Efficacy and safety of dexamethasone sparing for the prevention of nausea and vomiting associated with moderately emetogenic chemotherapy: a systematic review and meta-analysis of Clinical Practice Guidelines for Antiemesis 2023 from Japan Society of Clinical Oncology.

Background: Palonosetron, a second-generation 5-HT receptor antagonist (5-HTRA), is more effective than first-generation 5-HTRA. Several studies have investigated whether dexamethasone (DEX), when combined with palonosetron as a 5-HTRA, can be spared in the delayed phase after moderately emetogenic chemotherapy (MEC). In this systematic review, we aimed to determine which between 1- and 3-day DEX administration, when combined with palonosetron, is more useful in patients receiving MEC.

Methods: The PubMed, Cochrane Library, and Ichushi-Web databases were searched for relevant studies published between 1990 and 2020. We included studies that compared the efficacy of 1- and 3-day DEX administration in preventing nausea and vomiting associated with MEC. Outcomes were "prevention of vomiting (complete response rate and no vomiting rate)," "prevention of nausea" (complete control rate, total control rate, no nausea rate, and no clinically significant nausea rate)" in the delayed phase, "prevention of blood glucose level elevation," and "prevention of osteoporosis."

Results: Eight studies were included in this systematic review. The no vomiting rate was significantly higher in the 3-day DEX group than in the 1-day DEX group. However, the other efficacy items did not significantly differ between the two groups. Meanwhile, insufficient evidence was obtained for "prevention of blood glucose level elevation" and "prevention of osteoporosis."

Conclusions: No significant differences in most antiemetic effects were found between 1- and 3-day DEX administration. Thus, DEX administration could be shortened from 3 days to 1 day when used in combination with palonosetron.