Foods Interfere With Colon Cancer Drugs
Red Meat and OJ Among Foods That Keep Sulindac, DFMO From Lowering Risk of Colon Polyps
Jan. 25, 2010 (Orlando, Fla.) -- A drug combination that's been found to
pack a powerful punch against the risk of colon cancer may only work in people
who go light on certain foods, including red meat, corn, and orange juice, a
new study suggests.
Two years ago, researchers reported that a combination of the targeted
cancer agent DFMO and the arthritis drug sulindac lowered the risk of colon
polyps that can lead to colon cancer.
Now, the same research team has found that the drugs' dramatic
polyp-lowering effect may be limited to people with a low intake of foods rich
in polyamines -- chemicals in food that have been linked to an increased risk
of colon cancer.
DFMO and sulindac "clearly had no benefit" in people who consume a lot of
polyamines in their diet, says researcher Kavitha Raj, MD, of the University of
The findings were presented at the 2010 Gastrointestinal Cancers Symposium
(GCS), sponsored by the American Society of Clinical Oncology and three other
Colon cancer struck about 160,000 Americans in 2009. The risk of a person
getting colon cancer in his or her lifetime is about one in 19, according to
the American Cancer Society.
The Role of Polyamines
For the new study, Raj and colleagues went back and reanalyzed data on about
200 people who participated in their original study of DFMO and sulindac. All
had at least one colorectal polyp, also known as adenomas, removed in the past
Participants were divided into four groups depending on their level of
First, the researchers analyzed tissue samples that had been taken from the
participants before they started the study. They found that compared with those
with the lowest intake, people with the highest consumption of polyamines had
larger polyps and more advanced polyps with a greater odds of going on to
Then the researchers looked at the impact of polyamine levels on the study
results. In the study, patients were assigned to treatment with either a
combination of DFMO and sulindac, or placebo.
In the original study, in which participants were not stratified by
polyamine intake, colonoscopy exams after three years showed that people who
took DFMO and sulindac were 70% less likely to develop a new polyp, compared
with people given a placebo.
The picture drastically changed when polyamines were taken into account, Raj
People in the lowest quartile of polyamine intake were 81% less likely to
have developed a new polyp than people given a placebo. They were also 89% less
likely to have large adenomas and 94% less likely to have advanced
"In people in the highest quartile of polyamine intake, however, DFMO and
sulindac had no benefit whatsoever," Raj says.