An unusual type of breast cancer that does not surprisingly involve estrogen seems to pose an increased risk to obese women with a sedentary lifestyle, reveals a new study.
The name 'triple-negative breast cancers' indicates that the three hormones, estrogen, progesterone or HER2 protein are absent and since no hormonal therapy can be used, survival is difficult.
Although obesity is an important factor in estrogen-caused tumors since fat tissue is a source of estrogen, this study brought out the fact that being obese can also lead to cancers not caused by the hormone and this is very unusual according to study researcher Amanda I. Phipps, PhD, tells WebMD.
The health study brought up data that 35 per cent of the postmenopausal women investigated were obese and they faced the highest risk of developing triple-negative breast cancers than the thinnest women. It involved 155,723 participants, who were a part of the Women's Health Initiative (WHI), and starting from the early 1990s, tracked them for the next 15 years to evaluate their risk of developing cancer, heart disease, and osteoporosis.
The women were divided into four groups according to body mass index. Those with the highest BMI were 39 per cent more likely to develop estrogen-fuelled breast cancers and 35 per cent to develop triple -negative breast cancers. Hence, although hormones are one pathway through which cancers develop, the study proves that there are other factors too.
There are other interesting details that emerge from this study as well as earlier ones. Childbirth has been judged to be a protective factor against estrogen-caused cancer, whereas, women who had never given birth had a 40 per cent lower risk for triple-negative cancers.
Factors such as genetic predisposition known as BRCA1, being a African-American woman and of a comparatively young age - all important factors in breast cancers- cannot be changed; nevertheless, there are two intervention strategies that would be beneficial. Phipps says that women should work on maintain a healthy weight and taking up an exercise regimen to lower the risk of developing the disease.