Prostate-specific antigen (PSA) testing revolutionized prostate cancer screening. Although PSA was originally introduced as a tumor marker to detect cancer recurrence or disease progression following treatment, it became widely adopted for cancer screening by the early 1990s.
However, prostate cancer screening has been a controversial issue because decisions were made about adopting PSA testing in the absence of efficacy data from randomized trials. Subsequently, the European Randomized Study of Screening for Prostate Cancer (ERSPC) reported a small absolute survival benefit with PSA screening after nine years of follow-up.
I feel it is enough evidence to know what a PSA test as a screening tool be capable of.
PSA is a glycoprotein produced by prostate epithelial cells. PSA levels may be elevated in men with prostate cancer because PSA production is increased and because tissue barriers between the prostate gland lumen and the capillary are disrupted, releasing more PSA into the serum.
Determining the accuracy of PSA testing has been difficult because most men with normal PSA values will not undergo biopsy unless their digital examination is abnormal. This work-up bias tends to overestimate sensitivity and underestimate specificity. Performance can also be overestimated because PSA often detects clinically-unimportant cancers.
To summarise, there is no consensus on using any of the PSA modifications, and none of them has been shown in clinical trials to reduce the number of unnecessary biopsies or improve clinical outcomes. The total PSA cutoff of 4.0 ng/mL has been the most accepted standard because it balances the tradeoff between missing important cancers at a curable stage and avoiding both detection of clinically insignificant disease and subjecting men to unnecessary prostate biopsies.
wish it helps.
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