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
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.
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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.Pharmacoepidemiology and Drug Safety 12/2013; 22(12). DOI:10.1002/pds.3523 · 2.94 Impact Factor
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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.Nutrition and Cancer 12/2013; 66(2). DOI:10.1080/01635581.2014.863366 · 2.32 Impact Factor
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ABSTRACT: Epidemiological data suggest a close link between obesity and breast cancer, the most frequently occurring cancer in women. The metabolic syndrome is typically associated with abdominal obesity and comprises disturbances in glucose and/or lipid metabolism and/or hypertension. Recent studies have established a specific association between the metabolic syndrome - as well as its components - and breast cancer, indicating both an increased risk of developing breast cancer and a poorer prognosis. In premenopausal women, obesity might have a protective effect only on receptor-positive tumors, whereas a positive association was observed between obesity/abdominal obesity and an increased risk of triple-negative breast cancer (TNBC). Overall survival and disease-free survival were reported to be significantly shorter in premenopausal obese women with TNBC compared to non-obese women, but these results are still inconsistent and need further research. The metabolic syndrome is characterized by a state of insulin resistance/hyperinsulinemia and subacute chronic inflammation, with both conditions offering a plausible mechanistic link towards breast cancer. Thus, in addition to their increased risk of cardiovascular morbidity and mortality, women with this syndrome represent a group at elevated risk of developing breast cancer and with poorer prognosis.Breast Care 04/2014; 9(4):277-81. DOI:10.1159/000365951 · 0.63 Impact Factor
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