Western diet increases breast cancer risk in Asian women

January 27, 2016

Although Asian breast cancer rates are lower than those in the West, that appears to be changing and experts suspect changing dietary habits in countries such as China may be a factor.

A study of 3,000 women in Shanghai, half of whom were diagnosed with breast cancer, showed those who ate a "meat-sweet" diet were twice as likely to develop the disease as those on a vegetable-based diet.

The research suggests a Western-style diet high in meat, white bread, milk and puddings may put Asian women at a higher risk of developing breast cancer.

The researchers from the Fox Chase Cancer Center in Philadelphia say however that the two-fold increase in risk for women on a Western-style diet was found to exist only among post-menopausal overweight women and those with a Body Mass Index (BMI) of over 25 were found to be most at risk.

They say for post-menopausal Asian women, low consumption of a western diet along with successful weight control may protect against breast cancer.

A "vegetable-soy" diet more traditionally followed in China uses a variety of vegetables, soy-based products and freshwater fish but experts say overall it is difficult to determine the effects of diet on breast cancer risk.

According to the Chinese Anti-Cancer Association (CACA) the incidence and death rates of breast cancer in China's major cities rose respectively by 37% and 38.9% during the 1990s.

It is thought better diagnosis partly explains the rise, but environmental factors - including dietary changes are also thought to be factors.

Western scientists have estimated that obesity causes around 10% of breast cancer cases and many studies show that post-menopausal women who are overweight or obese have a raised risk of breast cancer.

But experts agree that it is still very difficult to pinpoint factors and to determine the effects of diet on breast cancer risk.

They say the study did not appear to take into account issues such as having children at a later age, not exercising or taking the pill.

The study appears in Cancer Epidemiology, Biomarkers and Prevention.

Neither MRI nor MRS uses the ionizing radiation (X-rays) that is used in traditional mammography and CT breast scans, and both procedures can be completed in a single sitting. Nor does adding MRS elevate the cost of the procedures substantially. There are already concerns about the higher cost of MRI compared to conventional mammography - breast MRI costs between $1000 and $2000, ten times that of a mammogram -- particularly in light of the million or more women who are likely to undergo breast MRI each year as a result of the new ACS guidelines. For those at higher risk, however, the extra cost is worthwhile.

UNLV's combined MRI/MRS technique will not be widely available clinically for several years. But Patton and Etnire are hopeful that as the public becomes more aware of the advantages to be gained from breast MRI, it will become a more widely used clinical technique for breast cancer detection, paving the way for the newer concept of coupling MRI with MRS.

While there are clear benefits to combining MRI and MRS, Srirama Swaminathan, a senior clinical scientist with Philips Medical Systems, cautions that there are still some limitations. For instance, not all breast cancers demonstrate elevated choline levels, and at least one form of breast cancer shows no choline signal at all. Nor will MRS detect very small lesions. "In spite of the added value MRS brings to improving specificity in characterizing lesions, it is not the 'magic bullet' for improving specificity across all types of lesions," he said.

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