The incidence of nausea in the absence of vomiting in patients receiving intravenous chemotherapy.

Background: The magnitude of the incidence and impact of nausea on patients receiving intravenous chemotherapy seems to be underestimated by healthcare professionals. Development of effective anti-emetic treatment has contributed to the resolution of chemotherapy-induced nausea and vomiting (CINV). However, there is a concern that vomiting has been the initial focus of anti-emetic research and nausea was perceived as a secondary endpoint. Through focusing on the incidence of nausea independently of the incidence of vomiting, valuable information has been gained on this distressing side effect, including identifying patient risk factors contributing to the increased experience of nausea.

Methods: The study followed a prospective, observational study design in a private oncology centre in Johannesburg, South-Africa. Ethical approval was obtained before commencement of the study, followed by the recruitment of one hundred patients over a seven-month period. Patient-reported outcome measures (PROMs) were used to measure nausea with an amended version of the Multinational Association of Supportive Care in Cancer antiemesis tool (MAT). Patients documented information in their diaries on the incidence, duration and severity of nausea, during the acute phase (0-24 hours), the delayed phase (25-120 hours), day 7 and day 10 after infusion of chemotherapy, with episodes of vomiting being recorded as a secondary endpoint. The demographic and clinical variables of the subjects, as well as patient risk factors known to cause CINV, were tabulated and summarised using descriptive statistics.

Results: The population consisted of 68 females and 27 males with a mean age of 57 years (25-84 years). The emetogenicity of chemotherapy regimens administered were well represented with 26.3% low emetogenic chemotherapy, 25.3% moderately emetogenic chemotherapy and 48.4% highly emetogenic chemotherapy (HEC). Despite all patients receiving guideline consistent CINV prophylaxis, nausea was still experienced by 57.9% patients during cycle one, 50.6% patients during cycle two and 45.6% patients during cycle three. The incidence of patients experiencing nausea (in the absence of vomiting) was 35%, compared to 2% of patients experiencing vomiting (in the absence of nausea). Patient characteristics with a known risk to impact CINV were documented, and significant impact in this study was found in female gender, age <60 years, history of motion sickness and history of morning sickness.

Conclusions: Guideline consistent CINV prophylaxes seem to have vomiting under control for most patients receiving intravenous chemotherapy. Nausea, however, still seems to be a persistent adverse event during treatment. Female gender, age <60 years, history of motion sickness and history of morning sickness increases the risk of experiencing nausea. A different approach is needed to manage nausea in the clinic setting, along with standardised tools to measure nausea specifically. More studies need to be done with nausea as the primary endpoint to address this ongoing medical need.