[Prostate cancer detection rates: comparison of standard biopsy with prompt rebiopsy and a one-time extended biopsy]. / Prostatakarzinomdetektionsraten : Vergleich zwischen der Standardbiopsie mit zeitnaher Rebiopsie und einer einmaligen extendierten Biopsie.

INTRODUCTION: Prostate biopsy is the gold standard for the detection of prostate cancer (PCA). While national and international guidelines recommend the extraction of 10-12 cores at initial biopsy, some authors plead to initially perform more extensive biopsy protocols. We assessed the PCA detection and complication rates of different biopsy schemes. MATERIALS AND METHODS: We relied on the data of 425 men who underwent their first prostate biopsy from April 2005 to May 2013. Exclusion criteria consisted of PSA > 20 ng/ml, prior surgery of the prostate, or intake of 5-α-reductase inhibitors. Overall 357 underwent a 10- to 12-core biopsy, while 68 patients underwent 20-core biopsy. In case of a negative biopsy in the 10-12 cohort, rebiopsy was performed within 6 months, while in the 20-core group clinical follow-up determined further course of action. Endpoints of the study were the overall PCA detection rate and the rate of severe complications, which were defined as complications requiring hospital admission. The effect of the respective biopsy scheme on the PCA detection rate was assessed using uni- and multivariable logistic regression analysis. In the subanalysis, the PCA detection rates between the two groups were compared solely in patients with PSA values ≤10 ng/ml. RESULTS: At initial biopsy, the overall PCA detection rate was 50.4% (214/425). In the 10-12 core group, the PCA detection rate at first biopsy was 52.4% (187/357) and rebiopsy detected a further 19 (11.2%) PCA cases, resulting in a cumulative PCA detection rate of 57.7% (206/357). In the 20-core group, the PCA detection rate was 39.7% (27/68). While the different PCA detection rates were not statistically different when the initial biopsies were compared, biopsy scheme reached independent predictor status when the cumulative PCA detection rate of the 10- to 12-core scheme was compared to the 20-core scheme (p=0.01). Comparable results were obtained only when patients with PSA ≤10 ng/ml were considered. The rate of severe complications was statistically higher in the 20-core group (6.1 vs. 2.4%; p=0.01). CONCLUSION: Our data indicate that an initial 20-core biopsy does not lead to a higher PCA detection rate compared to an initial 10- to 12-core biopsy. Moreover, the cumulative PCA detection rate of a 10- to 12-core biopsy and prompt repeat biopsy was significantly higher compared to a single 20-core biopsy.

Adaptive resistance of Saccharomyces cerevisiae to chronic treatment with mutagens being due to a dominant mutation.

The exposure of mammalian cells or tumors for weeks or months to low non-lethal doses of cytostatic drugs may induce multi-drug resistance, which can be enhanced by a variety of DNA-damaging agents. In yeast multi-drug resistance to a variety of drugs has been observed. DNA-damaging agents have not yet been tested. As the appearance of resistance is the result of long-term exposure, we decided to extend the application of test substances to a period of up to 400 days. In such long-term experiments S. cerevisiae MP1 adapted to treatment with low doses of mutagens. Consistent results were obtained for both alkylating and non-alkylating mutagenic substances. Furthermore, the adaptive resistance to the alkylating agent also adapted cells to the non-alkylating agent, which implies that there may be a single pathway for mutagens with different modes of action. Random spore analysis of adapted yeast cells and the back-cross to the parental wild type indicates that a single dominant mutation is responsible for the adaptive resistance.