Community
Breast Cancer Mapping
Huntington, Long Island
by Dr.
Scott Carlin, Southampton College, Long Island University
Abstract
The
Huntington Breast Cancer Action Coalition (HBCAC) recently
completed a survey of town residents regarding breast cancer.
This paper reports on recent efforts to map those surveys
using ArcView GIS. Breast cancer cases will be overlayed
onto various environmental maps, such as local toxic sites,
to look for general patterns among these variables. Basic
statistical analyses will also be summarized.
Introduction
Breast
cancer now accounts for almost one out of every three cancer
diagnoses among women. It is the most common form of cancer
for women, excluding non-melanoma skin cancers. Breast cancer
is also the leading cause of death for women between the
ages of 35 and 54 (1). While many cancer rates have fallen
in recent years, breast cancer rates continue to climb (2).
Huntington Breast Cancer Action Coalition (HBCAC) was formed
in 1993 to educate the residents of Huntington, New York
about their breast health . A similar coalition on Long Island,
in neighboring West Islip, had formed in 1992, and two years
later had developed a "'first of its kind' door-to-door
demographic mapping survey (3). Similarly, HBCAC decided
to launch a more detailed and comprehensive survey of Huntington
women over the age of 25. Following from West Islip's experiences,
HBCAC knew from the outset that they wanted to map their
survey. Maps were proving to be powerful tools for raising
public awareness about the prevalence of breast cancer on
Long Island. The Long Island Breast Cancer Maps are powerful
examples of community mapping.
Community
mapping projects have become an important tool for informing
and empowering local citizens. As the Common Ground Community
Mapping Project has stated, "Through the process of
creating and revising maps, communities are better equipped
to proactively address their interests and concerns"
(4). Community maps can touch upon a wide range of spatial
attributes associated with community life. Through maps, community
groups can address environmental, health, economic development,
social welfare, historic preservation, land use, demographics,
natural hazards and a host of other issues. Using GIS overlays,
community mapping projects can be an effective tool for looking
at the linkages among different sets of issues. For example,
we can use GIS to look at the way breast cancer patterns correlate
with demographic or environmental factors. Many of these land
features have traditionally been mapped by local planners,
academics, or private corporations. If that is true, then what
makes community mapping innovative?
First,
community maps raise community participation rates by engaging
a broad cross-section of the community in mapping projects,
most of whom have little or no prior background in mapping.
In Huntington, HBCAC had no internal mapping resources. HBCAC
knew, however, that they wanted to map breast cancer, and
they sought out volunteers and paid interns who could help
make that goal a reality.
Second,
community maps are important educational tools. Maps allow
many residents to better understand local issues in a more
concrete fashion. Although the residents of Huntington knew
breast cancer was an important issue, the maps helped the
community to understand the widespread prevalence of this
disease.
Third,
community maps are a valuable tool for critical thinking.
They are not simply learning about their communities by reading
maps; they are also asking questions of the maps and manipulating
the maps to provide those answers. Through that process,
citizens begin to see their community in a new light. Through
its maps and other campaigns, HBCAC wants local residents
to question whether pest-free lawns are worth the risks of
potentially higher breast cancer rates, or if residents really
should ignore the broad-based usage of toxic substances in
their community.
Fourth,
community mapping projects are distinctive because local
citizens, often working through non-profit organizations,
control the mapping process. They control what is to be mapped,
how maps are to be distributed, and how they are going to
be publicized. This shift can lead to mapping innovations,
like breast cancer maps. Citizens often bring new perspectives
to mapping, highlighting previously ignored issues and helping
to change local public agendas. Maps can strongly influence
community perceptions. In Huntington, HBCAC knew they wanted
to use maps to explore the relationship between environmental
contamination and breast cancer. They wanted to use their
maps to heighten public awareness of the usage of toxic substances
in Huntington and to explore whether those substances were
affecting local breast cancer rates.
Local
control of the mapping process is particularly important
because many community mapping projects focus on politically
sensitive issues. For that and other reasons, relying upon
government agencies for these maps can often lead to frustration.
Despite that tension, much of the information that community
mapping projects draw upon come from governmental data sources
and often require the cooperation of government officials.
Breast
cancer maps provide a good illustration of these tensions.
Debates about privacy and data confidentiality have been
a frequent source of conflict between government officials
and grassroots breast cancer organizations. From the perspective
of government, releasing detailed data about breast cancer
(or any cancers) can be an invasion of privacy. People's
lives can be seriously disrupted by the public release of
data describing their health histories. There's a fear that
local citizens will be stigmatized or that individuals may
lose their jobs. From the perspective of community health
advocates it is essential that the public understand the
extent of disease within their community. Detailed community
maps provide a powerful visual tool for exposing the ubiquity
of breast cancer on Long Island.
Fifth,
community mapping projects can reveal in powerful ways how
much the community's goals differ from their government's
goals. Community mapping efforts often begin in a fairly
naive way with local citizens believing that by creating
maps and mixing new and old sources of data in compelling
ways they can open a space in public discourse for considering
new alternatives. What community groups frequently learn
is that the pace of change in government is often much slower
than they anticipated or that key elements of their government
are hostile to their plans. Today, a wide chasm has opened
up in the environmental health field. On the one side are
government officials and academics, who feel that mapping
exercises should continue to focus on research. These individuals
argue that we do not understand the causes of breast cancer,
but improved research, particularly genetic research, and
to a much lesser extent mapping research, should proceed
and hopefully begin providing the answers we seek.
On
the other side are the environmental health advocates and
some environmental scientists. They believe cancers, like
breast cancer, are a direct product of industrial era chemicals.
In particular, much attention is now focusing upon groups
of chemicals that affect the body's hormonal system. In Our
Stolen Future, Dr. Theo Colburn and others argue that
synthetic chemicals mimic natural hormones and trigger hormone-related
cancers, like breast cancer (5).
Therefore
in the area of breast cancer, maps have become deeply politicized.
At one level community-based breast cancer maps are about
raising public education and awareness. But, at another level,
these maps are about changing our understanding of environmental
health. In her path breaking book, Silent Spring,
Rachel Carson begins by noting how intimately we
live with modern chemicals - how we eat, drink, and breathe
pesticides into our bodies without pausing to consider the
devastation that these chemicals cause. Dr. Sandra Steingrabber,
author of Living Downstream, also emphasized these
issues of intimacy. For example, she discussed how mothers
pass along PCBs and other chemicals to their newborn children
through their breast milk (6).
While
community-based maps do not create a two dimensional portrait
of these intimate health relationships, they do paint a powerful
picture of communities suffering silently, block after block,
through devastating illness. Breast cancer maps are a powerful
tool for breaking that silence and forcing the public to
confront its secrets.
Surveying
Women in Huntington (7)
In
the early 1990's the Town of Huntington had a population of 200,000
(90% white). HBCAC decided to survey the entire town with the goal
of mapping and studying breast cancer and reaching a 50% response
rate. The survey was written by Roger Grimson, PhD, biostatistian
at the Department of Preventive Medicine at the University Medical
Center at Stony Brook, along with physicians at Huntington Hospital
and local breast health activists. The survey was mailed out to
over 68,000 households in September 1993, all known households
in the town. The survey was sponsored by Huntington Hospital and
supported by Huntington Town officials and community volunteers.
The survey was written in both English and Spanish and publicized
in community newspapers, radio and television stations, local Parent
Teacher Associations (PTAs), and through other civic and religious
groups. In response, over 15,500 surveys were filled out and returned.
In
June 1994, the Junior League of Long Island and Suffolk County
Health Partnership sponsored a second mailing, targeting non-respondent
households. HBCAC collected another 9,000 surveys.
HBCAC
volunteers entered the surveys into a computer. Each survey was
reviewed, assigned a record number, and supplied with a 9-digit
zip code if not provided (Nine-digit zip code was obtained manually
from US Postal Zip Code books). The surveys were batched in groups
of 25. It took 1 to 1½ hours to enter a batch into the computer
database. The initial data entry program was written in 1993 by
volunteers in DOS and later revised for Windows.
A
Town Hall Meeting was held on the evening of March 25, 1995, where
HBCAC presented preliminary statistics for the 18,955 Breast Health
Surveys they had tabulated. Greenman-Pedersen Inc. geocoded and
mapped the survey data. Of the respondents, 5,421 indicated that
someone in their family had breast cancer (29%); 939 respondents
indicated they themselves had breast cancer at some time (5%).
In
July 1996 HBCAC completed a third mailing, bringing in another
5,000 surveys. Also, HBCAC utilized the Huntington Hospital, Town
Hall, local libraries, doctor offices, and beauty parlors to distribute
and collect additional surveys. Lastly, volunteers visited specific
addresses to urge non-responders to fill out the survey in a "Neighbor-to-Neighbor
Campaign." As a result, another 1,300 surveys were collected,
bringing the gross total number of surveys up to 30,800.
Errors
did occur in the data entry process. Upgrading the data from DOS
to Windows proved particularly problematic. The date-of-birth field
was lost on thousands of surveys and had to be re-entered. Again,
volunteers spent countless hours making the necessary corrections.
The
database was also checked for duplicates, which were removed. A
more careful verification of the survey was initiated by epidemiologist
Erin O'Leary, PhD, and initially consisted of a random selection
of 10% of the records, which were compared to the original hard
copy of the surveys. When these analyses were complete, 23,777
surveys were deemed acceptable for analysis. The difference between
the gross and final count was primarily due to duplicate surveys.
In the fall of 2000, after seven years of work, the survey was
completed.
In
the Spring of 1999, HBCAC, with assistance from Long Island University,
was awarded a Conservation Technology Support Grant (CTSP), which
provided the organization with sufficient resources to do its own
breast cancer mapping. Again with the assistance of Greenman-Pedersen,
Inc. the final surveys were geocoded with data provided by Geographic
Data Technology (GDT), Inc. In January, 2001, HBCAC presented their
preliminary findings from the completed survey.
Initial
Survey Results
HBCAC
asked Dr. Erin O'Leary to analyze the completed survey. Below are
some highlights from her findings (8):
| Total
number of Respondents |
23,777 |
| Number
of women in Huntington, over age 25 |
63,665 |
| Response
Rate |
37% |
| Number
of women diagnosed with breast cancer, over age 25 |
1,218 |
| Breast
Cancer Prevalence Rate |
5.1% |
| Average
age of respondents |
51
years |
| Average
age of women ever diagnosed with breast cancer |
61
years |
| Average
years in residence |
17
years |
| Average
years in residence of women over 25 with breast cancer |
23
years |
| Average
age at breast cancer diagnosis |
53
years |
Mapping
Breast Cancer in Huntington
Breast
cancer mapping in Huntington is still in an early phase of development.
The mapping process is envisioned as a three stage process. The
first stage is now complete. Cancer cases have been geocoded and
mapped using ESRI's ArcView software. The zip+4 geocoded centroids
provided by GDT enabled HBCAC to successfully geocode over 99%
of the survey. Greenman Pedersen, Inc. printed these maps on a
large format printer. The maps are now on display in local libraries.
The
second stage of the analysis is to examine the data for possible
cancer clusters. This analysis will begin this summer and will
hopefully be completed by the end of the year. HBCAC has been working
with two software packages: Dr. Martin Kulldorff's Satscan Software
and Dr. Gerry Rushton's spatial filtering software.
The
third phase of the research is to correlate breast cancer patterns
with known environmental hazards in the region. HBCAC has been
collecting environmental data sets and done some very preliminary
analysis with those datasets.
Stage
One: Geocoding and Mapping Breast Cancer in Huntington
Huntington
is located in Suffolk County, New York. Breast cancer cases were
mapped in two ways.
First,
we overlayed respondents who ever had breast cancer onto respondents
who never had breast cancer. Of the 23,777 respondents, 5% had
breast cancer in their life. Second, we mapped the percent of respondents
who ever had breast cancer at each zip+4. Many of these percentages
were 100%, reflecting the fact that the only respondent from that
zip+4 had been diagnosed with breast cancer. Those zip+4 with no
breast cancer cases (0%) were not mapped, to focus upon positive
cases.
Response
rates (Number of respondents/female population over 25) and prevalence
rates (have breast cancer/total respondents) were mapped by zip
code to provide some basic statistics about the distribution of
cases. Response rates were high in Huntington (11743) at 51% and
Centerport (11721) at 52%, exceeding the 50% response goal original
set by HBCAC. These were the only two zip codes to meet the original
goal. Response rates were surprisingly low in Commack (11725) at
17%, Cold Spring Harbor (11724) at 22%, and Greenlawn (11740) at
27%. Prevalence rates were highest in Cold Spring Harbor at 7%,
but this may simply be a product of the low response rate in that
community.
These
maps are descriptive and not analytical, nevertheless they are
a powerful tool for raising breast cancer awareness. These maps
were first showcased at a community forum in January 2001. The
maps will continue to be displayed at local libraries throughout
the year. So far, the public's response to these exhibits has been
very strong. Local residents are able to carefully examine the
maps and reflect upon the information they convey. Many residents
find the maps to be shocking, the maps starkly illustrate the prevalence
of this disease within their community.
Partially
in response to the grassroots breast cancer mapping efforts on
Long Island, New York State released cancer maps for the state.
In 1999, they released county level breast cancer maps. Local breast
cancer organizations complained that those maps were hardly sufficient
for their needs. In response, zip code level maps were released
in 2000. Local organizations were also disappointed with these
maps. In both cases the maps lacked sufficient detail to identify
specific cancer clusters. State officials countered that they could
not provide more detailed mapping information without compromising
patients' confidentiality. Yet the averaging and smoothing techniques
that these maps utilize mutes the appearance of problems. The choropleth
shading techniques used by the state dull the sense of crisis felt
by grassroots health advocates. On the state's maps there are a
few areas where rates are significantly higher than "expected," but
most communities on Long Island are not significantly above the "expected" rates.
Yet how does the state calculate these expected rates? They are
not based on national or international standards, but rather they
are calculated against state-wide averages. Yet, New York State
has among the highest rates of breast cancer in the country. It
is precisely these slights of hand that upset local health advocates.
The
dot density maps used by HBCAC present a very different picture
of breast health in Hungtington. Breast cancer rates in most of
Huntington's communities are within 15% of the expected rates,
according to the state's maps (9). But HBCAC's dot density maps
provide a vivid picture that a serious problem exists, a problem
that did not exist 40 or 50 years ago. Again, community maps allow
us to look at problems from perspectives that government agencies
(and private corporations) are reluctant or unable to share.
Stage
Two: Cancer Cluster Analysis
In
recent years much attention and controversy has emerged around
the issue of cancer clusters. Scientific experts are reluctant
to label neighborhoods with high incidence of disease a "cluster," when
they don't understand the causes of these high rates. Lacking a
well-established disease agent, many clusters do not meet standard
statistical thresholds for being significantly different from background
cancer rates. Cancers are never going to be uniformly distributed
across a geographic region. Some clustering is inevitable and can
be explained away as due purely to chance. Like marbles dropped
from a bag, some cancers "land" closer to other cases.
Local residents generally do not like these explanations because
many communities live near potentially hazardous land uses. Many
residents feel that such explanations are too dismissive of their
health fears.
HBCAC,
therefore, found itself in a unique position. HBCAC wanted to work
with the same tools that scientists were using to investigate their
datasets. By undertaking their own analyses, HBCAC did not have
to depend upon government agencies for this research and did not
need to worry that results were not being honestly provided back
to the community. But, HBCAC also learned it had a responsibility
to understand and to utilize scientific methodologies if they wanted
others to take their results seriously.
Of
the 1,250 cases of breast cancer in HBCAC's database (this total
includes some cases outside of Huntington), about half had lived
in their current homes for fifteen or more years prior to their
breast cancer diagnosis. If the residency is reduced to ten years,
then the total number of cases rises by 153 to 784 cases. Either
way, a significant number of the known breast cancer cases in the
dataset cannot be used for cluster analysis because of the need
to account for a minimum of 10 years of residency to relate environmental
contaminants to spatial patterns of breast cancer. Even this is
inadequate, because household exposure may not be the most relevant
pathway for understanding these spatial distributions. Nevertheless,
this is the best that we can do with the existing survey data.
The
cluster research will also try to account for the fact that cancer
cases in the town were diagnosed in very different time periods.
Therefore, it may be useful to control for the timing of diagnosis
in looking for cancer clusters in the community.
Stage
Three: Mapping Environmental Contaminants
HBCAC,
like many other breast health coalitions, have focused a lot of
their resources on trying to reduce the public's exposure to hazardous
chemicals. For example, HBCAC distributes "I am fed naturally" signs
for local lawns to encourage home owners to not use potentially
harmful pesticides on their lawns. One of the major goals of this
aspect of the mapping project is to raise public awareness about
the widespread usage of chemicals in the Huntington community and
to help reduce the public's exposure to harmful chemicals.
A
major part of HBCAC's mapping project is to identify toxic sites
in Huntington and to map those sites in relation to the breast
cancer survey data. HBCAC has been collecting data on a wide range
of land uses and toxic emitters for its GIS project. HBCAC now
has GIS coverages for: dry cleaning establishments, gas stations,
landfills and dumps, golf courses, land use in 1980, land use in
1994, toxic release inventory sites, current and archived U.S.
E.P.A. Superfund sites. HBCAC would also like to map the region's
water supply distribution system and continues to work with local
water supply providers to gain that information.
One
major issue that health organizations are just beginning to confront
is that industrial sources of contamination, while significant,
may not explain the widespread distribution of cancers, like breast
cancer. Lifestyle factors may also play a large role. These lifestyle
factors probably stem from multiple sources and could include low
levels of contaminants in drinking and bathing water, dairy and
meat products, pesticides, health care products, medical radiation,
plastics, fossil fuel combustion, etc. While the research is still
unclear on exactly which of these products is causing breast cancer,
researchers have begun focusing on man-made chemicals that mimic
bodily hormones like estrogen to explain rising breast cancer rates.
Many of the above substances have these properties.
While
HBCAC does not have survey data to understand these subtle lifestyle
effects for individuals, we can begin to look at the more concentrated
industrial pollution sites. As part of HBCAC's public presentation
last January, we examined sites listed on EPA's superfund list,
which includes both current superfund sites and sites that were
removed from further consideration for Superfund status. Most of
the sites on this list in Huntington are not superfund sites but
nevertheless, given that EPA was investigating these sites they
may have had pollution violations or other problems in the past.
We examined how breast cancer cases varied for women who lived
close to one of these sites as compared to women who lived further
away from these sites. We found that women who lived closer to
these sites did not have a higher risk of getting breast cancer. We
intend to do additional environmental analyses on this data in
the future.
Conclusions
When
I first began working with HBCAC on its survey, it wasn't clear
to me where this project would go. I was skeptical that a grassroots
mapping project could succeed where so many scientists had failed.
How could HBCAC help to define the causes of breast cancer or identify
new cancer clusters? But HBCAC's mapping project is much broader
in focus than these goals.
HBCAC's
map were recently center stage at a Congressional hearing held
in Garden City, Long Island. Senators Clinton (NY), Reid (NV),
and Chafee (RI), and the Long Island legislative delegation asked
a selected panel scientists and health advocates to discuss "Environmental
Contamination and Chronic Diseases. (10)" HBCAC's President,
Karen Miller, was one of those panelists, and three of HBCAC's
maps were placed on the stage alongside the elected officials.
The maps were filmed by a variety of news outlets covering the
event. At that event, Karen Miller asked the elected officials
to look at the maps and to understand that each survey respondent,
whether they had breast cancer or not, represented a woman who
wants better answers and is confident that detailed maps, like
HBCAC's, can be developed without compromising her privacy.
The
mapping project has already influenced the government's view on
health maps. Pressure on New York State from organizations like
HBCAC played a role in pushing the state to develop cancer maps
for the state and contributed to the state's decision to release
zip code level maps. But New York State must do more. While the
government should continue to protect patients' privacy, it's also
true that GIS tools can be used with greater spatial detail without
compromising that privacy. HBCAC's maps are a powerful reminder
of how much momentum exists at the grassroots level for stronger
governmental responses to this issue.
While
we are just beginning the process of understanding the analytical
value of mapping breast cancer in Huntington, the maps have had
a powerful effect on local awareness of breast cancer. Hopefully
more women and government officials will pay closer attention to
breast health issues. But hopefully, by mapping cancer and mapping
local sources of contamination, the maps can also play a role in
reducing the toxic burden on our bodies.
In
conclusion, community mapping efforts offer communities a powerful
tool for thinking about localities. Maps do indeed influence public
perceptions about place and GIS tools give community organizations
greater control over influencing those perceptions of place. Taking
control of breast cancer mapping in Huntington has freed the community
to ask questions about their community that government officials
frequently ignore. The process has also empowered HBCAC to demand
more of government. To reluctant officials, HBCAC members have
frequently said, "If we can create these maps, then so can
you." Specific policy changes have also been made. For
example, New York State passed a neighbor notification law for
pesticide spraying, which breast cancer groups actively supported. Many
more changes, however, still need to be made.
The
Common Ground Community Mapping Project believes that "community
mapping is a way for local citizens to reinhabit their home place.
(11)"
This is precisely the message that HBCAC is trying to create through
its maps. For HBCAC, GIS is an important tool for making communities
healthier places to inhabit.
Acknowledgments
I
want to thank HBCAC President, Karen Miller, and HBCAC Survey Director
Mimi Galgano for their efforts, along with David Mikolaitis of
Greenman-Pedersen, who prepared several of the maps shown here,
and Erin O'Leary of the Silent Spring Institute. This work
was also assisted by a Conservation Technology Support Program
Grant, administered by ESRI and Hewlett Packard.
References
(1)
Breast Cancer Action, "The Facts and Nothing But the Facts," http://www.bcaction.org/Pages/GetInformed/Facts.html
(2)
Associated Press, "Report: Cancer Rates on Decline," Newsday
6/6/01:A23
(3)
West Islip Breast Cancer Coalition, "Mission/History," http://www.wibcc.org/mission.htm
(4)
Common Ground Community Mapping Project, "Why Mapping," http://www3.telus.net/cground/mapping.html
(5)
Colborn, Theo, Dianne Dumanoski, and John Peterson Myers, 1997. Our
Stolen Future. NY: Plume Books.
(6)
Carson, Rachel, 1962. Silent Spring. NY: Fawcett Crest;
Steingraber, Sandra, 1997. Living Downstream: An Ecologist
Looks at Cancer and the Environment. MA: Addison Wesley
(7)
The survey summary is based upon the work of Mimi Galgano, HBCAC's
survey director and author of "Huntington Activists Conduct
Large Community Breast Health Survey."
(8)
Huntington Breast Cancer Action Coalition, "Breast Cancer
Prevalence Study, 1993-1998: Synopsis of Results," http://www.hbcac.org
(9)
New York State Cancer Surveillance Improvement Initiative (CSII). http://www.health.state.ny.us/nysdoh/cancer/csii/nyscsii.htm
(10)
Statements from Hearings, 107th Congress, First Session. "Environmental
Contamination and Chronic Diseases," June 11, 2001. http://www.senate.gov/~epw/stm1_107.htm#06-11-01
(11)
Common Ground Community Mapping Project, "What is Community
Mapping" http://www3.telus.net/cground/aboutus.html
Dr.
Scott Carlin
Institute for Sustainable Development
Southampton College, LIU
Southampton, NY 11968
Telephone: (631) 287-8238
email: scott.carlin@liu.edu
