Long-term trends in the incidence rates of upper digestive tract cancer in the Netherlands Antilles.

Data from the Cancer Registry in the Netherlands Antilles made clear that the incidence rate of cancer of the upper digestive tract in this country was among the highest in the world. To study the long-term trends in the incidence rate a retrospective population-based case-finding survey was performed. The author presents the results of the period 1958 to 1981; data from earlier periods appeared to be incomplete. The highest incidence rates were found in the indigenous populations of Curaçao and Bonaire. In the period studied, the rates of oral and esophageal cancer dropped approximately 3% per year, while a shift was seen towards a later onset of the disease. A breakdown of the rates by island of residency showed that the decline was highly significant only for the population of Curaçao, the main island, with 89% of the total population studied. The presence of a downward trend on the other islands might be obscured by the small size of the populations. No significant change was found in the incidence rate of pharyngeal cancer, although a tendency toward lower rates was observed. Abuse of alcohol and tobacco, mineral deficiencies, malnutrition, the use of sorghum in the daily diet, and reverse smoking by females, are factors believed to be responsible for high rates in the past. With the exception of abuse of alcohol and tobacco, these factors have changed considerably in a favorable direction. It has been claimed that these changes have contributed to the sharp decrease in the incidence rates of oral and esophageal cancer.