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N24 Comparison of two simple algorithms avoiding unnecessary prostate biopsy in PSA based prostate cancer detection program

      Introduction and Objectives

      Lithuanian early prostate cancer detection program is targeting 50–75 years old asymptomatic men and is based on PSA cut-off value of 3 ng/ml. PSA is the main trigger for prostate biopsy (Bx). Bx is an invasive procedure and is associates with more frequent complication in elderly men. Up to 64% of patients with elevated PSA have no prostate cancer (PCa) on biopsy. Our study is looking for simple algorithm to avoid unnecessary Bx in PSA based early PCa detection program.

      Material and Methods

      Case histories of asymptomatic men referred to urologist in a single academic hospital due to elevated PSA in 2008 were reviewed. Data collected: patient age, PSA value, prostate volume on transabdominal ultrasound (PV), results of digital rectal examination (DRE), results of Bx. Hard or/and ruff surface of prostate on DRE were considered as suspicious for PCa. Two algorithms to avoid unnecessary Bx were checked. First: set of cut-off values suggesting avoiding Bx if all criteria are met: age ≥65 years, PSA ≤ 7 ng/ml, PV ≥ 50 ml, unsuspicious DRE. Second: age-adjusted PSA values (50–59, 60–69, 70–79 years respectively PSA <3.5, <4.5, <6.5 ng/ml) and DRE.

      Results

      181 patients underwent Bx due to PSA> 3 ng/ml. 76 men had PCa on biopsy (41%). Median age 65 years, median PV 45 ml and these parameters were not significantly different in men with or without PCa. In PCa group average PV was lower (45.7 ml vs 49.7 ml) and average PSA level higher (15.2 ng/ml vs 5.7 ng/ml). Applying first algorithm to our data base 20 Bx could be avoided (11%), 2 diagnosis of PCa would be missed (2.6%). Of these 2 cases 1 is on active surveillance. Applying age-adjusted PSA and DRE 37 Bx could be avoided (20%), 5 diagnosis of PCa would be missed (6.6%). Of these 5 cases 2 are on active surveillance.

      Conclusions

      According to our data in PSA based PCa detection program a set of cut-off values age ≥65 years, PSA ≤7 ng/ml, PV ≥50 ml, unsuspicious DRE could be useful and more accurate than age-adjusted PSA and DRE. Set of cut-off values may prevent considerable number of biopsies while missing few PCa. This algorithm allows avoiding Bx specifically in elderly men with moderate PSA and relatively large prostates. We acknowledge bias of small sample size in a single institution and operator-dependant results of transabdominal ultrasound and DRE. This algorithm could be easily checked or improved on data available from large scale PCa screening trials.