The incidence of cancer in patients with idiopathic pulmonary fibrosis and sarcoidosis in the UK

Background: The aim of this study was to use a longitudinal computerised health care dataset (The Health Improvement Network) to provide information on the overall incidence of cancer, and on the incidence of organ-specific cancers, in people with idiopathic pulmonary fibrosis (IPF) and sarcoidosis in comparison to the general population. Methods: Incident cases of IPF and sarcoidosis were identified with up to four controls matched by age, gender and general practice. Cancer incidence rates were compared between cohorts using Cox regression and adjusting for age, gender and smoking habit. Results: One thousand and sixty-four incident cases of IPF (mean age at diagnosis 71.5 years; 62.4% male) were identified. Overall, the incidence of cancer was increased in people with IPF compared to the general population (rate ratio 1.51; 95% CI 1.20-1.90), but this was largely due to a marked increase in the incidence of lung cancer (rate ratio 4.96; 95% CI 3.00-8.18). One thousand one hundred and fifty-three incident cases of sarcoidosis (mean age at diagnosis 47.0 years; 47.2% male) were identified. There was an overall increased incidence of cancer in sarcoidosis (rate ratio 1.65; 95% CI 1.22-2.24) and this was largely explained by an increase in the incidence of skin cancers (rate ratio 1.86; 95% CI 1.11-3.11). Conclusions: This study provides further evidence of a marked increase in the incidence of lung cancer in people with IPF, but we found no increase in the risk of other cancers. People with sarcoidosis did have an increase risk of skin cancers, but not cancers at other sites.