Changes in Mortality and Incidence of Prostate Cancer by Risk Class in Different Periods in Italy: The Possible Effects of PSA Spread

Abstract

Purpose In Italy, the spread of prostate-specific antigen (PSA) testing varies in different areas. A peak of incidence was reached in 2003-2004 in some areas, while in others the incidence is still increasing. Mortality has declined since 1999 in some areas, while it remains stable in others. We compared mortality and the risk of advanced cancer over 2 periods (1996-1998; 2005-2007) and by geographic area characterized by a different spread of PSA, to understand the possible impact of PSA on the epidemiology of prostate cancer. Methods In 8 Italian Cancer Registries (CRs), 4,632 cases diagnosed over 2 periods, 1996-1998 and 2005-2007, were sampled to assess risk class. The CRs were classified into late and early phase of PSA testing depending on whether an incidence peak had been reached by 2008. Incidence by risk class was estimated based on overall incidence in each CR and on risk class distribution in the sample. We calculated standardized mortality (MRR) and risk class-specific incidence rate ratios (IRR) to compare the 2 periods. Results Incidence increased from 1996-1998 to 2005-2007 (IRR 1.5; 95% CI 1.4, 1.6). High-risk and metastatic cancer incidence decreased only in late-phase areas (IRR 0.78; 95% CI 0.69, 0.88; and 0.40; 95% CI 0.30, 0.54, respectively), while in early-phase areas, incidence remained virtually stable (IRR 1.2; 95% CI 1.0, 1.4; and 0.77; 95% CI 0.59, 1.0, respectively). Mortality decreased only in late-phase areas (MRR 0.81; 95% CI 0.85, 0.97; vs 1.1; 95% CI 0.92, 1.2) in early-phase areas. Conclusions Mortality reduction and a decrease in high-risk and metastatic cases occurred simultaneously only in areas in late phase of PSA spread.