NCI Dictionary of Cancer Terms

The NCI Dictionary of Cancer Terms features 8,468 terms related to cancer and medicine.

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A harmless substance or treatment that may cause harmful side effects or worsening of symptoms because the patient thinks or believes they may occur or expects them to occur. For example, in a clinical trial, patients who are not given an active treatment but are told what side effects the active treatment may cause may have the same side effects as the patients who are given the active treatment just because they expect them to occur.