This is an important story about an important topic – the effort to improve PSA screening for prostate cancer by using PSA velocity, or a measure of the rate of change in PSA readings over time. While the article does mention some of the limitations of PSA screening, the article does not discuss the broader controversies of whether prostate cancer screening by any method reduces the chance of death or improves quality of life, or in fact, whether early identification and treatment of prostate cancer does more good than harm. The question is whether the article, which is reporting on what factors may influence PSA velocity, should have discussed these more global issues. Because of the controversy and lack of proven benefit of PSA screening, the failure to address these larger issues is a critical omission. Finally, the story presents an example of disease-mongering when it describes prostate cancer as “lethal,” providing numbers of new cases and numbers of deaths, but failing to mention that these numbers taken together suggest that most men diagnosed with prostate cancer are not destined to die of it.
No mention of costs.
There is no discussion of the lack of proven benefit of PSA screening (using any
approach) to extend or improve quality of life, which is key whenever PSA screening is discussed. The question is whether
the article should have mentioned the lack of proven benefit of PSA screening, which we believe it should have.
The story does mention
some harms of screening, namely the chance that a man can still have cancer despite a normal screening result (a false
negative) and anxiety associated with screening. However, these are only a few of the harms associated with screening and
there was no discussion of the broader issues of whether screening and ultimately early treatment of prostate cancer does
more good than harm. Because the bigger issues are not discussed, the discussion of harms are not balanced.
There is no mention of the strength of the evidence. The latest study is an
observational study, but this may not be obvious to the reader and there is no comment about whether the study was performed
prospectively or retrospectively or the possibility of confounding (for instance, if the associations noted were based on
recall or more objective measures).
While the story very clearly states there are problems with PSA testing (and provides a very specific example showing that a
“normal” screening result may not mean a man does not have cancer), there is no discussion that screening may do more harm
than good. The key to the screening debate is that there is no proof yet that screening leads to longer or better quality of
life, yet can have definite drawbacks (such as further invasive testing, anxiety, and side effects from cancer treatment).
The story uses scare tactics to promote prostate cancer being “lethal” providing numbers of new cases and numbers of deaths,
but what the story doesn’t mention is that those numbers taken together suggest that most men diagnosed with prostate cancer
are not destined to die of prostate cancer.
verification of the study findings was obtained. The only interviewed expert was the lead researcher.
The story describes using serial PSA
testing to determine velocity and describes an alternative, using a single PSA reading to make decisions for biopsy.
Disadvantages of using PSA velocity are discussed–mainly that PSA velocity may provide no better measure than a single
reading since velocity can fluctuate as a result of non-cancerous processes. While it appears the criteria is satisfied,
there is no mention about not screening at all–a very reasonable alternative, given the lack of evidence that screening does
more good than harm. Because this is a key point in the screening controversy and was not mentioned, this is unsatisfactory.
velocity requires calculations based on a series of PSA tests taken over a minimum of a year. It seems fair to assume that
not all physicians endorse this or are familiar with calculating PSA velocity. If a patient is interested in using velocity,
it’s not clear whether he can go to his local doctor or not. Using PSA velocity for screening is also currently not part of
any known recommendations from guideline-issuing organizations, like the American Urological Association or United States
Preventive Services Task Force (USPSTF). This fact is also not discussed.
The article is not clear
whether measurements of PSA velocity are new.. The story does imply that physicians began to be interested in using PSA
velocity for screening after a 2004 study was published. However, PSA velocity has been around for years and used in other
applications, for instance, to follow disease progression (as opposed to screening) after surgery or radiation.