Overview of the Long Island Breast Cancer Study Project (Past Initiative)
The Long Island Breast Cancer Study Project (LIBCSP) is a multistudy effort to investigate whether environmental factors are responsible for breast cancer in Suffolk and Nassau counties (Long Island), NY, as well as in Schoharie County, NY, and Tolland County, CT. The investigation began in 1993 under Public Law 103-43, with funding and coordination provided by the National Cancer Institute (NCI), in collaboration with the National Institute of Environmental Health Sciences (NIEHS).
Collectively, the LIBCSP consists of more than 10 studies and the development of a research tool – the Geographic Information System for Breast Cancer Studies on Long Island (LI GIS). The studies include human population (epidemiologic) research projects, the establishment of a family breast and ovarian cancer registry, and laboratory research on mechanisms of action and susceptibility in development of breast cancer.
Findings from all of the studies have been reported. In addition, the LI GIS has been completed and is available to investigators with approved protocols to explore potential relationships between environmental exposures and breast cancer, as well as other diseases. There is no fee for investigators to use the LI GIS.
In summary, the LIBCSP studies have not identified any environmental factors that could be responsible for the elevated incidence of breast cancer on Long Island. No association was found between exposure to organochlorine compounds and increased risk of breast cancer. The compounds examined included the organochlorine pesticides DDT (and its metabolite DDE), dieldren, and chlordane, or with polychlorinated biphenyls (PCBs).
PCBs are a group of organochlorine compounds found in coolants and lubricants in transformers, capacitors, and other electrical equipment, and some consumer products. Both DDT and PCBs persist in the environment although DDT and use of PCBs in new equipment have been banned in the United States since the 1970s.
The investigators also did not find an association between exposure to electromagnetic fields (EMFs) and increased risk of breast cancer.
Three suggestions of associations between certain environmental exposures and increased risk of breast cancer were found. However, these possibilities would require confirmation in other population studies. The three findings concerned exposure to polycyclic aromatic hydrocarbons (PAHs), which are ubiquitous pollutants caused by incomplete combustion of various chemicals including diesel fuel and cigarette smoke (see Dr. Gammon below); proximity to hazardous waste sites (see Dr. O'Leary); and the organochlorine compound ß-hexachlorocyclohexane (ß-HCH) (see Dr. Stellman).
Some of the projects that comprise the LIBCSP are described below.
Breast Cancer and the Environment on Long Island and Follow-Up Study
Marilie Gammon, Ph.D.
This population-based, case-control study titled "Breast Cancer and the Environment on Long Island" is the cornerstone of the LIBCSP. It is the largest case-control study of the LIBCSP and was led by Marilie Gammon, Ph.D.
The study investigated whether certain environmental exposures increased risk of breast cancer in Long Island women including the organochlorine pesticides DDT (and its metabolite DDE), dieldrin, and chlordane, PCBs, and PAHs.
All women in Nassau and Suffolk counties who were newly diagnosed with breast cancer during a one-year period beginning in August 1996 (cases) were eligible to participate in the study. A comparison group (controls) of women who did not have breast cancer was randomly selected from the two counties. Altogether, 1,508 women who were newly diagnosed with in situ or invasive breast cancer, and a similar number of women who did not have the cancer participated in the study. (In situ breast cancer is early cancer that has not spread to neighboring tissue.)
The major findings were:
- The organochlorine compounds DDT and its metabolite DDE, dieldren, and chlordane, and polycyclic biphenyls (PCBs) were not associated with the elevated rates of breast cancer on Long Island.
- Many of the well-known breast cancer risk factors were confirmed among women on Long Island. These risk factors included increasing age, having a family history of breast cancer, having a first child at a later age (age 28 or older in this study), never having given birth to a child, and having higher income.
- PAHs were associated with a modest increased risk of breast cancer. That is, women in the highest quartile of levels of exposure to PAHs had a 50 percent increased risk of breast cancer compared to women in the lowest quartile of exposure. This PAH finding is consistent with a few, much smaller epidemiologic studies and suggests the need for additional research in other populations. (Compared to other known risk factors for cancer, a 50 percent increase in risk is modest. For example, smoking increases the risk of developing lung cancer by 900-1,000 percent. A family history of breast cancer increases risk by 100-200 percent.)
In 2001, Dr. Gammon received another NCI grant to conduct a follow-up study on 1,098 women with breast cancer who participated in the parent population-based case-control study. This study investigated whether the environmental factors examined in the parent study and other lifestyle factors influenced disease-free survival and overall survival in Long Island women. Among the findings, the investigators found that adult weight gain is associated with decreased survival from breast cancer. They did not find strong support for an association between PAHs and an effect on survival from breast cancer.
Dr. Gammon and other researchers continue to analyze data that were collected for the parent case-control study and the follow-up study and report on breast cancer susceptibility.
Electromagnetic Fields and Breast Cancer M.
Cristina Leske, M.D., M.P.H.
A subgroup of the women who participated in Dr. Gammon's initial study and who had lived in their current residences in Nassau and Suffolk counties for at least 15 years participated in a study to determine if electromagnetic fields (EMFs) were associated with increased risk of breast cancer. This study was led by M. Cristina Leske, M.D., M.P.H., of Stony Brook University.
Dr. Leske and colleagues conducted a comprehensive home assessment of the study participants' exposure to EMFs through personal interview and by taking a variety of EMF measurements within and around the outside of the home. There were 576 women who had been diagnosed with breast cancer (cases) and 585 women who had not had the cancer (controls) who participated in this study.
The investigators did not find residential exposure to EMFs to be associated with risk of breast cancer.
Environmental Exposures and Breast Cancer on Long Island
Erin O'Leary, Ph.D.
Erin O'Leary, Ph.D., while at the University of Buffalo, conducted a nested, case-control study to determine if residence in close proximity to hazardous waste sites, toxic release inventory sites, prior land use (for example, farm land), and exposure to various chemicals in drinking water may be associated with risk of breast cancer on Long Island.
The Long Island study population was selected from a cohort of New York State residents in 1980. Data on 105 women who had been diagnosed with breast cancer (cases) between 1980 and 1992 were compared to data on 210 randomly selected women who did not have the cancer (controls), and who were age and race matched to cases.
With no proven way to measure an individual's historical environmental exposure to most chemicals in the environment, Dr. O'Leary relied on proxies to estimate exposure. She linked data on each woman's residence with data on historical land use, drinking water, and proximity to hazardous waste sites and toxic release inventory sites, and estimated historical exposures to organochlorine and carbamate pesticides, and other chemicals. She used geographic information software to calculate the distance between residences and the point sources of pollution.
In this exploratory study, she found that women who lived within 1 mile of hazardous waste sites containing organochlorine pesticides had an increased risk of breast cancer, after adjusting for known risk factors. The small sample size limited the study's statistical power, however, and the findings could have been due to chance. In addition, no association was found between breast cancer and pesticides detected in drinking water or residence on or near agricultural land.
Long Island, Schoharie County, and Tolland County
Steven D. Stellman, Ph.D., and Tongzhang Zheng, Ph.D.
Among the other LIBCPS population studies, Steven D. Stellman, Ph.D., while at the American Health Foundation, Valhalla, NY, and colleagues conducted a hospital-based case-control study to investigate risk of breast cancer in relation to levels of organochlorine compounds, such as DDT and polychlorinated biphenyls (PCB).
The study included 232 women who had surgery for breast cancer (cases) and 323 women who had surgery for non-cancerous breast disease or for conditions unrelated to the breast (controls). The women were treated between 1994 and 1996 at Long Island Jewish Medical Center, New Hyde Park, NY, and North Shore University Hospital, Manhasset, NY.
The investigators focused on 7 organochlorine pesticides and 14 variants (types) of PCBs. The organochlorine pesticides or their products measured were: DDT and two related chemicals, DDD and DDE (the main breakdown product of DDT in the environment and in the body); oxychlordane and trans-nonachlor, which are products of chlordane; ß-hexachlorocyclohexane (ß-HCH), and hexachlorobenzene (HCB).
They did not find an association between past exposure to organochlorine compounds or PCBs with one exception. They found an increased risk of breast cancer recurrence associated with the organochlorine compound ß-HCH, but the number of study subjects was small and the finding would need confirmation in other research.
Other case-control studies on the environment and breast cancer were conducted in Schoharie County, led by Dr. Stellman, and in Tolland County, CT, led by Tongzhang Zheng, Ph.D., of Yale University, New Haven, CT. However, the numbers of women diagnosed with breast cancer in these two locations were too small to permit valid analyses.
Breast Cancer Family Registry
The Metropolitan New York Registry of Breast Cancer Families was established at Columbia University, NY, to enroll families with a history of breast or ovarian cancer who would be willing to participate in studies. This registry was funded initially under the LIBCSP and now continues to be supported through NCI's regular grant program as one of six sites that comprise the Breast Cancer Family Registry (B-CFR).
Geographic Information System
The Geographic Information System for Breast Cancer Studies on Long Island (LI GIS*) was developed under a contract awarded by NCI and completed in 2001. A geographic information system (GIS) is a powerful computer system that permits layers of information specific to a location to be superimposed and manipulated.
The LI GIS is designed primarily to study potential relationships between environmental exposures and breast cancer in Nassau and Suffolk counties, NY, but also can be used to study other diseases. It is available at no charge to investigators with approved protocols.
The LI GIS has more than 80 in-depth, high-quality datasets. This rich database includes:
- Topographic data, including locations of roads, water features, parks and landmarks, and base maps that define legal boundaries and serve as reference points;
- Demographic data, including the age, race, sex, and income of the population;
- Health outcome data, including relative breast cancer incidence and health facilities data;
- Environmental data, including land use and cover; railroads; traffic; water use and potential sources of water pollution; chemical releases into water, air, and soil; electrical power lines; information on toxic chemicals and hazardous and municipal waste; and radiation; and
- Data with less detail and geographic precision for areas within 31 miles of the two Long Island counties, and very limited data for areas within a 100-mile radius from the midpoint of the boundary line between the two counties. The extended area includes counties in Connecticut, New Jersey, New York, Pennsylvania, Rhode Island, and Massachusetts.
The LIBCSP has been a complex research effort that has charted new ground in environmental epidemiology The assessment of environmental exposures and determining their relationship with cancer is difficult. The investigators developed new environmental measurement and laboratory techniques, and explored new ways to study relationships between the environment and breast cancer.
Readers who wish to know more about the LIBCSP may be interested in a review paper "Science and Society: The Long Island Breast Cancer Study Project," Nature Reviews Cancer 2005 Dec;5(12):986-94.
NCI and NIEHS continue to support research on breast cancer and the environment. Readers may be interested in learning about four Breast Cancer and the Environment Research Centers (BCERCs) that have been funded by the two Institutes since 2003. This innovative project focuses on determinants of puberty in young girls and in animal models, and the effect of environmental factors on the process. This developmental window is thought to be important in breast cancer.
* The LI GIS was referred to under the acronym GIS-H in its early years.
Questions about the overall LIBCSP may be directed to:
Christie Kaefer, M.B.A., R.D.
Epidemiology and Genomics Research Program
Division of Cancer Control and Population Sciences
9609 Medical Center Drive, Rm. 4E230, MSC 9763
Bethesda, MD 20892
Telephone: (240) 276-6743