The question whether widespread use of the PSA test to test for risk of prostate cancer has a significant impact on prostate cancer-specific mortality continues to be highly controversial and to engender strong emotions among many medical professionals, patients, and prostate cancer advocates.
A newly published study by Outzen et al., in the journal Acta Oncologica, reports on an analysis of data from the national Danish Cancer Registry and Register of Causes of Death over the period 1978 to 2009 and includes all cases of prostate cancer and all deaths of men diagnosed with prostate cancer during this study period.
The authors report the following:
- During the 5-year period from 1978 to 1983, the age-standardized incidence of prostate cancer diagnosis in Denmark was 29.2/100,000 person-years.
- During the 2-year period from 2008 to 2009, the age-standardized incidence of prostate cancer diagnosis was 76.2/100,000 person-years.
- The increase in the incidence rate
- Became evident in the mid-1990s (corresponding to the increase in the use of PSA testing for risk of prostate cancer)
- Has been most pronouced among men of > 60 years of age
- Was highest among men born between 1943 and 1947
- The prostate cancer-specific mortality rate in Denmark has remained ”largely unchanged” over the entire 30-year study period — at about 19/100,000 person-years.
- In 1998, there was a significant change in stage distribution, and an increasing percentage of prostate cancer patients were being diagnosed with localized disease
Outzen et al. conclude that:
- “The observed increase in [prostate cancer] incidence during the period 1993-2009 in Denmark may be attributed primarily to increasing unsystematic use of … PSA … testing.”
- ”… there is not yet any major influence of intensified PSA screening and more frequent use of curatively intended therapy on the overall prognosis of [prostate cancer].”
[Editorial comment: Please note that the emphasis on the word "yet" in the quotation immediately above has been added by the editors and did not appear in the original.]
The “New” Prostate Cancer InfoLink is very conscious that a lot of people will not be enamored of these study results. However, please be aware that we are simply reporting the findings of a group of Danish investigators from a very highly structured data registry. Don’t blame the messenger!
Is it possible that a mortality effect might emerge in Denmark over time? Yes it is. Some are going to argue (with a degree of justification) that until some 20 years after the majority of men in Denmark are being diagnosed with localized disease (i.e., in 2018), it is actually unreasonable to expect to see a meaningful impact on prostate cancer-specific mortality. Conversely, the lack of any meaningful impact on prostate cancer-specific mortality over nearly 30 years tends to suggest that any meaningful impact is likely to be small if and when it does appear (which again raises the question of whether the risks justify the benefits on a national basis).