Obesity and prognosis of breast cancer

Abstract

Obesity has a complicated relationship to both breast cancer risk and the clinical behaviour of the established disease. It is suggested that obesity is associated with both an increased risk of developing breast cancer risk and worse prognosis after disease onset. In post-menopausal women, various measures of obesity such as body mass index, weight, weight gain and waist : hip ratio have all been positively associated with risk of developing breast cancer. In most but not all case-control and prospective cohort studies, an inverse relationship has been found between weight and breast cancer among pre-menopausal women. Some data suggest that adult weight gain and central obesity increase the risk of pre-menopausal breast cancer. Obesity at the time of diagnosis is thought to be significant as a poor prognostic factor. Obesity is associated with adverse outcomes in both pre- and post-menopausal women with breast cancer. Many cancer survivors seek ways to minimize the risk of recurrence and death because of breast cancer. Despite complex and at times controversial data, enough evidence is available at present to suggest that weight management should be a part of the strategy to prevent the occurrence, recurrence and death because of breast cancer. In this review the effect of obesity on the prognosis of breast cancer is examined in detail.

Body weight and risk of breast cancer in BRCA1/2 mutation carriers

“…The association between obesity and poor overall survival [18,[24][25][26] or prognosis of breast cancer [17,[27][28][29], might, if also true for BRCA1/2 carriers, have influenced our study results. The inclusion of prevalent cases, may have led toward bias to the null, overweight/obese prevalent cases may have been underrepresented because they had died prior to study entry [24,27,28].…”

“…The inclusion of prevalent cases, may have led toward bias to the null, overweight/obese prevalent cases may have been underrepresented because they had died prior to study entry [24,27,28]. We reduced this potential survival bias by restricting the analyses to personyears within 10 years prior to questionnaire completion.…”

“…Previous studies showed that excess body weight (defined as overweight (BMI between 25.0 and 29.9 kg/m 2 ) or obesity (BMI C 30.0 kg/m 2 ) decreases overall survival [18,[24][25][26] and breast cancer-specific survival [17,[27][28][29]. The association between obesity and poor prognosis of breast cancer was present in both pre-and postmenopausal carriers.…”

Lifestyle changes and breast cancer prognosis: a review

“…Obesity and weight gain after the diagnosis The majority of the existing literature indicates a negative relationship between obesity and poor prognosis of breast cancer in both pre-and post-menopausal women [30]. Weight gain after diagnosis has been reported frequently, possibly through increased caloric intake, changes in physical activity and change in host metabolic status [31].…”

Effects of adiponectin on breast cancer cell growth and signaling

“…For example, obesity is associated with increased risk for postmenopausal breast cancer (Trentham-Dietz et al, 2000;Morimoto et al, 2002;Carmichael, 2006). In addition, there are clinical studies indicating that increased BMI is associated with more aggressive breast cancer and a reduced survival period (Cleary and Maihle, 1997;Sweeney et al, 2004;Loi et al, 2005;Porter et al, 2006).…”