B-376 Performance of Pathological Anatomy Immunohistochemical Markers and Serum Tumor Markers in Prostate Cancer
Authors: Silva I C , Carvalho G C , Vilaca F A , Ramadan D R , Tufik S , Feres M C 
Published: September 2023

Abstract

Background
The gold standard method for diagnosing prostate cancer is systematic prostate biopsy under ultrasound guidance and local anesthesia.Serum tumor marker tests (PSA, Free PSA and testosterone) and confirmatory or classificatory immunohistochemical (IHC) complement the conclusion of the patient’s report. The maximum amount of information regarding the pathological anatomy and markers provided to physicians favors assertive decision-making in the conduct of treatment. However, the results of prostate biopsies after treatment with prostatectomy can differ significantly in the course of the disease. In this context, the authors’ objectives were to analyze the performance of the dosages of these widely used serum markers against the IHC markers of biopsies, as well as their indicators of positive and negative predictive values (PPV and NPV) for prostatic neoplasms. The authors analyzed the level of agreement between pathological prostate biopsy results and immunohistochemical (IHC) testing for 34ßE12, p63, and alpha-methylacyl-CoA racemase (AMACR) to provide final pathological results for prostate cancer, as well as their relationship with data provided by biochemical tests for the markers PSA, Free PSA and Testosterone.

Methods
Descriptive, retrospective study with a qualitative and quantitative approach, based on data obtained through IHC exams and available in a database of a large laboratory in São Paulo—Brazil. Data collection was based on anatomopathological results of male patients diagnosed with prostate cancer, aged between 40 and 69 years between August 2021 and December 2022 with a total of 1403 analyzes for biopsies using IHC combined markers such as 34ßE12 , p63 and AMACR, and a total of 144 analyzes for combined prostatic serum markers (total PSA, free PSA and testosterone). All analyzes were conducted using the R software version 4.1.0 (R CORE TEAM, 2021) and considered a significance level (α) of 5%.

Results
The Mann-Whitney test indicated that the distribution of the PSA variable (ng/dL) does not differ statistically between the 34ßE12 groups (W = 822.0; P = 0.224; r = 0.139 , p63 (W = 826.0; P = 0.361 ; r = 0.103), and AMACR (W = 610.0; P = 0.351; r = -0.106). Likewise, the Free PSA marker (ng/dL) did not differ statistically between 34ßE12 (W = 309.5; P = 0.473 ; r = -0.097), p63 (W = 319.5; P = 0.488; r = - 0.093 and AMACR (W = 372.0; P = 0.725; r = 0.048). The results of the ROC curve with PSA (ng/dL) as predictor of the biopsy result with the marker 34ßE12, p63 and AMACR the mean positive predictive values (MPVP) were 0.623 , 0.635 and 0.615 respectively. For Free PSA (ng/dL) with the markers respectively, the VPPM were 0.743, 0.750 and 0.455. As for testosterone, our sample was very small.

Conclusion
Our findings showed that all markers are important indicators for the diagnosis and monitoring of prostate cancer and that they complement each other. Free PSA showed good PPV for 34ßE12 and p63 markers and low PPV for AMACR.