[Use of prostatic specific antigen in primary care (PSA)]

In the literature it is shown that the use of PSA is occasionally wrong, by requesting this marker in very young or very old men, and repeated measurements in short periods of time. The main objective of this study was to describe the use of PSA in daily practice by primary care physicians in our area, dealing with aspects such as the importance of patient age, the value in the screening for prostate cancer, or the subjective beliefs about its usefulness. A secondary objective was the comparison of use, and beliefs among doctors who claim to know PSA well, and those who do not.

A descriptive and comparative study was conducted using questionnaires that were handed to primary care doctors in all health centres in our area. A descriptive analysis was performed and response rates among doctors who thought they had enough information about PSA, and those who did not, were compared using the Chi-squared test.

A total of 103 questionnaires were received from the physicians, with 83.5% claiming to have sufficient knowledge about the PSA. The professionals in this latter group request PSA at an earlier age (P=.029), with a higher frequency (P=.011) and have more doubts about its usefulness (P=.009) than those with less knowledge. Almost half (49.5%) said they request less than 50 determinations per year, and 33% between 50 and 100. More than half (53.4%) of doctors would not request the first PSA on a patient until their 50s, and up to 49% request it up to 80 years. The true value of PSA has been established many times by 64.1% of requesters, and 29.1% believe it is unhelpful in the diagnosis of cancer.

In our study, 64% of primary care physicians have considered the true value of the PSA several times, and 29% believe it to be of little use in the diagnosis of prostate cancer. In addition, some data suggest it has limited use due to the fact that 50% made less than 50 PSA requests per years, and 28% of the professionals would never request it on a male without urinary symptoms. In this study, it has been observed that those professionals who claim not to have enough information about the PSA make more requests in patients of an older age, and consider that it is of limited use as a marker.