A placebo-controlled clinical trial compares a new treatment with a placebo (inactive drug or treatment). Placebo-controlled clinical trials in cancer research are rare, but are used when there is no effective, standard treatment available. Read more about placebos in cancer clinical trials.
I never understood my clinical trial while I was on it. The information was all there in my informed consent. Even though the language was respectful and direct, I was unable to process it.
Understanding Clinical Trials: clinicaltrials.gov
I'm glad I participated in the trial, even if I don't understand it.