Hypoxia in human prostate carcinoma: An eppendorf P_O2 study

The purpose of this study was to characterize the extent of hypoxia in human prostate carcinoma using the Eppendorf P_O2 microelectrode. Custom-made Eppendorf P_O2, microelectrodes were used to obtain P_O2 measurements from the pathologically involved region of the prostate (as determined by the pretreatment sextant biopsies), as well as from a region of normal muscle for comparison. Fifty-nine patients with localized prostate cancer were studied, all of whom received brachytherapy implants under spinal anesthesia. A multivariate mixed effects analysis for prediction of tumor oxygenation was performed including the following covariates: type of tissue (prostate versus muscle), prostatic-specific antigen, disease stage, patient age and race, tumor grade, volume, perineural invasion, and hormonal therapy. Because of differences in patient characteristics, control measurements were obtained from normal muscle in all patients. This internal comparison showed that the oxygen measurements from the pathologically involved portion of the prostate were significantly lower (average median P_O2 = 2.4 mm Hg) compared with the measurements from normal muscle (average median P_O2 = 30.0 mm Hg), p < 0.0001. A multivariate, linear, mixed analysis demonstrated that the only significant predictor of oxygenation was the type of tissue (prostate versus muscle). This study, using in vivo electrode oxygen measurements, suggests that hypoxia exists in human prostate carcinoma. More patients will be accrued to this study to ultimately correlate the oxygenation status in prostate carcinoma tumors with treatment outcome.