Screening for prostate cancer leads to earlier detection

Results of a study published in the January 1st issue of the International Journal of Cancer suggest that after 12 years of follow-up, an early screening program for prostate cancer provides a reduced median lead time to diagnosis in men with a serum prostate specific antigen (PSA) level of at least 3.0 ng/mL.

“Screening serum levels of PSA is now a major strategy for early detection of prostate cancer,” Dr. Magnus Tornblom, of Karolinska Institute, Stockholm, Sweden, and colleagues observe. “Quantification of the lead time thus obtained is important both for understanding the development of prostate cancer and for evaluating the advantages and disadvantages of widespread screening.”The team notes that 946 randomly selected male Stockholm residents took part in the program. Detection of prostate cancer was based on digital rectal exam, transrectal ultrasonography, or a PSA level of at least 10.0 ng/mL. Suspicious findings were followed up by biopsy. Forty-two men who took part in the early detection program were diagnosed with the disease on the basis of this intervention. An additional 39 men with prostate cancer were diagnosed clinically during the 12 years of follow-up. The team compared the cumulative incidence of prostate cancer in the participants during 12 years of follow-up with that of a matched, randomly-selected reference population of 657 men for whom PSA levels were available.”When men with different PSA levels in the two populations were examined, the incidence curves for PSA levels of at least 3.0 ng/mL were seen to intersect after 10.6 years of follow-up,” the researchers point out.After 12 years of follow-up, the median lead time for screening-detected prostate cancer in men with PSA levels of at least 3.0 ng/mL, was 4.5 years. In the reference population, this interval was 7.8 years. At 20 years of follow up, the estimated median lead time in the reference group had increased to 10.7 years.Overall, the researchers conclude that detection lead time was influenced by the initial PSA level, but that the program was not associated with significant overdetection.(Source: Int J Cancer 2004;108:122-129: Reuters Health: January 28, 2004: Oncolink)