Is metabolic syndrome the link between obesity and postmenopausal breast cancer?.
Authors: Healy LA , Ryan AM , Quinn L , Connolly EM , Kennedy MJ , Boyle T , Reynolds JV 
Published: December 2010

Abstract #5040

Background&#x2028; Obesity is associated with an increased incidence of postmenopausal breast cancer and a poorer prognosis. The mechanism by which body weight affects breast cancer outcome is complex and incompletely understood. While there is convincing evidence that an obesity induced increase in estrogen production contributes to this risk, recent literature also recognizes other factors such as hyperinsulinaemia, increased IGF-1, high triglycerides and greater abdominal fat accumulation. The clustering of these risk factors is the cornerstone of metabolic syndrome (MetS) diagnosis. Although studies on MetS and cancer are scarce, the components of MetS have individually being linked to the development of cancer and combined these metabolic abnormalities may have an additive effect leading to a more aggressive tumor phenotype.&#x2028; Objective&#x2028; The primary aim of this study was to describe for the first time the incidence of MetS and central obesity in women with postmenopausal breast cancer and examine the relationship between its presence and tumor size, pathological stage and axillary nodal involvement in an Irish population.&#x2028; Design & Setting&#x2028; This was a prospective study of patients that presented to a specialist Breast Cancer Unit, in St James's Hospital, Dublin, with postmenopausal breast cancer between March 2007 and May 2008. Individuals underwent a metabolic and nutritional assessment. Studies performed included anthropometry, segmental body composition analysis by bioelectrical impedance, and quantification of fasting lipids, glucose, insulin, C-reactive protein and Serum Amyloid A.&#x2028; Results&#x2028; Seventy-nine female post-menopausal breast cancer patients were recruited. The median age was 68 years (Range 41-84). The mean Body Mass Index was 28.1 ± 5.1 kg/m2, with 70% patients overweight or obese and a further 84% centrally obese. There was no difference in method of detection, diagnosis or treatment between obese and non-obese patients. Over a third of patients (36%) had MetS, which exceeds the population norms reported at 21%. MetS was significantly associated with an adverse metabolic profile as well as increased total fat, trunk fat, an 8cm greater waistline, insulin resistance and hypertension. Moreover the presence of metabolic syndrome was significantly associated with larger tumors (P=0.006), a later stage of disease (P=0.010), lymphovascular invasion (p=0.006) and axillary node involvement (P=0.014) compared to patients without MetS.&#x2028; Conclusion We report for the first time, a high prevalence of MetS and central obesity in a cohort of Irish postmenopausal breast cancer patients. The presence of the MetS seems to be associated with a more aggressive tumor phenotype. The prevalence of these altered metabolic profiles may be a key factor in determining the metastatic potential and prognosis of postmenopausal breast cancer. Therapeutic strategies that correct these abnormalities represent an exciting avenue for future prevention and treatment of breast cancer.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5040.