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20.08.05 WASHINGTON - Very young children who often eat chips have a much higher risk of breast cancer as adults, researchers said this week. A study of American nurses found that one additional serving of fries per week at ages three to five increased breast cancer risk by 27 per cent. "Researchers are finding more evidence that diet early in life could play a role in the development of diseases in women later in life," said Dr Karin Michels, who led the study. "This study provides additional evidence that breast cancer may originate during the early phases of a woman's life and that eating habits during that phase may be particularly important to reduce future risk of breast cancer." For their study, Michels and colleagues used an ongoing survey of female registered nurses. They studied 582 women with breast cancer and 1569 women free of breast cancer in 1993. Writing in the International Journal of Cancer, the researchers said they looked at the women's diets and at questionnaires filled out by the participants' mothers. One risk factor for breast cancer stood out: women whose mothers said their daughters ate fried chips had a higher risk of breast cancer. This rose by 27 per cent for each weekly serving eaten. "This data has to be interpreted cautiously since the observed association between consumption of fries and breast cancer is dependent on the validity of the maternal recall of the diet," she said. "Mothers were asked to recall the preschool diet of their daughters after the participants' breast cancer status was known and it is possible that mothers of women with breast cancer recalled the diet differently than mothers of healthy women. "Other foods perceived as less healthy such as hot dogs or ice cream, however, were not associated with breast cancer risk." A high-fat diet has been linked to breast cancer, which affects more than 200,000 US women a year and is expected to kill 40,000 this year. |
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Addressing a major unknown in the longstanding debate over mammograms, a new study sponsored by the National Cancer Institute found that the screening test contributed to a pronounced drop in the death rate from breast cancer. The study, being published today in The New England Journal of Medicine, concludes that 28 to 65 percent of the sharp decrease in breast cancer deaths from 1990 to 2000 was due to mammograms. The rest was attributed to powerful new drugs to treat breast cancer. More than 80 percent of women 40 and over get mammograms now, and Dr. Russell Harris, a professor of medicine at the University of North Carolina and a member of the United States Preventive Services Task Force, which issues medical practice guidelines, said the new finding meant that women could feel confident the screening played a role in preventing breast cancer deaths. That is not something Dr. Harris would have said before the study was published. He and others cautioned that before deciding to be screened women should weigh the risks of mammograms, like false positives and being treated for tumors that would not have spread if they were left alone. The study was an effort to understand why the breast cancer death rate had dropped so drastically so rapidly - 24 percent from 1990 to 2000. Was it mammograms, which can find cancers early when they may be more treatable, or was it powerful new drugs to treat the cancers? The two factors had been tested in clinical trials, but researchers did not know what occurred in the real world, where women did not always follow medical advice and doctors did not always use the tests and drugs as carefully as in the studies. Most of the researchers expected that drugs would be working, because the clinical trials were so persuasive. But there was a sharp dispute over whether mammograms, whose clinical trials were more ambiguous, had much benefit outside those trials. The debate over the effectiveness of mammograms has been bitter, drawing in cancer researchers and advocates and involving questions about spending and whether opportunities to save lives were being squandered. Some experts said that mammograms were unlikely to be very effective and that it was a waste of money and resources to have every woman 40 and older have one a year. Other experts said that mammograms were crucial and that without screening to find cancer early, the treatments would not be nearly so effective. "The emphasis was always on mammograms, mammograms, mammograms," while treatment was given short shrift, said Fran Visco, director of the National Breast Cancer Coalition, an advocacy group. In fact, Ms. Visco said, until recently the federal government paid for poor women not on Medicaid to be screened but did not pay to treat them if cancer was found. Other experts like the American Cancer Society insisted that annual mammograms were essential. Dr. Carolyn D. Runowicz , a gynecologic oncologist at the University of Connecticut and the incoming president of the society, said the death rate would not have fallen without the increase in mammograms. The decline in deaths "is due to better screening, better use of screening," Dr. Runowicz said. For the new study, the National Cancer Institute asked seven research teams to explain what had occurred. The death rate was nearly flat from 1975 until 1990, when it was 49.7 per 100,000 women ages 40 to 75. In 2000, the rate dropped, to 38 per 100,000 for that age group. In the meantime, mammography for women older than 40 soared. In 1985, about 20 percent of women were estimated to have had mammograms in the prior two years. In 2000, the figure was 70 percent. At the same time, chemotherapy and hormonal therapy with tamoxifen, which blocks the effects of estrogen that can fuel breast cancer, had come on the scene, and their use had spread rapidly. To develop their estimates, the researchers built computer models of the disease, its detection and its treatment, asking whether they could explain the falling death rate from 1990 to 2000. The answer, they all agreed, was that they could explain it only if both mammograms and treatment were having an effect. The debate over mammograms began in the 80's, when the National Cancer Institute questioned their benefits for women in their 40's. In 2002, the British journal Lancet published a paper saying the benefits of mammograms for women of any age were unclear. One group, the P.D.Q., an independent group that analyzes data for the National Cancer Institute to present to the public, said it could no longer tell women that mammograms prevented breast cancer deaths. That group, of which Dr. Harris is a member, said the clinical trials of mammograms had not made a strong case that lives were saved. Just because a cancer is found early, the group added, does not mean that the patient is necessarily better off. Some cancers are curable, no matter when they are found. Others are incurable, no matter when they are found. To know that a screening test works, experts need strong evidence from clinical trials, and the evidence from the mammography trials was just not convincing to them. |