Background: Patients with idiopathic pulmonary fibrosis (IPF) are at risk of lung cancer development. Antifibrotic therapy could slow disease progression but there are limited data of its impact on lung cancer. Here, we aimed to investigate lung cancer incidence and the risk of mortality of patietns with IPF according to antifibrotic therapy.  

Methods: Data from the Korean National Health Insurance service database between October 2015 and September 2021 were used. The incidence of lung cancer and all-cause mortality in IPF cohort were analyzed depending on the prescription of pirfenidone. Those who diagnosed with lung cancer prior to the IPF diagnosis were excluded.

Results: Among 5,038 patients with IPF were eligible for the study, and pirfenidone was given to 880 patients. Median follow up duration was 4,872.8 and 23,612.1 person-year in group receiving pirfenidone or not, respectively. Incidence of lung cancer was significantly higher in pirfenidone group (2.44 per 100 person-years) than non-users (1.56 per 100 person-years; risk ratio 0.64; p<0.001). However, mortality was not different (4.67 per 100 person-years versus 4.50 per 100 person-years in group receiving pirfenidone or not, respectively; 0=0.330). All cause mortality was further analyzed by lung cancer development and pirfenidone therapy, then it was significantly lower in IPF with lung cancer patients when pirfenidone used compared to those not receiving pirfenidone therapy.  

Conclusion: Antifibrotic therapy possibly associated with survival benefit in patients with IPF who developed lung cancer, although lung cancer incidence was higher in those patients than those not receiving antifibrotic therapy.