INTRAPLEURAL TREATMENT WITH RECOMBINANT GAMMA-INTERFERON IN EARLY-STAGE MALIGNANT PLEURAL MESOTHELIOMA

Background. This report presents the results of a prospective multi-in stitutional study of intrapleural treatment with gamma-interferon in p atients with Butchart's Stages I and II epithelial or mixed malignant pleural mesothelioma. Methods. Interferon was administered at a dose o f 40 million units twice a week for 8 weeks intrapleurally via a cathe ter or an implantable port. Thoracoscopic or surgical biopsy was perfo rmed if computed tomography scan 2 weeks after the end of treatment de monstrated a reduction in tumor size. Survival was calculated after a followup of at least 18 months. Prognostic factors were identified by univariate and multivariate analyses (Cox model). Results. Eighty-nine patients were included over 46 months. Eight histologically confirmed complete responses and nine partial responses with at least a 50% red uction in tumor size were obtained. The overall response rate was 20%. Most responses were achieved in patients with early stage disease. Th e response rate for patients with Stage I disease was 45%. Tolerance o f interferon was good. Treatment was performed on an outpatient basis. The main side effects were hyperthermia, liver toxicity, neutropenia, and catheter-related infection. Conclusions. Gamma-interferon is effe ctive mainly Stage I mesothelioma, especially if the tumor is confined to the parietal or diaphragmatic pleura (Stage IA).