Colon cancer survivors should stick to a 'prudent' diet

Aug 14 2007

A new study has revealed that colon cancer survivors who consume a diet rich in red meat and fatty foods are three times more likely to experience a recurrence of their disease or die from it than those who avoid such foods.

The study by researchers from the Dana-Farber Cancer Institute in Boston and Harvard Medical School found that diet has a significant impact on whether colon cancer returns in people previously treated for it.

It has been shown in previous studies that a high-fat diet, in particular one with an abundance of red meat, may increase a person's risk of developing colon cancer.

This latest study is however the first to demonstrate that diet affects whether colon cancer returns in people who have already been treated for it.

For the study the researchers tracked 1,009 people treated with both surgery and chemotherapy for stage III colon cancer which is cancer that has spread from the large bowel area to the lymph nodes but not to other organs.

The group were followed over the course of five years and provided information on eating habits and diet.

The resulting data enabled the researchers to distinguish two distinct dietary patterns, a "western" pattern with lots of red and processed meats, sweets, desserts, French fries and refined grains; and a more "prudent" pattern avoiding those foods and including lots of fruit and vegetables, poultry and fish.

The research team found that those who most closely followed the "western" pattern experienced a risk more than 3 times higher for colon cancer recurrence or death than those following the "prudent" one.

The researchers say it is unclear why such a diet is associated with a poorer outcome, but they suggest that it may be related to increased insulin levels and insulin-like growth factors; insulin and related growth factors have been linked to the formation and growth of some types of tumors.

Dr. Jeffrey Meyerhardt who led the study, is an assistant professor of medicine at Harvard Medical School and he says it is already known that a variety of dietary factors affect people's risk of developing colon cancer, including high red meat intake and certain sugary foods; but he says what was unknown until now was how those factors affect people who already have colon cancer.

Meyerhardt says many colon cancer victims seek advice on diet following treatment to improve their outcomes and as a dietitian, he would not recommend the 'western' dietary pattern but instead recommend people choose a diet rich in fruits, vegetables, whole grains, low-fat dairy, and lean meats, such as lean beef.

Experts have welcomed the research as along with rectal cancer, colon cancer accounts for about 50,000 deaths annually in the United States alone.

The research is published in the Journal of the American Medical Association and was funded in part by grants from the National Cancer Institute and Pfizer Oncology.