Clinical usefulness and diagnostic value of digital rectal examination, prostate specific antigen and serum acid phosphatase, in the early diagnosis of prostatic carcinoma and benign prostatic hyperplasia

ABSTRACT

In seeking to define the relative value of digital rectal examination [DRE], prostate specific antigen [PSA and serum acid phosphatase [SAP] in prostate cancer [CaP] and benign prostatic hyperplasia [BPH], a series of 129 patients with symptoms of bladder outlet obstruction were studied prospectively and the findings compared. Out of the total 129 patients evaluated in this study, DRE detected malignancy in 46%, PSA in 32% and significantly elevated SAP suggested malignancy in 45% of cases. The diagnostic value for BPH of these three investigations were also compared with DRE detected BPH in 54%, PSA in 68% and SAP in 55% of patients. Age or the presence [or absence] of an indwelling catheter had no effect on PSA and SAP concentrations. The specificity of PSA for detecting prostate cancer in this study was 58.33% with a sensitivity of 100%, in contrast to values for SAP of 83.33% and 71.4% respectively. It was concluded that the routine use of SAP as a marker for CaP should be abandoned. The use of PSA as a screening test in a group of patients with prostatism appears justified, but with a positive predictive value of only 32%, its use in a general screening programme is not recommended