Decreasing trend in the incidence of stomach cancer in Mumbai, India, during 1988 to 1999.

The time trend in incidence of stomach cancer in males and females in Mumbai, India during 1988 to 1999 was estimated using data collected by the Bombay Population-based Cancer Registry. During the 12-year period, a total of 3657 stomach cancer cases (3.9% of all cancers) were registered by the Bombay Population-based Cancer Registry of which 2467 (5.1% of all male cancers) were in males and 1184 (2.6% of all female cancers) in females. For evaluation of the trend, we applied a linear regression model based on the logarithm of the observed incidence rates. The annual percentage changes were also computed for the incidence rates for evaluating the time trend. A statistically significant decreasing trend in the overall age-adjusted incidence rates of stomach cancer was observed during the period 1988 to 1999, with an yearly decrease of 4.44% in males and 2.56% in females. This decrease was most striking in males in the age groups 40-59 and 60+, and in females only in the age group 40-59. The probability estimates indicated that one out of every 92 men and one out of every 187 women will contract a stomach cancer at some time in their whole life and 95% of the chance is after his or her 40th birthday. The decreasing trend in the age-adjusted incidence rates of stomach cancer in both the sexes indicates that there is a critical change in the etiology of this cancer. The findings may provide clues relating to various life-style and environmental changes impacting on stomach cancer incidence.