Showing papers by "Bernhard Tribukait published in 2000"

Prognostic significance of tissue prostate-specific antigen in endocrine-treated prostate carcinomas.

Abstract: Fine-needle aspiration biopsy is a minimally invasive technique for obtaining sample material suitable not only for cytological grading but also for flow cytometry and for biochemical analyses. The prognostic value of tissue prostate-specific antigen (T-PSA) from fine-needle aspiration biopsies was compared with serum total and free prostate-specific antigen, the ratio of free:total serum prostate-specific antigen, tumor stage, cytological grade, and DNA ploidy in 179 patients with stage T2-T4 prostate cancer (CAP). The patients, who were free from bone metastases at the time of diagnosis, were treated by either orchidectomy or medical castration with GnRH analogues or high-dose parenteral depot estrogens. They were followed for at least for 71 months or until death, and the different variables were correlated to time to progression and time to death from CAP. Using Cox univariate analysis, T-PSA was shown to be the most important factor in predicting time to progression and time to death. When the patients were divided into three groups with respect to T-PSA, 56 of 60 (93%) of the patients with low T-PSA levels developed progressive disease, and 52 of 60 (87%) died of CAP. For patients with intermediate T-PSA levels, the corresponding figures were 9 of 60 (15%) and 6 of 60 (10%). None of the 59 patients with high T-PSA values developed progressive disease. Similar but less pronounced relationships were found between tumor progress and CAP-specific death on the one hand and clinical stage, cytological grade, and DNA ploidy on the other. In a Cox multivariate stepwise analysis, T-PSA was the only important factor for time to progression and death. This was also true for the subgroup of patients with stages T2 and T3 disease only. The study shows that T-PSA is superior to other hitherto routinely used markers for the prediction of outcome of hormone-treated patients with newly diagnosed CAP.

Reliability of DNA cytometric S-phase analysis in surgical biopsies: assessment of systematic and sampling errors and comparison between results obtained by image and flow cytometry.

Abstract: Three major parameters in DNA histograms that contribute to the reliability of S-phase analysis were evaluated. These parameters are (1) the extent of background in relation to the amount of S-phase cells (and the validity of its subtraction), (2) the size of the “free” S-phase range (Sfree), and (3) the sampling error of cell counting. Tests in histograms obtained from surgical biopsies by flow cytometry (FCM) showed that the background subtraction is reliable if the found S-phase fraction is higher than the fraction of background events in the histogram range of the cell population. The size of Sfree was determined in computer-generated test histograms as a function of variables such as the coefficient of variation (CV) and the DNA index (DI). To calculate the sampling error of cell counting above background and in Sfree, a model was developed that was validated by experimental data. This error can serve as an indicator of the uncertainty in S-phase analysis. The poor correlation found between %S values measured by image cytometry (ICM) and FCM in surgical biopsies was assigned to high uncertainty by low cell numbers in ICM histograms. A method is proposed to estimate quantitatively the reliability of S-phase analysis that can facilitate the interpretation of results. Cytometry (Comm. Clin. Cytometry) 42:196–208, 2000. © 2000 Wiley-Liss, Inc.