Re: Full-Dose Aspirin a Day, for 5 Years, Cuts Colon Cancer Risk by...


Full-Dose Aspirin a Day, for 5 Years, Cuts Colon Cancer Risk by over 70%

Group: sci.med.diseases.cancer Date: Fri, May 11, 2007, 2:20pm (EDT+7)
From: mna@xxxxxxxx (Matti Narkia) wrote:

According to the news report
An Aspirin A Day Keeps Colorectal Cancer Away
<http://www.medicalnewstoday.com/medicalnews.php?newsid=70463>
full-dose aspirin daily for five years may reduce colon cancer risk by
74%, but only after 10 years latency period. Here's the report:
        "Long term use of 300 mg or more of aspirin a
day for five   years can prevent colorectal cancer, conclude authors
of a   study published in this week's special gastroenterology  
edition of The Lancet.
        But the authors of the Article and an
accompanying Comment   stress that the potential risks of long term
aspirin use at   this dose and the availability of alternative
prevention   strategies mean that widespread use of aspirin for cancer
  prevention cannot be recommended in the general population.
        However, the benefits are likely to outweigh the
risks in   individuals at increased risk of colon cancer. The findings
  are also likely to influence the choice of antiplatelet drug   in
patients who require long-term treatment because of   vascular
disease.
        The study was conducted by Professor Peter
Rothwell,   University Department of Clinical Neurology, Radcliffe  
Infirmary, Oxford, UK and colleagues. In collaboration with   the
original investigators (Sir Richard Doll, Sir Richard   Peto and
Charles Warlow), they determined the delayed effect   of aspirin by
following-up patients from two large randomised   trials of aspirin
performed in the late 1970s and early 80s -   the British Doctors'
Aspirin Trial and the UK-TIA Aspirin   Trial.
        The researchers were particularly interested in
long term   follow-up due to the likely time delay in any effect of
  aspirin on colorectal cancer. Adenomas (the pre-cancerous  
growths that aspirin is thought to reduce) take at least 10   years to
develop into cancers. The study showed that use of   aspirin for five
years reduced the subsequent incidence of   colorectal cancer by 37%
overall, and by 74% during the   period 10-15 years after treatment
was started.
        In an accompanying analysis of observational
studies, the   risk of colorectal cancer also appeared to be reduced
by   between 50-70% in patients taking medium-high doses of  
aspirin for 10 years or more. This analysis also showed that   the
effects of aspirin were consistent regardless of age,   sex, race or
country of origin of patients studied (all of   which affect the
general rate of colorectal cancer) and that   the effect was also seen
in individuals with a family history   of colorectal cancer in a first
degree family relative (which   increases lifetime risk of an
individual acquiring the   disease by two to four times).
        The authors conclude: "Use of 300 mg or more of
aspirin a day   for about five years is effective in primary
prevention of   colorectal cancer, with a latency of about 10 years,
which is   consistent with findings from observational studies.
        "Long-term follow up is required from other
randomised trials   to establish the effects of lower or less frequent
doses of   aspirin."
        In an accompanying Comment, Dr Andrew Chan,
Gastrointestinal   Unit, Massachusetts General Hospital, Boston, USA,
says:   "Rothwell and colleagues' results, when viewed in the context
  of the preponderance of laboratory studies, epidemiological  
data, and adenoma recurrence trials, do provide convincing   evidence
that aspirin, at biologically relevant doses, can   reduce the
incidence of colorectal cancer.
        "However, with the concerns about the potential
risks of   long-term aspirin use and the availability of alternative
  prevention strategies (e.g. screening), these findings are   not
sufficient to warrant a recommendation for the general   population to
use aspirin for cancer prevention.""
Other news reports about this study:
Aspirin May Stop Colon Cancer
Study: 1 Full-Dose Aspirin a Day, for 5 Years, Cuts Colon Cancer Risk
By Daniel J. DeNoon
WebMD Medical News
<http://www.webmd.com/colorectal-cancer/news/20070510/aspirin-may-stop-colon-cancer?src=RSS_PUBLIC>
Aspirin 'prevents bowel cancer'
<http://news.bbc.co.uk/2/hi/health/6643547.stm>
Aspirin vs. colon cancer: study weighs benefits
<http://www.sciam.com/article.cfm?alias=aspirin-vs-colon-cancer-s&chanId=sa003&modsrc=reuters>
The reference for the study is
Flossmann E, Rothwell PM
Effect of aspirin on long-term risk of colorectal cancer: consistent
evidence from randomised and observational studies The Lancet, May 12,
2007; vol 369: pp 1603-1673. DOI:10.1016/S0140-6736(07)60747-8.
<http://www.thelancet.com/journals/lancet/article/PIIS0140673607607478/abstract>
(free registration required)
Below the abstract of the study:
        "Summary
        Background
        Randomised trials have shown that aspirin
reduces the short-   term risk of recurrent colorectal adenomas in
patients with a   history of adenomas or cancer, but large trials have
shown no   effect in primary prevention of colorectal cancer during 10
  years' follow-up. However, the delay from the early   development
of adenoma to presentation with cancer is at   least 10 years. We
aimed to assess the longer-term effect of   aspirin on the incidence
of cancers.
        Methods
        We studied the effect of aspirin in two large
randomised   trials with reliable post-trial follow-up for more than
20   years: the British Doctors Aspirin Trial (N=5139, two-thirds  
allocated 500 mg aspirin for 5 years, a third to open   control) and
UK-TIA Aspirin Trial (N=2449, two-thirds   allocated 300 mg or 1200 mg
aspirin for 1?7 years, a third   placebo control). We also did a
systematic review of all   relevant observational studies to establish
whether   associations were consistent with the results of the  
randomised trials and, if so, what could be concluded about   the
likely effects of dose and regularity of aspirin use,   other
non-steroidal anti-inflammatory drugs (NSAID), and the   effect of
patient characteristics.
        Results
        In the randomised trials, allocation to aspirin
reduced the   incidence of colorectal cancer (pooled HR 0·74, 95% CI
  0·56?0·97, p=0·02 overall; 0·63, 0·47?0·85,
p=0·002 if   allocated aspirin for 5 years or more). However, this
effect   was only seen after a latency of 10 years (years 0?9:
0·92,   0·56?1·49, p=0·73; years 10?19: 0·60,
0·42?0·87, p=0·007),   was dependent on duration of scheduled
trial treatment and   compliance, and was greatest 10?14 years after
randomisation   in patients who had had scheduled trial treatment of 5
years   or more (0·37, 0·20?0·70, p=0·002; 0·26,
0·12?0·56, p=0·0002,   if compliant). No significant effect on
incidence of non-   colorectal cancers was recorded (1.01,
0.88?1.16, p=0.87). In   19 case-control studies (20?815 cases) and
11 cohort studies   (1 136 110 individuals), regular use of aspirin or
NSAID was   consistently associated with a reduced risk of colorectal
  cancer, especially after use for 10 years or more, with no  
difference between aspirin and other NSAIDs, or in relation   to age,
sex, race, or family history, site or aggressiveness   of cancer, or
any reduction in apparent effect with use for   20 years or more.
However, a consistent association was only   seen with use of 300 mg
or more of aspirin a day, with   diminished and inconsistent results
for lower or less   frequent doses.
        Interpretation
        Use of 300 mg or more of aspirin a day for about
5 years is   effective in primary prevention of colorectal cancer in
  randomised controlled trials, with a latency of about 10   years,
which is consistent with findings from observational   studies.
Long-term follow-up is required from other   randomised trials to
establish the effects of lower or less   frequent doses of aspirin.
        Affiliations
        a. Stroke Prevention Research Unit, University
Department of   Clinical Neurology, Radcliffe Infirmary, Oxford OX2
6HE, UK
        Corresponding Author InformationCorrespondence
to: Prof Peter   M Rothwell, Stroke Prevention Research Unit,
University   Department of Clinical Neurology, Radcliffe Infirmary,
Oxford   OX2 6HE, UK"
--
Matti Narkia

That's useful info if true, however I have always been allergic to
asprin and any of it's derivatives. So would knowing this prior to
getting colon cancer have helped me? prolly not. It would be interesting
to know of the colon cancer cases that were diagnose late stage right
frrom the day they were discovered or for that matter what percentage of
colon cancer patients are or were allergic to asprin or it''s
derivatives. Sometimes it appears to me like our bodies or the cancers
within ceate certain conditions to make sure we can't prevent or stop
the spread.

Jonboy




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