Olanzapine for The Prevention of Nausea and Vomiting Caused by Chemoradiotherapy with High-Dose Cisplatin for Head and Neck Cancer.

Background: Chemotherapy-induced nausea and vomiting (CINV) are the most common and distressing adverse events in patients receiving anticancer therapy. Radiotherapy also induces nausea and vomiting, so concurrent chemoradiotherapy-induced nausea and vomiting (CRINV) are significant problems for patients undergoing chemoradiotherapy. Conventionally, three-drug combination therapy with dexamethasone, 5-hydroxytryptamine type 3 (5-HT3) receptor antagonist, and neurokinin-1 (NK1) receptor antagonist has been used to prevent CRINV induced by concurrent chemoradiotherapy with cisplatin for patients with head and neck cancer (HNC). Nonetheless, CRINV still remains a problem. The effectiveness of adding olanzapine to prevent CINV has been reported, suggesting the efficacy of four-drug combination therapy for CRINV. However, its effectiveness has hardly been reported in patient receiving chemoradiotherapy for HNC. Methods: A total of 109 patients with HNC who received concurrent chemoradiotherapy with cisplatin from April 2014 to March 2021 were included and divided into the following two groups according to antiemetic treatment regimen: the conventional group (Con group; n = 78) who received three-drug combination therapy and the olanzapine group (Olz group; Olz group, n = 31) who received four-drug combination therapy with olanzapine. Acute (0 to 24 h from cisplatin) and delayed (25 to 120 h from cisplatin) CRINV were then compared using the Common Terminology Criteria for Adverse Events. Results: No significant difference in acute CRINV were observed between both groups (P = 0.5761, Fisher's exact test). However, the Olz group had a significantly lower incidence rate of delayed CRINV over Grade 3 compared to the Con group (P = 0.0318, Fisher's exact test). Conclusion: Four-drug combination therapy with olanzapine was effective in suppressing delayed CRINV due to chemoradiotherapy with cisplatin for HNC.