Prediction of 20- to 30-year risk for advanced prostate cancer

In 2007, Hans Lilja and colleagues first used data from the Swedish cancer registries and blood banks to demonstrate that a single PSA value in men between 44 and 50 years of age was highly predictive of subsequent prostate cancer diagnosis in an unscreened population. New data now support that original finding, but with a 7-year-longer timeframe.

In their new paper, Lilja et al. again describe how blood was collected from 21,277 men aged between 33 and 50 years and living in Malmö, Sweden between 1974 and 1986 Swedish city. (This represented a 74 percent participation rate from the age-appropriate men in Malmö at that time.) However, in this new study, they have been able to identify all known cases of prostate cancer through 2006 (as opposed to just 1999, as in the original study).

By using data from the Swedish cancer registries, Lilja and his colleagues were able to identify 1,408 men whose blood samples were collected between 1974 and 1986 and who had subsequently been diagnosed with prostate cancer through 2006. They were able to go back and measure the PSA levels in the archived blood samples for 1,312/1,408 of these men (93 percent) and for another 3,728 “controls” (other men whose blood samples were collected in Malmö during the same timeframe, but who had never been diagnosed with prostate cancer).

The results of this new study are as follows:

• Average (median) patient follow-up was 23 years.
• At median follow-up, baseline PSA levels were strongly associated with
  • A subsequent diagnosis of prostate cancer
  • Occurrence of advanced cancer (clinical stage ≥T3 or metastases) at diagnosis
• 81 percent of patients with advanced prostate cancer were observed in men with a PSA above the median (0.63 ng/ml) at 44 to 50 years of age.
• This last finding correlates closely with the data from the original 2007 study.

Lilja and his colleagues now conclude that a single PSA value at or before age 50 can potentially predict risk for advanced prostate cancer diagnosed up to 30 years later. They further propose that use of an early PSA test to stratify risk (perhaps between the ages of 35 and 50) would allow a large group of low-risk men to be screened less often but to ensure frequent (annual?) testing of a smaller cohort of men known to be at high risk, thereby improving the risk-benefit ratio for regular testing among an appropriately targeted set of men over time.

The “New” Prostate Cancer InfoLink would suggest that this new paper further substantiates the premise for a risk-based approach to prostate cancer testing that has been described previously on this site.