[A 35-year report of the study of group on gastrointestinal cancer in Mexico City: variations in frequency of different digestive tract neoplasms among different socioeconomic statuses].

Background: Since the middle of the last century, North America and occidental countries have reported variations in the frequency of gastrointestinal neoplasms. Several environmental factors, mainly nutritional and dietary exposure, as well as habits have contributed to these changes. We have documented these changes in Mexico during the last 35 years.

Aims: To define the epidemiologic changes of gastrointestinal neoplasms during the last three decades in our population.

Methods: We summarized the evidence of an observational study, registering the frequency of different gastrointestinal malignancies from four institutions of socioeconomically different populations in Mexico City during 35 years. The Mexican National Academy of Medicine supported this effort. During this period, two nutritional surveys took place, letting us define the relationship between dietary changes and cancer occurrence.

Results: Replacement of gastric cancer by colorectal cancer as the leading gastrointestinal malignancy. Relationship between cancer and diet changes. Increase of esophageal adenocarcinoma in relation to epidermoid carcinoma secondary to gastroesophageal reflux and Barrett's esophagus rising incidence. Gall bladder cancer had a high frequency in one institution, probably related to genetic and racial factors.

Conclusions: This epidemiologic data should lead us to implement sanitary measures for the prevention, early diagnosis, and appropriate treatment of gastrointestinal neoplasms.