In a study of more than 2,400 post-menopausal women who were healthy after being treated for early stage breast cancer, those who followed a low-fat diet boosted their odds of remaining cancer-free by about 24% compared with women who stayed on their usual diets, according to research presented at the American Society of Clinical Oncology's annual meeting.

David Johnson, the oncology society's president, predicted that many doctors now will counsel patients about diet. And though cutting fat could be a challenge for many women, he said breast cancer patients could be motivated to increase their chance of a cure.

The study included only cancer patients, so scientists don't know whether low-fat diets also might help protect healthy women, Chlebowski said.

The women in the study were followed for an average of five years. The percentage of all low-fat dieters who had a recurrence of breast cancer was 9.8% compared with 12.4% for those who didn't change their diet, the study shows.

But a subset analysis found no statistically significant benefit to women with estrogen receptor-positive tumors, the most common type. Eating a low-fat diet was particularly beneficial for patients with a type of tumor whose growth isn't influenced by estrogen; they reduced their risk of relapse by 42%.

Researchers should conduct more studies to determine conclusively whether low-fat diets help all patients or mostly those with non-estrogen sensitive tumors, Chlebowski said.

In the study, women met with nutritionists to make sustainable changes, such as eating smaller portions of meat. Women on the diet limited fat to about 20% of their total calories, and non-dieters got about 29% of their calories from fat.

Dieters consumed about 18 fewer fat grams a day than non-dieters, which is about the same amount of fat as in a slice of cheesecake, said Karen Collins, a nutrition consultant for the American Institute for Cancer Research, which was not involved in the study.

Women in the study didn't change how much they exercised.

The dieters lost an average of 4 pounds, and Chlebowski said he could not rule out the weight loss as a contributing factor to the reduction of cancer risk.