Lung cancer in combined pulmonary fibrosis and emphysema: A large retrospective cohort analysis

Background: Combined pulmonary fibrosis and emphysema (CPFE) is characterised by upper lobe emphysema and lower lobe fibrosis. Our study aim was to determine the incident risk, presenting characteristics and outcome of lung cancer diagnoses in a cohort of CPFE patients over time. Materials and methods: We conducted a retrospective cohort study assessing patients with radiological CPFE followed over a median of 76 months (range 1-237 months). Interval development of lung cancer and clinicopathological characteristics of those with and without lung cancer were compared and survival analysis performed. Results: Lung cancer occurred in 26 (11.6%) out of 230 CPFE patients, dominated by nonsmall cell lung cancer (88%, n=23) with squamous cell carcinoma comprising the majority (57%, n=13). There was a predominance of lower lobe (62%) and subpleural (64%) radiological presentation. Survival was reduced for the whole cohort by lung cancer even after adjusting for a priori covariables of age, sex, smoking packyears, presenting forced vital capacity and radiological honeycombing. Univariable predictors of increased mortality after lung cancer diagnosis included honeycombing (hazard ratio (HR) 3.03, 95% CI 1.16-7.91; p=0.02) and later stage presentation (HR 4.77, 95% CI 1.8-14.94; p=0.001), with those able to undergo surgical resection having better survival (HR 0.29, 95% CI 0.09-0.87; p=0.02). Conclusion: Lung cancer occurred in 26 (11.6%) out of 230 CPFE patients and was dominated by squamous cell carcinoma presenting in a lower lobe peripheral distribution. Surgical resection appeared to improve survival in selected patients with earlier stage disease. Further studies are needed to develop a relevant screening programme for CPFE patients.