THE UTILITY OF PATIENT AGE IN EVALUATING PROSTATE-CANCER

The utility of age in examining patients for prostate cancer was asses sed. Of the 462 patients in the study, 138 had prostate cancer. The ag e distribution of the patients with cancer was similar to that found i n patients with prostate cancer in the US population, and a correlatio n between age and the serum prostate-specific antigen (PSA) value was noted (r=.4, P<.002). Selection of reference intervals had a significa nt effect on test performance. Using an interval of 0 to 4.0 ng/mL, se nsitivity of the PSA assay was 90% overall and varied from 78% (patien ts aged 50-59 years) to 94% (patients aged 70-79 years). In contrast, age-adjusted reference ranges yielded corresponding sensitivities of 8 4%, 78%, and 88%. With a single, fixed reference range, specificity de creased with advancing patient age (P<.001). This trend was eliminated by adjusting the cutoff in different age groups. In addition, age-adj usted reference ranges improved specificity by 10%, and by using the r esults of examination of a biopsy specimen as the ''gold standard,'' t he total number of patients classified correctly by PSA increased from 226 to 250 (49%-54%). For staging before treatment, patient age, clin ical stage, and Gleason score were combined to yield a single probabil ity estimate for organ-confined disease (P<.001). The use of age-adjus ted reference ranges is supported by this study, which demonstrates th at assay efficiency and specificity improve and sensitivity, although decreased overall, becomes more uniform across age groups. In this pat ient population, age was useful in determining the probability of orga n-confined prostate cancer. Use of this model in clinical decision mak ing should await evaluation in a prospective trial.