I highly suggest you take a good look at the Natural Cancer Protocol posted below your message, as well as the Minnesota Wellness Directory post about nutrition.
Oleander has had very good success against stomach cancer. All of the other suggestions are good ones too, except that cayenne pepper is probably a questionable idea in instances of stomach cancer.
Oleander and curcumin both help lessen the negative effects of chemo and protect the immune system if one chooses to use chemo. So does essiac tea.
Remember, just because mainstream medicine and their limited options of trying to cut out, poison out or burn out the symptoms of cancer has run out of options does not mean that nature has. Thousands and thousands of people who were given up on by mainstream medicine are alive and cancer free today.