Reduced maintenance of complete protection from emesis for women during chemotherapy cycles

Women have a significantly higher rate of chemotherapy-induced emesis. We observed that gender was the important predict factor for reducing the maintenance of complete protection from emesis during chemotherapy cycles. Four hundred patients were enrolled in one of two arms in a crossover fashion. Arm A: three 8-mg doses of ondansetron were given intravenously at 4-hour intervals plus dexamethasone 20 mg intravenously from the start of chemotherapy, followed by dexamethasone 5 mg intravenously every 12 hours. Arm B: as in arm A but with three 8-mg doses of ondansetron intravenously given at 24-hour intervals substituted for ondansetron intravenously given at 4-hour intervals. Rates for complete protection from vomiting/nausea through days 1 to 6 were 69.7%/58.4% for Arm A, and 71.2%/60.9% for Arm B, and 69.0%/60.0% for the first chemotherapy cycle. Risk factors for vomiting and nausea included gender and cisplatin dosage. Complete control of vomiting/nausea for patients without emesis during previous cycle(s) was maintained at 91.4%/86.6%, 91.1%/85.2%, 93.9%/89.9%, 94.7%/92.6%, and 94.9%/94.9% during the second through sixth cycles of chemotherapy, respectively. Complete protection from vomiting and nausea was significantly reduced for female patients (p = 0.048 and p = 0.0004, during the second cycle, and p = 0.0006 and p = 0.0008, during the third through sixth cycles, respectively). The results suggest that women had less maintenance for complete protection from both vomiting and nausea during chemotherapy cycles.