Research Article: Different spatial pattern of municipal prostate cancer mortality in younger men in Spain

Date Published: January 25, 2019

Publisher: Public Library of Science

Author(s): Lara Rodriguez-Sanchez, Pablo Fernández-Navarro, Gonzalo López-Abente, Olivier Nuñez, Nerea Fernández de Larrea-Baz, Jose Juan Jimenez-Moleón, Álvaro Páez Borda, Marina Pollán, Beatriz Perez-Gomez, Ana Paula Arez.

http://doi.org/10.1371/journal.pone.0210980

Abstract

Prostate cancer (PC) primarily affects elderly men. However, the specific features of cases diagnosed at younger ages (<65 years) suggest that they may represent a different clinical subtype. Our aim was to assess this suggestion by contrasting the geographical PC mortality and hospital admissions patterns in Spain for all ages to those in younger men. The Spanish National Institute of Statistics supplied data on PC mortality, hospital admission, and population data. We estimated the expected town-specific number of deaths and calculated the standardized mortality ratios. Spatial autoregressive models of Besag-York-Mollié provided smoother municipal estimators of PC mortality risk (all ages; <65 years). We computed the provincial age-standardized rate ratios of PC hospital admissions (all men; <60 years) using Spanish rates as the reference. A total of 29,566 PC deaths (6% among those <65 years) were registered between 2010–2014, with three high-mortality risk zones: Northwest Spain; Southwest Andalusia & Granada; and a broad band extending from the Pyrenees Mountains to the north of Valencia. In younger men, the spatial patterns shared the high risk of mortality in the Northwest but not the central band. The PC hospital discharge rates confirmed a North-South gradient but also low mortality/high admission rates in Madrid and Barcelona and the opposite in Southwest Andalusia. The consistent high PC mortality/morbidity risk in the Northwest of Spain indicates an area with a real excess of risk. The different spatial pattern in younger men suggests that some factors associated with geographical risk might have differential effects by age. Finally, the regional divergences in mortality and morbidity hint at clinical variability as a source of inequity within Spain.

Partial Text

Worldwide, prostate cancer (PC) is the second most common tumor among men, with an estimated 1.1 million new cases in 2012[1]. The steep increase in incidence in most countries in recent decades[2] is generally attributed to the increased detection of indolent prostate neoplasms (i.e. use of prostate-specific antigen [PSA] tests as screening tools)[3] a potentially increased exposure to unknown risk factors[4] accompanied by a sustained decrease in mortality[5], which, in Spain started in the late 1990s[6]. With an estimated 307,000 deaths in 2012, PC ranks fifth as the cause of cancer death worldwide among men and third among European and Spanish men[1,7]. Based on these figures, it is surprising that scarce evidence is available regarding PC etiology. To date, none of the main well-established risk factors -age, genetic susceptibility[8], black race, and familial history- are modifiable[4]. The association of this tumor with other factors such as chemical contaminants[9], diet[10], and medications[11], among others, is not yet clear.

Fig 1 shows the Spanish regional and provincial administrative distributions to help the reader to better understand the description of the results.

A total of 29,566 deaths due to PC (6% in men younger than 65 years old) were reported in 2010–2014. The mortality patterns are shown in Fig 2, which presents the spatial distributions of the risk of death due to PC for all PC cases, while Fig 3 shows this information for PC deaths in men <65 years of age. Each figure includes two maps: one depicting the municipal risk of death due to PC compared to the average in Spain and another representing the probability for each town of having an excess of risk (RR>1).

The spatial distribution of PC mortality by municipality in the period 2010–2014 in Spain showed high-risk zones in the north and the west, in line with period 2004–2008 [22], although with a more marked excess of mortality in the southwest of Andalusia. However, the most noteworthy result from the present study is the contrasting mortality patterns observed between all ages and those of younger men (<65 years) in the eastern part of the country. In conclusion, the consistently high PC mortality and morbidity risk in the northwest of Spain point to a higher risk of PC in this region. The different spatial pattern in men under 65 years of age suggests that some factors associated with the geographical risk might have differential effects by age group. Finally, the divergences in mortality and morbidity patterns in some regions, such as Madrid, Barcelona, or Huelva, indicate that variability in the patterns of care could be a relevant source of inequity among Spanish regions.   Source: http://doi.org/10.1371/journal.pone.0210980

 

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