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1997/03/07 -How do you feel when you read an article that says something
causes a
100%
increase in the relative risk for cancer? Or when you hear on
the news that
some anti-oxidants may be harmful in high doses, right after you
took your
multi-vitamin pill containing anti-oxidants?
Advances in medical science are reported each day, in
newspapers and
television broadcasts across the country. These news reports are
often based on
studies published in scientific journals, the accepted way
scientists
communicate among themselves. However, a problem arises when the
results of
those studies are reported to an audience who -- unlike the
scientists reading
the articles -- may not know the background of the research or
understand the
statistics.
"When science is not put into context, it can cause problems,"
notes
Joann
Schellenbach, director of media relations for the American
Cancer Society. "To
its credit, the media does an admirable job of reporting complex
stories to a
cross-section of Americans. However, we get calls from confused
people all the
time about something they just read or heard."
In the examples mentioned above, it may be helpful to know that
a 100%
increase in relative risk may not be that bad if the original
absolute risk was
only 1 in 100,000 people. A 100% increase would bring the total
cancers to 2 in
100,000, probably nothing to be unduly alarmed over (see below
for further
information). The anti-oxidant example was based on a National
Cancer Institute
research study that examined the effects of beta-carotene on
smokers to see if
it reduced their rates of lung cancer. The study was halted when
it showed
smokers getting beta-carotene were developing lung cancer at a
higher rate than
the group given nothing.
It may be useful to keep the following thoughts in mind when
reading or
hearing about a new study:
where was the study originally reported? The most well-known
journals, such
as The New England Journal of Medicine, Science, and Cancer,
have strict
peer-review criteria before they publish the study. Peer review
means that the
study was evaluated by scientists working in the same field in
which the
research was done. This process lends more credibility to
scientific reports.
where did you read or hear about the study? Network news
programs, national
newsmagazines, and city newspapers have science reporters who
carefully distill
scientific article into reports for the general public.
where was the research done? Most cancer research requires
sophisticated
scientific training, facilities, and equipment. Therefore, it
is no surprise
that most advances in cancer research come from well known
cancer centers,
hospitals, and universities.
does the study support or contradict past research? The more
evidence there is
for something, the more likely it is to be true. The search for
answers comes
through small steps in a long process.
who were the research subjects? Some news items report
studies from animal
research -- important, but not always immediately pertinent to
humans. Sometimes
specific age, racial, or ethnic groups are examined, such as
African American
men over 75 with a high risk of prostate cancer or Ashkenazi
Jewish women with a
tendency to develop breast and ovarian cancers. Specific
findings from such
studies may not always apply to other groups.
what type of study was it? A randomized clinical trial,
where groups of
individuals randomly assigned to different treatment groups are
compared,
generally is considered the "gold standard" in research done to
evaluate new
treatments.
if the study is a clinical trial, what phase was it? Phase I
clinical trials
are very early and as such, are intended to examine the safety
of the
intervention. Phase II trials, the next step, examine the
effects of a research
treatment on the specific disease under study. Phase III trials
are planned to
compare the new treatment with the standard treatment to see
which is more
effective.
how long did the study last and how large was it? Generally,
studies that
affect medical policy or guidelines are the result of years of
research
examining a large number of people. It usually takes a number of
such studies
before the experiment or trial is considered definitive.
do you understand the terminology used to describe cancer
risk in this study?
Terms such as relative and absolute risk, are a stumbling block
for many
non-scientists. To take the aforementioned example further, if a
certain
behavior or exposure is associated with a 100% increase in the
risk of
developing cancer, it sounds ominous at first. However, if only
one person out
of 100,000 currently develops that particular type of cancer, a
100% increase in
risk results in only 2 in 100,000 people. The relat
Joann Schellenbach
National Director Media Relations
American Cancer Society
212-382-2169
jschelle@cancer.org
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