Intrapleural cisplatin and cytarabine in the management of malignant pleural effusions: a Lung Cancer Study Group trial. Malignant pleural effusions are a common and significant problem in patients with advanced malignancies. Pleurodesis with tetracycline or other sclerosing agents is the usual treatment for malignant pleural effusions. In contrast to this approach, intrapleural chemotherapy has the potential advantage of treating the underlying malignancy in addition to controlling the effusion. Intracavitary cisplatin-based chemotherapy, which is cytotoxic rather than sclerosing, has proven safe and effective via the intraperitoneal route in ovarian cancer and malignant mesothelioma. There has been little previous experience, however, with intrapleural cisplatin-based chemotherapy. As part of a planned series of trials in malignant mesothelioma, the Lung Cancer Study Group first evaluated intrapleural cisplatin and cytarabine in patients with malignant pleural effusions from a variety of solid tumors. From April 1986 to November 1987, 46 patients with cytologically proven, symptomatic, and previously untreated malignant pleural effusions were entered on study. A single dose of cisplatin 100 mg/m2 plus cytarabine 1,200 mg was instilled into the pleural space via a chest tube, which was then immediately removed. Patients were evaluated for toxicity and response at 24 hours; 1, 2, and 3 weeks; and then monthly. No recurrence of the effusion was considered a complete response (CR). Partial response (PR) was defined as a 75% or greater decrease in the amount of the effusion on serial chest radiographs. One patient experienced reversible grade 4 renal toxicity, four patients had grade 3 hematologic toxicity, and five patients had grade 3 cardiopulmonary toxicity. The overall response rate (CR plus PR) at 3 weeks was 49% (18 of 37 patients). The median length of response was 9 months for a CR and 5.1 months for a PR. The outcome of this trial was sufficiently encouraging that this regimen has been incorporated into subsequent trials for malignant pleural mesothelioma. 