Cancer Research Lab

Dr. Hans Lilja and colleagues analyzed the long-term predictive power of tPSA, free PSA (fPSA) and human kallikrein 2 (hK2) levels measured between the ages of 44 and 50 years in 21,277 men enrolled in the Malmo (Sweden) Preventive Project between 1974 and 1986. The analysis focused on 462 participants who later developed prostate cancer and 1222 matched controls who did not.

The risk of prostate cancer in older age ranged from 1.0% to 7.5% if the mid-life tPSA was 0.5 ng/mL or lower, the investigators report in the February 1st issue of the Journal of Clinical Oncology.

Men with a tPSA of 0.51 to 1.0 ng/ml had a 2.5-fold increase in prostate cancer risk compared with men with tPSA levels of 0.5 ng/ml and lower.

Men with tPSA levels of 2.0 to 3.0, which are often considered within the normal range, had a more than 19-fold increase in prostate cancer risk compared with men with tPSA levels of 0.5 ng/ml and lower.

Free PSA and hK2 levels at baseline were also significant predictors of prostate cancer.

“The current data suggest that early biochemical changes (ie, slightly increased release of PSA and hK2 into blood) indicate a predisposition to prostate cancer that may be detectable two decades before the disease is diagnosed clinically,” Dr. Lilja and colleagues conclude.

They caution that “recommendations to undergo biopsy on the basis of our findings would be premature, given that biopsies performed 15 to 25 years before the cancer would otherwise be diagnosed may not be informative.”

“Our data strongly suggest that we should encourage all men to get a PSA test at age 45 to 50, not to try to detect cancer, but to work out their long-term cancer risk,” Dr. Lilja said.

“We should now focus our subsequent screening efforts on the men at highest risk, spending our time and energy making sure that these men come in for regular screening (e.g. yearly) and making sure that they get the very best tests available. Men at lower risk of cancer may not require such intensive screening.”