TRANSRECTAL ULTRASOUND-GUIDED BIOPSY CAUSES HEMATOGENOUS DISSEMINATION OF PROSTATE CELLS AS DETERMINED BY RT-PCR

Objectives. To determine if transrectal ultrasound-guided (TRUS) prost ate biopsy causes dissemination of prostate cells into the circulation as assessed by reverse transcriptase-polymerase chain reaction (RT-PC R) targeted against prostate-specific antigen (PSA) mRNA. Methods. RT- PCR PSA analysis was performed before and after prostatic invasive man ipulations in 50 men. The cases consisted of 47 patients with TRUS and 3 with transurethral resection of the prostate (TURF). Peripheral ven ous blood (8 mL) was drawn before and within 60 minutes after the proc edure. Total RNA was extracted from fractionated blood, and RNA/cDNA q uality was assured and normalized with beta-actin RT-PCR analysis. The PSA primers hybridize exons 3 and 5, yielding a 254-basepair PCR prod uct. The assay detects one LNCaP cell in a background of 100 million l ymphoid cells and a single copy of PSA cDNA on an ethidium bromide gel . Results. Among the 47 TRUS cases, 43 specimens were evaluable. Forty -two cases were negative before biopsy; among these patients, 4 cases (9.5%) converted to a positive RT-PCR PSA result. Both benign and mali gnant TRUS biopsies were capable of producing a positive RT-PCR PSA si gnal implicating iatrogenic dissemination of cells. All three TURF cas es converted from a negative to a highly intense positive signal. Conc lusions. We conclude that a positive RT-PCR PSA signal may result from release of prostate cells into the peripheral circulation after a TRU S biopsy and TURF. TURF causes greater dissemination than TRUS. Based on these preliminary data, we recommend that future molecular staging studies should be based on blood specimens drawn before performance of TRUS biopsy. This may be an important mechanism of prostate cancer di ssemination meriting further investigations. (C) 1997, Elsevier Scienc e Inc.