Comparison of the treatment of men with prostate cancer between the US and England: an international population-based study.

INTRODUCTION: The treatment of prostate cancer varies between the United States (US) and England, however this has not been well characterised using recent data. We therefore investigated the extent of the differences between US and English patients with respect to initial treatment. METHODS: We used the Surveillance, Epidemiology, and End Results (SEER) database to identify men diagnosed with prostate cancer in the US and the treatments they received. We also used the National Prostate Cancer Audit (NPCA) database for the same purposes among men diagnosed with prostate cancer in England. Next, we used multivariable regression to estimate the adjusted risk ratio (aRR) of receiving radical local treatment for men with non-metastatic prostate cancer according to the country of diagnosis (US vs. England). The five-tiered Cambridge Prognostic Group (CPG) classification was included as an interaction term. RESULTS: We identified 109,697 patients from the SEER database, and 74,393 patients from the NPCA database, who were newly diagnosed with non-metastatic prostate cancer between April 1st 2014 and December 31st 2016 with sufficient information for risk stratification according to the CPG classification. Men in the US were more likely to receive radical local treatment across all prognostic groups compared to men in England (% radical treatment US vs. England, CPG1: 38.1% vs. 14.3% - aRR 2.57, 95% CI 2.47-2.68; CPG2: 68.6% vs. 52.6% - aRR 1.27, 95% CI 1.25-1.29; CPG3: 76.7% vs. 67.1% - aRR 1.12, 95% CI 1.10-1.13; CPG4: 82.6% vs. 72.4% - aRR 1.09, 95% CI 1.08-1.10; CPG5: 78.2% vs. 71.7% - aRR 1.06, 95% CI 1.04-1.07) CONCLUSIONS: Treatment rates were higher in the US compared to England raising potential over-treatment concerns for low-risk disease (CPG1) in the US and under-treatment of clinically significant disease (CPG3-5) in England.