Obesity and Its Impact on Breast Cancer.

the Department of Epidemiology & Population Health, Albert Einstein Cancer Center, Albert Einstein College of Medicine, Bronx, NY.
American Society of Clinical Oncology educational book / ASCO. American Society of Clinical Oncology. Meeting 01/2013; 2013:52-59. DOI: 10.1200/EdBook_AM.2013.33.52
Source: PubMed


A positive association between obesity and the risk of incident postmenopausal breast cancer has been consistently observed in epidemiologic studies. Although most studies of premenopausal women have not found a similar relationship between breast cancer and obesity, the prognosis for both pre- and postmenopausal breast cancer is substantially worse among obese than normal-weight individuals. Increasing evidence suggests that these associations may be mechanistically related to sex hormones, insulin, and certain adipokines. Insulin, for example, has important mitogenic/antiapoptotic activity in addition to its metabolic effects, and many breast tumors express high levels of the insulin receptor (IR)-A isoform. Further, the use of metformin, a diabetes medication that reduces insulin levels, has been epidemiologically associated with reduced breast cancer risk among patients with diabetes, and a recent observational study found a higher rate of pathologic complete responses among patients with diabetes and breast cancer who were using metformin. Formal clinical trials of metformin as adjuvant breast cancer therapy have been initiated and are ongoing. Similarly, the effect of lifestyle changes on breast cancer outcomes is actively being investigated. Several lifestyle intervention studies have demonstrated that weight loss, increased physical activity, and dietary changes are feasible in breast cancer populations, and that individuals who make lifestyle changes after breast cancer diagnosis experience several physical and psychologic benefits. In this article, the authors review the evidence linking obesity with breast cancer risk and outcomes and provide an overview of lifestyle intervention studies in patients with breast cancer.

1 Follower
6 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: Obesity is associated with an increased risk of breast cancer, and increased risk of recurrence in women who develop breast cancer. Evidence suggests that the risk of estrogen-receptor (ER)-positive breast cancer is increased in obese postmenopausal women, whereas in premenopausal women the risk of triple negative breast cancer is increased. Nonetheless, the presence of obesity at diagnosis, and possibly weight gain after diagnosis, may independently contribute to an individual's risk of recurrence of both pre- and postmenopausal breast cancer. Factors associated with adiposity that are likely contributing factors include hyperinsulinemia, inflammation, and relative hyperestrogenemia. Some studies suggest that some aromatase inhibitors may be less effective in obese women than lean women. Clinical trials have evaluated pharmacologic (eg, metformin) and dietary/lifestyle interventions to reduce breast cancer recurrence, although these interventions have not been tested in obese women who may be most likely to benefit from them. Further research is required in order to identify adiposity-associated factors driving recurrence, and design clinical trials to specifically test interventions in obese women at highest risk of recurrence.
    No preview · Article · Nov 2013 · Journal of Mammary Gland Biology and Neoplasia
  • [Show abstract] [Hide abstract]
    ABSTRACT: We conducted a nested case-control study to evaluate the association between risk of cancer and mirtazapine use in depression patients in Taiwan. We obtained data from the Taiwan National Health Insurance Research Database to conduct a population-based nested case-control study. The study cohort included 16 897 patients diagnosed with depression between January 1, 2000 and December 31, 2008. We identified 530 cancer patients as the study group and matched 4 non-cancer subjects with each cancer patient by incident density, age, and sex. Odds ratios and 95% confidence intervals were estimated using multivariate conditional logistic regression analysis. Use of mirtazapine for depression did not have significant effect on overall cancer incidence (odds ratio: 1.03, 95% confidence interval: 0.72-1.48). Further analysis of annual mirtazapine dosages and the duration of mirtazapine use revealed no significant effect on cancer risk. The findings of this population-based nested case-control study suggest that mirtazapine use may not provide a tumor suppression effect in humans such as that seen in the animal model. Future large-scale and in-depth investigations in this area are warranted. Copyright © 2013 John Wiley & Sons, Ltd.
    No preview · Article · Dec 2013 · Pharmacoepidemiology and Drug Safety
  • [Show abstract] [Hide abstract]
    ABSTRACT: Triple negative breast cancer (TNBC) comprises approximately 15% of breast cancers and is associated with a poor prognosis. Many patients with TNBC relapse quickly and commonly develop metastases. There are no individualized targeted adjuvant or induction treatments for TNBC, and the current treatments are highly toxic. Development of chemoprevention methods using natural products would be beneficial to patients at risk of TNBC. To investigate the inhibitory effect of blueberries on inflammation-induced TNBC and identify the mechanism underlying modulation of inflammatory proteins by blueberries, we induced a proinflammatory microenvironment by feeding female MDA-MB-231 tumor-bearing mice a high fat western diet (W) with 5% whole blueberry powder (BB) and studied the effect on tumor formation and metastasis. We showed that mice fed a BB diet had significantly smaller tumors, less ulceration, and significantly less metastasis to the inguinal lymph nodes than mice fed a W diet. In BB-fed mice, serum levels of specific antiinflammatory cytokines were increased and specific cytokine expression was also altered. Together, these results suggest that blueberries may inhibit TNBC and TNBC-related metastasis by reducing inflammation via specific cytokine-driven pathways and thus reduce tumor growth and metastasis.
    No preview · Article · Dec 2013 · Nutrition and Cancer
Show more