Tumour response and radiation-induced lung injury in patients with recurrent small cell lung cancer treated with radiotherapy and concomitant interferon-alpha

The aim of this study was to determine whether either natural or recombinan t interferon (IFN)-alpha can improve the response to radiotherapy (RT) in p atients with small cell lung cancer (SCLC), and to assess the role of IFN i n radiation-induced lung injury. All patients had previously participated i n a randomised trial of chemotherapy alone or in combination with IFN-alpha in three arms (arm O: no IFN, arm I: natural IFN-alpha, arm II: recombinan t IFN-alpha). Patients with locally progressive disease in the lungs follow ing chemotherapy were treated with RT and they continued with their concomi tant IFN-alpha. The RT dose was 50 Gy. Radiation-induced lung injury was as sessed by lung function tests, computed tomography and bronchoalveolar lava ge fluid (BALF) analysis which included cell findings, Interleukin (IL)-1 a lpha/-1 beta expression by alveolar macrophages and surfactant components. Seventeen patients were entered in the study, 16 of whom were evaluable. Re sponse rates in Arms O, I and II were 50, 67 and 50%, respectively. Median survival was 18.5, 7 and 23 months respectively, and 1-year survival was 67 , 29 and 75% respectively. Long-term survival as assessed by 2- and 3-year survival rates was 29% in patients receiving natural IFN-alpha as compared to 17% in patients not receiving IFN (not statistically significant finding s). Every patient had abnormal results when assessed for radiation-induced lung injury. No statistically significant difference was found in toxicity between the treatment arms. A high surfactant protein (SP)-A/phospholipid r atio and a high level of SP-A in BALF before RT was associated with a high degree of radiation-induced lung injury measured by lung function tests and computed tomography in ail arms of the study. Thus, we could not show that the combination of IFN-alpha and RT induced more lung toxicity than RT alo ne as we did in our previous study. The role of high SP-A/phospholipid rati os and high SP-A levels in BALF before RT as predictors of the development of lung injury after RT needs to be determined in the future. (C) 1999 Else vier Science Ireland Ltd. AII rights reserved.