Utility of PAP test to assess prostate cancer aggressiveness

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Although Dr. Strum has been consistently recommending a PAP (Prostatic Acid Phosphatase) test among diagnostics for postate cancer staging, many doctors (and labs) consider the PAP test to be an outdated screen for prostate cancer that has been replaced by PSA.

My own urologist expressed this opinion and was reluctant to write a script for a PAP test after my initial diagnoses-- 'You know you have cancer, this would be a waste....' I also had difficulties in finding a local lab to do the PAP test. However, I am tracking PAP semi-annually as part of my Active Surveillance monitoring.

Below is a current abstract confirming the utility of PAP levels in assessing the likelihood of treatment (seeds + EBRT) failure. For men with higher-risk cancer, the pre-treatment PAP was a better predictor of treatment failure than either PSA or Gleason sum. Looks like it would be wise to add a PAP test to diagnostics to consider in selecting treatment after diagnosis.

10-Year post-Brachy+EBRT cause-specific survival rates=========================================pre-treatment PAP-------------------------below 1.5 93%1.5-2.4 87%2.5 + 75%

Gleason sum at diagnosis----------------------------------6 90%7 89%8 70%9 68%

PSA at diagnosis----------------------10 92%10-120 89%20+ 83%

The Best to You and Yours!

Jon

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Prostatic Acid Phosphatase Adversely Affects Cause-Specific Survival in Patients with Intermediate to High-Risk Prostate

Cancer Treated with Brachytherapy - Abstract Friday, 14 March 2008 Department of Radiation Oncology, University of Washington Medical Center, Seattle, Washington 98195, USA.

LMCFang@... email address is being protected from spam bots, you need Javascript enabled to view it To perform a retrospective analysis to assess the utility of pretreatment serum prostatic acid phosphatase (PAP) as a predictor of cause-specific survival (CSS) in patients with higher risk prostate cancer treated with palladium-103 (103Pd) brachytherapy and supplemental external beam radiotherapy (EBRT).

From 1992 to 1996, 193 patients with clinically localized prostate adenocarcinoma, a pretreatment PAP level, and Gleason score 7 or more, and/or a prostate-specific antigen (PSA) level of 10 ng/mL or more were treated with 103Pd brachytherapy and supplemental EBRT. The patients underwent EBRT of 41.4 Gy to a limited pelvic field and 103Pd brachytherapy with a prescribed minimum 103Pd dose of 80 Gy. Multivariate analysis was performed to analyze the predictive value of PAP, PSA, and Gleason score on CSS.

The 10-year CSS rate for patients with a PAP level of less than 1.5, 1.5 to 2.4, and 2.5 U/L or more was 93%, 87%, and 75%, respectively (P = 0.013). The 10-year CSS rate for patients with a PSA level of less than 10, 10 to 20, and greater than 20 ng/mL was 92%, 76%, and 83%, respectively (P = 0.393). The 10-year CSS rate for patients with a Gleason score of 6, 7, 8, and 9 was 90%, 89%, 70%, and 68%, respectively (P = 0.002). On multivariate regression analysis, PAP (hazard ratio 1.31, P <0.0001) and Gleason score (hazard ratio 2.37, P = 0.0007) were associated with CSS. PSA was not predictive of CSS (P = 0.393).

The results of this study demonstrated that PAP is a stronger predictor of CSS than PSA or Gleason score in men with higher risk prostate cancer treated with 103Pd brachytherapy and EBRT. Given the findings of this analysis, the use of PAP should be reconsidered in these patients.

Written by Fang LC, Dattoli M, Taira A, True L, Sorace R, Wallner K.

Reference: Urology. 2008 Jan;71(1):146-50. doi:10.1016/j.urology.2007.08.024PubMed Abstract PMID:18242384

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