- Who can get cancer?
- Consider the source
- Consider the science
- 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
What does this mean to you?
After going over what all of these things mean, here are some questions about new treatments you will want answered:
- Was the new cancer prevention method tested in the lab (on cells in a dish, called in vitro), in animals, or in humans (in vivo)?
- Who did the study? Was it done by known researchers and cancer treatment centers?
- Are there other studies that were done before that support this outcome?
- If the study was done in humans, how many were involved? How long were they followed?
- Was there a control group (people who got placebo or another prevention method)?
- Were similar people chosen at random to be in either the test group or the control group (randomized)?
- Was the study blinded (were the patients and/or researchers kept from knowing who got which prevention method while the patient was being watched for the effects)?
- Was there a difference in outcome between the group getting the new method and the group getting the placebo/standard prevention?
- Was the difference in outcome measured in numbers of new cancer cases, survival, or both?
- Was the study published in a respected, peer-reviewed journal? Was it presented at a conference or sent out in a press release?
- Is the prevention method likely to be harmful to me? What’s known about drawbacks or side effects?
What about heredity? How does it affect my cancer risk and prevention?
All cancers involve damage to genes that control the cell’s growth (division). But only about 1 in 20 cancers are linked to a damaged gene that is inherited (passed on) from a parent. If you inherit certain damaged genes, you may have a very high risk of getting one or more types of cancer. Genetic tests can be done to find out if there is an inherited problem if a certain type of cancer is common in your family. (See our document called Genetic Testing: What You Need To Know for more on how this works.)
This means 19 out of 20 cancers are not caused by inheriting damaged genes, but from damage that builds up over your lifetime. Mutations (changes) in your genes may be caused by internal factors such as hormones or the way nutrients are processed within cells. Or they can be caused by external factors such as tobacco, chemicals, and sunlight.
If you think you are at high risk for certain types of cancer, talk with a doctor about whether earlier screening or extra testing is needed. In some cases, there are medicines that can reduce your risk, too. (See our document, Medicines to Reduce Breast Cancer Risk.)
Using unproven methods that may reduce your risk
For those who are still searching for a guarantee – or even a boost in the right direction – there’s no shortage of other ideas as to how a person might be able to keep from getting cancer. Some ways have been studied, but most have not. Some methods have proven safe, but the safety of others is still unknown. Still, people want to be as healthy as possible, and if they find something that may help, they may want to try it even if there is no evidence. With thousands of possibilities that take years to study, there will always be theories waiting to be checked out.
In the meantime, even if the evidence isn’t there for a cancer prevention method, you may decide to use it anyway. The American Cancer Society supports the right of people to decide what’s best for them. But we encourage people to discuss prevention methods or treatments they may be thinking about with their doctors and other health care providers. We also encourage people to consider using methods that have either been proven to work or are being studied in clinical trials.
If you choose to use unproven measures, talk with your doctor about it to get his or her opinion of the method. If it’s a vitamin, herb, or supplement, see what you can find out about side effects, allergies, and other possible effects. You’ll also need to let your doctor know about it in case it causes problems with other medicines you are taking. Often, studies of “natural remedies” don’t collect this sort of information, and it can be hard to find.
We encourage you to learn all you can. You can always call your American Cancer Society. We can almost always help you get more information on any treatment or method you are considering.
Last Medical Review: 09/04/2012
Last Revised: 09/04/2012