Characteristics of prostate cancer detected by digital rectal examination only

To examine clinical and pathologic features and postoperative survival outcomes of men with prostate cancer detected by digital rectal examination (DRE) alone, elevated prostate-specific antigen (PSA) level alone, or abnormalities in both.

From 1989 to 2001, approximately 36,000 men participated in a prostate cancer screening study. We recommended biopsy for a PSA level greater than 4.0 ng/mL (until 1995) or greater than 2.5 ng/mL (after 1995) or DRE findings suspicious for cancer. The clinical and pathologic features were compared between patients with cancer detected by DRE alone and those with cancer detected by an elevated PSA level, regardless of DRE findings. We also evaluated progression-free survival, overall survival, and cancer-specific survival.

Overall 303 men were diagnosed with prostate cancer by DRE alone, 1426 because of PSA level alone, and 504 by abnormal results on both tests. Of the cancers detected by DRE alone, 60 (20%) were non-organ-confined and 56 (20%) had a Gleason score of 7 or higher. Prostate cancers detected because of abnormalities in both PSA level and DRE results were significantly more likely to have adverse pathologic features, as well as lower rates of progression-free survival, overall survival, and cancer-specific survival than those detected by either test alone (all P <0.0001).

A substantial proportion of prostate cancers detected by DRE at PSA levels less than 4 ng/mL have features associated with clinically aggressive tumors. The omission of DRE from screening protocols might compromise treatment outcomes because many of the cancers detected by DRE alone are potentially curable but may have worse outcomes by the time PSA also reaches a higher level.