Prostate Cancer Incidence Rates Have Started to Decrease in Central Italy

Abstract

The widespread use of prostate-specific antigen (PSA) testing has dramatically changed the epidemiology of prostate cancer. Growing incidence rates have been documented in almost all western countries following the increased usage of PSA screening. In the United States after a period of huge increase in incidence, rates have decreased to values lower than those of the pre-PSA era. Similar changes have been documented also in the area of the Tuscany Cancer Registry, central Italy, where prostate cancer incidence rates doubled from the early 1990s to 2003 and afterwards decreased. This is the first evidence, to our knowledge, of a decline in prostate cancer incidence in Italy following the screening-related increase.

In spite of the existing debate on the opportunity of prostate-specific antigen (PSA) screening for prostate cancer, given the evidence of efficacy but also of major overdiagnosis and overtreatment, ¹ spontaneous PSA use has increased throughout western countries since the early 1990s. A peak of incidence has been observed in almost all countries. In the United States, which is the most typical example, prostate cancer incidence has shown a steady increase from around 1989 to 1990, with a fast growth up to a peak in 1992, followed by a first decrease up to 1995 when rates had an increasing pace almost similar to that of the pre-PSA era, and then a new decrease from 2002, with incidence falling below that expected according to the pre-PSA era trend. ² The sharp increase of incidence is most likely due to a prevalence screening round effect, and the decline in rates, below the pre-PSA period levels since 2003, may represent the effect of screening anticipation: incidence has become lower than expected as cases that were bound to present have already been diagnosed at screening.

We believe it might be relevant to note that a similar figure has been observed in central Italy in the area of the Tuscany Cancer Registry where prostate cancer incidence rates almost doubled from the early 1990s to 2000. ³ This occurred as a consequence of widespread PSA use in Tuscany, showing values as high as 30% at age 55–69, or 40% at age 70–74 during 2004 and 2005, ⁴ in spite of estimated low compliance to biopsy prompted by elevated PSA.

Figure 1 shows standardized (European population) incidence rates from the Tuscany Cancer Registry from 1985 to 2005, for the age 50+ years. An increasing trend of incidence was observed since the early 1990s. A join-point analysis carried out to detect changes in linear trend documented a sharp increase in incidence from 1985 to 2003 (the annual percent change of rates, APC, was +4.9, 95% CI +4.3; + 5.4). Afterwards rates started to decrease (APC = –3.9; 95% CI –15.3; +8.9).

Figure 1

Tuscany Cancer Registry. Prostate cancer incidence, age 50+ years

The decline in incidence rate observed in Tuscany since 2003 may suggest that the spontaneous screening prevalence round effect is starting to subside. If this decreasing trend continues, it is possible to forecast that in 2008 we will reach the same incidence levels expected according to the pre-PSA (1985–1991) increasing rate (APC = +2.9).

This is the first evidence, to our knowledge, of a decline of prostate cancer incidence in Italy, following the screening-related increase.