New data from 15-year follow-up from a community screening study


Now come fascinating data from 15 years of follow-up of a Swedish screening study for prostate cancer conducted in 1988, at which time PSA  testing was already available in Scandinavia.

Kjellman et al. have evaluated the long-term survival of attendees and non-attendees of a one-time screening for prostate cancer.

In 1988, based on a total source population of 27,204 males in a target area, the investigators invited 2,400 randomly selected men, then aged between 55 and 70 years, to a prostate cancer screening event. Screening attendees were examined with DRE, transrectal ultrasound, and PSA analysis. When cancer was suspected, prostate biopsies were taken. They then tracked prostate cancer diagnosis and mortality of  the entire source population for 15 years.

The results of this study after 15 years of follow-up are as follows:

  • Of the original 2,400 invited men 1,782 (74 percent) attended the screening.
  • 65 men with prostate cancer were initially detected as a direct consequence of attendance at the screening event.
  • There was no effect of this screening procedure on the risk of death from prostate cancer: incidence rate ratio for all invited men vs. the source population = 1.10 (95% CI 0.83-1.46).
  • There was no effect of this screening procedure on the risk of death from other causes: incidence rate ratio for all invited men vs. the source population = 0.98 (95% CI 0.92-1.05).
  • Attending the screening program was associated with a significantly decreased risk of death from causes other than prostate cancer: incidence rate ratio vs. the source population = 0.82 (95% CI 0.76-0.90).
  • Not attending the screening program if invited was associated with a significantly increased risk of death from causes other than prostate cancer: incidence rate ratio vs. the source population = 1.53 (95% CI 1.37-1.71).

The authors conclude that they “found no evidence of a beneficial effect of this specific screening procedure but strong evidence of a difference in overall survival in screening attendees and nonattendees.” They suggest that these findings should be considered when interpreting previous and upcoming studies of the effect of screening programs.

The “New” Prostate Cancer InfoLink suspects that this study will receive far less media attention than the two studies published in the New England Journal of Medicine, but it probably deserves at least as much attention.

What this study tells us is that, in a true one-time screening trial, despite the fact that 65 patients were identified at the time of the trial, there was no overall impact on prostate cancer mortality over the following 15 years compared to the rest of the population regardless of what any patient may have done after that one time screening event.

The other thing that is evident from this trial is that those who tend to exhibit health-seeking behavior (i.e., they attended the screening) did have a significantly lower overall mortality rate than those who do not tend to exhibit health-seeking behavior (i.e., they did not attend the screening).

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