Despite the fact that an elevated level of prostate-specific antigen (PSA) in the blood has been shown to better predict a positive cancer biopsy result than a digital rectal exam (DRE), the rectal exam is still a necessary screening method for older men with higher, age-adjusted PSA levels, according to a study published in the December 2012 issue of The Canadian Journal of Urology
Penn State College of Medicine researchers sought to determine the effectiveness of the digital rectal exam in predicting prostate cancer when compared with a PSA test in older men. Because PSA levels naturally increase in men as they age, the researchers were interested in determining how age-specific cutoff rates could contribute to limitations in using the PSA test as the only cancer-screening method.
The researchers studied 806 men undergoing prostate needle biopsy from September 2001 to December 2008. They compared the results of initial testing with biopsy results for each of the participants. Of the 306 men determined to have prostate cancer, 136 had an abnormal DRE. Of the 136 with abnormal DRE results, 43 patients (or 31%) had normal PSA levels for their age.
“Our study confirms that the digital rectal exam remains an important part of screening [such] patients because 31% of cancers in our study would have been missed by using age-specific PSA cutoffs alone,” concluded the study authors.