August 21, 2007
American Cancer Society

What You Eat May Influence Colon Cancer Relapse

Diet High in Meats, Sweets Linked to Higher Risk

Summary: People treated for colon cancer may want to watch what they eat. A diet heavy with red meat, fatty foods, and desserts may put these survivors at greater risk of having their disease return, a new study suggests.

Why it's important: Colon cancer often can be treated successfully with surgery, chemotherapy, radiation, or some combination of these. If diet also has an impact on whether the colon cancer comes back, survivors may be able to improve their odds by watching what they eat, researchers from the Dana-Farber Cancer Institute say.

What's already known: Many studies have shown that what people eat can influence whether they develop colon cancer later in life. A high-fat diet, especially one that includes a lot of animal fat and red or processed meat, can raise a person's risk of developing colon cancer. However, less is known about how diet impacts people who have already had colon cancer. The few studies that have looked at this issue so far have had mixed findings.

What has been shown to have an impact? Body weight and exercise. There is evidence that people who weigh too much have shorter survival than people at a healthy weight, while people who get more physical activity seem to do better than sedentary survivors.

How this study was done: To get a better idea of the relationship between diet and colon cancer survival, the Dana-Farber researchers and colleagues from several other institutions studied people with stage III disease (colon cancer that has spread to the lymph nodes, but not distant parts of the body). All the participants had been treated with surgery and were taking part in a separate clinical trial testing 2 different types of chemotherapy given after surgery. During chemo and 6 months afterward, the participants answered questionnaires about their eating habits. They were followed on average for more than 5 years. The findings were published in the Journal of the American Medical Association.

What was found: The researchers looked at the effects of 2 main eating patterns: what they called a "prudent" diet -- high in fish, poultry, fruits, and vegetables -- and a "Western" diet -- high in red meat, fat, processed grains, French fries, and dessert. People who ate the most of these Western foods had almost 3 times the risk of their colon cancer returning compared to people whose diets were least Western. They also had a higher risk of dying from any cause. Their risk remained high even after the researchers controlled for factors like age, body mass index, exercise, number of lymph nodes affected by cancer, and what type of chemotherapy they received.

There were no significant differences in deaths or colon cancer recurrences based on how closely people followed the "prudent" diet. Still, lead researcher Jeffrey Meyerhardt, MD, MPH, says "patients in this category can improve their prospects by avoiding certain foods."

The bottom line: The study does not prove that a Western diet causes colon cancer recurrence, Meyerhardt and his coauthors stress. But it does suggest that watching what you eat can have some impact. More research is needed to figure out which aspects of each diet are the most harmful or helpful.

However, there are many good reasons for colon cancer survivors to eat healthfully, says Colleen Doyle, MS, RD, director of nutrition and physical activity for the American Cancer Society. A diet rich in fruits, vegetables, and whole grains that also limits refined grains, saturated fat and sugars can help reduce their risk of heart disease and other types of cancer, she notes.

Colon cancer survivors should try to maintain a healthy weight and get regular exercise. More information is available in the latest American Cancer Society guide for nutrition and physical activity during and after cancer treatment.