Here are some common questions and facts about placebos and everything you need to know about them in the context of cancer clinical trials. Do All Cancer Clinical Trials Involve a Placebo? Because placebos are generally only used in cancer clinical trials when there’s no other standard of care, Sivendran says a placebo will not make the cancer worse than what would be the natural course of the cancer. “Participating in a clinical trial can be a really important way to get access to innovative new treatments or combinations of existing treatments,” says Sivendran. You can withdraw from a clinical trial at any point in time.”The Takeaway