Double Hormone Replacement Therapy May Increase Breast Cancer Risk
Women who take both estrogen and progestin for symptoms of menopause may increase their risk for breast cancer.
While estrogen alone increases breast cancer risk by 1 percent for every year of use, adding progestin (synthetic derivatives of the hormone progesterone) increases the risk to 8 percent per year, according to a study of more than 46,000 women participating in the Harvard Nurses' Health Study.
Physicians originally began prescribing the combination to counteract the risk of uterine cancer associated with estrogen use alone. It has long been apparent that progestins do not block estrogen's breast cancer-promoting effect. These data suggest they may aggravate it.
"The commonly held belief that aging routinely requires pharmacological management has unfortunately led to neglect of diet and lifestyle as the primary means to achieve healthy aging," concludes Dr. Walter C. Willett, professor of epidemiology and nutrition at the Harvard School of Public Health.
Schairer C, Lubin J, Troisi R, Sturgeon S, Brinton L, Hoover R. Menopausal estrogen and estrogen-progestin replacement therapy and breast cancer risk. JAMA. 2000;283:485-491.
One More Reason to Quit
Women have a greater risk of developing smoking-related lung cancer, and the reason may be in their genes. A gene for the protein that encourages lung cancer is more active in women than men, say researchers, and nicotine increases the activity even further.
Researchers at the University of Pittsburgh studied lung tissue samples from men, women, and lung cancer patients and found higher levels of gene activity in women across the board—even for non-smokers. This means that women are likely to develop lung cancer after much less smoking and at a younger age.
Shriver SP, Bordeau HA, Gubish CJ et al. Sex-specific expression of gastrin-releasing peptide receptor: relationship to smoking history and risk of lung cancer. J Natl Cancer Inst. 2000;92:24-33.
© 2000, PHOTODISC
But Genes Aren't Everything! Behavior Is Key…Because It Can Be Altered
While researchers, doctors, and even some at-risk individuals may focus their attention on breast cancer genes, they may be missing behavioral risk factors that are proven keys to lowering cancer risk. A study of 119 women who had signed up to be tested for genetic mutations that have been linked to breast and ovarian cancer, found that 27 percent did not exercise regularly and 39 percent did not eat five servings of fruits and vegetables per day. Relevant to skin cancer, 46 percent did not protect themselves from sun exposure.
"Seventy to 80 percent of cancers have been linked to behavioral factors," said Karen Emmons of the Dana-Farber Cancer Institute, who led the study. Five to 10 percent of cancers are due to genetic mutations, so doctors shouldn't lose sight of the many practical steps people can take to lower their odds, she noted.
As smoking is linked to lung cancer, people who exercise and eat plenty of fruits and vegetables, especially vegetarians, have a much lower risk of many forms of cancer as well as heart disease.
Emmons estimates that only 10 to 20 percent of women who get the genetic test are also told how they can reduce their overall risk of cancer. The study supports the need for doctors to do a better job in promoting preventive steps.
Emmons KM, Kalkbrenner KJ, Klar N, Light T, Schneider KA, Garber JE. Behavioral risk factors among women presenting for genetic testing. Cancer Epidemiol Biomarkers Prev. 2000;9(1):89-94.
Vegetables Reduce Risk for Prostate Cancer
Men who ate three or more servings of vegetables per day had a 48 percent lower risk of prostate cancer compared to those who ate less, according to researchers at the Fred Hutchinson Cancer Research Center. Cruciferous vegetables such as cauliflower, broccoli, Brussels sprouts, sauerkraut, and coleslaw possessed the strongest risk-reducing effect. It is believed that the array of phytochemicals in vegetables activate enzymes that help weaken cancer-causing agents in the body.
The study looked at the associations of total fruit and vegetable consumption—as well as specific types of fruits and vegetables—with prostate cancer risk in 1,230 men aged 40 to 64. By studying younger men, researchers were better able to assess the impact of lifestyle factors such as diet on cancer risk.
Cohen JH, Kristal AR, Stanford JL. Fruit and vegetable intakes and prostate cancer risk. J Nat Can Ins. 2000;92:61-68.
Real Garlic May Protect against Cancer
Eating a clove each day appears to reduce stomach cancer risk by half, confirms a recent analysis of 17 studies on garlic. People who ate six cloves of garlic per week had one-third the risk of developing colon cancer as well.
Researchers, who looked at more than 100,000 people in several countries, believe that the key protective ingredient is allicin, which is also found in onions, scallions, leeks, and chives. Allicin appears to inhibit cancer growths and detoxify carcinogens in the body, say scientists at the University of North Carolina at Chapel Hill. It also inhibits Heliobacter pylori, the ulcer bug linked to stomach cancer.
Raw cloves appear most powerful, although letting a meal sit after cooking allows allicin to regenerate its protective power.
© 2000, PHOTODISC
More Cancer Deaths among African-American Women
African-American women with breast cancer are 67 percent more likely to die from the disease than their Caucasian counterparts. Researchers at the University of Iowa examined survival data of more than 135,000 U.S. women diagnosed with breast cancer between 1988 and 1995.
Several factors contribute to the disparity. African-American women tend to be diagnosed with breast cancer at an earlier age—33 percent are under 50 years old as compared to 25 percent of whites—and usually have more aggressive tumors, which have often spread throughout the body by the time the disease is diagnosed. Also, cultural barriers and less access to screening programs may prevent some African-American women from having regular mammograms. Exposure and susceptibility to chemical toxins, poverty, lower levels of education, and obesity in some populations may also play a role.
Joslyn SA, West MM. Racial differences in breast carcinoma survival. Cancer. 20001;88(1):114-123.
Does Mammography Save Lives?
There is no reliable evidence that screening decreases breast cancer mortality" was the conclusion of Danish researchers after reviewing eight studies on mammography.
The studies involved roughly half a million women in the U.S. and abroad. Although variations in age and socioeconomic status may have skewed the results in six of the trials, the researchers determined that the two best controlled trials showed mammography screening to have no effect on risk of death from breast cancer.
The review was prompted by a 1999 Swedish study that showed no decrease in cancer deaths from screening, even though mammography has been recommended there since 1985.
Asian countries which still adhere to traditional dishes of rice and vegetables with little meat and dairy products still have much lower rates of breast cancer than those in the West. Alcohol and "hormone replacement" increase risk, while exercise and plant-based diets appear to reduce it.
Gotzsche PC, Olsen O. Is screening for breast cancer with mammography justifiable? Lancet. 2000;355(9198):129-134.