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  • Net survival rates i e

    2019-08-11

    Net survival rates, i.e. the survival that would be observed if the prostate cancer was the only possible cause of death, were computed. To quantify survival associated with prostate cancer, net survival is much more relevant than observed survival since mortality rates due to other causes than prostate cancer among men aged over 75 years is relatively high. The net survival estimates were obtained from the Pohar-Perm method which included a weighting procedure to correct biases due to the informative censoring mechanism induced by the life-table variables [25,26]. This method required the expected mortality from the general population that was obtained from life tables provided by the INSEE. Net survival rates were computed by age group and grade, separately for cases diagnosed in 1991–1994 and 2000–2004: the first BAY-598 corresponded to a rather low level of incidence whereas the second period included the peak of incidence. For survival analyses, patients aged over 85 years were excluded because 8-years survival is not relevant among a group of patients with a short life expectancy. Survival rates were computed each year since diagnosis until 8 years after diagnosis. No results were reported for a specific time after diagnosis when unstable estimates were observed resulting in increasing survival rates with time. A log-rank-type test was realized to compare net survival distributions.
    Results
    Discussion Incidence rates of prostate cancer diagnosed in 2013 among men aged 75 and over in the Isère Département were similar with that obtained in the SEER programme in the United States for the 2009–2013 period with 686.3, 504.7 and 418.4 cases per 100,000 for men aged 75–79, 80–84 and ≥85, respectively [27]. Consistent with our results, a decrease of incidence rates for men aged 80 and over was observed in the United Kingdom from 1993 to 1995 to 2012–2014 [28]. On the other hand, data from the SEER program showed increase of standardized incidence rates during the 1980′s for all age groups including men aged 70–79 and 80 and over, followed by a decrease of incidence after 1992. The peak of incidence observed in 2005 in the Isère Département for younger men aged 60–74 was observed In the United-States in 1992 for men aged 60–69 [3] and in many European countries during the 2000′s [4]. Potential explanations for the variations of incidence rates include changes in the frequency of risk factors as well as changes in diagnostic methods such as the realization of a screening test [29]. Few risk factors have been established for prostate cancer [30] and their evolution seem unlikely to explain changes in incidence rates. The diffusion of a screening test induces changes of incidence rates as a consequence of lead time and overdiagnosis [31,32]. As a result, PSA testing could explain changes of incidence rates in the two age groups [33]. Indeed PSA has been widely used since 1987 for prostate cancer screening although no official guidelines recommend routine screening of prostate cancer based on this test [34,35]. PSA testing has been widely used as a screening test: a proportion of 82.3%, 89.7% and 93.1% of men aged 60–64, 65–69 and 70–74 had at least one PSA testing during the 2013–2015 period in France [36]. For men aged 75 and over, PSA testing remained frequent, with 87.9%, 77.6% and 59.4% of men who had at least one PSA testing for age groups 75–79, 80–84 and ≥85 during the same period [36]. Prostate cancer is one of the cancer with the highest survival rate [37]. Our estimates are consistent with net survival rates of 89% for men aged 70–79 and 66% for men aged 80–99 that were observed in England for cases diagnosed in 2009–2013 [38]. Compared to men aged 60–74, the lower survival rate of prostate cancers diagnosed among men aged 75–84 may be explained by a later stage at diagnosis and more aggressive tumors [39], as well as less extensive treatment due to the presence of comorbidities or shorter life expectancy [11]. The lower survival rate for men aged 75–84 that was still observed when restricting the comparison to high grade cancers, suggested that less extensive treatments were realized among elderly patients.