[Municipal distribution and trends in the incidence of colorectal cancer in the health area of Leon (1994-2008)]

Abstract

Background: There is an excess incidence of colorectal cancer (CRC) and mortality from this disease in the health area of Leon. The aim of the present study was to determine trends in CRC and its geographical distribution.

Methods: Cases included in the Hospital Registry of Tumors of the Centro Asistencial Universitario de León from 1994-2008 and occurring in patients residing in the health area of Leon were studied. Time trends were evaluated with a Poisson regression model. To analyze geographical distribution, the smoothed relative risks (RR) of the municipalities adjusted by the Besag, York and Mollié model were calculated, and their subsequent probability of an RR>1 (PP) was calculated using Bayesian methods.

Results: A total of 4,136 cases were included. Rates standardized to the European standard population ranged from 49.6 (1994-6) to 63.5 new cases per 100,000 inhabitants in men (2006-8) and from 29.6 to 33.8 in women. An annual 2% increase was found for all localizations, ranging from 1.8% in the rectum to 3.6% in the proximal colon. In all localizations, the increase was greater in men than in women. Several municipalities in the health area of Leon showed an excess risk. The geographical pattern observed was due especially to the distribution of colon cancer.

Conclusions: The incidence rates observed were high and were increasing. Special attention should be paid to CRC in the health area of Leon, mainly in the municipalities with excess risk.