Opposing trends in incidence of esophageal squamous cell carcinoma and adenocarcinoma in a multi-ethnic Asian country

Abstract

Objectives: To describe the incidence trends in esophageal squamous cell carcinoma (SCC) and adenocarcinoma among the three major ethnic groups in Singapore from 1968 to 2002.

Methods: Esophageal cancer cases in Singapore citizens and permanent residents obtained from the Singapore Cancer Registry and population data derived from the national census were used to calculate the incidence rates from 1968 to 2002.

Results: The age-standardized incidence rates (ASRs) for SCC decreased progressively from 8.31 to 3.85 per 100,000 men (p = 0.017) and from 3.43 to 0.81 per 100,000 women (p = 0.027). The rates fell for all three ethnic groups. The ASR for adenocarcinoma rose from 0 to 0.54 per 100,000 men and from 0.03 to 0.13 per 100,000 women, although these time trends did not achieve statistical significance. The frequency of regular smoking in the population decreased from 23% in 1966/1977 to 12.6% in 2004. The percentage of obesity in adults rose from 4.3% in 1982-1985 to 6.9% in 2004. The frequency of esophagitis in Singapore based on endoscopic findings increased from 3.9% in 1992 to 9.8% in 2001.

Conclusions: The decline in the incidence of SCC is likely to be associated with the known decrease in the frequency of smoking among Singaporeans. In contrast, there appears to be a trend toward an increase in the incidence of adenocarcinoma in Singapore, although the absolute incidence remains relatively low. This may be due to the associated rise in the frequency of reflux esophagitis and obesity in Singapore.