COPD is commonly underdiagnosed in patients with lung cancer: results from the RECOIL study (retrospective study of COPD infradiagnosis in lung cancer)

INTRODUCTION: Many patients with COPD are underdiagnosed, including patients with coexisting lung cancer. METHODS: We conducted a retrospective study of COPD prevalence and outcomes among all patients diagnosed with lung cancer at our institution during a 2-year period. Patients with known COPD (group A) were compared with those who received a diagnosis of COPD at the time of their oncologic workup (group B). RESULTS: A total of 306 patients were diagnosed with lung cancer during the study period, including 87 with COPD (28.6%). Sixty percent of patients with coexisting lung cancer and COPD were unaware of their obstructive airways disease prior to the lung cancer diagnosis. Patients in group A were older (74+9 vs 69+9 years; P=0.03), had more severe obstruction (% of predicted forced expiratory volume in one second [FEV(1)%] 55+17 vs 71+13; P=0.04), more emphysema (91% vs 65%; P=0.02), and worse diffusing capacity of the lungs for carbon monoxide 59+19% vs 72+22%; P=0.01) than patients in group B, but the latter had more advanced lung cancer (27.3% vs 13.8% stage IV disease; P=0.01) and consumed more outpatient resources (P=0.03). Overall mortality was similar (56% vs 58%). However, stage-adjusted mortality showed a trend toward greater mortality in group B patients (1.87 [0.91–3.85]; P=0.087). CONCLUSION: COPD infradiagnosis is common in patients with coexisting lung cancer and is associated with more advanced cancer stage, greater outpatient resource consumption, and may be associated with greater stage-adjusted mortality.