Changes in colorectal cancer incidence and mortality trends in Spain

Background: Some years ago, Spain registered a much lower colorectal cancer (CRC) incidence and mortality rate than did other European countries but the rates have since converged. This study sought to compare time trends for CRC incidence and mortality, identify change-points in these trends and thereby update available information in Spain. Methods: Incidence data were drawn from all population-based cancer registries in Spain which participated in the European Network of Cancer Registries and had been collecting data for at least 10 consecutive years during the period 1975–2004. Colorectal cancer corresponded to codes 153, 154 and 159.0 of the International Classification of Diseases ninth revision (ICD-9) and codes C18–C21 and C26.0 of the ICD-10. In all, the 13 registries included in this study cover ∼26% of the total Spanish population. We evaluated the time trends in incidence and mortality using transition change-point and age–period–cohort models. Results: Our results revealed an important increase in CRC incidence in Spain, which held constant across the entire study period but became slightly attenuated in both sexes around 1995, when a change-point was detected. The annual increase in incidence, which had been 4.3% per annum in men up to this point, declined to 2.5% thereafter. In women, the increase in incidence, albeit also of considerable magnitude, was more moderate. The incidence trend contrasted sharply with that for mortality, inasmuch as the latter changed in 1997–98, after which point mortality rates in both sexes began to decline. Conclusions: The divergence between incidence (upward trend) and mortality rates (downward trend from the mid-1990s onwards) would suggest that possible explanations may lie in improved accessibility to endoscopy increased early detection with a corresponding shift to an earlier disease stage and improvements in therapy. This trend is having important consequences insofar as disease prevalence and burden of care are concerned.