Intrapleural Hypotonic Cisplatin Treatment for Malignant Pleural Mesothelioma: In Vitro Experiments and Clinical Application

PURPOSE: We studied the inhibitory effects of hypotonic cisplatin on the growth of malignant pleural mesothelioma (MPM) cell lines in vitro, and assessed the effectiveness of intraoperative intrapleural hypotonic cisplatin treatment combined with extrapleural pneumonectomy for patients with this tumor. METHODS: In the in vitro experiments, mesothelioma cell lines were exposed to various concentrations of cisplatin in either saline solution or distilled water for up to 5 min. After 48 h incubation, we calculated the inhibition of cell growth. In the clinical study, five patients with MPM underwent intraoperative intrapleural hypotonic cisplatin treatment combined with extrapleural pneumonectomy. RESULTS: The hypotonic cisplatin treatment inhibited cell growth at a significantly greater rate than the isotonic cisplatin treatment. Just 1-5 min exposure to 10 microg/ml of hypotonic cisplatin inhibited growth by more than 80%. Clinically, no recurrence was found in four of the five patients after a median follow-up period of 27 months (range: 16-36 months), although contralateral multiple pulmonary metastases were found in one patient 10 months after surgery. CONCLUSION: Hypotonic cisplatin treatment is effective against MPM, and should be investigated further.