Extending the Prostate cancer screening interval to 2 or 4 years would substantially delay the detection of advanced prostate cancers, new research suggests.

Current guidelines recommend that men over age 50 should be offered a prostate exam every year. But some groups have suggested that screening at 2 or 4-year intervals may be sufficient in men with initially low PSA levels. PSA is a protein produced by the prostate gland and a rising PSA level in the blood can be a sign of cancer.

“Even though a relatively small percentage of men have rapidly rising PSA levels, they are the ones with life-threatening Prostate cancer,” Dr. William J. Catalona from Northwestern University, Chicago, told Reuters Health. “The widespread use of infrequent screening intervals could lead to delays in the detection of these potentially lethal cancers until the opportunity for cure is missed,” he added.

Catalona and others used data from more than 18,000 men screened for prostate cancer at 6-month to 1-year intervals to determine the potential delay in detection that could result from 2- and 4-year PSA screening intervals.

A total of 377 (2.0 percent) of the subjects were diagnosed with Prostate cancer over 8 years of follow-up.

Increasing the screening interval from 1 year to 2 years would have resulted in at least a 4-month delay in prostate cancer detection in 62 percent of the men, the researchers say. More than three quarters of the men would have experienced a mean delay of detection of 12 months were the screening interval extended to 4 years.

Many of these diagnosed tumors were “potentially aggressive,” they warn.

Infrequent screening may delay the detection of prostate cancer in men most likely to benefit from early diagnosis, they suggest. “Further careful study is indicated before recommending screening intervals longer than 1 year,” Catalona said.

SOURCE: The Journal of Urology April 2005.