Today I was talking to a friend at the beach and as we talked about our home town we keep going back to a fact that was very upsetting to me. Could Bradley Beach be a cancer cluster? We were saying we could name over 100 people who died in Bradley Beach of Cancer and over 200 who lived here who have had some type of cancer and our now in remission. So I as a good reporter called a couple of friends in the medical field and was told to look up "What does a cancer cluster look like?"
Cancer is a group of more than 100 different
diseases. Each type of cancer has its own risk factors and causes. This
is why true cancer clusters very rarely involve more than one type of
cancer. For it to be considered a true cluster, it usually must have one
of the following characteristics:
- There are several cases of a rare type of cancer.
- There are larger than expected numbers of a more common type of cancer.
- It is a type of cancer that is not usually seen in a certain group of people (for example, children getting a cancer usually seen in adults).
If the excess cancer cases include many
different types of cancer over a period of many years, it’s not likely
to be a true cancer cluster. And it’s very unlikely to be caused by a
single environmental factor or exposure.
It’s also important to remember that cancer
is common. Millions of new cases are diagnosed every year. Nearly half
of all men and a little over one-third of all women in the United States
will develop cancer during their lifetimes. So, it’s fairly common for
several people in a relatively small area to develop cancer around the
same time.
For most well-documented cancer clusters
that were found to be caused by a shared exposure, the exposure took
place in the workplace, rather than in the communities where people
lived. Workplace exposures may be more likely to cause disease because
the level of exposure tends to be higher and last longer than in other
settings. The length of exposure is important, because it usually takes
many years after exposure for cancer to develop. Workplace exposures can
also be easier to identify because the group of exposed people is
better defined and easier to trace as compared to groups in the
community. This is why the links between cancer and many cancer-causing
agents (called carcinogens) are often first found in studies of workers.
Statistics can usually help figure out if a
cancer cluster is strictly due to chance. But if the excess number of
cases reported in a cancer cluster looks significant based on
statistics, it does not mean that they are caused by something unique to
that area. Some clustering of cancer cases happens by chance, but
people tend to notice and report situations where rates seem to be above
average.
Who investigates cancer clusters, and how is it done?
People concerned about a possible cancer
cluster can report it to a local or state health department. Procedures
vary by state, but most health departments will first ask for
information, such as:
- The type(s) and number of cancers involved
- Any suspected exposure(s) that might cause cancer
- The area and time period in which the cases occurred
- Specific information about each person thought to be affected
- Specific information about the cancers themselves
After reviewing this information, most of the suspected clusters (as many as 4 of 5) are determined not
to be true clusters and no further investigation is done. According to
guidelines, some factors that do not support the need for further
investigation include:
- Cancer cases within family members who are blood relatives (especially cancers known to be strongly genetically linked)
- Different types of cancers not known to be related to one another
- A few cases of very common cancers, particularly when the people involved are of the usual age and sex for those cancers
- Cases involving people with cancer who didn’t live in the same place at the time an exposure would have to have taken place to cause that cancer
If the health department feels that the
potential cluster should be studied further, they collect more
information. They will need to make sure that the cases are cancer and
that they know the specific diagnosis. For example, there are several
kinds of leukemia, and it is important to know what kind each person
has. They also may want to see what risk factors for cancer affect the
people involved. This may involve contacting patients or relatives or
looking at medical records. The health department will look at the
number of cases in the affected area and those nearby to see if there
are really more cases than expected. Scientists in the health department
may also look at reports in the medical literature to see if other
clusters like this have been noted in the past.
If needed, the state or local health
department may ask federal agencies for help – they tend to have more
resources. The Centers for Disease Control and Prevention (CDC) is the
agency most often involved. Other agencies, such as the Environmental
Protection Agency (EPA) and the National Institute of Environmental and
Health Sciences (NIEHS), may also help investigate.
Federal agencies may do a more in-depth
investigation, including getting more thorough medical histories. These
agencies may also take and test samples from the environment (air, soil,
drinking water, etc.), especially if there is concern about a specific
toxin. They may also test blood or other body fluid samples from both
affected and non-affected people.
Suspected cancer clusters can cause a great
deal of concern and confusion in a community. It’s very important that
government agencies keep members of the community informed from the
start of and throughout the investigation. This should include giving
people a realistic idea of what may or may not be found.
What are the possible outcomes of a cluster investigation?
It may not be a true cluster.
In many cases, investigators can determine
that a “cluster” of cancers isn’t a true cluster. For example, the
number of cases may not really be higher than expected when other
factors that could explain the increase (such as age, gender, and
tobacco use) are taken into account. Or the types of cancer may not be
related to each other.
It is a cancer cluster and its cause is found.
Rarely, a true cancer cluster may be confirmed and a cause is identified. At that point, steps can be taken to address it.
A cancer cluster may be found, but no cause can be identified.
Even if investigators believe that it may be
a true cluster, it’s important to know that a cause is found very
rarely. There are several reasons why this is the case. For example:
Random patterns can form a cluster: Even
if the number of cases in an area is higher than expected, it still may
not be caused by a single factor or exposure. More cancer cases in the
United States are expected in large population centers or in places
where the population tends to be older. But even so, for the most part,
cancer cases in the United States are spread randomly across the
country.
As with any random pattern, there will be
more cases than expected in some spots, and fewer cases than expected in
others. The areas with more cases than expected are more likely to be
noticed. But many of these will be due to the “bull’s-eye effect” (which
is something like drawing a target on the wall after the darts have
been thrown). Suppose you took a map of the United States and started
drawing circles of different sizes in different locations. You would
find that some of the circles would contain more cancers than expected,
and some would have less. Some of the circles with more cases might be
clusters caused by a single carcinogen, but most would be due to chance.
You can see this more clearly on a smaller
scale if you look at balls on a pool table. Even if the balls are
randomly distributed, there are sections of the table with more and
other sections with fewer balls than the average for the whole table.
Random patterns are the most common reason for a cancer cluster with no identified cause.
It is very hard to figure out which of many exposures might be the cause: With
rare exceptions, scientists don’t have a way of telling what trigger
(if any) may have caused cancer in any one person, whether it’s part of a
cluster or not. Humans are not like lab animals – their environments
are not strictly controlled. People are exposed to many natural and
man-made substances during their lifetimes.
Think about how hard it would be to test for
everything you’ve been exposed to, even if you knew where to start.
Investigators may have a few clear leads or starting points, but they
need to look at all of the possibilities. Finding the one exposure that
may be the cause can be like looking for the needle in the haystack.
There is usually a long delay between exposure and cancer: In
clusters where the cause is known, mostly in workplace cases, the time
between exposure to the substance and the development of cancer has been
anywhere from a few years to several decades. Exposures are not likely
to cause cancers right away. And again, it’s not easy to study people
and their environments.
Suppose a group of people live in a
community that has a higher than expected number of cases of a certain
type of cancer. If there is a potential cause, investigators first have
to figure out when these people were exposed to it. Was it a single
event or has it been ongoing? Was it 5 years ago? 10? 20? And what did
the people with cancer have in common during that time? Added to this,
some people will have moved into the community, while others may have
moved away. Should the cases of people who moved into town in recent
years be included? And can the people who moved away be found?
The boundaries of the cluster area can be hard to define: Defining
the geographic cluster area is not always as clear-cut as one might
think it would be. Just how big should the “bull’s eye” be? Should it
include only the local neighborhood where most of the cases were found?
Or should it also include the larger community, or even nearby
communities? These areas may have cases that may or may not be related
to the others.
Not everyone who is exposed is likely to develop cancer: To
make things even more tricky, people may be more or less prone to
getting cancer based on their genes. It’s unlikely that everyone exposed
will develop cancer. At the same time, there may be people who were not
exposed who develop the same cancer by chance.
Questions may still remain
Scientists do their best to piece the puzzle
together when there is a cancer cluster, but more times than not, they
don’t find a likely link. This doesn’t mean that there isn’t one; it may
just be that one can’t be found with the methods scientists have at the
time.
Oftentimes there really isn’t a link, for
the reasons noted before, but it’s hard for everyone to feel sure of
that. This may be an unsatisfactory answer for people in a community
being affected, but it often is the case.
What should I do if I suspect a cancer cluster?
Concern about cancer clusters most often
comes up in schools, workplaces, and in certain areas of a community. If
you are concerned about a possible cancer cluster, you may want to
contact your local or state health department. If you don’t know who to
call in your area, the CDC has a list of web links to local and state
contacts at www.cdc.gov/nceh/clusters/statelocal.htm. (Also see the “To learn more” section.)
Some of your concerns may be relieved by
making a phone call. If not, the health department will probably look
into doing a brief investigation and then, if needed, will do a more
complete review of the situation. For more complex or urgent situations,
the health department may also call in experts from the CDC or other
agencies to do a more in-depth investigation.
The investigators may be able to figure out
with a fair amount of certainty that there is no true cluster, or that
there is a true cluster and it is probably caused by a certain exposure.
But in many cases, even when it seems there is a cluster, a single
cause cannot be found.
Suspected cancer clusters often greatly
distress those involved. It’s very important that these situations be
handled openly, promptly, and professionally. Even though thorough
investigations of potential cancer clusters rarely give clear-cut
answers, it’s important that communities keep reporting suspected cancer
clusters, and that health organizations respond to those concerns.
To learn more
More information from your American Cancer Society
The following information may also be
helpful to you. These materials may be ordered from our toll-free number
(1-800-227-2345) or read online at www.cancer.org.
So now the question is could Bradley Beach be a cluster? More to follow as a side note do you know anyone who has died or is in remission from Bradley Beach someone need to keep a list.
Wendy Ella May for the Tatler May 10th 2014
%5B3%5D.jpg)