Utilization and cancer detection by U.S. prostate biopsies (2005-2011).

Abstract

107 Background: To assess the positive biopsy rate and core sampling pattern in patients undergoing prostate biopsy in the US at a national reference laboratory and pathology laboratories integrated into urology group practices and analyze the relationship between positive biopsy rates and number of specimen vials per biopsy (sv/b). Methods: For the years 2005-11, we collected pathology data from a national reference laboratory (NRL) including number of urologists and urology practices referring samples, total specimen vials submitted per prostate biopsy, and final diagnosis for each case. The diagnoses were categorized as benign, malignant, prostatic intraepithelial neoplasia or atypical small acinar proliferation. Over the same period, similar data was gathered from urology practices with in-house laboratories performing global pathology services (urology practice labs, UPL) identified by a member survey of the Large Urology Group Practice Association. For each year studied, positive biopsy rate and number of specimen vials/biopsy were calculated in aggregate and separately for each site of service. Results: From 2005-11, 437,937 biopsies were submitted in 4,230,129 vials (9.4 sv/b); overall positive biopsy rate was 40.3%, identical at both the NRL and UPL (p=0.97). Nationally, the number of specimen vials/biopsy increased sharply from a mean of 8.8 during 2005-8 to 10.3 from 2009-11 (difference 1.5 sv/b, p=0.03). For the most recent 3 year period (2009-11), there was no significant difference between the NRL (10.0 sv/b) and UPL (10.6 sv/b) (p=0.08). Positive biopsy rate correlated strongly (p<0.01) with number of specimen vials/biopsy. Conclusions: The positive prostate biopsy rate of 40.3% is identical across sites of service. Although there was a national trend towards increased specimen vials/biopsy from 2005-11, from 2009-11 there was no significant difference in specimen vials/biopsy across sites of service. Increased cancer detection rate correlated significantly with increased number of specimens examined. Segregation of prostate biopsy cores into 10-12 unique specimen vials has been adopted by urologists across sites of service and can be considered the de facto national standard of care.