Intraperitoneal recombinant interferon-alpha 2b for recurrent malignant ascites due to ovarian cancer

Thirteen patients with malignant ascites due to recurrent ovarian cancer were treated with intraperitoneal interferon 2b (5 mu/m2 escalating to 15 mu/m2, administered twice weekly by indwelling intraperitoneal catheter). The study population included eight patients with ascites only and five patients with ascites plus tumor masses greater than 2 cm in diameter. Five of 13 responded to treatment. All the responses were seen in patients with ascites only. Although tumor mass was an important determinant of response there was also a correlation between clinical response and suppression of colony growth on soft agar after in vitro exposure of tumor cells to interferon-alpha (IFN alpha). The intraperitoneal use of IFN alpha should be explored further in tumors with a predominant intraperitoneal location and microimplantation growth pattern.