Incidence of lung cancer in patients with systemic sclerosis treated with extracorporeal photopheresis

BackgroundExtracorporeal 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. MethodsSeventy-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. ResultsWe 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. ConclusionWe 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.