ABSTRACT
BACKGROUND: Extracorporeal photopheresis (ECP) improves skin sclerosis in systemic sclerosis (SSc) patients. SSc is associated with an increased risk of lung cancer. As ECP is supposed to exert immunomodulatory effects, a possible impact of ECP on the incidence of lung cancer in SSc patients was evaluated. METHODS: Seventy-one SSc patients treated with ECP at the Photopheresis Unit of the Department of Dermatology at the Medical University of Vienna between 1991 and 2013 were analyzed retrospectively. RESULTS: We calculated a standardized incidence ratio (SIR) for lung cancer in ECP-treated SSc patients of 2.34 [95% confidence interval (CI) 1.63-2.49]. This is in accordance with recent meta-analyses demonstrating a significantly enhanced risk of lung carcinoma in SSc patients. Comparison of the lung cancer risks of these patients with our ECP-treated patients revealed that ECP has no influence. Each patient with lung carcinoma had previously been diagnosed with lung involvement of the non-specific interstitial pneumonitis (NSIP) type. CONCLUSION: We confirm that SSc patients are at significantly increased risk for lung cancer. However, ECP does not influence this risk. NSIP may be a risk factor for lung cancer in SSc patients.