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Prostate cancer in men with PSA values below 4.0 ng/ml is common in a screening population
Prostate cancer (PC) is one of the most common men’s cancers in Europe. It is estimated that 150.000 new cases will appear this year in the European Union and the number will rise in the years to come. In Europe there are currently more than one million men living with PC. Total serum Prostatic-specific antigen (PSA), first described in 1979, was considered as a useful marker for assessing treatment responses and follow-up of patients with PC. Today, with the widespread use of PSA screening, more PC are identified at an earlier stage and with PSA values below 4ng/ml, when they can be treated effectively. The aim of this study was to investigate PC detection rates and Gleason scores (Gleason score, as a surrogate for aggressive cancer) in two cohorts of patients: a) with serum PSA levels between 2.0 – 3.9 ng/ml and b) between 4.0 to 10.0 ng/ml in a population-based screening project. Of the PC detected, 37% were found in men with a PSA level of 2 to 4ng/ml with patients in the lower PSA group being younger and having a smaller mean prostate volume. Of PC-patients with PSA value of 2 to 3.9 ng/ml , 24% had Gleason score of 7 or higher as compared with 33% of patients with PSA value of 4.0 to 10.0ng/ml.
What dos that mean?
In all there is a general agreement among clinicians that PSA screening can detect early-stage PC and that most PC detected by PSA screening appear to be clinically important when their pathological characteristics are used as a surrogate for biologic potential. There is, however, disagreement as to what level of PSA should prompt a prostate biopsy. Our data suggest that in a population-based screening project, like this in Tyrol, Austria, 50% of the detected PC among patients with PSA values of 2 to 10 ng/ml were found in a PSA range between 2 to 4.8 ng/ml, and 37% were detected among those with PSA values of 2 to 3.9 ng/ml. This is a large amount of PC in the so called low PSA range.
But proceeding to biopsy for early PC-detection despite low PSA cut-off limits poses a dilemma.
With the use of higher PSA thresholds risks missing an important PC until it is too late for a cure, whereas the use of lower PSA thresholds increases not only unnecessary biopsies but also the proportion of biopsies that identify clinically insignificant disease (disease that would not have been detected in the absence of screening). In this study, the number of PC with a Gleason score of 6 in the patient subgroup with low PSA value (2.0 to 3.9 ng/ml) was higher in comparison to the subgroup of patients with a higher PSA value (4.0-10 ng/ml) while at the same time, there was no increase in the number of those with a GS less than 6 in the former group. The Gleason score is one of the most powerful predictors of PC progression and survival. There is a correlation between disease-free survival after surgical treatment and preoperative PSA level and final pathological Gleason score in most studies. Patients with a pathological Gleason score of 6 have an excellent progression-free survival, which can be up to 90%. However, men with a Gleason score of 7 PC have a 29-43% risk of death from PC within 20 years. Gleason scores of less than 6 are so called over detected PC hat would have no impact on patients life if not detected.
Therefore,
PC in younger patients with low cancer volumes and a Gleason score less
than 7 should be ideal candidates for potential curative treatments; they
are ideal candidates for retaining potency, continence, and tolerating the
surgery without complications. This is the population we found in our
study in the low PSA range (2 to 4ng/ml). Take
home message: This data suggest that prostate cancer in men with PSA values below 4.0 ng/ml is common in a screening population, comprising more than one-third of PC in men screened with PSA levels between 2 and 10 ng/ml. Low-PSA cancers occur in younger patients and at lower stages with smaller prostate volumes. These men are favourable candidates for potentially curative treatments , such as surgery or radiotherapy and are less likely to suffer from postoperative urinary incontinence and erectile dysfunction.
Bibliographical reference:
Alexandre E. Pelzer Department of Urology, Innsbruck Medical University, Innsbruck, Austria
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