Impact of chronic obstructive pulmonary disease on lung cancer symptom burden: a population-based study in Ontario, Canada

Background: Chronic obstructive pulmonary disease (COPD) and lung cancer commonly coexist and have significant symptom overlap. We sought to compare the symptom burden of lung cancer patients with COPD to those without COPD. Methods: We conducted a retrospective, cross-sectional study of stage I-IV lung cancer patients in Ontario, Canada, who completed the Edmonton Symptom Assessment Scale (ESAS) within 90 days of diagnosis. COPD was ascertained using a validated algorithm and patients were grouped as: no COPD, previously diagnosed COPD (at least 90 days prior to lung cancer diagnosis), and newly diagnosed COPD (within 90 days of lung cancer diagnosis). The association between COPD status and any moderate to severe symptom (ESAS ≥4) and the number of moderate to severe symptoms was determined using multivariable modified Poisson regression analyses. Multivariable linear regression analysis was used to compare total symptom distress scores. Analyses were stratified by limited (I/II) and advanced stage (III/IV). Results: Among 38,898 lung cancer patients, 53% had COPD (previously diagnosed 43%, newly diagnosed 10%). Collectively, those with previously diagnosed COPD had the most severe symptom burden. Across all stages, both COPD groups had a significantly higher risk of experiencing any (relative risk: 1.04 to 1.18) and multiple moderate to severe symptoms (RR 1.05 to 1.24), in addition to higher total symptom distress scores (P<0.0001). Differences in symptom burden between groups were most pronounced among early-stage patients. Conclusions: Lung cancer patients with underlying COPD have worse symptom burden, indicating a need for interventions that effectively alleviate symptoms.