Prostate cancer screening via use of a PSA (prostatic specific antigen) testing – a biological marker found in blood – is one of the most contentious things around. There is no such contention over seeking diagnosis and treatment for prostate symptoms. It is screening for problems when no symptoms exist that is the issue.
While the logical view may be that ‘catching things early’ is a good thing, the truth is rather different (I am getting deja vu: exactly the same thing applies to breast self-examination). PSA testing is even messier, though, in terms of potential harms. A high PSA result can be a false positive for cancer (instead inflammation or a benignly enlarged prostate can cause high results) or false negative (PSA is not elevated where there is prostate cancer present). Additionally, the surgical treatment for prostate cancer can result in major side effects (impotence and incontinence). The crux is, that for prostate cancers found at screening, there may be no benefit to the man in question in improving mortality, but there still may be harm done in terms of ‘treatment’.
While in the UK prostate cancer screening is not routinely done, in the US there is a culture that says ‘all men must know their own PSA’, despite the lack of evidence for this. However, today the US Preventive Services Task Force has said that “Current evidence is insufficient to assess the balance of benefits and harms of screening for prostate cancer in men younger than age 75 years” and “Do not screen for prostate cancer in men age 75 years or older”. There are trials ongoing which will hopefully give us better information, but in the meantime, the circumspect approach in the UK (where generally more information given about the limitations and potential harms of PSA screening leads to a decrease in the amount of men who end up having it done) looks like it is the right one.