Diet after treatment for ductal carcinoma of the breast

Ellen Sweeney, RD
Last Modified: August 11, 2002

Dear OncoLink "Ask The Experts,"
I was diagnosed with Stage I Invasive Ductal Carcinoma 2 years ago at age 44. Chemotherapy of Adriamycin and Cytoxin followed my mastectomy. I am currently taking Tamoxifen (my cancer was estrogen positive and progesterone negative). I want to try to do everything I know to decrease my chances of recurrence. I am very confused about what vitamins to take. Are there any vitamins or foods I should avoid that will interfere with the effectiveness of the Tamoxifen? What vitamins should I be taking to enhance my health? Are soy foods safe with my estrogen positive cancer history?

Ellen Sweeney, RD, Registered Dietitian at the Abramson Cancer Center of the University of Pennsylvania, responds:

In this situation no specific nutrients or vitamins have been found to be beneficial. However, research has shown that there are diet and life style factors that do seem to be protective against cancer in general. An article entitled "American Cancer Society Guidelines on Nutrition and Physical Activity for Cancer Prevention: Reducing the Risk of Cancer with Healthy Food Choices and Physical Activity" in the CA: A Cancer Journal for Clinicians Vol 52 No 2 p 92-119 provides a very thorough and extensive review of the impact of nutrition on reducing cancer risk.

Overall, obesity and a sedentary life style are associated with an increase risk of breast cancer. Diets that are high in vegetables and fruits may decrease risk, although the degree that they decrease risk and the specific nutrients that confer protection are still being studied. It is recommended to increase servings of fruits and vegetables to at least 5-7 servings (total) per day for the greatest nutrient benefit. Also, alcohol does slightly increase risk and should be consumed only in moderation with a maximum of one drink per day. The issue of soy is still controversial. While food sources of soy do not seem to problematic (soy milk, tofu, soy nuts, etc) the current recommendation limits soy foods to 1-2 servings per day for women with a history of estrogen positive breast cancer. Soy supplements and herbs should be avoided since the dangers of concentrated soy sources are not known and in addition, many herbs have estrogen like properties. Please refer to Are soy products linked to cancer prevention? for more information.

So, overall, the recommendation is a higher fruit and vegetable intake, less animal products (i.e. meats, animal fats, and whole milk dairy), soy in moderation, alcohol in moderation, and regular exercise to prevent weight gain and obesity.