Aspirin and other nonsleroidal antiinflammatory drugs inhibit prosi.r.'l.imlm
synthesis and tumor growth in many experimental systems, but
it is unclear which of these tumor models are relevant to humans. We have
reported reduced risk or fatal colon cancer among persons who used
aspirin in a large prospective study. This analysis examines other fatal cancers in relation to aspirin among 635,031 adults in that study who
provided information in 1982 on the frequency and duration of their
aspirin use and did not report cancer. Death rates were measured through
1988. Death rates decreased with more frequent aspirin use for cancers of
the esophagus, stomach, colon, and rectum but not generally for other
cancers. For each digestive tract cancer, death rates were approximately
40% lower among persons who used aspirin 16 times/month or more for
at least 1 year compared to those who used no aspirin. The trend of
decreasing risk with more frequent aspirin use was strongest among per
sons who had used aspirin for 10 years or more; it remained statistically
significant, except for esophagcal cancer, in multivariate analyses that
adjusted for other known risk factors. Biases such as early detection or aspirin avoidance among cases do not appear to explain the results. Our
data suggest that regular, prolonged use of aspirin may reduce the risk of
fatal cancer of the esophagus, stomach, colon, and rectum. Future epide
miológica) and basic research should examine all digestive tract cancers in
considering the chemopreventive or therapeutic potential of nonsteroidal
antiinflammatory drugs.