[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Breast Cancer in NE US...
Don't know if anyone on the list has seen
this so I thought I'd post it....
Regards,
Alex Sagady
Environmental Consultant
===================================
Office of Cancer
Communications
Building 31,Room
10A24
Bethesda, MD 20892
National Cancer
Institute
July 15, 1997
FOR RESPONSE TO
INQURIES
NCI Press Office
(301) 496-6641
Backgrounder
New Statistical Methodology Suggests
Elevated Breast Cancer Mortality in
Large Parts of Northeastern United
States
Using an innovative statistical technique, scientists
at the National Cancer Institute (NCI) have
discovered that women living in a broad stretch of
the metropolitan northeastern United States are
slightly more likely to die from breast cancer than
women in other parts of the Northeast. The study
does not explain why these women are at higher
risk of death, and the researchers note that the
increase may be due to geographic differences in
well-established risk factors for breast cancer
which they were unable to include in the analysis.
"The breast cancer mortality rate along a section
of the East Coast stretching from New York City
to Philadelphia is 7.4 percent higher than the rest
of the Northeast," said Martin Kulldorff, Ph.D.,
who led the study. "This is a statistically
significant finding, indicating that elevated risk of
breast cancer mortality in that area is not a
random occurrence, but may be due to some
underlying reason."
Kulldorff adds that "great caution should be
exercised in interpreting the study of geographic
clusters in cancer mortality." In particular,
ascribing the cause of a mortality cluster to some
local environmental exposure may be difficult or
impossible.
Previous studies have shown that the northeastern
United States (including CT, DE, MD, ME, MA,
NH, NJ, NY, PA, RI, VT. and DC) has about a
16 percent higher breast cancer mortality rate
than the rest of the country. However, even
within this region, there is substantial variation.
Delaware, Massachusetts, New Hampshire, New
Jersey, New York, Pennsylvania, Rhode Island,
and Washington DC have higher breast cancer
mortality rates than the national average. Breast
cancer mortality rates in four other northeastern
states -- Maryland, Vermont, Connecticut and
Maine -- are very close to the national average of
26.4 per 100,000 women.
During the five years (1988-1992) covered by the
analysis, 24,044 women in the New
York/Philadelphia region died of breast cancer.
This was about 200 more deaths per year than
researchers would have expected to find if this
area had the same breast cancer mortality rate as
the rest of the 11-state northeastern region of the
U.S. The study also showed the existence of four
smaller clusters of increased mortality within the
larger New York/Philadelphia area: northeast
New Jersey, central New Jersey, Philadelphia,
and Long Island, N.Y.
Long Island has been a major focus of research
on breast cancer, following a June 1993
Congressional mandate to initiate a
comprehensive study to ascertain whether
environmental factors might be related to elevated
breast cancer rates there. In light of this new
study, Long Island's elevated breast cancer
mortality rate should be seen as part of a larger
geographical trend in the New York/Philadelphia
area.
In the new study, published in the July 15, 1997
American Journal of Epidemiology, researchers
used a specially designed computer program that
places a circular "window" on a map of the 11
most northeastern states and the District of
Columbia. They then calculated breast cancer
mortality rates for the area inside the window's
circumference and for the remainder of the
northeastern United States.
A newly developed statistical method, called the
spatial scan statistic, was used to compare these
two rates. By resizing and moving the window
across the entire map, the researchers were able
to systematically scan for possible breast cancer
mortality clusters and identify approximate
boundaries for areas where mortality was
elevated. The moveable window freed
researchers from having to preselect which states
or parts of states they would examine. Instead,
they were able to let the data define the area for
them.
Researchers also found a higher breast cancer
mortality rate among women under 50 in the
District of Columbia, but this cluster was
explained by its proportionately larger
African-American population. On average,
African-American women have a higher mortality
rate from breast cancer than do white women. In
a paper published in the Feb. 5, 1997 Journal of
the National Cancer Institute, NCI epidemiologist
Robert E. Tarone, Ph.D., reported that breast
cancer mortality rates for black women in the
northeastern U.S. are no higher than those for
black women in other regions. It is thus unlikely
that widespread environmental exposures explain
the elevated breast cancer mortality rates among
white women in the Northeast.
The new study found that age, race, urbanization
and average number of children born could not
explain the elevated mortality rates for the larger
New York/Philadelphia region, or for the four
smaller clusters. However, the researchers could
not include in their analysis other important risk
factors for breast cancer such as age at first birth,
menarche, or menopause, or factors that are
known to affect mortality, including access to
health care and regular mammography screening.
A study published in the July 2, 1997 Journal of
the National Cancer Institute demonstrated that
elevated breast cancer incidence in the San
Francisco Bay Area could be entirely explained in
terms of such known risk factors. Results of
another study led by NCI epidemiologist Susan
Sturgeon, Dr.P.H., and published in the Dec. 20,
1995 Journal of the National Cancer Institute
showed that a large part of the regional
differences in breast cancer death rates among
white women in the United States would be
explained by known factors such as age at first
birth and mammography screening.
In 1997, there will be an estimated 180,200 new
cases of invasive breast cancer among women in
the United States, and an estimated 44,190
women will die from the disease. Breast cancer
mortality rates vary widely from state to state.
Hawaii's rate is 32 percent lower than the national
age-adjusted average of 26.4 per 100,000 women,
and Washington D.C.'s rate is 28 percent higher.
The new technique used in the study will help
researchers overcome a major problem in "cancer
cluster" investigations: the fact that the areas
studied as clusters have generally been selected
based on public concern rather than systematic
comparison of rates in different areas.
NCI, in collaboration with the National Institute of
Environmental Health Sciences, has undertaken
two large initiatives to investigate reasons for
elevated breast cancer death rates in the
Northeast/Mid-Atlantic regions. These studies are
being conducted by investigators at major medical
institutions in the East. Six studies, which
comprise the Northeast/Mid-Atlantic Study, are
focusing on organochlorine compounds, which are
commonly used as pesticides. The Long Island
Breast Cancer Study Project is investigating
whether environmental factors are responsible for
breast cancer risk in Nassau and Suffolk counties.
This research includes assessments of exposure
to organochlorines and other chemicals, magnetic
fields, contaminated drinking water, air pollution,
and hazardous and municipal waste.
----------------------------------------------------------------------------
Alex J. Sagady & Associates Email: asagady@sojourn.com
Environmental Consulting and Database Systems
PO Box 39 East Lansing, MI 48826-0039
(517) 332-6971 (voice); (517) 332-8987 (fax)