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.