Utilization Trends and Positive Biopsy Rates for Prostate Biopsies in the United States: 2005 to 2011

This article assesses the positive biopsy rate and core sampling pattern in patients undergoing needle biopsy of the prostate in the United States at a national reference laboratory (NRL) and anatomic pathology laboratories integrated into urology group practices, and analyzes the relationship between positive biopsy rates and the number of specimen vials per biopsy. For the years 2005 to 2011 we collected pathology data from an NRL, including number of urologists and urology practices referring samples, total specimen vials submitted for prostate biopsies, and final pathologic 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 were gathered from urology practices with in-house laboratories performing global pathology services (urology practice laboratories; UPLs) as identified by a survey of members of the Large Urology Group Practice Association. For each year studied, positive biopsy rate and number of specimen vials per biopsy were calculated in aggregate and separately for each site of service. From 2005 to 2011, 437,937 biopsies were submitted in > 4.23 million vials (9.4 specimen vials/biopsy); overall positive biopsy rate was 40.3%-this was identical at both the NRL and UPL (P = .97). Nationally, the number of specimen vials per biopsy increased sharply from a mean of 8.8 during 2005 to 2008 to a mean of 10.3 from 2009 to 2011 (difference, 1.5 specimen vials/biopsy; P = .03). For the most recent 3-year period (2009–2011), the difference of 0.6 specimen vials per biopsy between the NRL (10.0) and UPL (10.6) was not significant (P = 0.08). Positive biopsy rate correlated strongly (P < .01) with number of specimen vials per biopsy. The positive prostate biopsy rate is 40.3% and is identical across sites of service. Although there was a national trend toward increased specimen vials per biopsy from 2005 to 2011, from 2009 to 2011 there was no significant difference in specimen vials per biopsy across sites of service. Increased cancer detection rate correlated significantly with increased number of specimens examined. Segregation of prostate biopsy cores into 10 to 12 unique specimen vials has been widely adopted by urologists across sites of service.Key Words: Prostate cancer, Prostate biopsy, Utilization trends, National reference laboratory, Urology practice laboratoriesPublished data over the past decade suggesting that prostate cancer detection rates are enhanced with additional sampling of the prostate have resulted in modifications to the traditional 6-core (sextant) biopsy regimen^1,2 such that recent clinical guidelines recommend that extended biopsy schemes with 10 to 12 specimens be obtained.^3–5 There are also data that suggest that segregation of prostate biopsy tissue specimens into individual vials improves specimen handling, enhances tissue representation, and improves diagnostic accuracy.^6–8 Furthermore, focal prostate cancer treatment strategies gaining recent popularity are dependent on more precise tumor mapping, requiring even greater tissue sampling.⁹Over approximately the same time frame, there has been an increase in consolidation of medical practices into larger single- or multispecialty group practices. By incorporating efficiencies of scale, these groups afford physicians the opportunity to retain the characteristics of traditional medical practices while improving their ability to adapt to changing health care circumstances.¹⁰ These groups often integrate additional capabilities beyond professional services, including anatomic and clinical pathology, diagnostic imaging, and radiation therapy. Proponents of these arrangements argue that integration of medical services facilitates the development of coordinated clinical pathways, improves communication between specialists, offers better quality control of ancillary services, and enhances data collection—all of which can improve patient care and lead to lower costs.^11–13 Specifically with regard to anatomic pathology, recent data suggest that certain specimen handling errors are significantly lower (P = .018) at urology practices with integrated in-house pathology laboratories (urology practice laboratories [UPLs]) than at other sites of service¹⁴; however, some contend that group practice integration creates conflicts of interest and self-referral issues, which ultimately leads to increased utilization of services.^15–19 A recent study based on analysis of Medicare claims data purported that positive prostate biopsy rates and the number of samples submitted per biopsy are significantly different across sites of service²⁰; however, this study has been criticized as both methodologically flawed and scientifically inaccurate.²¹ Also problematic is the fact that calculation of prostate cancer incidence has been identified as particularly susceptible to error when determined by analysis of outpatient claims data alone.²²We sought to determine positive biopsy rates and utilization trends in the United States via direct analysis of laboratory records from both a national reference laboratory (NRL) and UPLs, and to determine if there was a correlation between positive biopsy rates and number of specimen vials submitted.