Pulmonary fibrosis and lung cancer: an analysis of the Clinical Practice Research Datalink linked to the National Cancer Registration Dataset.

We quantified the proportion of diagnoses of pulmonary fibrosis (PF) among 25 136 people with lung cancer and 250 583 matched controls and compared the natural history of lung cancer in people with and without PF. Diagnoses of PF were more common in people with lung cancer than those without (1.5% vs 0.8%, OR 1.97; 95% CI 1.77 to 2.21). Within people with PF, squamous cell carcinoma was more (22.9% vs 19.1%), and adenocarcinoma was less common (18.0% vs 21.3%). People with PF were less likely to have stage 4 disease at diagnosis (OR 0.43, 95% CI 0.28 to 0.65) but their survival was worse.