US Breast Cancer Rates Double Those in South America

Roxanne Nelson

August 26, 2010

August 26, 2010 — The rates of breast cancer in women in the United States are almost double those of women in some South American countries.

According to statistics from GLOBOCAN 2008, a project of the International Agency for Research on Cancer in France, 76 per every 100,000 women in the United States (adjusted for age) were diagnosed with breast cancer in 2008, compared with 44 per 100,000 in South America.

Although some of the differences between North and South America can be attributed to improvements in screening, diagnosis, and documentation, experts at the American Institute for Cancer Research (AICR) also point to differences in lifestyle.

We need to be more active, stay leaner, watch our weight, and consume less alcohol.

This "just underscores what we've been saying along," said Alice Bender, MS, RD, nutrition communications manager at AICR. "This is not a new message for us, and just adds more evidence that we need to be more active, stay leaner, watch our weight, and consume less alcohol."

THE AICR combined incidence numbers from GLOBOCAN 2008 with preventability figures from their recent policy reportFood, Nutrition, Physical Activity, and the Prevention of Cancer: A Global Perspective — which calculated the population-attributable fractions (FAPs) for various breast cancer risk factors. The FAPs are defined as the proportional reduction in cancer incidence that would occur in a population if, as in this case, cancer prevention recommendations for weight, activity, alcohol, and breastfeeding were followed.

The researchers estimated that approximately 4 of every 10 breast cancer cases in the United States could be prevented by staying at a healthy weight, consuming less alcohol, and being more physically active.

Risk Factors Higher in the United States

Overall, obesity rates are much lower in South America than in the United States, the AICR points out in a release. In Brazil, for example, 55% of the population has a body mass index in the range of 18 to 24 kg/m2, which is considered to be a healthy range. Conversely, only 36% of Americans fall within this range.

Alcohol consumption in the United States is also higher than in Brazil. Whereas the average adult in Brazil consumes about 5.3 L of alcohol per year, the average American adult consumes 8.1 L.

"We consume about 75% more alcohol than they do in Brazil, and we have fewer people in the healthy weight range," Ms. Bender said in an interview. "These are factors that have been associated with cancer risk."

A number of studies have found that obesity is linked to a higher cancer risk. Data presented at the 2009 European Society for Medical Oncology meeting suggested that in 2008, at least 124,000 new cancers in Europe might have been related to excess body weight. Being overweight or obese can also increase the risk for cancer-related mortality and for breast cancer recurrence.

Regular alcohol intake is associated with an increased risk for breast cancer and, as previously reported by Medscape Medical News, it can also elevate the risk for breast cancer recurrence.

The AICR notes that physical activity and breastfeeding might also play a role in the differences between Brazil and the United States. Figures from the policy report show that even though more Brazilians than Americans are inactive (50% vs 30%), the percentage of Brazilians who are highly active is 9 times greater that of Americans (37% vs 4%).

Brazilians are also more likely to breastfeed. Statistics from the La Leche League show that 93% of Brazilian women breastfeed their babies, compared with 74% of American women.

Many breast cancers can be prevented.

Breast cancer is the most frequently occurring cancer among women worldwide, with an estimated 1.38 million new cancer cases diagnosed in 2008 (23% of all cancers), according to GLOBOCAN 2008. Although survival rates are more favorable in the developed world, incident rates are much higher in industrialized nations. Incidence rates vary from 19.3 per 100,000 women in East Africa to 89.9 per 100,000 women in Western Europe.

"The breast cancer rates in the United States are more than 3 times higher than they are in China," said Ms. Bender, "and more than 4 times higher than in East Africa. We really have to get the message out that many breast cancers can be prevented."


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