Trends in gastric and esophageal cancer incidence in northern Portugal (1994-2009) by subsite and histology, and predictions for 2015.

Introduction: Gastric cancer (GC) and esophageal cancer (EC) share risk factors, and the incidence trends reflect differences in etiology according to their subtypes. We aimed to describe the incidence trends of GC (by topography) and EC (by histological type) in northern Portugal for 1994-2009 and to estimate the incidence for 2015. We further analyzed exposure to the main risk factors for these cancers in the region over the last decades.

Methods: GC and EC data were obtained from the North Region Cancer Registry of Portugal (RORENO). Joinpoint regression was used to compute annual percent changes (APC) in incidence trends. Poisson regression yielded estimates for 2015. A literature review up to 2014 provided data on exposure to risk factors.

Results: GC rates decreased in 1994-2009 (men, APC = -1.3; women, APC = -1.6); GC, unspecified subtype, had the steepest decline since the early 2000s (men, APC = -4.9; women, APC = -6.3). The incidence for 2015 will increase for EC in men (up to ≈190 cases) and stabilize in women (≈30) and for GC (≈730 men, ≈500 women). Increasing prevalence of tobacco smoking among women and overweight/obesity, fairly stable prevalence of alcohol, fruit and vegetable consumption, and no trend for Helicobacter pylori infection were observed.

Conclusions: The declining incidence of GC unspecified subtype indicated an improvement in cancer registration accuracy, but precluded a sound assessment of trends by subtype. Variations in the prevalence of exposure to some risk factors were consistent with observed incidence trends, and future studies should aim to quantify their contribution to the GC and EC burden in the region.