To study potential risk factors for the development of lung cancer in patients with scleroderma and explore the chronological relationship between onset of scleroderma symptoms and subtypes of lung cancer.
Linkage of two population-based registers to identify lung cancer cases and gender-matched controls with scleroderma, followed by retrospective case note review for clinical details.
Patients with scleroderma who smoke are seven times more likely to develop lung cancer than non-smokers (p=0.008). Smokers with scleroderma and cancer smoke more than smokers with scleroderma without cancer (p=0.019). Pulmonary fibrosis and anti-topoisomerase antibody do not increase the risk of lung cancer. Peripheral lung tumours occur earlier after the onset of scleroderma symptoms than bronchogenic tumours (p=0.05).
Smokers with scleroderma should be monitored for the presence of lung cancer and counselled to quit smoking. The earlier development of peripheral lung tumours is not consistent, with pulmonary fibrosis being an aetiological factor.