Clinical Usefulness of Prostatic Acid Phosphatase in Prostate Cancer : A Comparative Study with Prostate Specific Antigen

Kang, Joo Ho; Kim, Chun Il; Lee, Sung Choon

Abstract

PURPOSE: To evaluate the clinical usefulness of PAP in staging and monitoring of patient with prostate cancer, we performed a comparative study with PSA, retrospectively.
METHODS
We evaluated 72 patients with prostate cancer. Of these patients 11 had stage A, 6 stage B, 10 stage C, 5 stage D1 and 40 stage D2 prostate cancer. Serum PAP level was measured in all 72 patients and serum PSA level was measured concomitantly in 42 patients.
RESULTS
The mean initial PAP value was 13.40+/- 7.00 U/L. But only 40 (55.6%) had elevated PAP value above 1.5U/L at presentation. Of 55 advanced cases (stage C, D), 39 (76.9%) had elevated PAP values. Of the 42 patients, who underwent longitudinal PSA assessment, the mean initial PSA value was 178.0 +/- 33.3 ng/ml. Forty (95.2%) had elevated PSA value above 4 ng/ml at presentation. Of 41 advanced cases (stage C, D1, D2), 33 (80.5%) exceeded 50 ng/ml. None of the patient had elevated PAP value with normal PSA value at presentation. Among 42 patients, who had followed with longitudinal serum PSA and PAP, progression of the disease to the bone, lung, and rectum occurred in 26 patients; in all PSA was the first indicator of progression and in none of them PAP anticipated PSA elevation.
CONCLUSIONS
Although PAP value usually reflects advanced prostate cancer (70.9%), serum PSA also reflects it (80.5%). Serum PSA monitoring is superior to serum PAP monitoring in predicting disease progression. The use of PSA and PAP jointly to stage and monitor prostate cancer did not appear to enhance the clinical utility over that of PSA alone.