Tumor characteristics in screening for prostate cancer with and without rectal examination as an initial screening test at low PSA (0.0-3.9 ng/ml)

BACKGROUND. The value of rectal examination as initial screening test for p rostate cancer at low PSA values (0.0-3.9 ng/ml) was determined by evaluati ng the number and tumor characteristics of the cancers detected. METHODS. Two study populations were subjected to screening with (n=10,226) and without (n=10,753) rectal examination as initial screening test. The nu mber of cancers detected at low PSA values for both screening regimens, the corresponding biopsy and radical prostatectomy tumor characteristics were assessed. Possibly harmless cancers were defined as small (< 0.5 ml) organ- confined humors without Gleason growth-patterns 4/5. RESULTS. At low PSA, 26.6% (117/440) of screen-detected cancers were detect ed after the evaluation of a suspicious rectal examination. The number of c ancers and tumor aggressiveness features were highly associated with serum- PSA level. The proportion of possibly harmless disease steadily declined fr om 100% (PSA 0.0-0.9 ng/ml) to 15.4% (PSA 3.0-3.9 ng/ml). Rectal examinatio ns were performed unnecessarily in 94.7-100% of cases, when detection of cl inically significant disease was aimed at. Using PSA (and a cut-off of 3.0 ng/ml) as the only screening tool, 24.3% (121/498) of screen-detected cance rs were in the PSA range 3.0-3.9 ng/ml, and 60.0% were assessed as clinical ly significant. CONCLUSIONS. Rectal examination as initial screening test for prostate canc er at low PSA values may be replaced by screening using serum-PSA only. At PSA levels below 3.0 ng/ml, 289 rectal examinations are required to find on e case of clinically significant disease, and 96 rectal examinations are ne eded to diagnose prostate cancer of any size, grade, or stage. (C) 2001 Wil ey-Liss, Inc.