Diet, Recurrence RIsk, and Hot Flashes
I just reread a commentary in the Journal of Clinical Oncology regarding a large study by Gold et al on the association between dietary changes and breast cancer recurrence in women who were not experiencing hot flashes. Although the results were inconclusive and the studied population small and specific, this topic is of interest to many of us. How great it would be if we really knew that what we eat makes an impact on our cancer health (and we don't know that). Here is a summary, followed by a link if you want to read more.
Dietary Changes After Breast Cancer in Women
Way to Target Tumor and Host?
Matteo Puntoni, Medical Oncology Unit, Galliera Hospital; and Biostatistics Unit, Department of Health Sciences, University of Genoa, Genoa, Italy Bernardo Bonanni, Division of Cancer Prevention and Genetics, European Institute of Oncology, Milan, Italy Andrea Decensi, Medical Oncology Unit, Galliera Hospital, Genoa; and Division of Cancer Prevention and Genetics, European Institute of Oncology, Milan, Italy
One of the questions medical oncologists most frequently hear from patients recently diagnosed with breast cancer is whether dietary changes can help reduce the risk of disease recurrence. This is a pertinent question, and one that remains an unsettled scientific and clinical issue. The hypothesis of a negative influence of dietary fat and glucose load and of a beneficial effect of fiber, vegetable, and fruit consumption on breast cancer risk has existed for decades, even though epidemiologic evidence is not unanimous and a large primary prevention trial of a low-fat dietary modification has so far shown only a limited benefit.
Likewise, observational studies of the influence of dietary fat on breast cancer recurrence have yielded mixed results, with some suggesting a direct association of higher fat intake with risk of recurrence in postmenopausal women.
In this issue of Journal of Clinical Oncology, Gold et al demonstrate a disease-free survival advantage after dietary changes inwomen with early breast cancer without hot flashes at baseline. The article is a secondary analysis of the Women's Health Eating and Living study, a randomized trial testing whether a diet high in vegetables, fruit, and fiber and low in fat influenced prognosis in breast cancer survivors.
The primary analysis of the trial did not reveal any disease-free survival benefit after the dietary pattern change. However, on the basis of subsequent findings of improved disease-free survival in women with hot flashes (HF) undergoing tamoxifen treatment and higher circulating estradiol levels in patients without hot flashes (HF), the authors conducted a secondary analysis to test whether the dietary intervention had a beneficial effect on breast cancer recurrence in the HF subgroup (ie, those women with potentially higher estrogen levels and worse prognosis).
Nearly 3,000 women 18 to 70 years of age with operable breast cancer were randomly assigned to a dietary intervention or comparison group within 4 years of diagnosis. Women were analyzed for this study if they had hot flash status ascertained at baseline (n 2,967) with mean follow-up of 7.3 years. The intervention group underwent telephone counseling and attended cooking classes (approximately 1/month), whereas the control group was advised to eat five servings of fruit and vegetables daily. For women who were HF at baseline, a similar proportion (approximately 35%) had received adjuvant chemotherapy in both arms, whereas more women randomly assigned to the dietary intervention had received adjuvant tamoxifen, had had a prior oophorectomy, and had prior menopause hormone therapy.
Regardless of baseline hot flash status, the intervention group changed their dietary habits significantly. Although no weight loss was reported, fiber consumption rose by 33%, fruit servings by 20%, daily vegetable servings doubled, and energy from fat was reduced by 20%. After controlling for tumor characteristics and antiestrogen treatment, the HF women assigned to the diet intervention arm were 31% less likely than the HF women assigned to the control arm to have a breast cancer event (hazard ratio [HR] 0.69; 95% CI, 0.51 to 0.93). There was no differential effect according to hormone receptor subtype. The diet intervention did not influence prognosis in HF women. Both the intervention and comparison arms in the HF group had a better prognosis than the HF group. The conclusions drawn were as follows: a diet high in fiber, fruit, and vegetables, and with reduced fat improved recurrence-free survival inwomenwithout hot flashes at baseline and presumably with higher estrogen levels; and HF women had a worse prognosis than HF patients, regardless of the dietary intervention arm.
The study provides interesting findings on a thus far rather overlooked hormonal variable, namely the presence of hot flashes and its impact on the risk of breast cancer recurrence. Indeed, this vasomotor symptom may well turn out to be a significant prognostic and predictive factor for breast cancer, and possibly even a risk determinant for breast cancer in unaffected women. The study shows that a dietary intervention that curbed fat calories and increased vegetables, fruit, and fiber was effective in reducing recurrence by 30% overall and up to 47% in postmenopausal women, with a possible risk reduction of death from any cause in HF women. In the era of molecular signatures and pathways, this simple, host-related natural symptom may provide a different paradigm for our breast cancer treatment and prevention strategies, through a proactive and inexpensive treatment method that includes, in addition to conventional targeted drug therapy, a holistic approach on the basis of healthier eating habits, weight loss, and increased physical activity.
The latest version is at http://jco.ascopubs.org/cgi/doi/10.1200/JCO.2008.19.7764