Brain cancer incidence has increased in Navarre, Spain from 1973 to 2008
Etxeberria J, Román ES, Burgui R, Guevara M, Moreno-Iribas C, Urbina MJ, Ardanaz E. Brain and Central Nervous System Cancer Incidence in Navarre (Spain), 1973-2008 and Projections for 2014. J Cancer 2015; 6(2):177-183. doi:10.7150/jca.10482. Available from http://www.jcancer.org/
Different studies have pointed out Navarre as one of the regions of Spain with the highest incidence rates of brain and other central nervous system (CNS) cancer. Trend analysis for cancer incidence rates for long periods of time, might help determining risk factors as well as, assessing prevention actions involved in this disease.
The objective of this study was to describe the incidence of brain and CNS cancer using data from the population-based cancer registry of Navarre, (Spain) during the period 1973-2008 and provide forecast figures up to-2014. Crude and age-standardized (world population) incidence rates of brain cancer per 100,000 person-years were calculated by the direct method separately by gender, area (Pamplona and others), and age-groups. Penalized splines for smoothing rates in the temporal dimensions were applied in order to estimate and forecast cancer incidence rates.
Age-adjusted incidence rates showed an increase over the study and forecast periods in both sexes more marked in women than in men. Higher incidence rates were observed in men compared with women but the differences became smaller with time. The increase was due to the rise of rates in the oldest age groups since the rates for younger age groups remained stable or decreased over time.
As the entire aetiology of brain and other CNS cancer is not still clear, keep promoting healthful lifestyles for cancer primary prevention among the whole population is necessary.
According to the latest brain and other nervous system cancer figures published by GLOBOCAN, 139,608 and 116,605 new cases were diagnosed in 2012 worldwide in male and female, representing 3.9 and 3.0 per 100,000 person-years . Data from the International Agency for Research on Cancer (IARC) publication, Cancer Incidence in Five Continents (CI5C), Vol. X (2003-2007), show high brain cancer incidence rates in Navarre, Spain: 7.8 and 5.7 per 100,000 in male and female respectively ....
Due to the geographical differences observed for this cancer in Navarre, the area was also considered as an explanatory variable of the study. Navarre is a small region ( 644,477 inhabitants is 2011) and a third part of the population is concentrated in Pamplona (capital city) and hence most number of cases belong to the health areas of this city. Then, the observed cases were divided in two main areas: Pamplona, an urban area with more than 190,000 inhabitants (in the year 2012) and non-urban areas that correspond to the rest of Navarre ....
Table 2 shows the average annual percentage of change of overall brain cancer incidence rates. These results indicate a slight increase of rates during 1973 to 2008 by an AAPC of 0.5% (CI 95% 0.048%-1.005%). By gender, a significant increase of rates was also observed for women by an AAPC of 1.199% (CI 95% 0.187%-2.220%). The AAPC was not significant for male. The increase was also significant among 65-74 and 75+ age-groups, for which the highest AAPC were observed, 2.605% (CI 95% 1.016%-4.218%) and 5.885% (CI 95% 3.215%-8.625%) respectively.
Figure 3 illustrates trends in age-standardized cancer incidence rates from 1973 to 2008 and the predicted rates for 2014 in men and women (Figure 3A). An increasing trend was observed for both sexes, more pronounced in female than in male. Figure 3B shows the age-specific rate trends along the studied period and forecasts for 2014. For those under 64 years old slightly reduction of age-specific rates are observed for the last years of the studied and forecast periods, while for the oldest age-groups (65+) a sharp increase in rate is shown. For 2014, 78 incident cases of brain cancer are predicted.
The improvement on diagnostic techniques allows a more specific diagnosis of this tumour, which could have a double effect on the trends. On the one hand, improvement of diagnostic rate could lead a better morphological classification of these cancers reducing the number of unspecific malignant neoplasms. On the other hand, these techniques have contributed to a better coding of possible brain metastases that formerly could be classified as brain tumours. This could affect the trend in the opposite direction.
Some studies suggested that an exposure to electromagnetic fields or the use of mobile phones could be in association with brain cancer development. But most of the studies conclude that the association is small or non-significant. It has been also indicated that hereditary syndromes, diet and vitamins play an important role in adult brain cancers . Neither diet, tobacco smoking or alcohol consumption has been found strongly associated with increased risk or protective effects for brain cancer in adults . The brain cancer incidence rate has increased in recent years in the industrialized countries and survival is generally poor compared to many other cancers .
To summarize, age-adjusted incidence rates for brain cancer showed an increase over the study and forecast period in both sexes. This increase is mainly a reflection of the increase of rates in the oldest age groups since the rates for younger age groups remained stable or decreased over time. Few causal factors are established as a brain cancer risk factor and many others have been hypothesized. In this context it is necessary to continue promoting healthful lifestyles for primary prevention among all the population of Navarre.
Joel M. Moskowitz, Ph.D., Director
Center for Family and Community Health
School of Public Health
University of California, Berkeley
Electromagnetic Radiation Safety
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