Risk of cancer incidence in patients with idiopathic pulmonary fibrosis: A nationwide cohort study.

Background And Objective: IPF shares common risk factors and has pathogenic similarities with cancer. However, limited population-based data are available on cancer risk among patients with IPF. Herein, we investigated whether IPF is associated with an increased risk for cancer incidence from a nationwide database in South Korea.

Methods: In this population-based cohort study, patients with IPF were enrolled from 2009 to 2014, and matched controls were randomly selected at a control-to-case ratio of 3:1. In both groups, individuals diagnosed with any malignancy before the index date were excluded. The incidence rates of cancer were measured as the number of events per 1000 person-years. Multivariable Cox regression models were used to assess the cancer incidence risk.

Results: This study included 25 241 patients with IPF and 75 723 matched controls. The overall cancer incidence in patients with IPF was 29.0 cases per 1000 person-years, and it was significantly higher in the IPF group than in the non-IPF group (HR, 2.09; 95% CI, 1.96-2.16). Lung cancer showed the highest HR (5.89; 95% CI, 5.40-6.42), followed by lymphoma, skin, uterine cervical, multiple myeloma, thyroid, leukaemia, pancreatic, liver and prostate cancer. Moreover, adjustment for the effects of smoking and other cancer-associated covariates had little effect on the HR of overall and specific cancers.

Conclusion: The cancer incidence risk was higher in the IPF group than in the non-IPF group. Therefore, healthcare providers should be aware of this risk when treating patients with IPF.