RECOMMENDED PROSTATE-SPECIFIC ANTIGEN TESTING INTERVALS FOR THE DETECTION OF CURABLE PROSTATE-CANCER

Objective.-To evaluate prostate-specific antigen (PSA) testing interva ls that maintain the detection of curable cancer and reduce unnecessar y testing. Design and Patients.-Historical prospective study of serial PSA measurements at 2- and 4-year intervals from frozen serum samples of 40 men who eventually developed prostate cancer and 272 men withou t prostate cancer who were participants in a prospective aging study ( Gerontology Research Center of the National Institute on Aging, the Ba ltimore Longitudinal Study of Aging) and the case series of 389 consec utive men treated surgically for nonpalpable prostate cancer. Main Out come Measures.-Probability of a PSA conversion to 4.1 to 5.0 ng/mL and to greater than 5.0 ng/mL at 2 and 4 years and probability of detecti ng curable prostate cancer by age and PSA level. Results.-When the pre treatment PSA level was less than or equal to 4.0 ng/mL, nonpalpable p rostate cancers were highly likely (34/36, 94%) to be curable (organ-c onfined or capsular penetration with Gleason score <7 and negative mar gins), and the majority (25/36, 69%) were small cancers (confined tumo r less than or equal to 0.5 cm(3) with no Gleason pattern 4 or 5). Whe n the pretreatment PSA level was greater than 4.0 ng/mL and less than or equal to 5.0 ng/mL, cancers were highly likely to be curable (32/36 , 89%), and a minority were small cancers (12/36, 33%), When the pretr eatment PSA level was greater than 5.0 ng/mL, 96 (30%) of 317 cancers were noncurable. The PSA conversion (for cancer cases) to a level at w hich cure is less likely (>5.0 ng/mL) is rare (0%) after 2 or 4 years when the initial PSA is less than 2.0 ng/mL. PSA conversion to a range at which cancers are likely to be curable and less likely to be small (4.1-5.0 ng/mL) is rare after 2 years (0%-4%) when the baseline PSA l evel is less than 2.0 ng/mL but common when the baseline PSA level is between 2.1 and 3.0 ng/mL (27%) or 3.1 and 4.0 ng/mL (36%). Conclusion s.-These data suggest that for men with no cancer suspected on digital rectal examination, a PSA level of 4.0 to 5.0 ng/mL is an acceptable range for maintaining the detection of curable prostate cancer and a 2 -year PSA testing interval is not likely to miss a curable prostate ca ncer when the initial PSA level is less than 2.0 ng/mL. Recognizing th at 70% of a screened population between the ages of 50 years and 70 ye ars have PSA levels less than 2.0 ng/mL, elimination of annual PSA tes ting for these men would result in large health care cost savings.