CancerNet from the National Cancer Institute ****************************************************************************** * CANCER FACTS * * National Cancer Institute * * National Institutes of Health * ****************************************************************************** Studies Under Way To Assess Environmental Exposures and Risk of Breast Cancer A study in the April 21 issue of the Journal of the National Cancer Institute (JNCI) showed that women with high blood levels of DDE, a chemical from the pesticide DDT, had an increased risk of breast cancer. The women who participated in the study were from New York City, which is in an area of the United States where breast cancer rates are higher than expected. This report adds to a growing body of research that raises concern about the potential risk of breast cancer from exposure to fat-seeking halogenated chemicals such as the now-banned DDT (dichlorodiphenyltrichloroethane, an organochlorine pesticide) and PBBs (polybrominated biphenyls). While some of the regional variation in breast cancer death rates may be due to differences in the prevalence of known breast cancer risk factors, such as beginning menstruation before age 12 and bearing children after age 30, concerns remain that environmental hazards are partially to blame. In addition to pesticides such as DDT, questions have been raised about the possible effects of polychlorinated biphenyls (PCBs), vehicle exhaust, contaminated drinking water, extremely low frequency electromagnetic fields, chemicals formed in food by high temperature cooking methods, and many other occupational and environmental exposures. The National Cancer Institute (NCI) has set breast cancer as a major research priority and will spend $196.6 million for research on the disease in 1993. NCI and NCI-funded scientists across the country are exploring a wide variety of issues related to the causes, detection and diagnosis, treatment, rehabilitation, and prevention of the disease. Several studies assessing exposures to organochlorines and other fat-seeking halogenated compounds are expected to provide vital information on potential breast cancer risk factors in the environment. Northeast Studies Scientists at NCI are surveying populations with high breast cancer mortality in the Northeast and mid-Atlantic regions of the United States and areas of low breast cancer mortality in the South to obtain detailed information on known risk factors and selected environmental exposures. In conjunction with researchers from the National Institute of Environmental Health Sciences (NIEHS), NCI researchers will support research to determine how recognized risk factors and specific environmental exposures may be contributing to the excess breast cancer deaths. Some of the environmental exposures researchers are being encouraged to look at are electromagnetic fields, pesticides, and contaminants in the food and water supply. California Health Maintenance Study NCI-funded researchers are also studying women enrolled in the Kaiser Permanente prepaid health maintenance plan in California. Using previously collected samples of serum and newly collected breast biopsies and breast tumor tissue, the researchers will look for mutations of the p53 gene, which normally prevents a cell from turning cancerous. In collaboration with scientists from the NIEHS, the researchers will also search for residues of fat-seeking chemicals, such as organochlorine pesticides. Michigan Study In the mid-1970s, contamination of animal feed with PBBs on about 600 farms in Michigan led to widespread contamination of farm animals, milk, and residents in the area. Since 1978, NCI has been collaborating with the Centers for Disease Control and Prevention and the Michigan Department of Public Health to monitor the health effects of this exposure and to collect blood samples from the 4,000 residents with the highest exposures. These people are being evaluated in several case-control studies, including one in which the researchers will compare the levels of PBB residues from breast fat of women who are diagnosed with breast cancer to the level of residues from women without cancer. Alabama Survey Another group of individuals exposed to high levels of the pesticide DDT from about 1947 to 1971 live in a rural area in Alabama. During that time, a chemical company discharged tons of DDT waste into a nearby river. Residents in the area regularly ate fish from this river. This exposure was discovered in 1979, which led the CDC to investigate. CDC found that blood levels of DDE were 10 times higher in this group than the average level elsewhere in the country. This group is under medical surveillance and a health survey is being completed for all residents in the area. The NCI is planning to utilize the survey results in developing a case-control study to compare DDE residues in breast fat and blood of women with breast cancer to residues in individuals without cancer. In collaboration with the University of Alabama School of Nursing, NCI is developing a screening mammography program for the residents. Turkish Cohort A group of about 4,000 people in southeast Turkey accidentally ingested extremely high levels of the grain fumigant hexachlorobenzene (HCB). The result was an epidemic of severe HCB poisoning between 1955 and 1961. At one time, the neonatal death rate reached 100 percent because HCB is selectively taken up by the breast and secreted into breast milk. The NCI is having difficulties beginning a study in this group because of military activity and civil unrest in the area where the group lives. Farmer Study The Agricultural Health Study, a contract-supported intramural research project being carried out in collaboration with NIEHS and the Environmental Protection Agency, is the largest study ever undertaken to evaluate the relationship between exposures characteristic of an agricultural lifestyle and risk for cancer. The study will involve about 100,000 farmers, their spouses, and their children, and will assess exposures to such agents as pesticides, chemical solvents, engine exhausts, animal viruses, and sunlight. Cancer risks associated with diet, cooking practices, and the chemicals resulting from the cooking process will also be examined. Earlier this year, 5-year contracts were awarded to the University of Iowa College of Medicine, Iowa City, and Survey Research Associates, Durham, North Carolina, to carry out the study in their respective states. Iowa and North Carolina have large populations of farmers and pesticide applicators. The cohort will be followed for more than a decade to compare actual cancer cases and deaths to expected rates. As cancer cases are diagnosed, breast cancer cases will be incorporated into special studies to collect even more detailed information on possible exposures and risk factors. # # # The Cancer Information Service (CIS), a program of the National Cancer Institute, is a nationwide telephone service for cancer patients and their families, the public, and health care professionals. CIS information specialists have extensive training in providing up-to-date and understandable information about cancer. They can answer questions in English and Spanish and can send free printed material. In addition, CIS offices serve specific geographic areas and have information about cancer-related services and resources in their region. The toll-free number of the CIS is 1-800-4-CANCER (1-800-422-6237). __________________ The study in JNCI is entitled "Blood Levels of Organochlorine Residues and Risk of Breast Cancer" by Mary S. Wolff and colleagues.  Date Last Modified: 4/93 .