PHOSPHORUS-32-CHROMIC PHOSPHATE FOR OVARIAN-CANCER .1. FRACTIONATED LOW-DOSE INTRAPERITONEAL TREATMENTS IN CONJUNCTION WITH PLATINUM ANALOGCHEMOTHERAPY

For many years, P-32-Chromic phosphate (P-32-CP) intraperitoneal insti llations and platinum analogue chemotherapy have been used to treat di sseminated ovarian cancer. To investigate possible enhancement of P-32 -CP irradiation due to the concomitant administration of chemotherapy, in vitro studies were undertaken. Based on those laboratory investiga tions, a clinical regimen of combined P-32-CP and platinum analogue ch emotherapy was developed. Methods: In vitro enhancement of P-32-CP cyt otoxicity by cisplatin was studied in cultured human ovarian adenocarc inoma (CHOA) cell lines and in a fibroblast cell strain. In addition, ovarian cancer cells obtained from the malignant abdominal ascites and pleural effusions of 10 individual patients were also studied ex vivo . As part of routine clinical care, 30 patients with disseminated ovar ian adenocarcinoma underwent up to eight monthly cycles of platinum an alogue chemotherapy with concomitant intraperitoneal instillation of 5 mCi of P-32-CP at each monthly chemotherapy cycle. Results: There was an enhanced and possibly supra-additive effect of cisplatin on the cy totoxicity from P-32-CP irradiation. For the 30 patients, the survival rate at 3 yr was 63%. Conclusion: Phosphorus-32 CP low-dose intraperi toneal treatments in conjunction with platinum analogue chemotherapy i s a promising approach for the treatment of disseminated intraperitone al ovarian cancer.