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

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.     

Management and survival of screen-detected prostate cancer patients who might have been suitable for active surveillance

OBJECTIVE: Screening practices for prostate cancer have resulted in an increasing incidence of prostate cancers. Our knowledge about which prostate cancers are life threatening and which are not is limited. Thus, for ethical, medical, and economic reasons we need to define which patients can be managed by active surveillance. METHODS: From 1993 through 1999, men from the Rotterdam section of the European Randomized study of Screening for Prostate Cancer (ERSPC) were screened by two strict protocols, which were based on prostate-specific antigen (PSA), digital rectal examination, and transrectal ultrasound. For this study, men with criteria that reflect current active surveillance studies were selected: those with a biopsy Gleason score < or =3+3 in two or fewer cores, with a PSA density <0.2 and a maximum PSA-level of 15 ng/ml. Clinical stage had to be T1C or T2. RESULTS: Of the 1,014 prostate cancers detected in the prevalence screen, 293 men (28.9%) met the criteria for active surveillance. Their mean age was 65.7 and the mean PSA level was 4.8 ng/ml. Radical prostatectomy was elected by 136 men (46.4%), radiotherapy by 91 (31.1%), and watchful waiting by 64 (21.8%). The mean follow-up was 80.8 months. The eight-year prostate cancer-specific survival was 99.2%; the overall survival was 85.4%. Nineteen men who chose watchful waiting changed to definitive treatment during follow-up. CONCLUSION: Only three men died of prostate cancer, none of whom were on watchful waiting. Our observations provide preliminary validation of the arbitrary selection criteria for active surveillance.