External validation of the Prostate Cancer Prevention Trial and the European Randomized Study of Screening for Prostate Cancer risk calculators in a Chinese cohort

Abstract

Several prediction models have been developed to estimate the outcomes of prostate biopsies. Most of these tools were designed for use with Western populations and have not been validated across different ethnic groups. Therefore, we evaluated the predictive value of the Prostate Cancer Prevention Trial (PCPT) and the European Randomized Study of Screening for Prostate Cancer (ERSPC) risk calculators in a Chinese cohort. Clinicopathological information was obtained from 495 Chinese men who had undergone extended prostate biopsies between January 2009 and March 2011. The estimated probabilities of prostate cancer and high-grade disease (Gleason >6) were calculated using the PCPT and ERSPC risk calculators. Overall measures, discrimination, calibration and clinical usefulness were assessed for the model evaluation. Of these patients, 28.7% were diagnosed with prostate cancer and 19.4% had high-grade disease. Compared to the PCPT model and the prostate-specific antigen (PSA) threshold of 4 ng ml(-1), the ERSPC risk calculator exhibited better discriminative ability for predicting positive biopsies and high-grade disease (the area under the curve was 0.831 and 0.852, respectively, P<0.01 for both). Decision curve analysis also suggested the favourable clinical utility of the ERSPC calculator in the validation dataset. Both prediction models demonstrated miscalibration: the risk of prostate cancer and high-grade disease was overestimated by approximately 20% for a wide range of predicted probabilities. In conclusion, the ERSPC risk calculator outperformed both the PCPT model and the PSA threshold of 4 ng ml(-1) in predicting prostate cancer and high-grade disease in Chinese patients. However, the prediction tools derived from Western men significantly overestimated the probability of prostate cancer and high-grade disease compared to the outcomes of biopsies in a Chinese cohort.

Prostate cancer risk assessment tools in an unscreened population

“…another study by Zhu et al [19] retrospectively tested the PcPt and erSPc-rcs in a chinese cohort (n = 495). Prostate cancer was diagnosed in 28.7 %, and high grade prostate cancer in 19.4 % of this patient cohort.…”

Development and external multicenter validation of Chinese Prostate Cancer Consortium prostate cancer risk calculator for initial prostate biopsy

“…For instance, the PTCP-RC involved family history and prior biopsy. Family history [10] and prior biopsy [26] were important indicators in Western countries with higher incidence rate and screening projects. However, the incidence of PCa was quite low in the past few decades in Asian countries, thus there are very few people with family history and previous negative biopsies.…”

“…The PCa detection rate of Korean men (19.6%) receiving mainly extended biopsy (75.3% patients underwent extended biopsy) [8] and Chinese men (25.3%) receiving mainly extended biopsy (mean number of cores: 10.4-10.7) [9] was 19.6% and 25.3%, respectively. Urologists in China [10] and Korea [11] found that these 2 RCs would overestimate the risk of PCa by approximately 20% at predicted probabilities from 20% to 80%, indicating the necessity of developing risk prediction models in Asian populations. Secondly, the original ERSPC-RC and PCPT-RC did not include information of prostate volume (PV) or free PSA ratio.…”

A nomogram based on age, prostate-specific antigen level, prostate volume and digital rectal examination for predicting risk of prostate cancer

“…The existing evidence indicates that evaluation of prostate cancer risk should be tailored for different races. [8][9][10] As a result, the development and use of a nomogram for the population from which the nomogram was derived is particularly pertinent. To our knowledge, no nomogram to evaluate the risk of prostate cancer in a Chinese population has been published to date.…”

“…We recently reported that baseline PSA and PSA velocity in young Chinese men without prostate cancer differ from those of African American and Caucasian American men. 9 Furthermore, Zhu et al 10 recently reported that the PCPT and ERSPC risk calculators overestimated the probability of predicting prostate cancer and high-grade disease when independently validated using a Chinese population. The existing evidence indicates that evaluation of prostate cancer risk should be tailored for different races.…”