Abstract
BACKGROUND: Increasing evidence suggests a relation between patient expectancies and chemotherapy-induced nausea. However, this research has often failed to adequately control for other possible contributing factors. In the current study, the contribution of patient expectancies to the occurrence and severity of postchemotherapy nausea was examined using more stringent statistical techniques (namely hierarchical regression) than other similar studies that have relied on bivariate correlations, chi-square tests, and stepwise regression, and further extended upon previous research by including quality of life (QoL) in the analysis. METHODS: In all, 671 first-time chemotherapy patients taking part in a trial comparing antiemetic regimens answered questions regarding their expectancies for experiencing nausea. Patients then completed a diary assessing both the occurrence and severity of their nausea in the 4 days after their first infusion. RESULTS: Stronger expectancies for nausea corresponded with greater average and peak nausea after chemotherapy and this was after controlling for age, sex, susceptibility to motion sickness, diagnosis, and QoL. Interestingly, patients classified as highly expectant (first quartile) experienced significantly greater average and peak nausea than those classified as somewhat expectant, slightly expectant, and not expectant (second, third, and fourth quartiles, respectively), whereas there were no significant differences between these lower levels of expectancy. Furthermore, increases in average nausea led to a significant reduction in QoL after chemotherapy. CONCLUSIONS: Patient expectancies appear to contribute to postchemotherapy nausea and patients that are highly expectant of experiencing nausea appear to be at particular risk. Interventions that target these patients should reduce the burden of nausea and may also improve QoL.