ANAHEIM, CaliforniaA single PSA test at mid-life can predict who will develop advanced prostate cancer within the next 25 years, according to a study of archived serum from more than 20,000 Swedish men reported at the American Urological Association annual meeting (abstract 1876).
"In this large unscreened representative population, a single PSA measure at age 44 to 50 was a very strong predictor of later diagnosis of prostate cancer of unquestionable significance," said senior investigator Hans G. Lilja, MD, PhD, attending research clinical chemist at Memorial Sloan-Kettering Cancer Center.
This study was a re-analysis of earlier work by Dr. Lilja and his colleagues showing that a single PSA test at age 44 to 50 could predict prostate cancer in general for up to 25 years. The new study was meant to answer the question of how many of those cancers are clinically important (stage T3 or higher or metastatic disease at diagnosis).
The researchers analyzed archived serum from 21,277 men, and matched each case with three controls based on age and date of blood sample. They used conditional logistic regression to determine the association between PSA or kalikrein 2 (KLK2 or hK2) levels and development of advanced prostate cancer.
Two-thirds of the 161 cases diagnosed with advanced prostate cancer occurred in men with PSAs in the top 20% of PSA levels (0.9 ng/mL or higher before age 50), Dr. Lilja reported (see Table).
The median delay from baseline to prostate cancer diagnosis was 17 years, and plasma levels for both markers were strongly associated with development of advanced cancer (P < .01).