Changes in colorectal cancer incidence and mortality trends 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 similar to 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.