Contribution of dexamethasone to control of chemotherapy-induced nausea and vomiting: a meta-analysis of randomized evidence.

PURPOSE To synthesize the available randomized evidence on the efficacy of dexamethasone when used for protection against acute and delayed nausea and vomiting in patients receiving highly or moderately emetogenic cancer chemotherapy. MATERIALS AND METHODS A meta-analysis was performed using trials identified through MEDLINE (1966 to April 1999), Embase, Derwent Drug File, and the Cochrane Library's Database of Controlled Trials. Data on acute and delayed emesis and nausea were collected. All randomized studies comparing dexamethasone to placebo, no treatment, or other antiemetics qualified, including cross-over trials providing first-cycle data. RESULTS Of 1,200 citations screened, 32 studies with 42 pertinent comparisons and 5,613 patients were included in the meta-analysis. Dexamethasone was superior to placebo or no treatment for complete protection from acute emesis (odds ratio, 2.22; 95% confidence interval [CI], 1.89 to 2.60) and for complete protection from delayed emesis (odds ratio, 2.04; 95% CI, 1.63 to 2.56). The results were similar for complete protection from nausea. The pooled risk difference for complete protection from emesis was 16% for both the acute and delayed phases (95% CI, 13% to 19% and 11% to 20%, respectively). The beneficial effect was similar in subgroups defined by various study design parameters. No trial addressed the efficacy of dexamethasone in the delayed phase without having administered dexamethasone for acute-phase protection as well. CONCLUSION Dexamethasone is clearly effective in protecting from emesis both in the acute and delayed phases, with emesis avoided in one patient out of six treated. Future trials should determine whether the delayed-phase effect is independent of the acute-phase benefit.