The severity of nausea and vomiting depends on the drug or drug combinations the patient receives, the dose and administration schedule, and other variables particular to each patient. Radiation therapy directed at specific sites in the body including the gastrointestinal tract, liver, or brain can also cause nausea and vomiting. Nausea, an unpleasant, wavelike feeling in the stomach and throat that may or may not result in vomiting, is controlled by the part of the central nervous system that governs involuntary functions.
Many patients say that nausea is far more unpleasant than vomiting.
Anticipatory nausea and vomiting occurs before or during chemotherapy or radiation therapy among individuals who experienced severe symptoms with previous treatment sessions. Anticipatory nausea and vomiting is triggered by specific odors, tastes, or objects that a patient associates with treatment, not by the actual presence of chemical agents in the blood. Acute nausea and vomiting occurs within 24 hours after cancer treatment. Delayed nausea and vomiting occurs more than 24 hours after cancer treatment and may continue for several days. It can cause serious problems such as dehydration and may result in hospitalization.