Using PSA more intelligently may reduce prostate cancer deaths

March 1, 2008

Since the introduction of PSA screening, prostate cancer-specific deaths have declined by 35%, but the number could be lowered even further.

New Orleans-Since the introduction of PSA screening, prostate cancer-specific deaths have declined by 35%, but the number could be lowered even further, according to one expert.

"Epidemiologic studies have shown that the more PSA testing, the less late-stage disease, and the lower the prostate cancer death rate, and this is especially true in younger men," said Dr. Catalona, professor of urology at Northwestern University's Feinberg School of Medicine, Chicago.

"This indicated there is a lot of aggressive prostate cancer in the range of 2.0 to 4.0 that could be detected on biopsy," he said.

Dr. Catalona and his colleagues have determined median PSA levels to be 0.7 ng/mL for men age 40 to 49 years and 0.9 ng/mL for men age 50 to 59. For individuals with levels above these medians, the rate of cancer is increased seven- to eight-fold (J Urol 2007; 177:1745-8). He has concluded that men with a PSA level of 2.6 to 4.0 ng/mL, regardless of age, have a 20% risk of having prostate cancer detected on biopsy.

With a cutoff of 2.5 ng/mL, cancer is detected earlier, about 80% being pT1-2 and 17% qualifying as so-called "insignificant cancer," he said. By the lower cutoff, more cancers are organ-confined, have less volume of cancer, and are associated with a better progression-free survival. Cancers detected in the 2.6- to 4.0-ng/mL range have a 10-year progression-free survival of 89%, compared with 80% for a 4.1- to 7.0-ng/mL cutoff, and a cure rate of approximately 90%.

Dr. Catalona acknowledged performing significantly more biopsies with the lower cutoff, but noted that his positive biopsy rate is 22% to 25%, the same as when he used 4.0 ng/mL as his cutoff for biopsy.

"We do recommend more biopsies, but most of these patients would eventually have biopsies anyway," he said. "We are just doing them earlier, when the tumors are more curable."