Objective: The risk of lung cancer in smoking patients with chronic obstructive pulmonary disease (COPD) is increasing. It is aimed to determine the prevalance of COPD according to the sex in patients who diagnosed lung cancer in our clinic, and to evaluate whether presence of COPD is a risk factor for lung cancer.

Materials and Methods: The demographic characteristics, smoking histories, pulmonary function tests, tumour histological types, and stages of the patients who diagnosed as primary lung cancer in our clinic were examined retrospectively.

Results: Of 153 patients included into the study, 117 were male, and 36 were female. The prevalence of COPD in all patients was 47.1% [Male; 66 (56.4%), female; 6 (16.7%)]. The prevalence of COPD in male was significantly higher than female at the time of lung cancer diagnosis (OR; 6.736, %CI; 2.333-19.449, p<0.001). Although no difference was observed in smoking habit between sex, smoking duration in current or ex smoker men was significantly higher than female (p<0.001). According to the logistic regression analysis, it was determined that current smoking habitus (OR; 3.178, %CI; 1.96-5.14, p<0.0001) was independent risk factor for COPD in all lung cancer patients. When only current smokers were evaluated, it is determined that ≥26 pack/year smoking (OR; 77.58, %CI; 10.46-575.60, p<0.0001), and being older than 65 years (OR; 99.8, %CI; 13.47-739.78, p<0.0001) were independent risk factors for COPD.

Conclusion: It is concluded that the prevalence of COPD is high in patients with lung cancer and, sex, smoking habitus, older age were independent risk factors in the development of COPD.