Purpose: The number of patients in Sweden treated with radical prostatectomy for localized prostate cancer has increased exponentially. The extent to which this increase reflects treatment of nonlethal disease detected through prostate-specific antigen (PSA) screening is unknown.
Experimental design: We undertook a nationwide study of all 18,837 patients with prostate cancer treated with radical prostatectomy in Sweden from 1988 to 2008 with complete follow-up through 2009. We compared cumulative incidence curves, fit Cox regression and cure models, and conducted a simulation study to determine changes in treatment of nonlethal cancer, in cancer-specific survival over time, and effect of lead-time due to PSA screening.
Results: The annual number of radical prostatectomies increased 25-fold during the study period. The 5-year cancer-specific mortality rate decreased from 3.9% [95% confidence interval (CI), 2.5-5.3] among patients diagnosed between 1988 and 1992 to 0.7% (95% CI, 0.4-1.1) among those diagnosed between 1998 and 2002 (P(trend) < 0.001). According to the cure model, the risk of not being cured declined by 13% (95% CI, 12%-14%) with each calendar year. The simulation study indicated that only about half of the improvement in disease-specific survival could be accounted for by lead-time.
Conclusion: Patients overdiagnosed with nonlethal prostate cancer appear to account for a substantial and growing part of the dramatic increase in radical prostatectomies in Sweden, but increasing survival rates are likely also due to true reductions in the risk of disease-specific death over time. Because the magnitude of harm and costs due to overtreatment can be considerable, identification of men who likely benefit from radical prostatectomy is urgently needed.