AGE-SPECIFIC PROSTATE-SPECIFIC ANTIGEN - A REASSESSMENT

BACKGROUND. Our objective was to compare expected survival benefits wh en screening for prostate cancer with PSA, using an age-specific bound relative to a cutoff of 4.0 ng/ml. METHODS. We used a decision analys is modeling the cancer yield in a cohort screened by both screening te sts, and the survival of cancer cases given screen detection and in th e absence of screening. Expected cancer yields and positive predictive values were from an ultrasound-guided biopsy series. Stage distributi ons of screen-detected cases were obtained from the literature. For lo calized cases, survival given screen detection was assumed to be equal to normal life expectancy for the population. For these cases, surviv al in the absence of screening was modeled as time from clinical diagn osis to death added to time remaining after time of screen and before clinical diagnosis was made (lead time). For nonlocalized cases at scr een detection, survival given screen detection was assumed to be equal to survival in the absence of screening. The average difference betwe en expected survival with and without screening as calculated for age- specific PSA and for PSA >4.0 ng/ml and compared. RESULTS. Average yea rs of life saved per subject screened using PSA >4.0 ng/ml were compar able to those using the age-specific bound. Average years of life save d per cancer case, however, appeared to be potentially greater for PSA >4.0 ng/ml than for age-specific PSA. PSA >4.0 ng/ml detected markedl y more prostate cancer cases than age-specific PSA. CONCLUSIONS. Using a bound of 4.0 ng/ml for all ages appears to be more efficient in ide ntifying men with cancer in a screening cohort, which translates into a greater expected survival benefit per cancer case. (C) 1996 Wiley-Li ss, Inc.