June 10, 2005
Lifestyle Can Dictate Course of Breast Cancer
Exercise, food consumption, even a common spice may have impact, studies find
More evidence is trickling in that aspects of everyday life, including exercise, eating habits and even a common spice, can affect the incidence and course of breast cancer.
Three studies chronicling such findings are being presented this week at the Department of Defense Breast Cancer Research Program meeting in Philadelphia. The program is collaboration between the military, scientists, clinicians and breast cancer survivors.
In the first study, researchers at Penn State University found that women with breast cancer who exercised after chemotherapy experienced an increase in infection-fighting T-cells.
It is already well known that chemotherapy reduces a person's lymphocytes, compromising the immune system. "Chemotherapy will destroy dividing cells, including cells in the immune system," confirmed study author Andrea Mastro, a professor of microbiology and cell biology.
Exercise has been shown to help prevent cancer, help patients survive cancer and increase T-cells in AIDS patients.
For this study, 49 women between the ages of 29 and 71 were assigned to either an exercise group or a non-exercise group. Women in the exercise group began their routines usually within a month of finishing chemotherapy. The workouts, which could be done at home or at a gym, consisted of stretching, Flexbands for resistance training, and an aerobic activity, such as a treadmill, exercise bike or walking.
Not only did the exercisers show more activated T-cells than non-exercisers, they also showed improvements in upper-body strength, maximal oxygen intake, quality of life, social well-being and fatigue.
"There's no evidence that there was any harm," Mastro said. "The women on the exercise program were more physically fit, had a better outlook and a better quality of life. As a bonus, their immune cells were better."
The second study provides evidence that curcumin, a component of the spice turmeric, may reduce the spread of breast cancer to the lungs, at least in mice.
The experiment, which was done twice, involved growing grafts of human breast cancer in mice, surgically removing them, then dividing the mice into four groups and treating them with curcumin alone; Taxol (a chemotherapy drug) alone; curcumin plus Taxol, or nothing.
At the end of five weeks, all but the control group had shown signs of containing the cancer, with the greatest impact seen in the two groups of rodents receiving the curcumin.
The second time the study was done, the results were similar except that curcumin outshone even Taxol.
"In the first study, curcumin and Taxol together were very synergistic," said study author Bharat B. Aggarwal, chief of the Cytokine Research Section in the Department of Experimental Therapeutics at the University of Texas M.D. Anderson Cancer Center in Houston.
"In the second study, we found that we did not need even Taxol. Curcumin alone gave the same results. We still we do not know if we need Taxol, or if we can do without it. We'll only know that if we do a third study," he added.
Aggarwal and his colleagues are applying for funding for that third study, which would observe the effects of curcumin in humans.
Finally, another mouse study indicated that on-again, off-again dieting may actually prevent breast cancer in postmenopausal women. Mice on the so-called "yo-yo" diet regimen had a 96 percent reduction in cancer, compared to the animals allowed to eat whatever they wanted.
The results were surprising to the researchers who had initially thought the effect of this yo-yo pattern would be detrimental.
"This is the way people used to eat. For many, many centuries for human beings it was feast or famine," said study author Margot Cleary, an associate professor at the University of Minnesota's Hormel Institute in Austin. "Maybe the body has adapted to that."
Whether the findings will apply to humans remains to be seen but, if they do, they would add a new twist to what is known about nutrition and disease.
"It's been well known for decades that chronic food restriction is protective against lots of things, not just cancer, but it was thought the protective effect existed to the degree you restricted calories," Cleary said. "Our results show that it's really the manner that you receive these calories that can have a significant effect on what the impact is."
The National Cancer Institute has more on breast cancer.