Value of the serum prostate-specific antigen-alpha 1-antichymotrypsin complex and its density as a predictor for the extent of prostate cancer.

ABSTRACT

OBJECTIVE: To determine whether serum levels of the prostate-specific antigen-alpha1-antichymotrypsin complex (PSA-ACT) and its density (ACTD) in patients scheduled to undergo radical prostatectomy for clinically localized prostate cancer can predict organ-confined vs extraprostatic disease. PATIENTS AND METHODS: Serum samples were obtained from 62 patients with clinically localized prostate cancer before they underwent radical prostatectomy. PSA and PSA-ACT were measured using immunofluorometric techniques with different monoclonal antibodies against PSA and ACT, respectively. Furthermore, the PSA and PSA-ACT densities of the whole prostate (PSAD and ACTD, respectively) were calculated. The relationships of serum PSA, PSA-ACT, PSAD, ACTD and the pathological stage of the prostatectomy specimens were analysed. RESULTS: The disease was organ-confined or extraprostatic in 30 and 32 men, respectively. In men with organ-confined cancer, the mean PSA and PSA-ACT levels were significantly lower than in those with extraprostatic disease. Furthermore, there were significantly higher mean PSAD and ACTD levels in men with extraprostatic than with organ-confined disease. There were also significant differences in PSA, PSA-ACT, PSAD and ACTD levels at each pathological stage, whereas there was no significant association between these variables and the Gleason score. Receiver-operating characteristic curve analysis for detecting organ-confined disease showed that PSA-ACT and ACTD had a larger area under the curve than PSA and PSAD, respectively, but these differences were not significant. Furthermore, PSA-ACT and ACTD provided significantly better sensitivity for detecting organ-confined disease than PSA and PSAD, respectively. CONCLUSIONS: Measuring PSA-ACT and ACTD may improve the preoperative evaluation of patients scheduled to undergo radical prostatectomy, because these factors better differentiate extraprostatic from organ-confined disease than PSA and PSAD.