Washington Breast cancer victims can cut the chances their tumors will come back by adopting low-fat diets, according to the first study to produce direct evidence that a lifestyle change can fend off any type of tumor.
The study of more than 2,400 middle-aged and elderly women found that those who reduced the fat in their diets after undergoing standard treatment for early breast cancer were significantly less likely to suffer a recurrence in the next five years, researchers reported Monday.
The findings indicate that low-fat diets, which are also being tested to protect women against getting breast cancer in the first place, could become a standard weapon for fighting the disease -- the most common cancer among women.
"Many breast cancer survivors are looking for things they can do to improve their chances," said Rowan Chlebowski of the Harbor-UCLA Medical Center in Los Angeles, who led the study. "Now we have evidence women can play a role in the management of their disease."
The study provides the most powerful evidence yet that people can influence their risk of cancer by making a lifestyle change such as eating better and exercising more, experts said.
Previous research has suggested that might be the case, but the new study is the first to show a benefit from carefully changing a single behavior -- other than quitting smoking -- in a large number of patients and following them to see what happens.
"For the first time, we have scientific data about what patients can do for themselves as a lifestyle change that can significantly improve their chances," said Charles Balch, executive vice president of the American Society of Clinical Oncology, which is sponsoring the meeting in Orlando, Fla., where the findings were unveiled. "This is a highly significant advance."
Although Chlebowski and other experts said the findings needed to be confirmed by additional research, they added that breast cancer patients might consider reducing their fat intake in the meantime since such a step could have other health benefits as well.
"It's a very strong signal that lifestyle change may play a role in risk reduction," Chlebowski said in a telephone interview before his presentation.
Chlebowski noted that the diet tested in the study was designed to be practical for most people.
"It doesn't require eliminating meat from the diet or any drastic steps. It's mostly just substituting one food for another -- like eating cereal in the morning instead of a sweet roll for breakfast, cutting back on butter on bread and reducing portion sizes," he said.
Researchers are uncertain why low-fat diets might reduce the risk of cancer recurrence, but some evidence has suggested that reducing fat in the diet may cut the amount of the hormone insulin in the blood, Chlebowski said.
In addition to controlling blood sugar levels, insulin may also promote cancer growth.