Weight and Breast Cancer: A Well-Established Association

Weight and Breast Cancer: A Well-Established Association

It has long been known that obesity is influential in the development of breast
cancer and negatively affects a patient’s prognosis. A variety of large-scale studies
have confirmed this association, including the European Prospective Investigation
into Cancer and Nutrition (EPIC), which reported a 31 percent greater risk of
developing breast cancer in obese women compared to nonobese women (Lahmann,
Lissner, and Berglund 2004). What’s more, overweight women, particularly those
with ER+ tumors, have a higher risk of local lymph node involvement (Verreault et
al. 1989). Sadly, it is estimated that up to 50 percent of breast cancer deaths in
postmenopausal women in the United States can be attributed to obesity (Petrelli et
al. 2002).

Why do we see such an elevation of risk in overweight women? It appears to
come down to a constellation of risk factors that converge into what one cancer
researcher has dubbed an “oncometabolic state” (Wallace 2010). Features of this
oncometabolic state include an abundance of belly fat, elevated glucose or elevated
fasting insulin levels (or both), excessive blood lipids (fats), abnormal blood
coagulation, and elevated inflammation levels. If these markers sound familiar, it’s
because they are very similar and, in fact, overlap with markers for a more wellknown
condition known as metabolic syndrome, also known as insulin resistance or
prediabetes.