Every woman who has ever opened a magazine knows her “shape”. “Pear shaped” women accumulate fat on their hips and thighs, “hourglass shaped” women do the same but also have large breasts, “ruler” women have broad shoulders and larger waists and “apple shaped” people accumulate their fat on their waists and guts. While obviously comparing human beings to produce is objectifying, these measurements now seem to have added value. A recent study looking at the link between body fat and breast cancer risk has pointed out that not only are obese women at higher risk of dying of breast cancer, but also that those who accumulate fat on their mid-section are at higher risk. In other words “apple shaped” women are at higher risk from breast cancer – especially if they are significantly overweight or morbidly obese.
This is only one in the growing number of studies linking obesity with the risk of being diagnosed with cancer in general (including rectal and ovarian cancers) and breast cancer in particular. In fact, obesity is the second highest environmental cancer risk after smoking, and one that is increasing year after year both in the industrialized and in the developing world. In particular, the association between breast cancer and obesity is believed to have a lot to do with what fat cells get up to when nobody is looking. Fat cells (or adipocytes) are supposed to be simple storage pods for molecules of fat, storing energy in times of plenty in anticipation of times of need. However, fat cells also secrete estrogen, especially when they are experiencing a state of inflammation. Estrogen is one of the key hormones that is released during the female reproductive cycle and also one of the key molecules that drives breast formation and, unfortunately, has been involved in driving certain types of breast cancer.
Broadly speaking, breast cancer cases can be classified as either sensitive to estrogen (or estrogen-receptor positive, ER+) or not sensitive to estrogen (or estrogen-receptor negative ER-). ER- breast cancer is the harsher form of the disease, mainly because it is harder to treat. ER+ breast cancer is responsive to hormone therapy as a first line of defense and usually carries a much sunnier prognosis than ER- breast cancer, where the only options are chemotherapy and radiotherapy. Obese people who always have a lot of estrogen in their system are more likely to develop ER- breast cancer, especially when the fat is localized around the abdomen. This means that obese or “apple-shaped” patients will have the tougher form of the disease as well as being more likely to receive a breast cancer diagnosis in general.
What does this mean for overweight people around the world? This is yet another wake-up call for how sorely we need to start implementing programs to help people loose weight as a crucial matter of public health. We can all do our bit!