Weighing The Pros And Cons Of Aspirin Regimens

A pair of new studies find that taking aspirin daily may significantly reduce the risk of many cancers and prevent tumors from spreading. Many experts view the findings as promising, but public health officials warn that the risks may still outweigh the benefits.

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This is TALK OF THE NATION. I'm Neal Conan.

For years, doctors told people at risk of a heart attack to take a baby aspirin every day. And now, a pair of new studies finds that a daily dose of aspirin significantly reduces the risk of several cancers and seems to prevent tumors from spreading. The studies were published in the British medical journals, The Lancet and Lancet Oncology. Some experts say it's encouraging news. Others remain skeptical. And public health officials worry the risks may still outweigh the benefits.

If you have questions about aspirin and cancer, give us a call: 800-989-8255. Email us: talk@npr.org. You can also join the conversation on our website, go to npr.org, and click on TALK OF THE NATION. NPR science correspondent and senior editor Rob Stein joins us here in Studio 3A. Nice to have you with us.

ROB STEIN, BYLINE: Oh, nice to be here.

CONAN: And based on these studies, how long would somebody – you'd expecting a lot of people to start buying baby aspirin?

STEIN: Yeah, yeah. Looks like the lowly aspirin is getting its 15 minutes of fame today, with this new research. You know, as you've mentioned, aspirin has been something that doctors have recommended for patients at risk for heart attack to take every day - a baby aspirin every day - for a long time. And there has been evidence accumulating for some time that it might also reduce the risk for cancer, specifically colon cancer. That was the cancer for which it showed the strongest evidence. This new research suggests that it may actually have broader effects, in that it could reduce the risk for lots of other cancers.

CONAN: And why did it take so long for the humble aspirin, for its benefits, to be studied?

STEIN: Well - yeah, that's a good question. This is something people have been looking at for a long time. It's one of those things that's hard to sort out. And it's also important to note that these studies don't - aren't definitive. This is just, sort of, evidence suggesting that that might be the case, and there's got to be a lot more research done before anybody runs out and starts taking aspirin on a regular basis to reduce the risk for cancer. What's happened here is this is a group at the University of Oxford that's, sort of, been focusing on this for a long time.

And what they did is they went back and they dug up a lot of old data from a lot of studies that had been done for other reasons, primarily about heart disease, and reanalyzed that data to see what they could find out about cancer from that research.

CONAN: And what they found out is pretty startling. After five years, the risk of dying of cancer was reduced by 37 percent among those taking aspirin. Now that's significant.

STEIN: Right, right. Yeah. No, these are - they're pretty impressive numbers. As you said, they showed a reduction in death of 37 percent for people who have been taking small doses of aspirin every day. After about five years, they also showed that it seemed to decrease the risk that cancer would spread, people who have already been diagnosed with cancer. So the results are pretty interesting. And I talked to a number of researchers today at the National Cancer Institute and the American Cancer Society, and they said this is, you know, this is very encouraging and definitely going to follow up with more research.

CONAN: Daily aspirin use, one study found, reduced the risk of metastatic cancer by 36 percent. That's when it spreads to the body. And the risk of adenocarcinomas, those are common solid cancers that include colon, lung and prostate cancer, by 46 percent.

STEIN: Right. That's - one of the most interesting parts of this is that, as I said before, that, really, the evidence that part of this had been that aspirin might reduce the risk for colon cancer. This is suggesting that it might have a much broader effect. They found effects on prostate cancer, on lung cancer, and these are very common cancers. So if, in fact, aspirin could reduce the risk for those diseases, that would be pretty significant.

CONAN: You said you asked people at the National Institutes of Health about this, and they said, well we're going to start research. There are questions about whether there is going to be research. Can - nobody's going to make any money on aspirin.

STEIN: Right, right. This is the sort of thing that you're not going to get a big drug company to invest a lot of money into study. But there are lots of academic researches and government-funded researches out there that are looking at aspirin and the possible beneficial effects. And actually, really, the thing that people are mostly excited about is the possibility of developing another drug that might have the same effects of aspirin without the side effects, without the risk, because there are some significant risk from taking aspirin.

CONAN: And I was just to ask about that. The risk that people were always told about was it can cause problems with your stomach.

STEIN: Yeah. The big one that people are worried about is that aspirin - the reason of why it reduces the risk of heart attack is that it has an effect on the blood clotting and...

CONAN: It thins the blood.

STEIN: It thins the blood. It affects platelets. It causes clots. And that's a good thing when you're trying to prevent a heart attack. It's a bad thing because it can cause bleeding, gastrointestinal bleeding, something that people might not even be aware of until it's very fairly progressed and they are really at risk. It can be fatal.

CONAN: So those risks do occur, but it was interesting in the studies they found that over time - and these studies continued for years - that over time those risks seem to be diminished as well.

STEIN: Yeah. That was one of the encouraging parts of the study is that they did find that, in fact, taking aspirin did increase the risks for bleeding, but it seemed to diminished over time and the risks seem to go down. That's for gastrointestinal bleeding. There are some other risks that people are worried about aspirins, specifically it can also increase the risk for strokes, which is obviously a very serious complication if it occurs.

CONAN: Here's an email from Tony(ph) in Detroit: What exactly is the means by which aspirin blocks cancer? Would it be its effect on blood circulation?

STEIN: Yeah, that's a good question. The short answer to that is nobody knows. But there are a bunch of theories, and the two leading ones is that does - is the effect that aspirin has on platelets, which is how it reduces the risk for heart attacks. There's some evidence that platelets also may play a role in cancer, for example, by providing blood supply to tumors so they can grow. If you block the activity of platelets, you might block the blood flow to tumors and prevent cancer from occurring.

CONAN: Let's see if we can get some callers in on the conversation, 800-989-8255. Email: talk@npr.org. Michael is on us - on with us from Davis in California.

MICHAEL: Hi. Thanks for taking my call.

CONAN: Sure.

MICHAEL: I have two questions. One was, were the effects found be equal for both men and women? And what kind of age range are we talking about? And then the second question was the dose as compared to, like, a normal dose you can buy at the store here. I'll take my question off the air.

CONAN: Those are actually three questions Michael, but we'll take them anyway. Low dose aspirin, as I understand, the baby aspirin?

STEIN: Yeah. They're actually - in these studies, they looked at a variety of doses ranging from about 75 milligrams to more than 100 milligrams. But generally the evidence seemed to suggest that the amount of aspirin that's typically found in a baby aspirin, which is about 81 milligrams, something in that range is what has the beneficial effects.

CONAN: And the effects, any difference in terms of age?

STEIN: So far in these studies, it seemed to have equally effective for both men and women and across the board for different age groups.

CONAN: And men and - so it seems to be across the board?

STEIN: Yeah, both men - yeah, both genders and all ages.

CONAN: Email question from Alice(ph) in Memphis: Does aspirin show benefit for ovarian and other gynecological cancers?

STEIN: Yeah. It basically seemed to have this beneficial effect across the board for all sorts of cancers. They didn't tease it out for every single cancer. In the biggest studies that they published this week, they were looking at overall risk of being diagnosed with cancer and overall risks of dying from cancer, and that's where you saw the big effects.

CONAN: This email is from Lindsay(ph) in Columbus: I'm predisposed to liver problems. I've always been told to avoid aspirin. Now, I feel like I have to ask myself, is it better to risk liver failure or cancer?

STEIN: Yeah. This is - that's right. I mean, we think of aspirin as a sort of this inert drug in our medicine cabinet that's no big deal to take. You have to be really careful. Aspirin is a very powerful drug, can have all sorts of effects, and nobody, based on this study, should just go out and start taking an aspirin on a daily basis. What they should do is go to talk to their doctor and find out if, based on their risk profile, the risk for cancer versus the risk for heart disease versus the risk for liver disease, whether it make sense for them to start taking aspirin on a regular basis.

CONAN: This is one of the authors of the study. Dr. Peter Rothwell was quoted as saying, in terms of prevention, anyone with a family history would be sensible to go take aspirin.

STEIN: Yeah, I talked to Dr. Rothwell this morning, and, yeah, he was saying - he didn't quite go that far when I talked to him this morning. He said anybody with a family risk of cancer or family history of cancer should go talk to their doctor about taking aspirin to see whether it makes sense because you really have to think about this very carefully because there are significant risks. There may be significant benefits, but you have to weigh those very carefully before you start taking it.

CONAN: I just want to re-emphasize that I've read that word cancer to come on the market today, it would be a prescription drug. It's not the cure-all that we all - well, it does help with a lot of things, but it does come with risks. We forget this.

STEIN: That's right. That's right. If, you know, just like any other drug, if you read the small print for aspirin, you'd, you know, you'd see a lot of things you never - you didn't think about. And so you have to be careful that it's - because it's a double-edged sword. It has this potent effect that could beneficial, but because it's so powerful, it can also have negative effects.

CONAN: Let's go next to next to Derek(ph). And Derek is with us from Muskegon in Michigan.

DEREK: Yeah. Hi, Neal. I was wondering if the effects are also seen with other NSAIDs, like ibuprofen and the Aleve products.

STEIN: No. Not, I mean, they are not in this research. This research was focused specifically on aspirin and the benefits they found was only for aspirin. We don't really know if that - those other pain relievers have the same...

CONAN: Have studies been done to see if they might?

STEIN: Yeah, and so far there hasn't been anything really this strong showing that that's the case.

CONAN: It was interesting also - and, Derek, thanks very much for the question - there had been two earlier American studies about aspirin and cancer. They did not have daily doses, and the authors of this study said, well, those American studies did not show that aspirin reduced cancer. But we're throwing those results out because they didn't use daily doses.

STEIN: Yeah. I'm glad you brought that up because that's one of the key criticisms that I've been hearing today when I've talked to experts about this British researchers that it did not include those two big American studies. And those were two big very well respected studies. One is the nurses' health study. I mean, the women's health study, and the other one is called the physician's self study.

They both were run at Harvard, and they both took a look at the subject and found no effect. They did not find any benefit in reducing the risks for cancer from taking aspirin. As you said, they were somewhat different and somewhat different dosages, and they involved taking aspirin every other day instead of every day. And that's why they were excluded from the study, but the negative effects from those studies do raise a lot of questions in peoples' minds about really what's going on here.

CONAN: We're talking with Rob Stein, NPR science correspondent and senior editor, about two studies published in British Medical Journals today, respected journals we should point out, The Lancet and The Lancet Oncology, that show that aspirin can significantly reduce the risk of cancers and very serious cancers and very significant reduction in the risks. But there are risks, of course, to taking aspirin. You're listening to TALK OF THE NATION from NPR News. Let's go next to Jan(ph). Jan is with us from Tucson.

JAN: Hi. I wanted to ask because I - if I recall correctly, about a month ago, it might have been about two months ago actually on NPR, they were talking about aspirin, and it may not have been, but I thought what they were talking about was that aspirin actually can exacerbate asthma or create asthma in people.

CONAN: Do you remember that, Rob?

STEIN: You know, I'm not remembering the details of that study, but, yeah, that sounds somewhat familiar that there might have been some risks. And again, that's one of the things you have to keep in mind that it depends on your personal medical history on - the effects of these drugs can have in you. On one person, it might be very beneficial. In other people might stir up some problems.

JAN: OK. So there's - you don't have any specific recall of any studies, but I - so is it - so just basically, if you have asthma though, you don't have to panic and not take any aspirin? Because I'm prescribed it because of, you know, just, you know, for the heart, but I was concerned so I stopped the aspirin. So...

CONAN: I have to say, Rob's not a doctor. We can't prescribe for you on the radio.

JAN: Yeah, I know.

STEIN: Yeah, but I would say if your doctor has specifically suggest that you take aspirin, a baby aspirin, every other day because you have a history of heart disease, you should not discontinue it based on some possible suggestion that it might increase the risk for asthma.

JAN: Thank you very much. Bye-bye.

CONAN: Jan, thanks very much for the call. Another question about methodology in the studies and that was that the studies were originally designed to test aspirin's efficacy on heart patients. And some doctors say, well, wait a minute, they were looking for one thing and they found another. We have to redo this.

STEIN: That's always a red flag when you're dealing with research. When you take one study and the data from one study that was designed for one purpose and try to use it for another purpose, that can cause all sorts of problems, and you have to be very careful about interpreting the results. And you're right, all of the studies that they used in this research was for something else. It was looking at the effects of aspirin for reducing the risk for heart disease.

CONAN: Here's an email from Jolene(ph): How was — how has diet factored into the research? Aren't heart disease patients also put on healthier diets? Could higher fiber, lower acidity be the cause of lower incidents of cancer rather than the aspirin directly?

STEIN: Yeah, well, absolutely. I mean, the lifestyle factors like diet and exercise are very important and they - in this research, they try to take that into account. They try to account for other factors that may influence results, and they think they did that, but, you know, you never can be sure and again, especially when you're taking data for a study that was designed for one purpose and you're using it for another.

CONAN: Let's go next to Stewart(ph), Stewart with us from Birmingham. Stewart, you're on the air. Go ahead, please.

STEWART: I just had a question about aspirin versus the stomach, whether the enteric-coated aspirin that's designed to dissolve in the intestine instead, whether that might reduce or even prevent problems with the stomach bleeding.

STEIN: Right. Yeah, there is some suggestion when it comes to heart disease that those aspirin might be somewhat less effective. But they do have the benefit of not irritating the stomach as much, so there's a sort of a tradeoff there.

CONAN: Thanks very much for the call, Stewart. When you talk to people at NIH, when will this research get underway? How soon might we expect results? These studies take years, no?

STEIN: Yeah, they do take years, and this is not something that's going to happen overnight. I think what's going to happen more quickly is that some of the major medical groups like the American Cancer Society and the National Cancer Institute will probably sit down, take a look at this data and decide whether to change their guidelines, their recommendations for how doctors should advise their patients when it comes to aspirin.

CONAN: Let's get Lynn(ph) on the line. Lynn, you're on the air. Go ahead, please.

LYNN: Yes. I'm a physician, and these studies that you mentioned, it's looking retrospectively. It studies a bunch of other studies that were done for a different reason. They're called meta-analysis. And it's that kind of study that said that people should take estrogen for heart disease, and we know now after the definitive, you know, double-blind control study that that was wrong. So I just emphasize that the definitive study is the perspective going forward study, where you look at this specific issue and you do it in a double-blind way because the meta-analysis are very problematic. So before anyone acts on this, they should really wait until more significant information is known.

And the second little issue is the number of asthmatics who were made worse by aspirin, it's a very specific group of people. It's not just everyone with asthma. So again, your directive to talk to your doctor and raise these issues with your specific case is very important. The other thing you mentioned...

CONAN: Very quickly, Lynn, if you would.

LYNN: OK. Just that you made the point that drug companies will not do a study on medicine that's basically almost free, that's why we need government funding for research so that important issues like this can be looked at. Aspirin is a miracle drug, but the government needs to provide the money because the...

CONAN: Lynn, thanks very much for the call. We appreciate it.

LYNN: OK, sure. Bye-bye.

CONAN: And, Rob Stein, more on this later?

STEIN: Yeah, I think those are very important points, and the point she made specific about hormone therapy, I think, it's a good cautionary note that that's a case where it all seem to make sense and turned out to be wrong.

CONAN: NPR science correspondent and senior editor Rob Stein, who joined us here in Studio 3A. Tomorrow, looking for ways to hold colleges accountable. One option, a standardized test. We'll talk about that tomorrow in this hour. It's the TALK OF THE NATION from NPR News. I'm Neal Conan in Washington.

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