The effect of digital rectal examination on prostate-specific antigen levels.

OBJECTIVE--To identify the effect of digital rectal examination (DRE) on serum prostate-specific antigen (PSA) levels. DESIGN--A prospective trial before and after DRE. SETTING--Multicenter outpatient screening program. PATIENTS--A total of 2754 healthy men aged 40 years and older who presented to a prostate cancer screening program and consented to two phlebotomies. MAIN OUTCOME MEASURE--Changes in serum PSA levels after DRE. RESULTS--Patients were divided into four groups based on their initial serum PSA levels. The levels were chosen based on previous studies that showed different incidences of prostate cancer within these groups. The two groups with the lowest initial PSA values (0.1 through 4 micrograms/L and 4.1 through 10 micrograms/L) were found to have statistically insignificant changes in the serum PSA levels after DRE. The group with initial PSA levels of 10.1 through 20 micrograms/L had increases in serum PSA values that showed a trend toward statistical significance. The group with initial PSA levels of greater than 20 micrograms/L had statistically significant increases in serum PSA values after DRE. The alterations in serum PSA levels in the two groups with the highest PSA values were not clinically important as the patients' clinical treatment was not altered. CONCLUSIONS--No clinically important effects on serum PSA levels were noted after DRE.