Re: Аспирин оказался лекарством против рака
Давайте почитаем после перепевов первоисточник:
1) http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(10)61543-7/fulltext#article_upsell
Long-term effect of aspirin on colorectal cancer incidence and
mortality: 20-year follow-up of five randomised trials
Prof Peter M Rothwell FMedSci a , Michelle Wilson BSc a, Carl-Eric
Elwin MD b, Prof Bo Norrving PhD c, Prof Ale Algra MD d, Prof Charles
P Warlow FMedSci e, Prof Tom W Meade FRS f
Summary
Background
High-dose aspirin (?500 mg daily) reduces long-term incidence of
colorectal cancer, but adverse effects might limit its potential for
long-term prevention. The long-term effectiveness of lower doses
(75--300 mg daily) is unknown. We assessed the effects of aspirin on
incidence and mortality due to colorectal cancer in relation to dose,
duration of treatment, and site of tumour.
Methods
We followed up four randomised trials of aspirin versus control in
primary (Thrombosis Prevention Trial, British Doctors Aspirin Trial)
and secondary (Swedish Aspirin Low Dose Trial, UK-TIA Aspirin Trial)
prevention of vascular events and one trial of different doses of
aspirin (Dutch TIA Aspirin Trial) and established the effect of
aspirin on risk of colorectal cancer over 20 years during and after
the trials by analysis of pooled individual patient data.
Results
In the four trials of aspirin versus control (mean duration of
scheduled treatment 6.0 years), 391 (2.8%) of 14 033 patients had
colorectal cancer during a median follow-up of 18.3 years. Allocation
to aspirin reduced the 20-year risk of colon cancer (incidence hazard
ratio [HR] 0.76, 0.60--0.96, p=0.02; mortality HR 0.65, 0.48--0.88,
p=0.005), but not rectal cancer (0.90, 0.63--1.30, p=0.58; 0.80,
0.50--1.28, p=0.35). Where subsite data were available, aspirin reduced
risk of cancer of the proximal colon (0.45, 0.28--0.74, p=0.001; 0.34,
0.18--0.66, p=0.001), but not the distal colon (1.10, 0.73--1.64,
p=0.66; 1.21, 0.66--2.24, p=0.54; for incidence difference p=0.04, for
mortality difference p=0.01). However, benefit increased with
scheduled duration of treatment, such that allocation to aspirin of 5
years or longer reduced risk of proximal colon cancer by about 70%
(0.35, 0.20--0.63; 0.24, 0.11--0.52; both p<0.0001) and also reduced
risk of rectal cancer (0.58, 0.36--0.92, p=0.02; 0.47, 0.26--0.87,
p=0.01). There was no increase in benefit at doses of aspirin greater
than 75 mg daily, with an absolute reduction of 1.76% (0.61--2.91;
p=0.001) in 20-year risk of any fatal colorectal cancer after 5-years
scheduled treatment with 75--300 mg daily. However, risk of fatal
colorectal cancer was higher on 30 mg versus 283 mg daily on long-term
follow-up of the Dutch TIA trial (odds ratio 2.02, 0.70--6.05, p=0.15).
Interpretation
Aspirin taken for several years at doses of at least 75 mg daily
reduced long-term incidence and mortality due to colorectal cancer.
Benefit was greatest for cancers of the proximal colon, which are not
otherwise prevented effectively by screening with sigmoidoscopy or
colonoscopy.
Ищем дальше - в результате находим оригинальную статью, и читаем ее:
2) Оригинальная статья http://www.natap.org/2010/HIV/aspirinectal.pdf
... 4 потенциальных ограничения:
...Our study does have some potential limitations. First,
it is possible that patients assigned to aspirin would have
had more investigations because of adverse effects such
as anaemia, dyspepsia, gastrointestinal bleeding, and
constipation, potentially resulting in earlier diagnosis of
colorectal adenoma or cancer. However, there was no
evidence of earlier diagnosis of colorectal cancer in any
of the trials (webappendix p4), and any such effect would
be greatest for distal colon and rectal cancers. Second,
our analysis of the long-term follow-up of the Dutch TIA
trial suggested that 30 mg daily was ineffective or at least
less effective than 300 mg daily, but the number of
cancers was too small to be certain. Further follow-up of
the Womens Health Study (aspirin 100 mg alternate days
vs placebo) could provide more data, but lack of an effect
of aspirin on rates of patient-reported colorectal adenomas
suggests that a substantial reduction in risk
of colorectal cancer is unlikely. Third, we might have
overestimated the latent period duration before an effect
of aspirin on death due to colorectal cancer. The number
of deaths due to colorectal cancer during the first few
years of follow-up was small, partly because patients with
a recent diagnosis of cancer were ineligible for inclusion
in any of the trials, so we cannot confirm or exclude a
reduction in mortality by aspirin in patients with
established colorectal cancer. Fourth, our results cannot
be generalised to less frequent use of aspirin. Although
alternate-day aspirin seems to be as effective as daily
aspirin in prevention of vascular events, because of the
irreversible inhibition of COX-1 in platelets, irreversible
inhibition would not be expected in other tissues, and
observational studies have highlighted the importance of
daily aspirin for reducing the incidence of colorectal
cancer.All trials of aspirin in secondary prevention of
adenomas have also used daily doses...
Сообщение, бесспорно, заставляет задуматься. Но снижение
"потенциальных онкологических рисков" не означает, что другие "риски"
(какие-нибудь геморрагические, например) не возрастают...
С уважением,
Сергей
web: http://antiaging.org.ua/
Thursday, December 9, 2010, 6:43:35 PM, you wrote:
T> 08.12.2010] Аспирин оказался лекарством против рака
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