Cancer and aspirin - Aspirin as Cancer Prevention Pill Still a Long Way Off
- From: J <nexsw@nvalid,anon>
- Date: Sun, 13 May 2007 16:30:52 -0400
<
http://www.cancer.org/docroot/MED/content/MED_2_1x_Study_Links_Adult_Dose_Aspirin_to_Moderate_Drop_in_Cancer_Risk.asp
Atlanta 2007/04/17
For their study, American Cancer Society researchers led by Eric J.
Jacobs, PhD, addressed the potential effect of using adult-strength
aspirin on overall cancer risk. A large study published by Harvard
University researchers in 2005 found that taking a low-dose aspirin (about
100 mg) every other day did not lower risk of any cancer, suggesting that
higher doses may be required to help prevent cancer. Adult-strength
aspirin has been associated with reduced risk of colorectal cancer in
previous studies, but this new study is the first to examine the
relationship between long-term daily use of adult-strength aspirin and
overall risk of cancer. Aspirin use was determined by a questionnaire.
During 12 years of follow up, nearly 18,000 men and women in the cohort
were diagnosed with cancer. Those who reported daily use of adult-strength
aspirin for at least five years had an approximately 15 percent relative
reduction in overall cancer risk. The decrease was not statistically
significant in women. The researchers looked at specific cancer sites and
found men who used aspirin daily had a 20 percent lower risk of prostate
cancer and that men and women who used aspirin had a 30 percent reduction
in the risk of colorectal cancer. Aspirin use had no effect on the risk of
other cancers studied: lung cancer, bladder cancer, melanoma, leukemia,
non-Hodgkin lymphoma, pancreatic cancer, and kidney cancer. The
researchers also found aspirin use for less than five years was not
associated with decreased cancer risk.
?The American Cancer Society does not recommend using aspirin to prevent
cancer because aspirin can cause serious gastrointestinal bleeding,? said
Dr. Jacobs. ?Recommendations for aspirin use should continue to be based
on prevention of heart disease and stroke, not cancer. However if further
research confirms that daily adult-strength aspirin can meaningfully
reduce cancer risk, future recommendations could take cancer prevention
into account when deciding on the best dose for people who already need to
take aspirin to prevent cardiovascular disease.?
Article: Jacobs EJ, Thun MJ, Bain EB, Rodriguez C, Henley SJ, Calle EE. A
Large Cohort Study of Long-Term Daily Use of Adult-Strength Aspirin and
Cancer Incidence. J Natl Cancer Inst 2007; 99: 608-615
<
http://www.cancer.org/docroot/NWS/content/NWS_1_1x_Long-term_Aspirin_Use_Linked_to_Lower_Cancer_Risk.asp
Long-term Aspirin Use Linked to Lower Cancer Risk
But Aspirin as Cancer Prevention Pill Still a Long Way Off
Article date: 2007/04/18
Summary: A large analysis by American Cancer Society researchers suggests
that daily long-term use of adult-strength aspirin may reduce cancer risk
by about 15% in both men and women. But don't start popping pills yet.
Aspirin can cause serious side effects, and the evidence for cancer
prevention isn't strong enough yet to justify a recommendation, the
researchers caution.
Why it's important: More than 1 million people get cancer each year in the
US. Although modern treatments can help many people with cancer live long,
productive lives, finding ways to keep people from getting cancer in the
first place is an important avenue of research. Aspirin is inexpensive and
widely available; if it worked to prevent cancer, it might have a
significant impact on the toll this disease takes.
What's already known: Daily aspirin use is often recommended for
preventing heart disease and stroke in people at high risk of these
problems. The aspirin-cancer link has been widely studied, but researchers
have not been able to come to any firm conclusion about whether it is
useful for cancer prevention. In animals, aspirin inhibits the development
of many types of cancer, including colorectal, breast, prostate, lung,
bladder, and skin. Studies on people have been harder to interpret. Some
have shown that aspirin can reduce the risk of colorectal cancer and
polyps (growths that can lead to cancer). Others have linked aspirin use
to lower risk of stomach and esophageal cancer, as well as breast,
prostate, and lung cancer. Still others have found no effect on cancer at
all.
But these studies were not uniform in their design; important factors like
the dose of aspirin, how often it was taken, and how long people used it
were not the same. Also, most studies in people have been observational,
meaning the researchers just looked at the participants' reports of
aspirin use. More accurate, reliable information can be gathered from
randomized controlled studies that compare groups of people randomly
assigned to use either aspirin or a placebo.
How this study was done: Because many previous studies had looked at low
doses of aspirin (80-150 mg) and brief periods of usage (a few years),
American Cancer Society epidemiologists focused on long-term use of
adult-dose (325 mg or more) aspirin. They compared cancer rates and
aspirin use in nearly 70,000 men and more than 76,000 women who were
taking part in a large study of lifestyle and cancer called the Cancer
Prevention Study II Nutrition Cohort. Participants answered periodic
questionnaires between 1992 and 2003 that included information on aspirin
use. The findings were published in the Journal of the National Cancer
Institute.
What was found:
Overall cancer rates were about 15% lower in people who used adult-dose
aspirin daily for 5 years or longer, compared to people who used no
aspirin. However, the difference was only statistically significant for
men. T
hat means in women, the lower risk could have been due to chance rather
than linked to aspirin use. When the researchers looked at specific
cancers, they found a 30% lower risk of colorectal cancer and a 20% lower
risk of prostate cancer, both of which were statistically significant.
Breast cancer risk was about 15% lower in women who took aspirin, but this
decline also was not statistically significant and may have been due to
chance.
Aspirin use was not linked to an effect on other cancers examined (lung,
bladder, pancreatic, kidney, melanoma, leukemia, and non-Hodgkin
lymphoma).
People who took aspirin less frequently or for less than 5 years did not
have a lower risk of cancer.
The bottom line: Although the findings are tantalizing, they are not
strong enough to warrant recommending aspirin for cancer prevention, the
researchers say. Aspirin can cause serious stomach bleeding (among other
side effects), and the risk of side effects increases with higher doses.
"Recommendations for aspirin use should continue to be based on prevention
of heart disease and stroke, not cancer," says Eric Jacobs, PhD, lead
author of the ACS study. "However, if further research confirms that daily
adult-strength aspirin can meaningfully reduce cancer risk, future
recommendations could take cancer prevention into account when deciding on
the best dose for people who already need to take aspirin to prevent
cardiovascular disease."
Jacobs and his colleagues say a large randomized controlled trial that
lasts at least 10 years would be needed to determine whether adult-dose
aspirin can prevent cancer. But because of the time and expense that would
be involved in such a study, they say more large observational studies
must first confirm the potential for aspirin to reduce cancer risk before
it could be justified.
Citation: "A Large Cohort Study of Long-Term Daily Use of Adult-Strength
Aspirin and Cancer Incidence" Published in the April, 18, 2007 Journal of
the National Cancer Institute (Vol. 99, No. 8: 608-615). First author:
Eric J. Jacobs, PhD, American Cancer Society.
.
- Follow-Ups:
- Prev by Date: Re: Full-Dose Aspirin a Day, for 5 Years, Cuts Colon Cancer Risk by...
- Next by Date: o evaluate the association between alarm symptoms and the subsequent diagnosis of cancer in a large population based study in primary care.
- Previous by thread: Re: Full-Dose Aspirin a Day, for 5 Years, Cuts Colon Cancer Risk by...
- Next by thread: Re: Cancer and aspirin - Aspirin as Cancer Prevention Pill Still a Long Way Off
- Index(es):
Relevant Pages
|
