Incidence of cancer in outpatients with chronic obstructive pulmonary disease

Abstract Introduction The relationship between chronic obstructive pulmonary disease (COPD) and the overall incidence of cancer is poorly understood. The aim of this study was to analyze the incidence of cancer (pulmonary and extrapulmonary sites) in patients with COPD followed up in a specialized outpatient unit, and to assess the relationship to the degree of airflow obstruction. Methodology A prospective observational study was conducted with a cohort of 308 patients with COPD followed up at pulmonology outpatient clinics from January 2012 to December 2015. The neoplasms diagnosed during this period were divided into a pulmonary and an extrapulmonary group. Results The overall yearly incidence rates of cancer, lung cancer and extrapulmonary cancer cases per 1000 patients with COPD were 10.3, 3.4 and 7.3 cases, respectively. The most frequent cancer types were lung cancer (31%), genitourinary tract cancer (29%) and gastrointestinal cancer (21%). Mild to moderate stages (grade I–II of the 2009 GOLD classification) and the increase in the pack-year index (PYI) were related to an increase in the onset of neoplasia, with an odds ratio (OR) of 2.16 (95% confidence interval [95% CI]: 1.087–4.309; p  = .026) and 1.01 (95% CI: 1.002–1.031; p  = .023), respectively. Conclusion The incidence of extrapulmonary cancer in patients with COPD was twice that of lung cancer; stages I–II of the 2009 GOLD classification and the PYI were significantly related to the onset of neoplasia.