Studies Address Presence of More Lethal Breast Cancer Among Black Women, Diet-Cancer Link

Black women are more likely to develop breast cancer tumors that are more advanced and more aggressive than white women, and biology is thought to be a major factor behind the disparity, according to a study published in the journal Cancer, the Bloomberg/Bergen Record reports (Zimm, Bloomberg/Bergen Record, 7/10).

For the study, researchers Edith Mitchell and Gloria Morris from Thomas Jefferson University Hospital's Kimmel Cancer Center examined more than 2,200 medical records of cancer patients seen at the hospital between 1990 and 2002. According to the study, white women were more likely to have tumors that contained estrogen or progesterone receptors -- known as HER2 -- and could be treated with available drugs, but black women's tumors were less likely to carry the treatable estrogen receptor. Tumors without such HER2 receptors are called triple-negative and can only be treated with chemotherapy.

In addition, the new study found that black women's tumors were more likely to have two molecular markers of aggressive spread and growth. According to the Inquirer, the finding could lead researchers to develop new targets to attack the more-aggressive tumors (Flam, Philadelphia Inquirer, 7/10). Morris said the reason behind the findings is "not necessarily related to socioeconomic and demographic differences," adding, "Now there is a strongly emerging biological basis that African-Americans are more likely to have more-aggressive tumors" (Bloomberg/Bergen Record, 7/10). She suggested further research on triple-negative tumors and the development of drugs to treat them (Philadelphia Inquirer, 7/10).

An abstract of the study is available online.

Diet-Cancer Link
In related news, two separate studies recently examined the link between diet and cancer among minorities. Summaries of news coverage on the studies appear below.

• Chinese women and breast cancer: Postmenopausal Chinese women who consume a "Western-style" diet have a greater risk of developing breast cancer than those who consume traditional Chinese diets, according to a study published on Tuesday in the journal Cancer Epidemiology, Biomarkers & Prevention, Reuters reports. For the study, researcher Marilyn Tseng of the Fox Chase Cancer Center and colleagues tracked about 3,000 women in Shanghai, about half of whom were diagnosed with breast cancer. They found that those who consumed a Western-style diet -- beef, pork, shrimp, chicken, candy, desserts and dairy products -- were 60% more likely to develop breast cancer than those who ate mostly vegetables and soy products, which is typical of a Chinese diet. In addition, postmenopausal women consuming a Western-style diet had a 90% increased risk of a type of breast cancer involving estrogen-receptor positive tumors. The study's findings suggest that the Western diet might increase Chinese women's risk for breast cancer because of the added risk of obesity, Reuters reports (Dunham, Reuters, 7/10).
  
  
• Racial disparities and diet: Diet might contribute to racial disparities between whites and blacks in terms of breast and prostate cancers, according to study published in the journal Ethnicity and Disease, Reuters Health reports. Minorities are more likely than whites to have less nutritious diets and to be overweight or obese, according to Reuters. For the study, researchers Hope Ferdowsian and Neal Barnard of the Physicians Committee for Responsible Medicine -- which promotes vegetarian diets -- examined previously conducted research on diet and cancer. In one study of 2,400 women who had been treated for breast cancer, researchers found that those instructed to follow a low-fat diet were about 25% less likely than others to have a cancer recurrence. In another study, breast cancer survivors who consumed a diet low in fat and high in fiber, fruits and vegetables experienced a decline in estrogen, while women who maintained their normal eating habits experienced a rise in estrogen, which can fuel tumor growth. According to the researchers, there is evidence that black women have relatively higher average levels of estrogen than white women. The findings also might explain why black men are more likely than white men to develop and die from prostate cancer, which also is driven by hormones, according to the study (Reuters Health, 7/9).