Jeffrey Meyerhardt, MD
Colon cancer patients who eat a diet high in red meat, fatty
products, refined grains, and desserts — a so-called "Western" diet —
may be increasing their chance of disease relapse and early death,
report researchers at Dana-Farber Cancer Institute.
The study, published in the Aug. 15 issue of the Journal of the American Medical Association,
involved 1,009 patients with stage III colon cancer that has been
treated with both surgery and chemotherapy. Stage III colon cancer is
characterized as being localized to the large bowel area with cancer
cells in the lymph nodes near the tumor. The investigators found that
those who most closely followed a Western diet were three-and-a-half
times more likely to have colon cancer recur than those whose diets were
"We know from previous research that diet and lifestyle influence
people's risk of developing colon cancer," says the study's lead author,
Jeffrey Meyerhardt, MD, MPH, of Dana-Farber. "This is the first large
observation study to focus on the role of diet in recurrence of the
disease. Our results suggest that people treated for locally advanced
colon cancer can actively improve their odds of survival by their
The participants, who were enrolled in a large, phase III clinical
trial sponsored by the National Cancer Institute of follow-up
("adjuvant") chemotherapy, had their tumors surgically removed within
the two months prior to enrolling in the study. They reported their
dietary intake on specially designed questionnaires at two different
time points – during the period they were receiving chemotherapy and six
months after the completion of chemotherapy.
Meyerhardt and his colleagues identified two major dietary trends
within the group: A "prudent" pattern characterized by high intakes of
fruits and vegetables, poultry, and fish, and a "Western" pattern
characterized by high amounts of red and processed meats, sweets and
desserts, French fries, and refined grains. Participants didn't fall
neatly into one category or the other, but were scored in each by how
closely they matched the Western and prudent models.
The survival benefit for those whose diets least resembled the
Western pattern held true even after researchers controlled for factors
such as gender, age, body mass, degree of cancer spread to lymph nodes,
and physical activity level. Investigators do not know why such a diet
is associated with a poorer outcome, but speculate 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.
In contrast to the negative effect of a Western diet, researchers
found that following a prudent-pattern diet did not significantly
influence cancer recurrence or mortality. "The message is that patients
in this category can improve their prospects by avoiding certain foods,"
comments Meyerhardt, who is also an assistant professor of medicine at
Harvard Medical School. Meyerhardt adds that more research is needed to
better understand what components of diet are most responsible for the
study findings, and why.
The senior author of the study is Charles Fuchs, MD, MPH, of
Dana-Farber. The co-authors are Robert Mayer, MD, of Dana-Farber; Donna
Niedzwiecki, PhD, and Donna Hollis, MS, of Duke University School of
Medicine; Leonard Saltz, MD, of Memorial Sloan-Kettering Cancer Center;
Frank Hu, MD, PhD, of Brigham and Women's Hospital; Heidi Nelson, MD, of
the Mayo Clinic Foundation; Renaud Whittom, MD, of Hopital du
Sacre-Coeur, in Montreal; Alexander Hantel, MD, of Loyola University
Chicago Stritch School of Medicine; and James Thomas, MD, of the
University of Wisconsin.
The study was funded in part by grants from the National Cancer Institute and Pfizer Oncology.
Dana-Farber Cancer Institute (www.dana-farber.org)
is a principal teaching affiliate of the Harvard Medical School and is
among the leading cancer research and care centers in the United States.
It is a founding member of the Dana-Farber/Harvard Cancer Center
(DF/HCC), designated a comprehensive cancer center by the National