A large study from Europe suggests it does not hurt to wait a few years between prostate cancer screenings, but the research will not end debate over the value of prostate-specific antigen (PSA) tests.

Millions of men in the United States have their blood tested every year for PSA, although routine screenings are controversial.

The American Cancer Society believes that health care professionals should offer the prostate-specific antigen blood test and digital rectal exam yearly to male patients beginning at age 50. Although it suggests African Americans be offered the test yearly at age 45, and men at high risk should begin testing at age 40.

High PSA levels can mean cancer or just an enlarged prostate; only a biopsy can tell. Moreover, prostate cancer usually grows slowly, and there is little way to predict which early-stage tumors will threaten life. Since treatment can cause incontinence or impotence, PSA testing may do more harm than good for some men.

European men receive less frequent PSAs, so Dutch scientists decided to see if skipping a few years mattered. They tracked 4,200 Swedish men tested every two years, and 13,300 men tested every four years in The Netherlands.

More frequent testing spotted more tumors overall but did not reduce diagnosis of aggressive tumors that formed between visits, researchers report Wednesday in the Journal of the National Cancer Institute.

Over a decade, 13 percent of the men tested every two years were diagnosed with prostate cancer compared with 8 percent of men tested every four years.

Only a handful of those aggressive between-test cancers formed in each group, a statistical tie, concluded researchers at Erasmus Medical Centre in Rotterdam.

The study does not prove that four years between PSAs is safe, Dr. E. David Crawford of the University of Colorado cautioned in an accompanying editorial. The Dutch men may have been healthier.

Specialists hope results of a huge U.S. study of PSA screening, due in 2009, will settle how much benefit it really provides.

More than 218,000 U.S. men are expected to be diagnosed with prostate cancer this year, and about 27,000 men will die of it.