Do cancer clinical trials use placebos?

Placebos are rarely used in cancer treatment trials. In most cancer trials, one group gets the new treatment being studied. Another group gets the treatment already seen as the standard of care for that cancer. Researchers then compare how each group does.

Placebos are more likely to show up in a few specific situations. One is when there is no standard treatment for the condition being studied. Another is when researchers compare standard treatment plus a placebo against standard treatment plus the study drug. Placebos are also used in some cancer prevention trials.

If a trial does use a placebo, you are always told ahead of time. This is covered in the informed consent process and in the consent form you read before you decide whether to join. So you can ask about placebo use before you agree to anything. You can ask how likely you would be to get one, and what you would still receive if you did.