Nausea is an unpleasant wavelike feeling in the back of the throat and/or stomach that may or may not result in vomiting. Vomiting is the forceful elimination of the contents of the stomach through the mouth. Retching is the movement of the stomach and esophagus without vomiting and is also called dry heaves. Although treatments have improved, nausea and vomiting continue to be worrisome side effects of cancer therapy. Nausea may be even more distressing for patients than vomiting.
It is very important to prevent and control nausea and vomiting in patients with cancer. Uncontrolled nausea and vomiting can interfere with the patient's ability to receive cancer treatment and care for himself or herself by causing chemical changes in the body, loss of appetite, physical and mental difficulties, a torn esophagus, broken bones, or the reopening of surgical wounds.
Nausea and vomiting that are caused by cancer therapy are classified as follows:
ACUTE NAUSEA AND VOMITING: Usually occurs within 24 hours after beginning chemotherapy.
DELAYED NAUSEA AND VOMITING: Occurs more than 24 hours after chemotherapy. Also called late nausea and vomiting.
ANTICIPATORY NAUSEA AND VOMITING: If a patient has had nausea and vomiting after the previous 3 or 4 chemotherapy treatments, he or she may experience anticipatory nausea and vomiting. The smells, sights, and sounds of the treatment room may remind the patient of previous episodes and may trigger nausea and vomiting before a new cycle of chemotherapy (or radiation therapy) has even begun.
CHRONIC NAUSEA AND VOMITING: May affect people who have advanced cancer. It is not well understood.
Studies strongly suggest that patients receiving chemotherapy experience more acute and delayed nausea and vomiting than is estimated by health care providers.