past six months(WL).Kaplan-Meier curves and Cox proportional hazard regression models were adopted for survival analyses.Results:After excluding ineligible patients,2480 patients were included in the analysis,705(28.4％)of whom were considered to be ca-chexic.A WL of 10％was determined to be the optimal threshold for diagnosing malnutrition according to the Patient-Generated Subjective Global Assessment.Notably,WL＞10％was a predictor of survival outcomes only in the general population(HR=1.218,95％Cl=1.002-1.481,P=0.048),but not in the cachexic population,based on the multivariable Cox regression model.A larger proportion of cachexic pa-tients with WL＞10％had a nutritional risk screening 2002 score ≥ 3(25.7％vs 13.7％,P＜0.001)and a modified Glasgow Prognosis Score=2(12.8％vs 7.8％,P=0.032).No significant difference was observed in the degree of decreased muscle strength or quality of life(P＞0.05).Conclusions:Weight loss is a predictor of impaired survival in the general population,but not in the cachexic population.The present study shows that cachexic patients with severe weight loss had a higher risk of malnutrition,a worse systemic inflammation status,and more severe malnutrition,but that the weight loss itself was not associated with the prognosis of these patients or the progression of their cachexia.