a special program of the National Emergency Medicine Association (NEMA)
Week: 545.4 Guest: Dr. Joann Zujewski, Research Oncologist, Nat'l. Cancer Institute Topic: Breast Cancer Studies Producer/Host: Steve Girard
NEMA: We're with Dr. Joann Zujewski, a research oncologist at the National Cancer Institute near Washington, D.C. Doctor, we always hear about research, and rarely about the people doing the pioneering. What's your background?
ZUJEWSKI: What I've had is three years of residency training after my MD degree, and then several years of a fellowship training in medical oncology. Then I came to the National Cancer Institute, and have been doing clinical trials in their intramural program, which is on campus...which is about ten to twenty percent of the National Cancer Institute's funding, is intramurally. The other 80 % or so is extramurally, and many of the trials I'll be talking about, the larger ones, are done in the extramural community.
NEMA: Doctor, I originally called to ask you about studies about the connection between fat intake and the risk of breast cancer...and you said the NCI is involved in something related to that right now....
ZUJEWSKI: Basically, there's been some population studies that show that countries that have a higher fat diet, also have a higher incidence of breast cancer. And that when those populations migrate to the United States for example, they adopt the breast cancer incidence of the country that they migrate to. So it was thought that diet, especially fat, was important. These were also supported by some animal studies, which demonstrated that rats that were fed higher fat diets developed breast cancer. So, a series of what we call case-control' studies were done, where patients with breast cancer were identified, and then they also identified controls which they tried to match for other features, and they discovered that more of the cases had a higher fat diet than the controls. But those are always subject to biases of what people remember...people with breast cancer may have a different memory than those without..it's more like a selection bias or recollection bias.
NEMA: So, Dr. Zujewski, what do researchers come up with when an issue remains foggy because these case control studies have this bias?
ZUJEWSKI: They've done some prospective cohort studies, where they've looked at individuals over time, to see if those who have a higher fat diet actually do develop more breast cancer than those with a lower fat diet. And those are the studies you were asking me about that have been coming up negative, one that was recently published, a very large study, actually, was published in the New England Journal of Medicine earlier this year...and they found no evidence of a positive association between total dietary fat and the risk of breast cancer. And it may not mean that fat isn't important, it may just mean that fat's not important at the age of the women that they're studying...or that the dietary fat intake that was important was at an earlier time in life. For example, during puberty when their breast is developing...or it may mean that the connection between fat is actually one of nutrition, because women who have a higher caloric diet start menstruating earlier, and we know that some of those hormonal factors influence your risk for breast cancer. Women who have an earlier age of menarche, for example, have a higher risk of breast cancer. And women with a higher nutritional status also have an earlier age of menarche.
NEMA: Though a link between a higher fat diet and breast cancer has not been established, there are still many good health reasons to keep fat intake less than 30%. You may know that October has been breast cancer awareness month, and we'll talk with Dr. Zujewski next time on a huge study called the Women's Health Initiative, which will attempt to find out more about the effects of a good diet on breast and colon cancers, hormone replacement therapy, and vitamin supplementation. Come back and join us....I'm Steve Girard.