Gastric adenocarcinoma trends in the central region of Rio Grande do Sul (Southern Brazil): what has changed in 25 years?

CONTEXT: Gastric cancer is the fourth most common malignancy in the world. Its incidence varies greatly by geographic region. The highest rate is in Eastern Asia, mainly in Japan and China. In Brazil, gastric cancer is the third most common cancer in males and the fifth most common cancer in females. Rio Grande do Sul state, in Southern Brazil, has similar figures. The main histological type of gastric cancer is adenocarcinoma.

OBJECTIVE

To assess the trends of this cancer over 25 years in a reference center in central Rio Grande do Sul.

METHODS

We reviewed the records of upper gastrointestinal endoscopies performed at the University Hospital of Santa Maria, RS, between 1986 and 2010. We evaluated the incidence, age and gender distribution, anatomical subsite and histological subtype of gastric cancer throughout this 25-year period.

RESULTS

We identified histologically confirmed primary gastric adenocarcinoma in 335 (1.6%) of the 20,521 patients who underwent upper gastrointestinal endoscopy during the study period. The mean age of patients was 62.4 (± 13.0) years, and 67.8% were male (a male: female ratio of 2.0:1). Cardia cancer accounted for 14.3% of the cases, and non-cardia cancer accounted for 85.7%. According to Lauren's classification, 48.1% were intestinal subtype and 40.9% were diffuse subtype. There were no differences in mean age or gender distribution by anatomical location or histological subtype. There was also no difference in the proportions of histological subtypes by anatomical location. Over the 25-year period, there was no change in the anatomical distribution of tumors, but there was a significant decrease in the intestinal subtype and a steady increase in the diffuse subtype (P = 0.02). The subset of 39 patients (11.6%) who presented at < 45 years of age was more likely to be female and to have tumors of the diffuse subtype than was the total series of patients.

CONCLUSIONS

Over this 25-year period, there were no significant trends in age, gender distribution, or the proportions of cardia and non-cardia gastric adenocarcinomas in this series of patients from Southern Brazil. There was a significant decrease in the intestinal subtype and a steady increase in the diffuse subtype of this malignancy. In patients under 45 years old, gastric cancer was more frequent in women, and the diffuse subtype predominated.