TUESDAY, Aug. 14, 2007 (HealthDay News) -- Colon cancer patients who eat a diet rich in fruits, vegetables, poultry and fish can significantly lower the risk of their cancer returning, new research suggests.
"We know a lot about how certain dietary things affect the risk of developing colon cancer in the first place but we didn't know, before this study, how diet affected persons who already have cancer," explained study author Dr. Jeffrey A. Meyerhardt, an assistant professor of medicine at the Dana-Farber Cancer Institute in Boston.
Although the findings, which appear in the Aug. 15 issue of the Journal of the American Medical Association, need confirmation, colon cancer patients might want to consider improving their eating habits.
"This is not a substitute for standard therapy, but it's not unreasonable for oncologists to use this data to start talking about diet," Meyerhardt said. "There are benefits in other regards, such as benefits for heart disease, and it does give us some initial information that may affect people's outcome."
"Maybe the message is it's never too late to change your diet," added Dr. Andrejs Avots-Avotins, an associate professor of internal medicine at Texas A&M Health Science Center College of Medicine and a gastroenterologist with Scott & White Hospital in Temple, Texas. "A healthy diet is going to be so helpful in so many different ways that even if you do end up with a cancer that may or may not have been related to your diet, this may be of benefit in prolonging your survival."
Diet and other lifestyle factors have been strongly implicated in the risk of developing colon cancer. It's been less clear what effect diet has on the course of established colon cancer.
The authors asked 1,009 patients with stage III colon cancer (cancer that had spread to the lymph nodes) who were participating in a chemotherapy trial to answer dietary questionnaires during and after the time they received treatment. All participants had already undergone surgery to remove the cancer.
The study was funded partially by the U.S. National Cancer Institute and Pfizer Oncology.
Two major dietary patterns were identified: Western (high intakes of meat, fat, refined grains and dessert) and prudent (lots of fruits and vegetables, poultry and fish).
A Western diet was associated with a significantly worst prognosis, both in terms of recurrence and death, than a prudent diet.
Compared with patients ranked in the lowest 20 percent of a Western dietary pattern, those in the highest 20 percent had almost three-and-a-half times the risk of recurrence or death. Those in the highest 20 percent of a Western diet were also 2.9 times more likely to see their cancer recur than those in the lower 20 percent.
"There's a biological basis for this. The Western type of diet affects insulin levels and insulin-like growth factors that help promote cancer's growth and metastases," Meyerhardt explained. "The magnitude of the effect was surprising, however."
Visit the U.S. National Cancer Institute for more on colon and rectal cancer.