Breast cancer recurrence, current knowledge:

The majority of research has focused on the risk of getting breast cancer and unfortunately little is known about the ways diet and lifestyle can affect cancer recurrence and prognosis. DietCompLyf is studying the diets and lifestyles of women with breast cancer in order to generate more reliable advice that can be given to patients after diagnosis, with the potential to improve prognosis and quality of life.

Herbal remedies and dietary supplements: No herbal remedy, dietary supplement or alternative therapy has been scientifically proven to treat breast cancer. More research is needed before these remedies can be recommended as some may interfere with breast cancer medicines or cause their own side effects.

Dairy: Despite some media messages, no evidence exists to support a harmful role for milk and dairy products in relation to breast cancer risk or prognosis1,2,3. As milk is a complex mixture of substances, dairy is a difficult food group to study. Some animal studies have suggested an increase in cancer cell growth with very high intakes of the milk protein IGF-1, but it is not known if this protein has the same action in humans. In contrast, high intakes of dairy products have been linked with reduced risk of pre menopausal breast cancer3. As dairy products are an important source of calcium, which is essential for bone health, moderate consumption of low-fat dairy produce is advised.

Green tea, black tea, and coffee: Teas and coffee are also difficult to study as they vary so much. There have been promising animal studies which suggest that green tea extracts work in combination with breast cancer drugs (such as tamoxifen) and have the potential to reduce treatment time and drug side effects. Further research is required to confirm these results in humans and also to establish the effects of black tea and coffee. Animal studies suggest that coffee may help with hormonal balance, but large population studies have failed to show any consistent connection between breast cancer risk (or recurrence) and coffee consumption4,5.

Fat: Fat in the diet has been studied but it is still not clear if the total amount of fat eaten is a cause of postmenopausal breast cancer6. The type of fat however, may play a role and is a focus of current research. Consuming less saturated fats (found in butter, lard, ghee, and meat) and trans-fats (found in stick margarine, vegetable shortening and most store bought cakes and biscuits) is generally advised for a healthier lifestyle.

Alcohol: There is convincing evidence that alcoholic drinks can increase the risk of both pre and post menopausal breast cancer6. Epidemiological studies investigating the role of alcoholic drinks on prognosis, however, have been conflicting. Some studies have shown a link between reduced survival following breast cancer with increasing amounts of total alcohol intake6,7 while others have either shown improved prognosis8 or no effect9. Until a scientific consensus has been reached it is advisable that any alcohol consumption should be low or moderate.

Physical activity and weight: There is ample evidence that physical activity reduces the risk of post-menopausal breast cancer, but the link is less clear for pre menopausal breast cancer10. Being overweight, and having excess weight around the stomach is related to post menopausal but not pre menopausal breast cancer10. Keeping active, eating a balanced and low fat diet to maintain a healthy weight and limiting alcohol intake, are all important for general health and wellbeing, and may also reduce the risk of breast cancer recurrence.

Please contact your health professional if you would like advice on diet and lifestyle. Or see: www.cancerhelp.org.uk

[1] J National Cancer Inst 2002;94:17:p78.

[2] J Natl Cancer Inst. 2002;94:17:p1301

[3] Arch Intern Med 2007; 167:p1050

[4] Ann Epidemiol 2001;12: p21.

[5] Ann Epidemiol 2006; 16:p503.

[6] Cancer Causes Control 2002;13:p543.

[7] Cancer Causes Control. 2001;12:p895.

[8] J Clin Oncol. 2008 ;26:p3310.

[9] Int J Cancer. 2008 Nov 1;123(9):2188-94.10: World Cancer Research Fund, AICR. Food, nutrition, physical activity, and the prevention of cancer: a global perspective. Washington DC:AICR, 2007.