The vesturhorn acid-basic intrusion of S.E. Iceland

Imperial Users onl

Algorithms, nomograms and the detection of indolent prostate cancer

Purpose: Prostate cancer is the most commonly diagnosed cancer in men. However, only about 12% of the men diagnosed with prostate cancer will die of their disease. Result: The serum PSA test can detect prostate cancers early, but using a PSA based cut-off indication for prostate biopsy results in unnecessary testing in app. 75-80% of the men and perhaps even more important the serum PSA test cannot tell how aggressive the cancer is. To decrease unnecessary testing different test results are often combined, converted into a probability and displayed graphically. There are more than 40 of these so called nomograms in the case of prostate cancer. These nomograms can be divided into two categories, namely those that predict biopsy outcome using results from serum determination(s) or non-invasive tests such as the DRE and TRUS. The second category represents those nomograms that predict tumor characteristics and prognosis using information coming from pathology review. Conclusion: The ultimate nomogram able to predict tumor characteristics and progression purely based on non-invasive testing will for a large part put an end to the negative side effects and uncertainties that coincide with the early detection of prostate cancer, if it will ever be made

Quasiparticle relaxation rate and shear viscosity of superfluid 3He-A_1 at low temperatures

Quasiparticle relaxation rate,$\tau_{p}^{-1}$, and the shear viscosity tensor of the A_1-phase of superfluid 3He are calculated at low temperatures and melting pressure, by using Boltzmann equation approach in momentum space. The collision integral is written in terms of inscattering and outscattering collision integrals. The interaction between normal and Bogoliubov quasiparticles is considered in calculating transition probabilities in the binary, decay and coalescence processes. We obtain that both $\tau_{p\uparrow}^{-1}$ and $\tau_{p\downarrow}^{-1}$ are proportional to $T^2$ >. The shear viscosities $\eta_{xy}$, $\eta_{xz}$ and $\eta_{zz}$ are proportional to $(T/T_c)^{-2}$. The constant of proportionality of the shear viscosity tensor is in nearly good agreement with the experimental results of Roobol et al., and our exact theoretical calculation.Comment: 8 pages, some typos were correcte

Case-control studies in evaluating prostate cancer screening: an overview

Objectives: Ongoing randomized controlled screening trials for prostate cancer have not shown a beneficial effect on prostate cancer mortality reduction yet. A large number of observational (non-randomized) studies on prostate cancer screening have been published with contradictory outcome. This paper reviews the current case-control studies. Methods: Seven case-control studies of screening for prostate cancer were identified in a PubMed search, published from 1991 onwards, all conducted in North America. The screening test was either digital rectal examination (DRE) alone or in combination with PSA. Results: One DRE case-control study, found a significant preventive effect, whereas two others showed no effect of DRE screening on prostate cancer mortality nor on the occurrence of metastatic disease. Conflicting results were also observed in the studies assessing the effect of PSA/DRE. Only one study showed a significant 27% mortality reduction in the White male cohort, but found no effects in Blacks. The most recent study showed that screening with PSA/DRE was not protective in reducing prostate cancer mortality. Conclusions: Our review of the case-control studies does not indicate a benefit of prostate cancer screening. An answer has to come from the ERSPC trial, in Europe, and the PLCO trial, in the US, of which the outcomes are expected in 2007–2010. # 2006 European Association of Urolog

Ethnicity and prostate cancer: The way to solve the screening problem?

In their analysis in BMC Medicine, Lloyd et al. provide individual patient lifetime risks of prostate cancer diagnosis and prostate cancer death stratified by ethnicity. This easy to understand information is helpful for men to decide whether to start prostate-specific antigen testing (i.e. screening). A higher lifetime risk of prostate cancer death in some ethnic groups is not automatically a license to start screening. The potential benefit in the form of reducing metastases and death should still be weighed against the potential risk of over diagnosis. In case of ethnicity, this harm-to-benefit ratio does not differ between groups. Stratifying men for screening based on ethnicity is therefore not optimal and will not solve the current screening problem. Other methods for risk-stratifying men have been proven to produce a more optimal harm-to-benefit ratio

Personalized strategies in population screening for prostate cancer

This review discusses evidence for population-based screening with contemporary screening tools. In Europe, prostate-specific antigen (PSA)-based screening led to a relative reduction of prostate cancer (PCa) mortality, but also to a substantial amount of overdiagnosis and unnecessarily biopsies. Risk stratification based on a single variable (a clinical variable or based on the presence of a lesion on prostate imaging) or based on multivariable approaches can aid in reducing unnecessary prostate biopsies and overdiagnosis by selecting men who can benefit from further clinical assessment. Multivariable approaches include clinical variables, and biomarkers, often combined in risk calculators or nomograms. These risk calculators can also incorporate the result of MRI imaging. In general, as compared to a purely PSA based approach, the combination of relevant prebiopsy information results in superior selection of men at higher risk of harboring clinically significant prostate cancer. Currently, it is not possible to draw any conclusions on the superiority of these multivariable risk-based approaches since head-to-head comparisons are virtually lacking. Recently initiated large population-based screening studies in Finland, Germany and Sweden, incorporating various multivariable risk stratification approaches will hopefully give more insight in whether the harm-benefit ratio can be improved, that is, maintain (or improving) the ability to reduce metastatic disease and prostate cancer mortality while reducing harm caused by unnecessary testing and overdiagnosis including related overtreatment