Does eating raw fish increase your chance for stomach cancer?
No. If anything, it would pose a reduced risk of stomach cancer
relative to highly cooked foods. Highly cooked foods increase
levels of HCAs, which may increase the risk of stomach cancer. The
increase in risk is very slight from HCAs. A more important thing
to be concerned with is the possibility of contracting a food-borne
illness from consuming tainted, undercooked fish. Parasites, such
as tapeworms, can also be contracted from consuming raw fish. The
risk is small but real; most places serving raw fish take care to
make sure that the fish is properly stored, but contracting an
illness is still possible.