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

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.

Prostate Cancer Racial Disparities: A Systematic Review by the Prostate Cancer Foundation Panel

“…In either case, the most pressing need with respect to disparities research is validation of predictive models in non-White populations. Most existing PCa prognostic tools were developed using data for men of European ancestry; these may be acceptably accurate across diverse populations, but without sufficient data capture to permit validation efforts, we cannot be sure that use of such models in non-White populations is not exacerbating disparities [62]. For future studies, biomarker discovery and model training that focuses on or explicitly oversamples from Black and other non-White populations will lead to more equitable and reliable prognostic models across heterogeneous populations.…”

Predicting the diagnosis of prostate cancer with a scoring system based on novel biomarkers

“…Carbunaru et al explored the effectiveness of these calculators in a multi-ethnic cohort and found the AUC for clinically significant Prostate Cancer was lower than the originally published articles at 64% (95% CI 0.61–0.68) for PCPT and 65% (95% CI 0.62–0.68) for PBCG [ 14 ]. A limiting factor of using these more established scoring systems, is that they may not reflect the Asian population.…”

Clash of the calculators: External validation of prostate cancer risk calculators in men undergoing mpMRI and transperineal biopsy

“…The performance of the ERSPC‐RC was found to be poorer than the MRI‐ERSPC‐RC with Radtke et al, Mortezavi et al, Poyet et al, and Lundon et al describing an AUC of 0.77, 0.8, 0.73, and 0.69, respectively, for estimating the risk of significant PCa 22,25‐27 . The performance of the PBCG‐RC has previously been evaluated with Saba et al identifying an AUC of 0.69, Mortezavi et al finding an AUC of 0.76, and Carbunaru et al identifying an AUC of 0.65 for the detection of clinically significant PCa 24,25,28 . These studies were all performed in European or American populations, whereas our study was the first validation study performed in an Australian population.…”

“…7 Our results are comparable to other validation studies of the MRI- 22,[25][26][27] The performance of the PBCG-RC has previously been evaluated with Saba et al identifying an AUC of 0.69, Mortezavi et al finding an AUC of 0.76, and Carbunaru et al identifying an AUC of 0.65 for the detection of clinically significant PCa. 24,25,28 These studies were all performed in European or American populations, whereas our study was the first validation study performed in an Australian population. The consistency demonstrated across these validation studies with the present study suggests that these risk calculators may potentially be utilized in other populations of men for risk stratification of significant PCa.…”