Age-specific prostate-specific antigen (PSA) cutoffs were previously suggested and were found to miss significant cancers in older men. We assessed the influence of an age-adjusted PSA cutoff to optimize the diagnostic performance (sensitivity and specificity) of complexed PSA (cPSA) and total PSA (tPSA) in the differentiation of benign disease from prostate cancer using a contemporary referral patient cohort. The cPSA and tPSA values were determined using the Bayer Immuno 1 system. The diagnostic utility of tPSA and cPSA was assessed using a diverse contemporary test population consisting of sera prospectively collected between June 1999 and October 2000 from 3597 men who recently underwent a systematic biopsy by urologists in clinical practices throughout the United States. This contemporary patient sample had biopsy diagnoses of either no evidence of malignancy (NEM; n = 2189) or prostate cancer (n = 1408). All serum samples had tPSA values between 2.0 and 20.0 ng/mL. The mean tPSAs (ng/mL) for the NEM and prostate cancer groups were 7.1 ± 3.2 and 7.3 ± 3.3, respectively (P = 0.026). The mean cPSAs (ng/mL) for the NEM and prostate cancer groups were 5.6 ± 2.7 and 6.0 ± 2.9, respectively (P <0.001). As the tPSA increased from 2.0 to 10.0 ng/mL, the cancer detection rate remained relatively constant at approximately 39% when evaluated using increments of 2.0 ng/mL for tPSA. For fixed sensitivities of 80%, 85%, 90%, and 95%, as the age range increased (45 to 59, 60 to 69, 70 to 79, ≥80), the tPSA and cPSA assay cutoffs required to sustain the specified sensitivity level markedly increased, with the exception of the 95% sensitivity level, where the cutoffs only slightly increased between the age ranges of 45 to 69 and ≥70. Overall, cPSA showed a marginal improvement in specificity versus tPSA across all age groups at all sensitivity levels. In this community referral population, the cancer detection rate remained fairly constant over the tPSA range of 2.0 to 20.0 ng/mL. This study demonstrated that to maintain a given sensitivity level for cPSA and tPSA in the age ranges studied, continuous upward adjustment of the cutoffs was required as age increased.
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