Changing Patterns of Gastric Cancer in Cali, Colombia.

The Population based Cancer Registry of Cali, Colombia has been in continuous operation since 1962. The RPCC have contributed data to be published in all nine volumes of Cancer Incidence in Five Continents.

Study objective- To describe time trends in gastric cancer incidence in Cali, and to investigate time period and birth cohort as determinants of such trends.

Methods: Incidence data for the period 1962-2007 were obtained from the RPCC database. The analysis was based on 11518 cases of invasive cancer, 91.3% were stomach and remaining in the esophagus. Trends of rates were evaluated by the annual percentage change (APC), using the weighted least squares method. Age, period and cohort curvature trends for stomach cancer incidence were estimated through the Poisson Regression model proposed by Holford.

Results: The overall gastric incidence rate fell in males and females through 1926-2007, with corresponding APCs of -1.7[CI95%:-1.9;-1.5] and -1.6[CI95%:-1.9;-1.4]. There was an increase from 0.2 to 1.3/100 000 of tumours of the cardias and 0.2 to 0.4 for tumours of the esophagus (distal). The incidence rates were stables in esophagus (proximal). Stomach (non-cardias) cancer incidence significantly decreased for males and females, with corresponding APCs of -1.8[CI95%:-2.0;-1.6] and 1.6[CI95%:-1.8;-1.3]. The risk of developing stomach cancer declined in generations born between 1890 and 1960 and rose in subsequent birth cohorts in both sexes.

Conclusion: Trends in stomach cancer rates seem to be mainly linked to birth cohort effect.