Female Obesity and Breast Cancer

"Obesity seemed to carry a higher risk of breast cancer recurrence and death, even in women who were healthy at the time that they were diagnosed, and despite the fact that they received the best available chemotherapy and hormone therapy.
"Insulin levels are known to be higher in patients who are obese because they develop insulin resistance... (and) insulin can stimulate the growth of breast cancer cells."  Researcher Joseph Sparano, associate chairman of medical oncology at the Montefiore Einstein Center for Cancer Care in the Bronx, New York

Results from previous studies into the relationship between female obesity and worsening cancer outlooks have provided what appears to be a clear link between obesity and heightened opportunities of breast cancer.  Along with a fiercer outcome in women who have already been diagnosed with breast cancer.  A new study has confirmed that breast cancer is likelier to return and to prove fatal, for overweight women.

Hormones linked to body weight may also fuel tumour growth in the most common form of breast cancer, identified as estrogen receptor-positive cancer.  The study was based on data from trials sponsored by the U.S. National Cancer Institute - of women with stages I, II and III breast cancer who received standard treatment with dosages of drugs calibrated to reflect the women's weight.

Researcher Joseph Sparano and his colleagues discovered that compared to women of normal weight, those who were obese were 40% likelier to experience a breast cancer recurrence over the study period of eight years, and fully 69% more likely to die from breast cancer.  Those women who were merely overweight, but not obese, demonstrated a trend toward higher risk of both recurrence and death with increasing weight.

That link between obesity in women and the prevalence and ferocity of the disease turned out to be particularly strong for women with the most common type of breast cancers, estrogen-receptor-positive.  The new study, emphasized the researchers, does not prove that additional weight and fat directly impact certain breast cancers, only that it appeared to be "biologically plausible".

"There is as yet no proof that women with cancer are capable of improving their long-term prognosis by undertaking weight loss.  The highest priority is just getting through the chemotherapy if chemotherapy is necessary and taking their endocrine therapies.

"But for those who are obese or overweight, there may be additional benefits that one can achieve through diet and through weight reduction that may produce a reduction in the risk of recurrence that's just as significant as the reduction that they get from the standard therapies", explained Dr. Sparano.