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Prostate-specific antigen (PSA) is a protein produced by cells of the prostate gland (both normal and cancerous) that can be found both in seminal fluid as well as in blood and? It works as a marker for prostate cancer. Its easy detection (through a simple analysis) has made it the ideal tool for mass screening for this disease. However, this significant increase in the number of cases detected in the last 40 years does not correspond with a decrease in mortality linked to this diseaseaccording to a new study just published in the scientific journal The British Medical Journal. In other words: mass screening may have been causing overdiagnosis of the disease.
more cases detected
The study, based on a large systematic review of 219 million men aged 34 to 86 from 26 European countries over the past 40 years, found a large variability between diagnosed cases and mortality rates during the study period. Thus, mortality rates during 1980-2020 were much lower and less variable than the incidence rates. In addition, the researchers point out, “the inverted U shape of the age-specific curves for incidence contrasts with the mortality pattern, which increases progressively with age.”
Misdiagnoses
Although the signatories of the research point out that these data should be taken with caution, their conclusions indicate that in A large number of cases may have been misdiagnoseds, “which suggests that many of the cancers detected could be harmless and would not have impacted the lives of patients – points out Rafael Marcos-Gragera, epidemiologist at the Epidemiology and Cancer Registry Unit of Girona of the Catalan Institute of Oncology to SMC – which could lead to rrisks such as unnecessary treatments, deterioration in quality of life and inefficient use of health resources.”
Other experts argue, however, that overdiagnosis does not make PSA less effective as a technique for mass screening, since this method “only produces changes in the incidence of this disease, little or no change in mortality from prostate cancer, with a null effect on mortality from all causes (overall mortality), sinceand does not add life expectancy“, says Marcos Luján Galán, head of the Urology Unit at Hospital Infanta Cristina and researcher in the Spanish branch of the European Randomized Study of Screening for Prostate Cancer, in statements to SMC.
Additional testing, a possible solution
According to Luján, screening is currently going through including Tests that reduce overdiagnosissuch as the use of magnetic resonance imaging. In addition, he points out, studies that validate screening strategies for prostate cancer require a long follow-up time (for example, more than 10 years) so if there are results, it will take a while to see them.
But the fact that PSA does not serve to reduce mortality does not mean that it is not a useful tool to increase the early detection of prostate cancer, the most common tumor and the third cause of cancer death among men, according to data from the Spanish Association Against Cancer. “LThe findings are not very different from other studies recent ones carried out in Spain, “in which an increase in the incidence of prostate cancer is documented until 2003,” says Gragera, who states that from 1994 to 2018 an increase in survival rates is observed. The analysis, points out the expert, is “especially relevant for the possible implementation of prostate cancer screening programs at the population level. If their introduction is considered in the future, such programs should be carefully designed to minimize and monitor the adverse effects of overdiagnosis in the population.”
However, they point out from the National Association of Prostate Cancer (ANCP), the PSA continues being a tool what revolutionized diagnosis and helped localize prostate cancer since the 1980s, which has led to a reduction of up to 21% in deaths caused by this tumor.
However, the entity points out, There is no value that indicates with certainty the existence of a tumor, It is possible to find a high concentration of PSA in many types of non-malignant conditions such as benign prostatic hyperplasia, prostatitis, urinary retentionThis does not mean, however, that there is no possibility of these ailments appearing together with a tumor.
For this reason, the ANCP points out, the PSA is a better predictor of prostate cancer that digital rectal examination or transrectal ultrasound, so it would be advisable for people with risk factors to undergo preventive analysis.
