ENHANCED REVERSE-TRANSCRIPTASE POLYMERASE CHAIN-REACTION FOR PROSTATE-SPECIFIC ANTIGEN COMBINED WITH NEEDLE-BIOPSY RESULTS - A SUPERIOR PREDICTOR OF PT3 DISEASE

Background: Preoperative staging for prostate cancer underestimates th e final pathology stage in approximately 40-50% of the cases. Previous work from our institution demonstrated that an enhanced reverse trans criptase polymerase chain reaction (RT-PCR) assay for prostate-specifi c antigen (PSA) enabled more accurate staging of presumably localized prostate cancer. The goal of the current study is to determine if need le biopsy results when combined with the RT-PCR for PSA assay are a be tter predictor of final pathology stage. Methods and Results: One hund red sixty-two men with needle biopsy-diagnosed prostate cancer had blo od drawn for the RT-PCR for PSA assay before undergoing radical prosta tectomy. Polymerase chain reaction primers specific for the PSA gene w ere run, along with appropriate controls. Tumor was characterized usin g the TMN staging system: organ confined (pT2a-c), capsular penetratio n (pT3a-b), seminal vesicle involvement (pT3c). Surgical margins and l ymph nodes were also evaluated. Of the 162 patients, the majority had localized disease by digital rectal examination: T2 = 97% and T3 = 3%. On needle biopsy, 48 cases (30%) had a Gleason score greater than or equal to 7 and 35 cases (22%) had perineural involvement (PNI). The RT -PCR for PSA assay was positive in 50 patients (31%). Final pathology revealed 39% of patients had pT3 disease; none of the 162 patients had lymph node involvement. Statistical analysis revealed that a Gleason score greater than or equal to 7 had 81% specificity and 46% sensitivi ty in predicting pT3 disease (odds ratio 3.6). The presence of PNI on needle biopsy was 89% specific and 38% sensitive in predicting pT3 dis ease (odds ratio, 4.9). The RT-PCR for PSA assay was 89% specific and 62% sensitive in predicting pT3 disease (odds ratio, 13.0). All 14 cas es with both RT-PCR for PSA and PNI positivity had pT3 disease. Logist ic regression analysis demonstrated the independent predictive strengt h of PNI on needle biopsy, Gleason score greater than or equal to 7, a nd RT-PCR for PSA positivity for identifying pT3 disease; their combin ed odds ratio was more than 180. Conclusions: Using the RT-PCR for PSA assay in conjunction with needle biopsy results increases the predict ive strength for pT3 disease in patients with presumed organ-confined prostate carcinoma.