The research –presented at the recent CTRC-AACR San Antonio Breast Cancer Symposium – suggests that consumption of high carbohydrate starchy foods is associated with a greater risk for low-grade breast cancer recurrence.
The research team warned that dietary modifications targeting starch intake in breast cancer patients, “warrant further investigation as a preventive measure.”
"The results show that it's not just overall carbohydrates, but particularly starch," said Jennifer Emond, from the University of California, San Diego, USA, – who led the study.
"Women who increased their starch intake over one year were at a much likelier risk for recurring," she warned.
Emond and her colleagues noted that breast tumours over express hormone receptors known as insulin-like-growth-factor receptors (IGF-IR). These receptors are activated by growth factor hormones and help tumour cells to grow by increasing blood vessel formation.
The researchers noted that expression of IGF-IR receptors has been related to tumour grade in cancer patients.
They noted that dietary factors, particularly carbohydrate intake, have previously been suggested to stimulate activation of IGF-1R, therefore affecting the incidence and prognosis of cancer tumours.
The study included 2,651 women with breast cancer who from the Women's Healthy Eating and Living (WHEL) Dietary Intervention Trial. The team followed performed an annual check up with the women every year for an average of seven years – to assess diet and breast cancer recurrence status.
Emond and her team found that, on average, women whose cancer returned over the study period consumed an average of 2.3 more grams per day of carbohydrates during the first year of the study – while women with no recurrence consumed an average of 2.7 fewer grams of carbohydrates per day over the first year.
The team said that starches accounted for a big part of this change in carbohydrate intake, with Emond noting that changes in starch intake accounted for 48% of the variation in carbohydrate intake.
In the first year of the study, they found that women who decreased starch consumption the most had a breast cancer recurrence rate of 9.7%, while women who increased their starch consumption the most had a breast cancer recurrence rate of 14.2%.
However, after analysing patients by tumour grade, the team found the increased risk was limited to women with lower-grade tumours.
Emond said the results highlight a need for more research on dietary recommendations that consider limited starch intake among women with breast cancer.