Comparison of stage migration patterns between Europe and the USA: an analysis of 11 350 men treated with radical prostatectomy for prostate cancer

Abstract

OBJECTIVE To examine the stage migration patterns in patients treated with radical prostatectomy (RP) for prostate cancer in Europe and in the USA in the last 20 years. PATIENTS AND METHODS Between 1988 and 2005, RP was performed in 11 350 men: 5739 from Europe and 5611 from the USA. Independent‐samples t‐test and the chi‐square test were, respectively, used for comparisons of means and proportions. The trend test was used to test the statistical significance of trends in proportions over time. RESULTS Temporal patterns in patients’ age, stage and PSA level at presentation were similar on both continents. Conversely, temporal patterns in Gleason sum distribution differed. In the USA, the rate of biopsy Gleason sums of 2–5 decreased from 32.8% to 0.2% (P < 0.001), while the rate of Gleason sums of 7 and 8–10 increased (P < 0.001). Conversely, in Europe the rate of Gleason sums of 6 increased from 40% to 64% (P < 0.001) at the expense of all other Gleason sums. At RP, the rate of Gleason sums of 2–5 decreased on both continents and the rate of a Gleason sum of 7 increased in the USA. Moreover, no important differences in pathological stage trends (organ confinement, extracapsular extension and seminal vesicle invasion) distinguished either population. Finally, the rate of lymph node involvement increased in the USA but remained stable in Europe. CONCLUSIONS Stage and grade migration affected the USA and Europe to different extents. These differences should be accounted for when prediction tools or comparisons between the USA and Europe are considered.