To analyze the clinical characteristics of patients with COPD who are more likely to develop lung cancer, and the cancer risk factors conferred by COPD. Therefore, we can get a better understanding of the mechanisms linking the two diseases and the implementation of lung cancer screening in high risks population of patients with COPD which potentially result in more timely early diagnosis and treatment.

A retrospective study was performed in 195 patients with COPD and lung cancer who were admitted in the Respiratory and Thoracic surgery of the Second Affiliated Hospital of Xi′an Jiaotong University between March 2017 and December 2019. Additionally, in the same time another cohort consisting of 189 hospitalized COPD patients without lung cancer were recruited as negative control set.

the percentage of older population (≥60 years) and male patients in COPD patients with lung cancer (COPD/LC) was significantly higher than that in COPD-only group, and the categorical analysis of smoking populations and subgroup of HSI ≥400 revealed considerably larger numbers in COPD/LC group than those in COPD-only group (all P<0.05); The prevalence of a range of symptoms was notably higher in COPD/LC group than those in COPD-only group, including hemoptysis, chest pain, pleural effusion, fatigue, and weight loss (all P>0.05); The pH value and FEV₁ value of COPD/LC group was apparently higher than that of COPD-only group, and compared to COPD-only set, COPD/LC group exhibited larger population of patients with GOLD grade Ⅱ (all P<0.05); The values of a set of laboratory tests were clearly elevated in COPD/LC group than those in COPD-only group, including WBC, PLT, NEUT, EO, EO%, PT, INR, FIB, PFDP and CRP (all P<0.05); There were mainly effective ways we performed to diagnose COPD patients with lung cancer is bronchoscopy. the main lesion distribution of 195 COPD/LC patients was in the right lung. the main tumor sub-location was central-type lung cancer. The mainly histopathological type in male was SCC, and in female was AC. the mainly TNM staging system of lung cancer are stage Ⅲ/Ⅳ. In addition, 131 out of 195 COPD/LC patients were found distant metastasis at the time of initial diagnosis with lung cancer; The proportion of patients receiving ICS treatment in COPD-only group was significantly higher than that in COPD/LC group (P<0.01); the potential lung cancer risk factors in COPD patients included smoking, higher eosinophil count, as well as elevated levels of fibrinogen, and the protective factors was inhalation of ICS.

COPD patients should adhere to regular inhaled ICS treatment. The COPD patients with a history of hemoptysis, chest pain, pleural effusion, fatigue and weight loss during the illness, or with symptoms such as elevated platelet, eosinophil count, blood coagulation index, and CRP, may be at increased risks of becoming lung cancer and do need to be altered.