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Which Study Results Are the Most Helpful in Making Cancer Care Decisions?
    Posted: 06/12/2003
Summary: Questions to Ask About a Cancer Study

In summary, the following questions may help as you look through various cancer studies, looking for the most medically definitive findings:

Question
Look For
  • Was the study a clinical trial? In other words, was the study experimental (there was an intervention that people were asked to take or do) and prospective (investigators followed study participants forward in time)?
A study that is both
experimental and prospective
  • What phase was the trial -- phase I, phase II or phase III?
A phase III study
  • Did the clinical trial have a control group? That is, did one group of participants receive the experimental intervention while another did not?
A controlled study
  • Were participants randomly assigned to either the investigational group or the control group?
A randomized study
  • How many participants were enrolled in the study?
A study that is large enough for the results to be statistically significant;
not due to chance



Glossary Terms

controlled clinical trial (kun-TROLD KLIH-nih-kul TRY-ul)
A clinical study that includes a comparison (control) group. The comparison group receives a placebo, another treatment, or no treatment at all.
experimental (ek-SPER-ih-men-tul)
In clinical trials, refers to a drug (including a new drug, dose, combination, or route of administration) or procedure that has undergone basic laboratory testing and received approval from the U.S. Food and Drug Administration (FDA) to be tested in human subjects. A drug or procedure may be approved by the FDA for use in one disease or condition, but be considered experimental in other diseases or conditions. Also called investigational.
phase III trial
A study to compare the results of people taking a new treatment with the results of people taking the standard treatment (for example, which group has better survival rates or fewer side effects). In most cases, studies move into phase III only after a treatment seems to work in phases I and II. Phase III trials may include hundreds of people.
prospective (proh-SPEK-tiv)
In medicine, a study or clinical trial in which participants are identified and then followed forward in time.
randomized clinical trial
A study in which the participants are assigned by chance to separate groups that compare different treatments; neither the researchers nor the participants can choose which group. Using chance to assign people to groups means that the groups will be similar and that the treatments they receive can be compared objectively. At the time of the trial, it is not known which treatment is best. It is the patient's choice to be in a randomized trial.
statistically significant
Describes a mathematical measure of difference between groups. The difference is said to be statistically significant if it is greater than what might be expected to happen by chance alone. Also called significant.