Abstract: Objective The objective of this study was to provide a way to assess the nutritional status of patients and to afford targeted nutritional supports during the radiotherapy on the basis of the laboratory parameters related to nutrition and chest muscle size in lung cancer patients at the different time.Methods The laboratory parameters were obtained in a cohort of 160 lung cancer patients who received thoracic radiotherapy in our department from March 2012 to November 2015.Fourteen patients who had complete chest CT scan images during radiotherapy were selected to evaluate chest muscles volume.The Chest muscles and its volume were delineated and calculated by CT scan images.Results The levels of(Hemoglobin)HGB,lymphocyte,total protein and albumin were decreased in different degrees during and after radiotherapy,which had the positive correlation with the number and doses of radiotherapy(P＜0.05).The changes of hemoglobin and lymphocyte were more obviously among them;these indicators began to recover after 5 weeks of radiotherapy.Chest muscle volume was also the same as the trend of hematological indicators(P＞0.05).Conclusion Cancer patients were prone to suffer from malnutrition during radiotherapy.The intake of energy and protein was less than the requirements.We should always take the nutritional status of patients into account and provide targeted nutritional support to improve treatment tolerance and quality of life of patients during radiotherapy.

Key words: Lung cancer, Radiotherapy, Chest muscles, Nutrition