- This document only addresses ways to look at information on methods that are said to prevent cancer, but some of the same principles can be used when looking at information on cancer treatment, sympto
- Look at the science behind the prevention method
- Types of human studies on cancer risk
- Studies that observe humans
- Human testing: Clinical trials
- A closer look at the evidence
- Other questions about studies on new ways to prevent cancer
- What does this mean to you?
- To learn more
- Appendix A
This document only addresses ways to look at information on methods that are said to prevent cancer, but some of the same principles can be used when looking at information on cancer treatment, sympto
Can cancer be prevented?
Sometimes cancer can be prevented. It’s quite possible that more than half of cancer deaths could be prevented – if everyone avoided tobacco, controlled their weight, got enough physical exercise, and took other steps to improve their health. Of course, that’s a big “if.”
There’s no guaranteed way to prevent cancer.
So far, nothing has been found that’s proven to prevent every cancer. Right now we know there are ways to help prevent many cancers in large groups of people. And there are things you can do that might help reduce your personal chance of getting cancer. (See Appendix A at the end for the American Cancer Society’s recommendations for reducing cancer risk.) But, as of today, even the best methods to try to reduce your cancer risk (called cancer risk reduction) cannot prevent all cancers.
Because certain methods and drugs can help prevent some cancers in large groups of people, we will still use the term cancer prevention here.
Early detection can help save lives
If cancer does develop, there are early detection tests that can improve the odds that some types of cancer will be found at an early stage (when they’re small and easier to treat). To read about proven methods to find cancer before it causes symptoms, see our American Cancer Society Guidelines for the Early Detection of Cancer.
Although early detection alone rarely prevents cancer, it can often prevent cancer deaths.
When you hear about something new to prevent cancer
You’ve just heard about something new that might possibly prevent cancer, something you haven’t heard about before. If you’re worried about getting cancer, you might wonder if this might work for you. Even though your doctor might not have mentioned it, you want to find out more about this. You want every possible chance of never getting cancer.
But before you put your money, time, and energy on the line, you need to know more about the new prevention method so you can decide if it’s worth it.. At this point, you probably don’t know if it will actually reduce your risk of cancer, or if it could even harm you. Here are some of the things you may hear about:
FDA-approved drugs: The new method may be a drug that your doctor recommends to reduce your cancer risk. It’s pretty easy to find out more about FDA-approved drugs, since there are many trustworthy sources and careful scientific studies involved. We can help you find out more, and there are others who can help, too. (See the “To learn more” section at the end of this document.)
Methods being studied for FDA approval: Maybe the method you heard about hasn’t been approved, but is “in the pipeline” to become a mainstream cancer prevention method in the future. It may be a pill, a treatment, or something else. It’s usually not too hard to find information about these kinds of treatments. If the treatment has ever been approved by the FDA for any medical use, you can usually find good information on its risks and side effects. But it may be harder to find out about how well it works for cancer prevention.
Non-prescription herbs, supplements, diets, and special treatments: Other methods you hear about may be herbs, vitamins, other dietary supplements, health tonics, “body cleansings,” or special diets that are supposed to boost the immune system, among many other things. In the past, almost no studies were done to look at these methods, but researchers are now trying to study more of them in the same careful ways that they study other methods.
Lifestyle changes: You may hear about other things you can do that can help reduce your cancer risk. For instance, quitting tobacco, eating more fruits and vegetables, getting more exercise, cutting back on alcohol and red meats, and staying at a healthy weight have all been given more attention lately. Studies on some of these are fairly easy to find.
Whatever method you’re thinking about, take the time to see what you can learn about it from sources you trust. Here are some ideas to help you when you’re searching for more information.
Look at where the information came from
To start, you’ll want to consider the source of the information on the cancer prevention method.
- Was there a report in a newspaper or magazine?
- Was it discussed on a television or radio program?
- Did the news come from an Internet site that also happens to be selling the treatment or is otherwise connected to the seller?
- Did a health food store or nutrition center employee suggest it?
- Was there a study published in a respected, peer-reviewed medical journal such as the Lancet or the Journal of the National Cancer Institute?
- Did someone tell you how well this new method is working for them or someone else?
Did it come from news reports?
If you see a report in a respected newspaper or magazine
Don’t just look at the headlines – sometimes they can be overstated, confusing, or even misleading. Read the article carefully to find out where the reporters got their information. Look for these things:
- Is this a press release from a company announcing a new breakthrough in cancer prevention?
- Is it a report from a clinical study that was given at a scientific conference?
- Is it a report from a study that was published in a respected medical journal?
- Where was the study done? What do you know about the research center that conducted and sponsored the study?
If the report was on the TV or radio
You’ll want to know if what you saw or heard can be trusted. Was the news reviewed and reported by a doctor, or was it a non-medical person such as a reporter or news anchor? Some news organizations hire medical reporters so that medical and health news can be reported more clearly to the public. Journalists without medical training don’t usually understand all of the medical background and related research on the subject, so they may not be able to give a clear, unbiased view.
If it was a commercial or infomercial
Keep in mind that these are ads that tell you only what they want you to hear. You have to listen carefully to learn if studies have been done, and find other reliable sources to learn more. (See the section called “Was it from a promotion from a seller?”)
If you heard about a study on a reliable TV or radio news report
Try to remember the details. Look for the kind of information that you would try to get from a newspaper, including where the new information came from. Getting these facts from broadcasts can be much harder than from printed reports, because it’s hard to remember everything you hear on a short TV or radio spot. And you can’t always go back and search for the facts after the broadcast is over. Even if you can recall everything you heard, important details may have been left out because they have so little time to cover the subject.
Some news outlets post extra information or replay their newscasts online. If you can’t find more on their website, you might want to try contacting the TV or radio station to get your questions answered. It’s better to do this right away. Sometimes, a question that might be answered easily a day or two after the broadcast becomes impossible after a month or two. If it turns out that part of their report was wrong, you might find corrections or clarifications online soon after the report was aired.
In the section, “Consider the science,” we go into more depth about the important details you’ll want to get from a news report, no matter where it came from.
Was it anecdotal information?
If someone told you that he or she (or their friends or family) is healthy and feeling great using this method, it’s called anecdotal information. This is the personal report of one person or very few people. Really learning about cancer prevention means looking at a lot of people over time.
Older people get cancer much more often. It’s pretty rare for younger people to develop cancer, whether or not they use some method to prevent it. This means it’s no surprise if a large number of people haven’t developed cancer while using a certain prevention method for a few years.
Still, if you’ve been told someone’s personal story, how do you find out more? Keep in mind that a person may credit an herb or supplement with feeling better, even though there may be other factors involved. And sometimes, a person’s belief in a method could be enough to make a person feel better for at least a short time. (See our document called Placebo Effect for more on this.)
There are many other ways that people with good intentions can reach the wrong conclusion from a single person’s experience, or even the experiences of a group of people. This is why scientists look at cancer prevention methods under such careful conditions.
Was it a promotion from a seller?
If the report came from a seller on the internet, you may have lots of searching to do. Most of the cancer prevention methods sold online talk about the powers of herbs and supplements that have never been proven to reduce cancer risk or make people healthier. They often make vague claims about their product activating or strengthening the immune system, and other statements that are impossible to prove.
Some sellers have been caught using outright lies and fraud to make their websites look official. Some have written fake quotes from doctors. Others have reported on studies that were either never done or were misrepresented, saying they were from well-known cancer centers. There have been ads or websites with people dressed up as doctors who appeared to use or endorse the product.
Some marketers have implied their product was endorsed by the American Cancer Society. Some have even falsely said that their device or treatment was approved by the US Food and Drug Administration (FDA). Others note that their device is “registered” with the FDA. Even if that’s true, registration is not the same as approval. Registration doesn’t require proof that the device works or is safe. Another take on this is that a device is said to be FDA approved, and it is – but when you investigate, it’s not approved for the purpose they claim. You can find out more about these claims by calling the FDA. (See the “To learn more” section.)
Sometimes the staff at nutrition centers and herbal shops will suggest ideas or even prescribe “immune boosting” or “cleansing” herbs to help prevent cancer and other conditions. Studies on the accuracy of information from nutrition centers and herbal shops on cancer prevention methods are not available. But studies have been done on people who reported that they already had cancer, and asked nutrition center staffs about possible treatments. The research showed that treatments were often recommended that were not proven to help people with cancer. In fact, some of the suggested treatments could have caused harm. (For more information on these treatments, see our documents Complementary and Alternative Methods and Cancer and Dietary Supplements: What Is Safe?)
There are also commercials and infomercials that present new cancer preventives on TV. These are often set up to look like news interviews, and can be very misleading because they are carefully scripted by the sellers of the product. Some will cite studies without saying where they came from, or they’ll quote statistics from unreliable sources. Even worse, some will give glowing information and say it came from a reliable source – but when you go to look for it, the information isn’t there at all. In fact, you may learn that some of the people who sell prevention methods and other “secret cancer information” in these ways have been jailed for fraud. But when such reports are first aired, they can sound very promising.
What about press releases?
Sometimes a company will put out a press release about some promising substance or compound that claims to prevent cancer. Press releases are offered by many companies, including legitimate organizations, about matters that are important to the public. Sometimes they’re offered to generate good publicity for their company or organization. But those that are put out by a company that stands to make money from a product they’re touting should be looked at in the same way as ads and infomercials. Some press releases appear on the company’s website or online newsletters. After that, they may be and republished by magazines, bloggers, or others.
Some press releases offer preliminary details about a lab study, an animal study, or a small clinical trial (a type of study in humans). Even if the press release came out after a large study was done, the company or organization is only telling the press what they want the public to hear. This is not the same as putting out information after fellow scientists have taken a careful look at the study methods and outcome (the peer review process). You’ll want to know more about the final study outcome after it’s been evaluated by other experts in the field, not just the parts the company wants the public to know.
Is it from a conference presentation?
Sometimes researchers will share information with other doctors and health professionals at scientific conferences. This information is often an early look at a study that can sometimes sound very dramatic and make headlines. News reporters go to these conferences looking for just this kind of story.
Again, it helps to know who is doing the study and where they work. Sometimes, the study is being done using all the careful methods of a well-run clinical trial, and the researcher is sharing early data with the audience. But the final outcomes of these studies are not complete at the time the findings are presented. And, in most cases, the science review (or peer review) that’s needed before a study is published has not yet been done. You’ll still want to look at the final report to find out what was done and how it turned out after the data was fully analyzed. By the time the study is published – if it gets published at all – the results may be quite a bit different from the conference presentation.
Last Medical Review: 10/09/2014
Last Revised: 11/21/2014