Abstract: The rates of chronic obstructive pulmonary disease(COPD) and lung cancer morbidity in Xuanwei city of Yunnan province are among the highest nationwide, and COPD is an major risk factor for lung cancer. The concurrence of COPD and lung cancer is common in clinical practice. There are common causative environmental risk factors and pathogenic processes between the two diseases, which provides new ideas for the study, prevention and treatment of both diseases. Additionally the discussion of the relationship between COPD and lung cancer can provide references for further studies of both diseases.

Key words: COPD, lung cancer, causative environmental risk factors, mechanistic links