Questions to ask about new cancer treatments

What’s the research behind the treatment?

If you want to use a cancer treatment with a proven track record, look at how the treatment was tested. The way tests are set up can affect the outcome, and sometimes can make a treatment look like it works when it really doesn’t.

Pre-clinical tests

Studies in cells (laboratory studies or in vitro studies)

Scientists usually start by testing a new treatment on cancer cells in a dish in the lab, to find out if it has any effect there. If it doesn’t, they may change the formula or use different types of cells to try it again. If they find the effect they want in the dish, they may move on to animals.

Because some of these cell study reports are published, you may hear about them on the news. But often the headlines do not clearly say what kind of study is being reported. Very few of the substances that are tested in these early stages look promising enough to even be tested in humans.

Studies in animals (in vivo studies)

If the researchers find the effect they want in cells in a dish, they may move on to animal tests or tests in living creatures. Some of these reports are published and may be reported on the news.

If the study was done in living animals, good outcomes may sound promising. Keep in mind, though, that drugs that work in animals don’t always work when they are tested in people. Sometimes, the drug works in almost the exact same way in people as it does in animals. But as any veterinarian can tell you, people use many drugs that don’t work on animals, and vice versa. So while animal tests can give researchers certain types of valuable information, they still may not show how the drug will affect people. There are many hurdles between lab studies and those done in humans that must be overcome for the study to progress to the next phase.

News stories on lab and animal studies can mislead

In both lab studies and animal studies, the research report may be published. Usually, the researcher’s own report makes it clear that more studies need to be done to see if the substance makes a difference in people. But if a news group picks up the story and publishes it, the story may not clearly say what kind of study was done. Sometimes the news reports on this very early research make it sound like the method will work in people, which can lead to confusion. This is why it helps to look at the whole printed story, and then see if you can find out more about the details of the research. Always keep in mind that there’s a huge difference between positive results in lab or animal studies and good results in human studies.

Testing in humans

After it’s tested in the lab, the treatment may be ready to be tested in humans. Before this decision is made, the results from cell and animal tests are carefully reviewed. Other evidence may be weighed, such as the effects of related drugs, what’s already known about the class of chemicals, and other such information. If the drug is a new substance, the company must tell the US Food and Drug Administration (FDA) why they think the drug will work in humans, and share research from the lab and animal studies. They must also have some evidence that it will be safe for people to take. If the FDA approves human testing, researchers must decide how to design clinical trials and find volunteers who are willing to take the drug.

Clinical trials are research studies in which people volunteer to help doctors find ways to treat a disease or improve care. Today’s cancer treatments are mostly based on what was learned in past clinical trials. Cancer treatments have improved because of clinical trials. It’s important to continue this kind of research, so that cancer treatments can keep getting better. You can find a lot more information about this in Clinical Trials: What You Need to Know.

Is the study published and peer reviewed?

Publishing the findings in a respected, peer-reviewed journal means that the methods and information from the study were looked at by other doctors or scientists. When they look at the information, they want to be sure that the scientific procedures were properly followed.

Sometimes you will find news about studies that comes from other sources, such as magazines or journals that are not peer reviewed, or books and letters that are supposed to have been written by experts. Be extra careful of this information.

Good science is cautious

It takes more than one study to prove something works. One study with a good outcome, even a human study, doesn’t mean a treatment works. Future studies that try the same thing sometimes get different results, even if the study is done the same way. This can happen because the second study tests the method on a different group of people that doesn’t respond the same way as the first group. Or the treatment may be used in a slightly different way, or with some other small difference that may not have been noticed. Or the treatment looks good in the first study based on random factors that couldn’t be controlled. Sometimes a treatment looks great in the first study, but then no other study gets the same outcome – meaning that real-life patients couldn’t expect those great results either.

It’s rare to find a respected cancer researcher who wants to use a new treatment based on just one study. But even if it looks that way, behind that study is almost always a lot of other information that’s been built up over a long time. When one large clinical trial makes the news, keep in mind that if a treatment actually works, it usually has a good track record from earlier studies.

What do I need to know about treatments that are not in line to be approved by the FDA?

Many herbs and food extracts are advertised as having an effect on cancer. As long as these food-related products are generally regarded as safe, there are few restrictions on their sales. Those who make or sell the products are not required to submit proof that the herb or supplement is safe or effective, and they don’t address the supplements’ effects on the body.

But some supplements have been found to not contain what’s listed on the label, and others have been found to contain substances that were not on the label. You can get more information in Dietary Supplements: What Is Safe?

Because there’s growing interest in dietary supplements, researchers have started studying some of them using the same methods used for cancer treatments. Large sums of money are not usually available for clinical studies to look at herbs, so these studies tend to be smaller. But because the safety of the substance isn’t called into question, there’s less need for safety testing.

When looking at studies of herbs or supplements in people, consider the same questions you would use for clinical trials. Keep in mind that until recently, many of these studies were poorly designed and many didn’t get published. Or, if they did, some were published someplace other than peer-reviewed scientific journals.

On the Internet, at conferences, and in health food stores, those who sell herbs sometimes try to use lab studies or animal studies as evidence that the herbs work. Some sellers will refer to studies that are not published in peer-reviewed journals. The studies may be written up in a “natural cures” book or posted on a website. Sometimes sellers will show letters on a doctor’s or hospital’s letterhead, often from another country where it’s impossible to check the facts. You have no way of knowing that the studies were done as they’re presented.

It also happens that researchers will isolate a chemical from an herb and test it in the lab to find out if it affects cells. Because the effects of the isolated chemical might be different (especially in large doses), this kind of treatment is tested from the ground up, like a new drug. This type of study is usually written up in scientific literature and can be found there. But if sellers of an herb learn about scientific studies done with herbal extracts, some of them will talk about the study’s findings as if the success in the study is linked to the whole herb, not a concentrated extract of one of its parts. Purified extracts don’t work the same way as the whole herb, and these 2 types of studies cannot stand in for one another.

What if different studies of the same treatment show different outcomes?

Different outcomes can be very confusing, especially at first. Even when the studies are set up well, clinical trials often end up showing very little difference, if any, between the people who took the study treatment and those who didn’t.

When the treatment really doesn’t have any effect, random chance will often tip the scales in one direction or another – sometimes enough that the results seem to be significant. This means that sometimes the placebo group will do a bit better than the test group, while at other times, the group that gets the new treatment does a little better.

In most cases, when results conflict with one another like this, it means that the treatment really has very little effect. But sometimes conflicting results can be caused by study design problems, or other factors that affected the outcomes.

This leads to another problem that can creep in as studies are published. Sometimes, the studies that show no difference between the treatment and placebo, or the ones that show the placebo group doing better, are never published. After all, it isn’t exactly exciting news when something doesn’t work. But these kinds of studies could really help people who are trying to decide whether it’s worthwhile to get the treatment.

Worse, if the only clinical trials published are the ones that show the treatment helps, a person reviewing the published information won’t be able to find those studies that showed no difference. He or she might conclude that the treatment was helpful, because those are the only studies that were published. This is an example of what’s called publication bias.

Does this new cancer treatment really make a difference to people?

Even if a study finds that the difference between an old treatment and a new one is significantly different, it may not make that much difference in people’s lives. For instance, a very large clinical trial can show that a treatment improves survival by an average of 10 days and that this was not by chance. Even though it’s significant statistically, for most patients, a treatment that extends life a bit more than a week may mean that the treatment may not be worth the side effects.

Sometimes, it’s hard for even doctors to know how helpful a treatment may be when balancing its benefits with its side effects and other costs. Still, if you ask your doctor about a certain treatment that was found helpful in a good study, he or she may be able to talk to you about whether it might be worthwhile for you.

What if I want to get an unapproved treatment?

Even if the evidence isn’t there, you may decide to use a new treatment. If you choose to do this, talk about it with your doctor to get his or her opinion of the treatment. See what you can find out about side effects, allergies, drug interactions, and other possible effects.

The most common way to get a treatment that has not yet been approved is to take part in a clinical trial. But there are other situations where a drug may be used before the FDA approves it for general use, even if you can’t be in a clinical trial.

Sometimes a new drug has already been approved by the FDA for one purpose and is being used for another. This means it might be available for you if your doctor agrees it might help you. (See Off-Label Drug Use for more on this.)

Sometimes the drug can be used for certain people even before the FDA has approved the drug if “expanded access” or “compassionate use” are allowed. If this is the case, doctors can use the drug for certain problems, usually when other treatments are not working. (See Compassionate Drug Use to learn more about this option.)

Unfortunately, insurance companies sometimes refuse to pay for treatments that are used to treat conditions for which they were not approved. Off-Label Drug Use and Compassionate Drug Use tell you how to deal with this.

Questions you should ask about new cancer treatments

After going over what all of these things mean, here’s a recap of questions about new treatments you will want answered:

  • Was the new treatment 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 at a reputable cancer treatment center?
  • 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 (observed)?
  • Was there a difference in outcome between the group taking standard treatment and the group taking the new treatment?
  • Was the difference in outcome measured in survival, recurrence, symptoms, or some other marker?
  • Was the study published in a respected, peer-reviewed journal, or was it presented at a conference or sent out in a press release?
  • Is the treatment only being used in clinical trials in humans or has it been approved by the FDA?
  • If the treatment hasn’t been approved, is it available through expanded access or compassionate use? (Compassionate drug use is when seriously ill patients use a new, unapproved drug when no other treatments are available. Call us to learn more about this.)
  • Is the treatment likely to be harmful? What’s known about side effects?
  • Is the treatment safe to use along with other treatments I’m getting?

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

American Society of Clinical Oncology. Medical News: How to Know If It's Accurate. 06/2014. Accessed at on May 10, 2016.

Govani SM, Higgins PDR. How to Read a Clinical Trial Paper: A Lesson in Basic Trial Statistics. Gastroenterology & Hepatology. 2012;8(4):241-248.

Miller JD. When is significant not important? Finding Clinical Meaning in Cancer Data. Journal of the National Cancer Institute. 2007;99:1832-1835.

Rubin EH, Gilliland DG. Drug development and clinical trials—the path to an approved cancer drug. Nat Rev Clin Oncol. 2012;9(4):215-22.


American Society of Clinical Oncology. Medical News: How to Know If It's Accurate. 06/2014. Accessed at on May 10, 2016.

Govani SM, Higgins PDR. How to Read a Clinical Trial Paper: A Lesson in Basic Trial Statistics. Gastroenterology & Hepatology. 2012;8(4):241-248.

Miller JD. When is significant not important? Finding Clinical Meaning in Cancer Data. Journal of the National Cancer Institute. 2007;99:1832-1835.

Rubin EH, Gilliland DG. Drug development and clinical trials—the path to an approved cancer drug. Nat Rev Clin Oncol. 2012;9(4):215-22.

Last Revised: May 10, 2016

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