Nausea and emesis in cancer chemotherapy: aspects of occurrence, assessment and treatmeant
Abstract: Nausea and emesis are two of the most distressing side-effects cancer patients may experience during chemotherapy. The general aim of this thesis was to acquire knowledge to be used for improving the care of cancer patients during chemotherapy, in particular for the prevention and palliation of chemotherapy-induced nausea and emesis. The studies are predominantly related to four topics: aspects of patients' experiences of well-being during chemotherapy, the effects of different antiemetic treatments on acute and delayed nausea and emesis, risk factors for nausea and emesis and methodological issues involved in measuring the intensity of nausea. A total of 226 patients have participated in six studies. Thirty-nine patients were diagnosed with testicular cancer and the other 187 were ovarian cancer patients. All patients received combination chemotherapy based on cisplatin at the Department of Oncology/Radiumhemmet, Karolinska Hospital in Stockholm. Data were mainly collected with questionnaires assessed before, during and after chemotherapy, in up to four chemotherapy cycles. The results illustrate the recognition of nausea and emesis as the most distressing factor during treatment in a group of men diagnosed with testicular cancer. The important progress made in the pharmacological treatment of acute nausea and emesis is reflected in this thesis, as well as the problems remaining with delayed symptoms. The first step towards improved antiemetic treatment was indicated in the pilot study. The results indicated that ondansetron, a new S-HT3 receptor antagonist, was superior as a single drug to a combination of high-dose metoclopramide and dexamethasone in the prevention of acute, but not delayed, nausea and emesis. The administration of a single, high dose of dexamethasone with ondansetron increased the antiemetic efficacy for acute symptoms, as compared to ondansetron only, but not delayed symptoms. A 15-day follow-up investigating prognostic factors for delayed nausea and emesis revealed that delayed symptoms were more common among older patients with a large tumour burden and tended to be persistent. An evaluation of two of the most frequently used scales for measuring intensity of nausea showed good agreement between findings using a visual analogue scale and a verbal category scale. When the focus is on monitoring the individual patient, the visual analogue scale may be a more sensitive instrument. Despite having a lower prevalence and intensity of acute nausea and emesis, patients treated with a combination of ondansetron and dexamethasone did not report better well-being than patients receiving an antiemetic treatment comprising high-dose metoclopramide and dexamethasone combined with non-pharmacological interventions. The duration of acute nausea was an important factor in explaining the variance in well-being during chemotherapy. This highlights the complicated relationship between different antiemetic interventions, improved antiemetic effect and the patients' assessment of general well-being. Well-being may be an outcome variable to consider, as a complement to the traditional measures of frequency, intensity and duration of nausea and emesis.
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