Background: Chronic obstructive pulmonary disease (COPD) and lung cancer commonly coexist and have extensive symptom overlap. 

Aim: To determine whether lung cancer patients with COPD experience more severe symptom burden.

Methods: We conducted a retrospective, population-based cohort study of stage I-IV lung cancer patients in Ontario, Canada who completed the Edmonton Symptom Assessment Scale (ESAS) within 90 days of lung cancer diagnosis. COPD was ascertained using a validated algorithm, with patients 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). Multivariable modified Poisson regression analyses stratified by early (I/II) and advanced stage (III/IV) were used to determine the association between COPD status and any moderate to severe symptom (ESAS ? 4) and the number of moderate to severe symptoms. Linear regression analyses were used for total symptom distress, physical, and emotional symptom scores.

Results: Among 38,898 lung cancer patients, 53% had COPD (previously diagnosed 81%, newly diagnosed 19%). Collectively, individuals with previously diagnosed COPD had the most severe symptom burden. Across all stages, both COPD groups had a significantly higher risk of experiencing any (RR 1.04 to 1.18) and multiple moderate to severe symptoms (RR 1.07 to 1.25), in addition to worse symptom distress and physical symptom scores (p < 0.0001). Differences were most pronounced among early-stage patients with previously diagnosed COPD. 

Conclusions: Lung cancer patients with underlying COPD have worse symptom burden, suggesting a greater need for integrated care that prioritizes symptom management.