Defining optimal control of chemotherapy-induced nausea and vomiting-based on patients' experience

A considerable challenge when comparing antiemetic trials for chemotherapy-induced nausea and vomiting (CINV) is the large number of outcome measures for nausea and vomiting. The objective of this study is to determine the optimal definition of CINV control from the patients' perspective.

Patients with early-stage breast cancer who had received anthracycline-cyclophosphamide-based chemotherapy were surveyed. They were asked about their experiences of CINV and perceptions of different CINV assessment tools.

Of 201 patients approached, 168 (83 %) completed the survey. Patients consistently ranked nausea over vomiting as the "worst side effect from chemotherapy." Despite the use of multi-agent antiemetic regimens, 71 % of patients experienced nausea and 26 % vomiting. Only 57 % of patients with any nausea or vomiting took rescue medications and only then when the symptom was severe. Most (76 %) patients believed that the primary end point of antiemetic trials should include the absence of both nausea and vomiting. Patients felt that CINV should be evaluated for the overall period post chemotherapy (i.e., days 1-5) and not simply the acute (the first 24 h) or delayed (days 2-5) periods.

Patients strongly favored a CINV end point that includes the absence of both nausea and vomiting. Patients' experience with CINV is underestimated when nausea is not included in composite end points. "Use of rescue medication," a commonly used surrogate for emesis control, is inappropriate as it underestimates nausea. A standardized primary end point that includes nausea is essential if CINV control is to be improved.