A new study published in the Journal of Clinical Oncology has found that men who have higher-than-normal prostate-specific antigen (PSA) levels are more likely to have fatal prostate cancer later in life. Screening plasma levels of PSA for detection of prostate cancer can benefit prostate cancer prognosis and decrease death rates because of the benefits of early detection. However the PSA test still remains a highly controversial topic as it frequently leads to over diagnosis and over treatment of men who may not necessarily be at risk for the disease. Researchers with the Brigham and Women’s Hospital and the Harvard T.H. Chan School of Public Health have found that measuring PSA levels in younger men (between the ages of 40 and 59) could accurately predict future risk of lethal prostate cancer.
This nested, case-control study examined data from the Physicians’ Health Study (PHS), a randomized, placebo-controlled trial examining risk of cardiovascular outcomes and aspirin use. The PHS began in 1982 and US male physicians who took part in it provided blood specimens before the trial began. Using data from 234 patients with prostate cancer at age 40 to 59 years and 711 age-matched controls, researchers measured PSA levels from stored plasma samples and examined the men’s outcomes over time. A total of 71 participants developed lethal prostate cancer, and these were re-matched to 213 controls.
The researchers found that this single, baseline PSA level measured at midlife could accurately predict future risk of prostate cancer: Of the lethal prostate cancer events, 82 percent, 71 percent and 86 percent occurred in men with a baseline PSA above the median at ages 40-49, 50-54 and 55-59, respectively. In addition, men with a PSA below median (<1.0 ng/mL) at 60 years were significantly less likely to develop lethal prostate cancer in the future.
“These data support the recommendation that risk-stratified screening for prostate cancer based on mid-life PSA should be considered in men aged 45 to 59,” said senior author Lorelei Mucci, ScD, associate professor of Epidemiology in the Department of Epidemiology at Harvard T.H. Chan School of Public Health. “Our study does not imply prostate biopsy or definitive treatment is immediately required in younger men with higher PSA levels at baseline, as this could lead to over diagnosis. Rather, these men should undergo more intensive PSA screening to enable earlier identification of cancer and potential cure while still possible.”
The authors note that study limitations include that the study population consists primarily of Caucasian men, includes limited lethal events and that an unknown proportion of participants may have undergone opportunistic screening prior to the study.
