Characterizing and assessing antiemetic underuse in patients initiating highly emetogenic chemotherapy.

Patients initiating highly emetic chemotherapy (HEC) are at a 90% risk of chemotherapy-induced nausea and vomiting (CINV). Despite guideline-concordant antiemetic prescribing preventing CINV in up to 80% of patients, studies suggest that guideline-concordant antiemetic regimen use by patients initiating HEC is sub-optimal. However, these studies have been limited to single-site or single-cancer type with limited generalizability. The objective of this study was to describe antiemetic fill regimens and to assess predictors of underuse in the USA.