Sustained Weight Loss and Risk of Breast Cancer in Women 50 Years and Older: A Pooled Analysis of Prospective Data

Abstract

Background Excess body weight is an established cause of postmenopausal breast cancer, but it is unknown if weight loss reduces risk. Methods Associations between weight change and risk of breast cancer were examined among women aged 50 years and older in the Pooling Project of Prospective Studies of Diet and Cancer. In 10 cohorts, weight assessed on three surveys was used to examine weight change patterns over approximately 10 years (interval 1 median = 5.2 years; interval 2 median = 4.0 years). Sustained weight loss was defined as no less than 2 kg lost in interval 1 that was not regained in interval 2. Among 180 885 women, 6930 invasive breast cancers were identified during follow-up. Results Compared with women with stable weight (±2 kg), women with sustained weight loss had a lower risk of breast cancer. This risk reduction was linear and specific to women not using postmenopausal hormones (>2–4.5 kg lost: hazard ratio [HR] = 0.82, 95% confidence interval [CI] = 0.70 to 0.96; >4.5–<9 kg lost: HR = 0.75, 95% CI = 0.63 to 0.90; ≥9 kg lost: HR = 0.68, 95% CI = 0.50 to 0.93). Women who lost at least 9 kg and gained back some (but not all) of it were also at a lower risk of breast cancer. Other patterns of weight loss and gain over the two intervals had a similar risk of breast cancer to women with stable weight. Conclusions These results suggest that sustained weight loss, even modest amounts, is associated with lower breast cancer risk for women aged 50 years and older. Breast cancer prevention may be a strong weight-loss motivator for the two-thirds of American women who are overweight or obese.

Personalized early detection and prevention of breast cancer: ENVISION consensus statement

“…Notably, the efficacy of weight loss programmes has been shown to be greater among individuals who are aware of being at high risk of developing breast cancer 143 . Importantly, weight loss 144 and regular exercise 145,146 not only decrease breast cancer risk but also the risks of other cancers and CVDs. Considering the general health benefits, lifestyle interventions could be recommended to women at all levels of breast cancer risk 147 .…”

Obesity and Breast Cancer: A Case of Inflamed Adipose Tissue

“…Another possibility is to treat the obesity itself, and there are a few clinical studies looking at the effect of weight loss on breast cancer, including the Breast Cancer WEight Loss (BWEL) study (NCT0270826). The effect of weight loss as a method for lowering breast cancer risk is supported by a few studies, including a large prospective study that found that sustained weight loss in women over 50 is associated with a reduced risk of developing breast cancer [ 176 ]. Other studies looking at obese patients who underwent bariatric surgery for weight loss have shown that they have a reduced risk of several types of cancer, including breast cancer [ 177 , 178 ].…”

Adipose tissue—more than just fat

“…There are also studies that predict a relation between obesity and the risk to develop cancer. 25,26 Nowadays, adipose tissue is not only understood as a fat storage that releases free fatty acids but as a complex endocrine organ that influences hormone balance, metabolic regulation and inflammatory levels, to name just a few. 23 Although the regulatory effects of adipose tissue on oxidative stress, insulin resistance and inflammation are not fully understood (for more reviews see Ref.…”

“…Those clinically relevant outcomes are for example: sleep apnoea‐induced intermittent hypoxia, effects on endothelial cell calcium signalling and alterations in renal sympathic nerve activity. There are also studies that predict a relation between obesity and the risk to develop cancer …”