Hypoxic regions exist in human prostate carcinoma

Objectives. The purpose of this study was to characterize, by use of the Eppendorf microelectrode, the extent of hypoxia (range/heterogeneity) in human prostate carcinomas, Methods. Custom-made Eppendorf pO(2) microelectrodes were used to obtain pO(2) measurements from the pathologically involved side of the prostate, as well as from a region of normal muscle for comparison. Each set of measurements comprised approximately 100 separate readings of pO(2), for a total of 2145 individual measurements. Twelve patients were studied, 7 of whom underwent brachytherapy, 3 a radical prostatectomy, and 2 a cystoprostatectomy. The pO(2) measurements were obtained in the operating room, using sterile technique, under spinal anesthesia for the brachytherapy group patients and under general anesthesia for the surgery group patients. The Eppendorf histograms were recorded and described by the median pO(2), mean pO(2), and percentage of measurements less than 5 mm Hg and less than 10 mm Hg. Results, Because of differences in patient characteristics and the anesthesia employed, control measurements were obtained from nearby normal muscle as an internal control in all but 2 patients. This internal comparison showed that the oxygen measurements from the pathologically involved portion of the prostate were significantly lower than those from normal muscle. Similarly, higher pO(2) readings were obtained from the pathologically normal prostates (in the patients with bladder cancer) than from the prostates of patients with prostate carcinoma. Increasing levels of hypoxia were observed with increasing clinical stage. Significant predictors of oxygenation include the type of tissue (pathologically involved prostate versus normal muscle or normal prostate), clinical stage, and type of anesthesia. Conclusions. This report, to our knowledge, represents the first study to obtain in vivo electrode measurements of oxygen levels in patients with prostate cancer and suggests that hypoxic regions exist in human prostate carcinoma. More patients will be accrued to this prospective study to correlate the oxygenation status of prostate carcinoma with known prognostic factors and treatment outcome. UROLOGY 53: 11-18, 1999. (C) 1999, Elsevier Science Inc. All rights reserved.