Sing Tao Daily, Rong Xiaoqing
Audience served: Chinese and Chinese Americans
Breast Cancer Rates Higher among Chinese Immigrants: Balanced Diet and Screening Best Prevention
By Rong Xiaoqing, staff reporter, Sing Tao Daily. Published Oct. 22,200. Translated from Chinese by Rong Xiaoqing
Many people know that the breast cancer rate among Chinese women is much lower than women in many other racial groups. But being born as a Chinese person doesn’t make you immune from getting the disease. Scientists have found that the rate can shoot up when Chinese women adopt a Western lifestyle. Despite the belief that the difference may be associated with diet, scientists say it’s not wise to avoid or increase the intake of any particular food. Rather, they say, a balanced diet plus regular screening is the best way to reduce the risk.
The disparities between breast cancer rates among Asian women and Caucasians have long been a hot topic among scientists. Generally speaking, Asian women are less likely to get breast cancer than Western white women. Although breast cancer rates vary and among some ethnic groups (such as Japanese and Filipinos) can be higher, women in many Asian countries enjoy very low rates. In China, the breast cancer incidence per 100,000 people is only 18.7. China is ranked the 142th in the world for this disease, compared to the top-ranking United States, which reaches 101.1 breast cancers per 100,000 people of all races and ethnicities.
A similar pattern of disparities applies when looking only within the United States. The rate among Chinese American women is 55 per 100,000 people, compared to 142 per 100,000 among white Americans. Chinese American women enjoy the second lowest rate among Asian ethnic groups, after only Korean Americans.
Checking some other figures, though, could be alarming. Scientists have found breast cancer rates among Chinese women who have been in the United States for more than ten years to be 80 percent higher than their newly arrived peers. And the rate among American-born Chinese women is almost the same as white women. Furthermore, in China, breast cancer rates have jumped more than 20 percent over the past ten years. The situation is worse in big cities. In Shanghai, for example, the rate increased 31 percent during this period.
Many studies have examined the association between these disparities in breast cancer rates and dietary habits. A study released this past summer by the Philadelphia-based Fox Chase Cancer Center found that a Western-style diet greatly increased breast cancer risk for post-menopausal Chinese women.
The study examined the dietary habits of 1,602 women who were diagnosed for breast cancer between August 1996 and March 1998, compared to 1,500 healthy women. All of the women lived in Shanghai, China, and their age ranged from 25 to 64. After adjusting for other possible factors such as when and whether the women bore children, the study found that post-menopausal women who followed a “meat and sweet” Western-style diet were 60 percent more likely to get breast cancer than same-age women who followed a “soy and vegetable” traditional Chinese diet. The effect was more significant for estrogen-receptor positive tumors, whose growth is nurtured by estrogen. The risk of getting this type of breast cancer was increased 90 percent by the Western-style diet.
The study, although conducted in China, may have broader implications. “It is definitely applicable to Chinese women in the U.S. because it’s even harder for them to avoid Western-style diet,” said Marilyn Tseng, one of the researchers in the study.
Tseng, however, won’t single out any element in the Western diet as a “risk factor” for breast cancer. Scientists suspect that there could be ingredients in the diet that increase mutations to the DNA or cause hormonal changes that increase cell proliferation—both can lead to cancer—but no study on this subject has identified a mechanism behind the dietary findings. “We really don't know what it is in the diet or how it’s working to increase breast cancer risk,” said Tseng.
Tseng also pointed out that the study doesn’t mean the ingredients in traditional Chinese diets can reduce breast cancer risk. The study didn’t find any evidence on this front. Components popular in Asian food but not in Western food, especially soy products like tofu, have been a focus for scientists who try to decode the secret of the low breast cancer rate among many Asian women. But rather than identifying soy as the magic protector,
recent studies have found that the relation between soy and breast cancer risk is much more complicated.
“Soy was originally thought to explain the huge difference in breast cancer incidence between Asian and Caucasian women. But now we don't know,” said Leena Hilakivi-Clarke, a professor of oncology in Georgetown University in Washington, D.C.
Professor Hilakivi-Clarke and her colleagues did studies on the effect of genistein, a key component of soy, in breast cancer. Genistein is an estrogenic compound that could help the growth of the estrogen-receptor positive tumor, she explained. But it’s possible, she adds, that any negative effects are counteracted by other ingredients in soy. She also points out some experiments that found that extremely high does of estrogen sometimes stopped
the growth of estrogen-receptor positive tumors. Scientists so far cannot explain the irony. According to professor Hilakivi-Clarke’s study, early life intake of soy, especially as a fetus during a mother’s pregnancy and throughout all of childhood, may help women’s breasts to be more protective. But to start the intake in adulthood may not help at all.
Is there a way for Chinese women to reduce their risk by altering their diet? Scientists say the answer is “yes,” but the attention should not be put on any single element in the diet. Rather, the overall balance is important. “More research needs to be done in this field to give us a clear idea of what we should eat and what should not. But before that, the best way is to follow the old Golden Rule—a balanced diet and exercise,” said Ming-der Chang, executive director of the Eastern Division Chinese Unit of American Cancer Society.
Chang also emphasizes the importance of self-breast exams and mammogram screening. She suggests that women over 40 years old get screening once every year and that younger women examine the area on and around their breasts with their fingers once every month. “Breast cancer can be cured when it is detected early,” said Chang.
Tips on Science Reporting for Ethnic Media from Rong Xiaoqing
- Make sure you know the precise meaning of the ethnic groups that the scientists or studies you are using meant. This was proved to be a very important point when I tried to show the disparity of breast cancer rates between Asian and Caucasian women. For example, does Asian mean Asian American, or Asian people living in Asian countries, or both? Does it include South Asian or only East Asian, like Chinese, Korean and Japanese? These choices could make the figures have different meanings. Pinning down terms is especially important to ethnic media outlets where sometimes terms for ethnic groups are used regularly and reporters are likely to take the words for granted and without question.
- Is the study a controlled one? The conclusions of scientific studies could be so appealing to reporters that we rush to pick them up without thinking whether they really are relevant to our stories. In my fellowship story, I quoted research done by the Fox Chase Cancer Center in Philadelphia on 1,602 women living in Shanghai to show that a Western-style diet could increase breast cancer risk among Chinese women. DNA Files science editor Sally Lehrman asked whether the study considered other factors that may also play a role in risk rates, such as the participant's age, whether she’s given birth, etc. Fortunately, the study was a controlled one and these factors had been addressed. But this is an important question to ask the researchers.
- How to read research papers? I read and quoted a scientific paper by Professor Leena Hilakivi-Clarke and her colleagues at Georgetown University. I have to admit that it was not an easy task to concentrate on reading the 16- page paper full of terms that were unfamiliar to me. But during the reviewing process with Sally, I realized that there were at least two things that I should have considered while I was reading. One, what are the new findings of the paper and what is concluded from previous research. Scientists often bring in previous research and further develop it in the new study. So when quoting figures and findings, reporters should be careful about whom the quotes should be attributed to (it may not be the author of the paper you are reading). And, two, reporters should consider whether the paper was based on studies in people, or on animals, or on cell samples. In this case, the paper presented both human data and animal data. But before being reminded, I didn't even think about it.
- Double-check everything. Reporter should proofread and double-check all the figures and terms before handing their story to an editor. This should be common sense, but unfortunately it's often not followed in reality. Most of the time we leave the job to the editor. But scientific stories may involve a lot of figures and sometimes, medical terms. An egregious mistake could easily dodge untrained eyes. So read your story and self-edit it before filing.