Baseline and clinical characteristics, as well as laboratory measurements of each eligible individual, were obtained from the electronic medical record system of the Affiliated Hospital of Jiangsu University. The latest peripheral blood samples were collected from patients with an empty stomach in the early morning before diagnosis and any treatment, with a time span of no more than 1 week between the two. Routine blood tests were performed using a SYSMEX XN3000 automated haematology analyzer (Sysmex Corporation). Serum albumin was detected using a BEKMAN AU5800 automatic biochemical analyzer (Beckman Coulter, Inc.). The serum carcinoembryonic antigen (CEA) and cytokeratin 19 fragment antigen 21-1 (CYFRA21-1) levels were determined using the ABBOTT ARCHITECT i2000sr (Abbott Pharmaceutical Co., Ltd.) and MAGLUMI X8 Analyzer (Shenzhen New Industry Biological Engineering Co., Ltd.), respectively, using a chemiluminescence immunoassay with kits from the corresponding manufacturer (cat. no. 7K68-78; cat. no. 130201013M). The normal range of all indicators was recorded according to the manufacturer's instructions. The MRR, NRR, LRR and LA of each group were calculated as follows: MRR was defined as the monocyte count (×109/l) to red blood cell count (×1012/l) ratio, NRR was defined as the neutrophil count (×109/l) to red blood cell count (×1012/l) ratio, LRR was defined as the lymphocyte count (×109/l) to red blood cell count (×1012/l) ratio, and LA was defined as the product of the lymphocyte count (×109/l) and albumin concentration (g/l).