PATIENTS treated for advanced pelvic malignancy by perfusion have shown a wide variation in clinical response. 1,2 There has been no predictable pattern of palliation or of tumor regression. Predictions based on tumor type and histology have been unreliable. It was the purpose of this investigation to determine whether uric acid levels measured postoperatively might be of value in predicting tumor response. Uric acid is a final metabolic product of cellular destruction. It becomes clinically significant in the chemotherapy of leukemia, when the massive destruction of leucocytes releases large amounts of xanthine and hypoxanthine. Hypoxanthine is converted to xanthine and then to uric acid by xanthine oxidase. The resultant hyperuricemia precipitates renal crystal formation, with secondary renal tubular obstruction. There have been no reports on uric acid release by the chemotherapy of solid human tumors. No reports are available to indicate whether a toxic hyperuricemia could be invoked or whether