PSA tests have been lauded as important diagnostic tools for prostate cancer, however much of the data used to make this conclusion were generated in the early to mid 1990s, when prostate biopsies were performed differently than they are today. Since that time, there has been an increase in the number of prostate biopsies performed and an increasing number of biopsy samples taken from each patient.
Douglas Scherr, MD, Michael Schwartz, MD, and colleagues at the New York Presbyterian Hospital of the Weill Medical College of Cornell University, in New York City, set out to assess whether changes in prostate biopsy practices might have changed the predictive value of PSA tests.
The researchers performed a retrospective analysis of all prostate biopsies performed at their institution between 1993 and 2005, finding 1,607 that satisfied their inclusion and exclusion criteria. Douglas Scherr, MD and his team divided patients into three groups based on when they received their biopsies: 1993-1997, 1998-2001, and 2002-2005. They examined each group for the number of biopsies performed, the number of positive biopsies, patient age, most recent PSA prior to biopsy, prostate volume, and number of biopsy samples taken. With these data in hand, they assessed potential correlations between PSA levels and positive biopsy rate.
The investigators found that the number of biopsies performed, the percentage of positive biopsies, and patient ages did not change significantly over time. However, there was a significant decrease in the median PSA level in patients undergoing biopsy and an increase in the median number of samples taken at the time of biopsy. Also, fewer biopsies were performed for the indication of a suspicious digital rectal exam and there was an increase in the percentage of patients undergoing biopsy for PSA readings between 2.5 and 3.99 ng/ml. (According to the American Cancer Society, the PSA level usually goes above 4 ng/ml when prostate cancer develops, but about 15% of men with a PSA below 4 ng/ml will have prostate cancer on biopsy.)
The positive biopsy rate in men with PSA levels in the 2.0 to 3.99 ng/ml range equaled or surpassed that for patients with higher PSA readings. Therefore, the researchers concluded that ¡°the correlation between PSA and positive biopsy rate no longer holds true in our patient population for men with a normal digital rectal exam and PSA ¡Ý2.0 ng/ml.¡±
While changes in biopsy practice patterns have improved cancer detection, these very changes ¡°have negatively influenced the predictive value of PSA in men with a normal digital rectal exam such that, using current biopsy practice patterns, PSA no longer correlates with positive biopsy rate,¡± note the authors. They cite the urgent need for new blood or urinary markers to better determine who needs a prostate biopsy, adding that aside from family history or prior atypical biopsy findings, there is little other information available to help physicians decide who needs a biopsy and who does not.
Amy Molnar | EurekAlert!
The personality factor: How to foster the sharing of research data
06.09.2017 | ZBW – Leibniz-Informationszentrum Wirtschaft
Europe’s Demographic Future. Where the Regions Are Heading after a Decade of Crises
10.08.2017 | Berlin-Institut für Bevölkerung und Entwicklung
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
22.09.2017 | Life Sciences
22.09.2017 | Medical Engineering
22.09.2017 | Physics and Astronomy