The utility of patient age in evaluating prostate cancer

The utility of age in examining patients for prostate cancer was assessed. Of the 462 patients in the study, 138 had prostate cancer. The age distribution of the patients with cancer was similar to that found in patients with prostate cancer in the US population, and a correlation between age and the serum prostate-specific antigen (PSA) value was noted (r = .4, P < .002). Selection of reference intervals had a significant effect on test performance. Using an interval of 0 to 4.0 ng/mL, sensitivity of the PSA assay was 90% overall and varied from 78% (patients aged 50-59 years) to 94% (patients aged 70-79 years). In contrast, age-adjusted reference ranges yielded corresponding sensitivities of 84%, 78%, and 88%. With a single, fixed reference range, specificity decreased with advancing patient age (P < .001). This trend was eliminated by adjusting the cutoff in different age groups. In addition, age-adjusted reference ranges improved specificity by 10%, and by using the results of examination of a biopsy specimen as the "gold standard," the total number of patients classified correctly by PSA increased from 226 to 250 (49%-54%). For staging before treatment, patient age, clinical stage, and Gleason score were combined to yield a single probability estimate for organ-confined disease (P < .001). The use of age-adjusted reference ranges is supported by this study, which demonstrates that assay efficiency and specificity improve and sensitivity, although decreased overall, becomes more uniform across age groups. In this patient population, age was useful in determining the probability of organ-confined prostate cancer. Use of this model in clinical decision making should await evaluation in a prospective trial.