Comparison of radical treatment and mortality in patients with nonmetastatic prostate cancer in England and the United States.

Abstract

46 Background: Prostate-cancer mortality in the U.S. is amongst the lowest globally. Given historical differences in management between England and the U.S., this paper aims to determine if risk-adjusted prostate-cancer mortality is inferior amongst men in England compared to the U.S. Methods: Patients diagnosed with non-metastatic prostate-cancer between 2004 and 2008 were identified using English hospital admission records linked to national cancer registry data, and the American Surveillance, Epidemiology and End Results program. Complete data were available for 222,163 patients. Patients were stratified into low-, intermediate-, and high-risk groups according to disease characteristics. Patient demographics from the two countries were compared using the Chi-square test. Competing-risks survival analyses were used to estimate relative six-year prostate-cancer mortality. Results: In comparison to patients in the U.S., English patients were more likely to present at an older age (70 to 79: England 44.2%, USA 29.3%, p<0.001), with higher clinical tumour stage (cT3-4: England 25.1%, USA 8.6%, p<0.001) and higher Gleason score (GS 8-10: England 20.7%, USA 11.2%, p<0.001). They were also less likely to receive radical therapy, with greatest disparity amongst patients with high-risk disease (England 30%, U.S. 83%, p<0.001). After adjusting for age, ethnicity, year of diagnosis, Gleason score, and tumour stage, English patients were more likely to die of prostate cancer (all risk groups: HR 1.9, 95% CI 1.7-2.0, p<0.001). However, this difference was no longer statistically significant on adjustment for radical therapy (all risk groups: HR 1.0, 95% CI 1.0-1.1, p=0.336). Conclusions: After risk adjustment, prostate-cancer mortality is significantly higher in England compared to the U.S. for men with intermediate- and high-risk disease. This difference appears to be explained by decreased use of radical therapy in England.