bjbjLULU JEFFREY BROWN: Next: A new batch of studies point to the potential benefits
of taking aspirin to treat cancer, but also raises important questions.
Ray Suarez has the story.
RAY SUAREZ: The new findings were published in a series of studies in the medical journal
The Lancet.
They add to other research suggesting aspirin could play a role in combating a variety of
cancers.
Among the most significant findings: A daily low dose of aspirin taken for three years
reduced the risk of cancer by roughly 25 percent.
And regular use of aspirin over more than six years also reduced the chances of a cancer
metastasizing.
Patients had few side effects from the aspirin.
But some doctors and researchers say the case for using aspirin as a way of preventing or
treating cancer is hardly closed.
Dr. Andrew Chan wrote a commentary about these issues to accompany the studies in The Lancet.
He's an associate professor of medicine at Massachusetts General Hospital and Harvard
Medical School.
And, Dr. Chan, The Lancet is pretty straightforward.
The articles conclude regular use of aspirin reduces the long-term risk of several cancers.
What numbers did they crunch from already existing aspirin studies to come to that conclusion?
DR.
ANDREW CHAN, Massachusetts General Hospital: Well, what the authors did was, they looked
at a series of clinical trials that were conducted in the '80s and '90s and through the 2000s
to look at the use of aspirin in the prevention of vascular disease.
And what they did was looked at cancer outcomes in those particular trials and also linked
those trials to cancer registries in the United Kingdom.
And what they found was that the individuals that were in the study that were randomized
to the treatment of aspirin did have a lower risk of dying from cancer over time.
RAY SUAREZ: Now, are we talking among the several thousand people they were watching
about a few.
. . DR.
ANDREW CHAN: Right.
RAY SUAREZ: . . . less -- less-often-occurring cases of cancer, or are we talking about a
significant effect in that population?
DR.
ANDREW CHAN: No, we're seeing pretty significant effects.
I think overall they saw about a 15 percent reduction in death from any cancer over time.
So it is a substantial reduction, when you think about the fact that cancer is one of
the leading causes of death for patients.
RAY SUAREZ: Was this therapy found to be particularly effective against certain kinds of cancer?
DR.
ANDREW CHAN: Yeah.
They did see some particularly strong reductions in the risk of colon cancer.
And also they did see some strong reductions in the risk of other types of female reproductive
cancers, like uterine cancer and cancers of the breast.
So there are various cancer types that seem to be particularly affected.
But there was a uniform benefit across all cancers.
RAY SUAREZ: Is it possible to speculate on why this happened?
We know what aspirin does when it's used to treat other maladies.
What could it have been doing mechanically in the body that also provided this effect
against cancer?
DR.
ANDREW CHAN: Well, there's definitely been a wealth of data that's emerged in the last
couple of decades, even, that has shown that aspirin does have very significant anti-cancer
effects.
There have been a range of mechanisms proposed.
I think one of the leading mechanisms that's been shown is that aspirin seems to block
key enzymes that are responsible for cancer's growth and spread.
These enzymes known, known as cyclooxygenases, produce prostaglandins.
And prostaglandins are known to be cancer-promoting.
So that's one predominant mechanisms that s been hypothesized to be at play.
But there really are other mechanisms.
And one of the things that we're really learning more and more about aspirin is that aspirin
has many, many different effects in the body, and it just happens that many of these effects
seem to be anti-cancer in nature.
RAY SUAREZ: But we also know about aspirin's side effects, gastrointestinal bleeding and
ulcers, brain bleeds, higher risk of stroke.
How do you measure the added risk of these side effects against the cancer suppression
effects of aspirin?
DR.
ANDREW CHAN: Yes.
I mean, that's definitely the caveat of these studies is that aspirin is definitely not
for everyone.
And we do understand that aspirin does have significant side effects, as you mentioned,
including gastrointestinal bleeding, and, more rarely, intracerebral or intracranial
bleeding or bleeding strokes.
And those are definitely circumstances that can be potentially dangerous and significant.
So people do have to worry about those, particularly if they're taking aspirin over a long period
of time.
So I think what we really need to move forward on is understanding how people need to individualize
their risks of these side effects in the context of their individualized risks of developing
either cancer or vascular disease.
So I think at this point in time, we're not ready to make a broad recommendation that
people take aspirin.
I think, instead, we're really encouraging folks to talk to their doctors to see if aspirin
makes sense from them, in view of their particular risks of either developing cancer and heart
disease or having a side effect from treatment.
RAY SUAREZ: So, let's follow up on that a little more.
What do we have to know before we, in effect, go wide with suggestion of this as a therapy?
After all, it's a very cheap drug with known side effects.
Would family history, a predisposition to cancer be something that might have a doctor
recommend it to an individual patient?
DR.
ANDREW CHAN: Well, it's a great question.
And I think it's something that remains to be investigated further.
I think we know that there are certain risk factors that seem to be particularly important
to consider.
I think, last year, there was a very important clinical trial looking at the use of aspirin
in patients that had a hereditary form of colon cancer.
And in that study, they showed over a long-term follow-up that those patients did have a lower
risk of developing colon cancer over about a 10-year period.
So, certainly, patients that have a genetic predisposition to some problems, like, you
know, colon cancer, would probably stand to benefit, and in view of the side effects,
would probably -- the benefits probably would outweigh the risks.
But beyond that, I think we're still looking at different risk factors and trying to analyze
sort of what are the most important ones to consider.
A lot of that work has been done in the cardiovascular literature.
So there does appear to be certain algorithms that people can use to assess someone's cardiovascular
risk, and use that as a way to kind of stratify folks for aspirin therapy.
But that work is still relatively preliminary in the cancer field, and I think what we're
going to see in the coming years is more and more of an effort to individualize treatment
and prevention in patients for cancer, because different risk factors are at play for different
types of cancer.
RAY SUAREZ: Dr. Andrew Chan, thanks for joining us.
DR.
ANDREW CHAN: Sure.
My pleasure.
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