(RxWiki News) The statistics are pretty clear that most American men are not going to die of prostate cancer. But the question remains: who should be screened and how often? A new crystal ball may be on the horizon.
Researchers have found that men who had high PSA (prostate-specific antigen) levels in their early 40s to mid-50s were most likely to have an aggressive prostate cancer decades later.
The authors suggest these findings may offer an opportunity for more clearly defining which men need to have regular PSA screenings.
"Learn about prostate cancer risks."
Researchers traced the prostate cancer histories of men who first underwent PSA testing in middle age. Andrew Vickers, PhD and attending research methodologist at Memorial Sloan-Kettering Cancer Center in New York, was the first author.
PSA screenings have been used for years to predict a man’s risk of prostate cancer. These tests have come under fire lately.
PSA levels are impacted by a number of factors. So, it’s difficult to know which men should have biopsies (gathering and testing tissue samples from the prostate) based solely on PSA screening results.
In this study, researchers were trying to learn if there was a way to identify men who would benefit most from PSA screenings and how often these individuals should be tested.
Researchers in the US and Sweden carried out a case control study (actual cases of prostate cancer versus healthy controls), taking data from the Malmo Preventative Project (MPP) cohort (group).
The Malmo cohort included 21,277 men between the ages of 27 and 52 who participated in the MPP between 1974 and 1984.
All of the men provided blood samples, and about 5,000 participants gave a second blood sample roughly six years later.
The researchers identified 1,369 documented clinical diagnoses of prostate cancer, 241 cases of metastasis (spread) and 162 deaths from prostate cancer.
Three age groups were studied: early 40s, 45 to 49 and 51 to 55.
The study showed that 44 percent of prostate cancer deaths occurred within the following 30 years among men who had a PSA of 1.5 ng/ml or more during the ages 45 to 49. The risk of death was 10 times higher in these men compared to same-aged men who had the lowest PSA levels of less than 1.5 ng/ml.
The risk of metastatic cancer in individuals with higher PSA levels at age 40 was less than 1 percent (0.6 percent) after 15 years of follow-up.
Risk of advanced disease was much higher (5.2 percent) in men aged 50 to 55 with higher PSA levels.
The study also examined screening intervals and concluded that men with lower PSA levels in their 40s do not need to be screened more frequently than every five years.
“Measurement of PSA concentration in early midlife can identify a small group of men at increased risk of prostate cancer metastasis several decades later,” the authors wrote.
“Careful surveillance is warranted in these men. Given existing data on the risk of death by PSA concentration at age 60, these results suggest that three lifetime PSA tests (mid to late 40s, early 50s, and 60) are probably sufficient for at least half of men,” they concluded.
The study was published April 16 in BMJ.
This study was funded by the National Cancer Institute; Swedish Cancer Society; the Sidney Kimmel Center for Prostate and Urologic Cancers; David H Koch through the Prostate Cancer Foundation, the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre; Fundación Federico SA, and MSKCC PCPR (Prevention Control and Population Research Program) Goldstein Grant.
Various authors reported holding current or pending patents for various PSA tests, assays, statistical models, along with financial relationships with GlaxoSmithKline, Genomic Heath and Arctic Partners, OPKO.
