A comparative effectiveness analysis of the PBCG vs. PCPT risks calculators in a multi-ethnic cohort

Samuel Carbunaru,Pooja Gogana,Adam B Murphy,Borko Jovanovic,Roohollah Sharifi,Irene B Helenowski,Oluwarotimi S Nettey,Edward Schaeffer,Rick A Kittles,Peter Gann,Courtney M P Hollowell,Maria Ruden

doi:10.1186/s12894-019-0553-6

Abstract

BackgroundPredictive models that take race into account like the Prostate Cancer Prevention Trial Risk Calculator 2.0 (PCPT RC) and the new Prostate Biopsy Collaborative Group (PBCG) RC have been developed to equitably mitigate the overdiagnosis of prostate specific antigen (PSA) screening. Few studies have compared the performance of both calculators across racial groups.MethodsFrom 1485 prospectively recruited participants, 954 men were identified undergoing initial prostate biopsy for abnormal PSA or digital rectal examination in five Chicago hospitals between 2009 and 2014. Discrimination, calibration, and frequency of avoided biopsies were calculated to assess the performance of both risk calculators.ResultsOf 954 participants, 463 (48.5%) were Black, 355 (37.2%) were White, and 136 (14.2%) identified as Other. Biopsy results were as follows: 310 (32.5%) exhibited no cancer, 323 (33.9%) indolent prostate cancer, and 321 (33.6%) clinically significant prostate cancer (csPCa). Differences in area under the curve (AUC)s for the detection of csPCa between PCPT and PBCG were not statistically different across all racial groups. PBCG did not improve calibration plots in Blacks and Others, as it showed higher levels of overprediction at most risk thresholds. PCPT led to an increased number of avoidable biopsies in minorities compared to PBCG at the 30% threshold (68% vs. 28% of all patients) with roughly similar rates of missed csPCa (23% vs. 20%).ConclusionSignificant improvements were noticed in PBCG’s calibrations and net benefits in Whites compared to PCPT. Since PBCG’s improvements in Blacks are disputable and potentially biases a greater number of low risk Black and Other men towards unnecessary biopsies, PCPT may lead to better biopsy decisions in racial minority groups. Further comparisons of commonly used risk calculators across racial groups is warranted to minimize excessive biopsies and overdiagnosis in ethnic minorities.

Highlights

Predictive models that take race into account like the Prostate Cancer Prevention Trial Risk Calculator 2.0 (PCPT Risk Calculators (RC)) and the new Prostate Biopsy Collaborative Group (PBCG) risk calculators (RCs) have been developed to equitably mitigate the overdiagnosis of prostate specific antigen (PSA) screening
Since PBCG’s improvements in Blacks are disputable and potentially biases a greater number of low risk Black and Other men towards unnecessary biopsies, Prostate Cancer Prevention Trial 2.0 (PCPT) may lead to better biopsy decisions in racial minority groups
Black men present with higher PSA levels, are at higher risk of developing clinically significant Prostate cancer (PCa), and have higher mortality rates compared to Whites [7, 8]

Summary

Introduction

Predictive models that take race into account like the Prostate Cancer Prevention Trial Risk Calculator 2.0 (PCPT RC) and the new Prostate Biopsy Collaborative Group (PBCG) RC have been developed to equitably mitigate the overdiagnosis of prostate specific antigen (PSA) screening. Few studies have compared the performance of both calculators across racial groups. Black men present with higher PSA levels, are at higher risk of developing clinically significant PCa (csPCa), and have higher mortality rates compared to Whites [7, 8]. The commonly used Prostate Cancer Prevention Trial 2.0 (PCPT) and the new Prostate Biopsy Collaborative Group (PBCG) RCs both take race into consideration, but were developed in largely European ancestry populations [9, 10]

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Conclusion