Obesity and Breast Cancer: Not Only a Risk Factor of the Disease
- 1.4k Downloads
Obesity not only is an independent risk factor of postmenopausal breast cancer (BC), and in particular estrogen receptor-positive/progesterone receptor-positive BC, it is also a prognostic factor of the disease. Substantial evidence has shown that obesity, as measured by body mass index (BMI) is linked to BC outcomes. All-cause and BC-specific mortality risk increase for each BMI unit increase in pre- and postmenopausal BC survivors is estimated to range from 8 to 29 %, depending on when BMI is ascertained. The positive associations in pre- and postmenopausal BC and in hormone receptor-positive and hormone receptor-negative BC are not significantly different. Furthermore, the negative impact of abdominal obesity on BC survival highlights the need of using fat distribution (waist circumference, waist-hip-ratio) as well as general obesity (BMI) to evaluate prognosis in the clinical setting. More research is needed to elucidate possible differential associations in pre- and postmenopausal BC that are defined by hormone receptor and/or human epidermal growth factor receptor (HER), and in advanced tumors; for which the data are limited and less clear. Current evidence on treatment toxicity supports the guidelines from the American Society for Clinical Oncology, which recommends the use of full weight-based chemotherapy to treat obese cancer patients. Several studies have shown that lifestyle interventions are feasible and safe; more research is needed on specific diets for health maintenance and weight loss in BC survivors. Being physically active (≥150 min/week of moderate intensity activity) helps manage body weight (normal BMI 18.5–24.9 kg/m2), improves survival, and has secondary health benefits. Oncologists should recommend their patients to be physically active and control body weight when the conditions of the patient allow it.
KeywordsGeneral obesity Abdominal obesity Breast cancer prognosis Lifestyle modifications
Compliance with Ethics Guidelines
Conflict of Interest
Doris S.M. Chan and Teresa Norat declare that they have no conflict of interest.
Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
References and Recommended Reading
Papers of particular interest, published recently, have been highlighted as: • Of importance •• Of major importance
- 1.GLOBOCAN. GLOBOCAN 2012: estimated cancer incidence, mortality and prevalence worldwide in 2012. 2012. Available at http://globocan.iarc.fr/Pages/fact_sheets_cancer.aspx. Accessed 3 Nov 2014.
- 2.American Cancer Society. Cancer treatment and survivorship facts & figures 2014–2015. Atlanta: American Cancer Society; 2014.Google Scholar
- 5.World Cancer Research Fund/American Institute for Cancer Research. Food, nutrition, physical activity, and the prevention of cancer: a global perspective. Washington DC: AICR; 2007.Google Scholar
- 26.•Ligibel JA, Alfano CM, Courneya KS, et al. American Society of Clinical Oncology position statement on obesity and cancer. J Clin Oncol. 2014;32:3568–74. In recognition of the significance of obesity in cancer prognosis, ASCO has released this position statement to feature the multipronged initiative to combat obesity.PubMedCrossRefGoogle Scholar
- 27.••American Society of Clinical Oncology. Obesity and cancer. A guide for Oncology Providers. 2014. Available at http://www.asco.org/sites/www.asco.org/files/obesity_provider_guide_final.pdf. Access 3 Nov 2014. This is one of the tools provided by ASCO to help oncology providers address obesity with their patients. Strategies to promote weight loss and/or prevention of weight gain in cancer survivors are provided.
- 28.World Health Organization. Global database on body mass index. BMI classification. 2014. Available at http://apps.who.int/bmi/index.jsp?introPage=intro_3.html. Accessed 3 Nov 2014.
- 29.•Chan DS, Vieira AR, Aune D, et al. Body mass index and survival in women with breast cancer-systematic literature review and meta-analysis of 82 follow-up studies. Ann Oncol. 2014;25:1901–14. This systematic review provided supporting evidence that higher BMI is consistently associated with lower survival in BC survivors before and after cancer diagnosis.PubMedCentralPubMedCrossRefGoogle Scholar
- 35.Cancer Progress.Net. Progress Against Breast Cancer. 2014. Available at http://www.cancerprogress.net/sites/cancerprogress.net/files/category-downloads/progress_against_breast_cancer_timeline.pdf. Accessed 3 Nov 2014.
- 44.Sturtz LA, Melley J, Mamula K, et al. Outcome disparities in African American women with triple negative breast cancer: a comparison of epidemiological and molecular factors between African American and Caucasian women with triple negative breast cancer. BMC Cancer. 2014;14:62.PubMedCentralPubMedCrossRefGoogle Scholar
- 49.Christiansen N, Chen L, Gilmore J, et al. Association between African American race and outcomes in patients with nonmetastatic triple-negative breast cancer: a retrospective analysis by using results from the Georgia Cancer Specialist Database. Clin Breast Cancer. 2012;12:270–5.PubMedCrossRefGoogle Scholar
- 57.von Drygalski A, Tran TB, Messer K, et al. Obesity is an independent predictor of poor survival in metastatic breast cancer: retrospective analysis of a patient cohort whose treatment included high-dose chemotherapy and autologous stem cell support. Int J Breast Cancer. 2011;2011:523276. doi: 10.4061/2011/523276.Google Scholar
- 58.World Health Organization. Waist circumference and waist-hip ratio: report of a WHO Expert Consultation. Geneva; 2008.Google Scholar
- 59.••World Cancer Research Fund International. Continuous Update Project Report: diet, nutrition, physical activity, and breast cancer survivors; 2014. This report published by WCRF contains lifestyle recommendations to BC survivors, based on evidence of body fatness and physical activity along with other dietary factors and survival in women with BC.Google Scholar
- 60.•George SM, Bernstein L, Smith AW, et al. Central adiposity after breast cancer diagnosis is related to mortality in the Health, Eating, Activity, and Lifestyle study. Breast Cancer Res Treat. 2014;146:647–55. Results from the HEAL study support the role of body fat distribution in BC survival. The association may be mediated by insulin resistance and inflammation.PubMedCrossRefGoogle Scholar
- 62.•Fontanella C, Lederer B, Gade S, et al. Impact of body mass index on neoadjuvant treatment outcome: a pooled analysis of eight prospective neoadjuvant breast cancer trials. Breast Cancer Res Treat. 2015;150:127–39. Results from this pooled analysis of 8,872 BC patients in 8 neoadjuvant trials show that higher BMI was associated with lower pCR and a detrimental impact on survival; chemotherapy compliance and dosage may partly explain the results.PubMedCrossRefGoogle Scholar
- 64.•Hourdequin KC, Schpero WL, McKenna DR, et al. Toxic effect of chemotherapy dosing using actual body weight in obese versus normal-weight patients: a systematic review and meta-analysis. Ann Oncol. 2013;24:2952–62. This systematic review supports the use of full weight-based chemotherapy doses in obese patients with solid tumors, based on the findings of 12 relevant studies that showed similar or lower rates of toxic effects, and similar survival outcomes compared with normal weight patients.PubMedCrossRefGoogle Scholar
- 68.Pfeiler G, Stoger H, Dubsky P, et al. Efficacy of tamoxifen +/- aminoglutethimide in normal weight and overweight postmenopausal patients with hormone receptor-positive breast cancer: an analysis of 1509 patients of the ABCSG-06 trial. Br J Cancer. 2013;108:1408–14.PubMedCentralPubMedCrossRefGoogle Scholar
- 77.•Goodwin PJ. Obesity and endocrine therapy: host factors and breast cancer outcome. Breast. 2013;22 Suppl 2:S44–7. This article is a concise review of the RCTs that evaluated the impact of BMI in the aromatase inhibitor (AI) efficacy in BC patients and concluded that the findings do not support the use of BMI as a predictor of AI vs. tamoxifen benefit in the adjuvant setting in postmenopausal BC.PubMedCrossRefGoogle Scholar
- 83.••Goodwin PJ, Parulekar WR, Gelmon KA, et al. Effect of metformin versus placebo on weight and metabolic factors in initial patients enrolled onto NCIC CTG MA.32, a multicenter adjuvant randomized controlled trial in early-stage breast cancer (BC). J Clin Oncol. 2013;31. NCIC CTG MA.32 published promising preliminary results that showed non-diabetics early-stage BC patients using metformin had improved body weight and obesity-related biomarkers compared with placebo.Google Scholar
- 88.••Rock CL, Doyle C, Demark-Wahnefried W, et al. Nutrition and physical activity guidelines for cancer survivors. CA Cancer J Clin. 2012;62:243–74. This report published by the ACS summarizes the findings on the scientific evidence and best clinical practices related to optimal nutrition and physical activity after the diagnosis of cancer and contains useful lifestyle recommendations for cancer survivors.PubMedCrossRefGoogle Scholar
- 89.••Courneya KS, Segal RJ, McKenzie DC, et al. Effects of exercise during adjuvant chemotherapy on breast cancer outcomes. Med Sci Sports Exerc. 2014;46:1744–51. START is the first aerobic or resistance exercise intervention to publish results on BC survival endpoints, which showed promising results of improved survival compared with patients who received usual care during adjuvant treatment.PubMedCrossRefGoogle Scholar
- 90.•Reeves MM, Terranova CO, Eakin EG, et al. Weight loss intervention trials in women with breast cancer: a systematic review. Obes Rev. 2014;15:749–68. In this systematic review, BC survivors in 8 out of the 14 intervention trials attained significant weight loss and health benefits with no adverse effects, which provided supporting evidence of the feasibility and beneficial effects of weight loss through diet and/or exercise.PubMedCrossRefGoogle Scholar
- 91.•Goodwin PJ, Segal RJ, Vallis M, et al. Randomized trial of a telephone-based weight loss intervention in postmenopausal women with breast cancer receiving letrozole: the LISA trial. J Clin Oncol. 2014;32:2231–9. The LISA trial is the latest weight loss intervention trial to publish results and showed that significant weight loss could be achieved in BC survivors through simple lifestyle modification strategies that were delivered through telephone counselling.PubMedCrossRefGoogle Scholar
- 98.U.S. Department of Health and Human Services. 2008 Physical Activity Guidelines for Americans. 2008. Available at http://www.health.gov/paguidelines/pdf/paguide.pdf. Accessed 3 Nov 2014.
- 99.World Cancer Research Fund International. Our cancer prevention recommendations. 2014. Available at http://www.wcrf.org/int/research-we-fund/our-cancer-prevention-recommendations. Accessed 3 Nov 2014.
- 100.National Comprehensive Cancer Network. NCCN Guidelines for Treatment of Cancer by Site. Breast Cancer. 2014. Available at http://www.nccn.org/professionals/physician_gls/pdf/survivorship.pdf. Accessed 3 Nov 2014.