Characteristics Of Prostate Cancer Detected By Digital Rectal Examination Only

A report in the December, 2007 issue of Urology by Dr. Okotie and the group of Dr. William Catalona suggests the digital rectal examination (DRE) remains an important element of prostate cancer (CaP) screening. The group performed the study, as others have suggested that DRE is no longer necessary to CaP screening. For example, the European Randomized Study of Screening for Prostate Cancer states that a prostate biopsy should be offered for a PSA level of >3.0ng/ml but omits DRE.

From Dr. Catalona's database of 36,000 men participating in CaP screening between 1989 and 2001, 3,568 (10%) were diagnosed with CaP. Prior to 1995 a PSA level >4.0ng/ml and after 1995 a PSA level >2.5g/ml was the indication for prostate biopsy. The other indication has always been a DRE suspicious for CaP. Among men who had a prostate biopsy due to a suspicious DRE, 18% were diagnosed with CaP. Of the 3,568 men diagnosed with CaP, 2,233 underwent radical prostatectomy. Of the men treated with surgery, 303 (14%) were diagnosed with CaP by DRE alone, 1,426 (64%) on the basis of PSA, and 504 (22%) due to abnormalities in both the PSA and DRE.

Among men diagnosed with CaP due to an abnormal DRE alone who underwent surgery, 60 (20%) were non-organ confined, 56 (20%) had Gleason score 7 or higher, 49 (16%) had positive surgical margins, 8 (3%) had seminal vesicle invasion and 4 (1.3%) had lymph node metastasis. Comparing these pathologic features to CaP detected due to abnormalities in both PSA and DRE findings revealed that adverse pathology was significantly more likely if both the PSA and DRE were abnormal, compared to either test alone. The 10 year progression-free survival rate was 83%, 82%, and 63% for CaP detected by DRE only, PSA only, and both PSA and DRE, respectively. Overall survival and cancer-specific survival were also significantly higher for CaP detected by an abnormality on only DRE or PSA compared to both tests. This data supports a role for both DRE and PSA in CaP screening.