Normal findings in selected men with elevated PSA may justify delaying a second prostate biopsy.
Researchers in the Netherlands who examined the value of digital rectal examination (DRE) in prostate cancer screening concluded that in a subgroup of men, DRE may be useful in avoiding unnecessary biopsies. They also found that men with an abnormal DRE are more likely to have aggressive tumors.
Claartje Gosselaar, MD, and collaborators at University Medical Center in Rotterdam studied men aged 55-75 years who participated in the European Randomized Study of Screening for Prostate Cancer, Rotterdam. A PSA of 3 ng/mL or higher prompted a transrectal ultrasound-guided sextant biopsy.
All men had a DRE prior to biopsy. During three consecutive screenings, the researchers evaluated 5,040 biopsy sessions for the presence of prostate cancer in relation to the DRE result.
At initial screening, the positive predictive value (PPV) of a suspicious DRE, in conjunction with an elevated PSA level, for detecting prostate cancer was 48.6% compared with 22.4% for men with a normal DRE, the researchers reported in European Urology (2008;54:581-588). Both PPVs declined in consecutive screens. In the first, second, and third screenings, 71%, 68.8%, and 85.7% of all prostate cancers with a Gleason score greater than 7 were detected in men with a suspicious DRE.
In general, the authors said, “the added value of DRE in conjunction with the PSA cutoff of 3.0 ng/mL is limited, since a suspicious DRE does not modify the biopsy indication.” The authors noted, however, that men with a suspicious DRE have a greater risk of harboring high-grade malignancy compared with men who have a normal DRE.
In men with a previous cancer-negative biopsy, a PSA level of 3 ng/mL or higher, and a normal DRE, the odds of detecting prostate cancer in screenings 2 and 3 were relatively small (10.4% and 14.9%, respectively). The potentially aggressive tumors in these subjects amounted to 0.3% of all cancers detected in screenings 2 and 3, the researchers reported.
“It may be justified to postpone biopsy to a later screening in men with a previous negative biopsy, an elevated PSA level, and a normal DRE in order to lower the risk of overdiagnosis…and to reduce the number of unnecessary biopsies,” the authors wrote.