Intraperitoneal cisplatin with systemic thiosulfate protection

Seventeen patients with intraperitoneal tumors were treated by 4-hour intraperitoneal dialysis with cisplatin alone, or in combination with an intravenous neutralizing agent, sodium thiosulfate. Cisplatin alone, 90 mg/m2 body surface area intraperitoneally, produced nephrotoxicity. When intraperitoneal cisplatin therapy was combined with intravenous thiosulfate treatment, the dose of cisplatin could be escalated to 270 mg/m2 body surface area without causing an increase in serum creatinine levels or undue myelosuppression. Even at doses up to 270 mg/m2, no local toxicity occurred. The peak peritoneal concentration of free reactive cisplatin averaged 21-fold higher than the plasma level, and the area under the peritoneal cisplatin elimination curve averaged 12-fold more than the area under the plasma curve. Neither of these ratios varied significantly with cisplatin dose. Regression of intraperitoneal tumor masses was observed in patients with far-advanced ovarian carcinoma, mesothelioma, and malignant carcinoid.