Cancer Research Lab

Digital rectal examination (DRE) should not be excluded from prostate cancer screening protocols, according to a report in the December issue of Urology.

“To offer the patient a better evaluation of his prostate gland, the physician should perform the DRE as well as the PSA test,” Dr. William J. Catalona from Northwestern University Feinberg School of Medicine, Chicago, said.

Dr. Catalona and colleagues compared clinical variables and survival outcomes between patients diagnosed with prostate cancer by DRE alone versus those diagnosed by PSA level, regardless of DRE findings.

Of 2233 men who were diagnosed with prostate cancer and underwent radical prostatectomy, 303 (14%) were diagnosed on the basis of DRE alone, 1426 (64%) on the basis of PSA alone, and 504 (22%) based on abnormalities of both tests, the authors report.

Eighteen percent of men who underwent a prostate biopsy because of abnormal DRE findings alone were diagnosed with prostate cancer.

Twenty percent of cancers detected by DRE alone were nonorgan-confined, 20% had a Gleason score of 7 or higher, 16% had positive surgical margins, 3% had seminal vesicle invasion, and 1.3% had lymph node metastases.

Adverse pathology was significantly more likely in men with abnormalities in both DRE and PSA than in those detected by either test alone, the researchers say.

Ten-year progression-free survival was similar for cancers detected by DRE only (83%) or PSA only (82%), but significantly lower for cancers detected by abnormalities in both DRE and PSA (63%), the investigators note. Similar results were seen for overall survival and cancer-specific survival.

“Eliminating DRE from screening protocols would miss a significant proportion of patients with a clinically important and potentially curable prostate cancer,” the authors conclude.

However, “it may be reasonable to avoid DRE in men with a PSA level less than 1 ng/mL,” they add.

“PSA testing and DRE must be continued on a regular (annual) basis to be most effective, and persistent changes over time are as important as the absolute findings at any one point in time,” Dr. Catalona said.