EFFECT OF PATIENT AGE ON EARLY DETECTION OF PROSTATE-CANCER WITH SERUM PROSTATE-SPECIFIC ANTIGEN AND DIGITAL RECTAL EXAMINATION

This study was designed to determine the effects of age by decade on t he efficacy of digital rectal examination (DRE) and serum prostate-spe cific antigen (PSA) for early detection of prostate cancer in men aged fifty and over. A prospective multicenter clinical trial was conducte d at six university centers. All 6,630 male volunteers underwent a ser um PSA (Hybritech, Tandem) determination and DRE. Quadrant biopsies of the prostate were performed if PSA was > 4 ng/mL or DRE suspicious. A total of 1,167 biopsies were performed, and 264 cancers were detected . The cancer detection rate increased from 3 percent in men aged fifty to fifty-nine to 14 percent in men eighty years or older (p < 0.0001) . PSA detected significantly more of the total cancers than DRE at all age ranges (p < 0.05). The positive predictive values (PPV) for PSA w ere 32 percent (50-59 years), 30 percent (60-69 years), 34 percent (70 -79 years), and 38 percent (80 + years). The corresponding PPVs for DR E were 17 percent, 21 percent, 25 percent, and 38 percent. Eighteen pe rcent of the cancers were detected solely by DRE, whereas 45 percent o f cancers were detected solely by PSA. Thus, the use of both tests in combination provided the highest rate of detection in all age groups. One hundred-sixty patients underwent radical prostatectomy and patholo gic staging. Cancer was organ-confined in 74 percent (25/34) of men ag ed fifty to fifty-nine, 76 percent (65/86) of men aged sixty to sixty- nine, and 60 percent (24/40) of men aged seventy or over (chi2, < 70 v s. greater-than-or-equal-to 70, p < 0.05). Early detection programs yi eld a lower, yet still substantial, cancer detection rate in younger m en, and there is a greater likelihood for detection of organ-confined disease in this age range. Younger men have the longest projected life expectancy and, therefore, the most to gain from early prostate cance r detection.