A phase II study of intraperitoneal cisplatin and thiotepa in residual ovarian carcinoma. A gynecologic oncology group study

Objective. Patients with advanced epithelial ovarian cancer treated with salvage therapy using new combinations of systemic chemotherapy, radiation therapy, and systemic immunotherapy have had limited success. Since the most common site of relapse or failure to conventional systemic chemotherapy has been the peritoneal cavity, intraperitoneal (IP) chemotherapy was selected to treat small-volume residual disease. Methods. Sixty-five patients were entered on a protocol using intraperitoneal cisplatin and thiotepa following a response to intravenous cisplatin-based chemotherapy, Patients had surgically documented residual disease (0.5 cm or less maximum tumor diameter) at completion of preprotocol surgery and had no clinical, radiologic, or histologic evidence of extraperitoneal disease. Cisplatin (100 mg/m(2)) and thiotepa 30 mg/m(2) was delivered intraperitoneally every 4 weeks for a maximum of six cycles. The dose of thiotepa was reduced to 12 mg/m(2) due to unexpected severe myelosuppression. Results. Of the 52 evaluable patients, grade 4 neutropenia, thrombocytopenia, neurotoxicity, and nephrotoxicity were observed in 31, 19, 13, and 6% of patients, respectively, For all evaluable patients, the complete response rate was 19% and the partial response rate was 2% for a total response rate of 21%. Of 16 patients who had a reassessment laparotomy, 10 patients achieved a surgically documented complete response and 1 patient had a partial response. Four patients are still in response for 67+, 70+, 70+, and 73+ months after third-look surgery. Three patients who did not undergo third-look surgery after chemotherapy are alive and clinically free of disease at 49+, 69+, and 85+ months. Conclusion. Thiotepa, when used with cisplatin for IP salvage therapy in patients with advanced or recurrent ovarian cancer, may produce significant myelosuppression and doses must be adjusted accordingly. In cisplatin-sensitive patients with small-volume residual ovarian cancer, IP cisplatin and thiotepa appears to have activity. Determining the utility of this approach will require a randomized trial. (C) 1998 Academic Press.