Thesis (MNutr (Interdisciplinary Health Sciences. Human Nutrition))--Stellenbosch University, 2008. / Background This study aimed to define the prevalence of side-effects and the change in weight and BMI during radical radiotherapy for head and neck malignancies (HNM) at Tygerberg Academic Hospital (TBH), Western Cape, South Africa. Acute side-effects may delay or prevent the delivery of a complete curative radiotherapy dose. Weight loss has been shown to significantly worsen prognosis and increase prevalence of treatment complications. However, weight maintenance may lead to beneficial outcomes. Assessing the impact of radical radiotherapy on patients with HNM is therefore critical and can promote development and implementation of medical and nutritional interventions. Methods Patients were weighed before and weekly during radiotherapy. Blood was drawn before, during and at the end of radiotherapy so that the Prognostic Inflammatory and Nutritional Index (PINI) could be calculated. Selected clinical data, clinical grades of mucositis and the diagnosis of a fungal infection of the oral cavity were extracted from clinical records. The McMaster Head and Neck Radiotherapy Questionnaire and a Lifestyle and Dietary Questionnaire were administered weekly. Descriptive statistics and the following were used: ANOVA, Repeated Measures ANOVA and McNemar Chi-square tests. Results Thirty-eight patients were recruited and 21 completed the study. Follow-up occurred over a maximum of nine weeks. A decrease in the weight (p = 0.01) and BMI (p = 0.01) and increase in the PINI (p = 0.04) occurred during radiotherapy. The mean absolute weight loss was 3.2kg (4.8), the mean percentage weight loss was 4.5% (6.7) and the mean decrease in BMI was 1.2kg/m2 (1.8). There was an increase in the prevalence of malnutrition (p = 0.02), as defined in this study. Oral mucositis occurred in all participants from Week 4; the majority developing Grade II or III Mucositis. Fungal infection of the oral cavity was prevalent throughout radiotherapy, with the highest prevalence (30%) in Week 4. Increases in severity of symptoms related to the mouth (p = 0.0000), throat (p = 0.05) and skin domains (p = 0.0000) occurred. Fifty-nine percent of inpatients and 45% of outpatients were prescribed supplementation drinks and most participants reported that a dietitian had not consulted them, in each week of radiotherapy. Discussion Severe side-effects in the mouth, throat and skin were experienced and a decline in nutritional status was observed. The poor nutritional status prior to commencing and weight loss during radiotherapy could have increased the severity of side-effects. The induction of the acute phase response indicated that this could have contributed to the decline in nutritional status observed. In addition, the infrequent nutritional support is likely to have further contributed to the lack of weight maintenance. Conclusion This first study conducted in South Africa has demonstrated the prevalence of significant side-effects and change in weight and BMI in this patient population. It is recommended that more effective analgesic medication is prescribed and that measures are taken to improve oral hygiene of participants to prevent fungal infection of the oral cavity. Improved nutritional support in terms of regular dietetic follow-up of all patients and more frequent prescription of supplementation drinks during radiotherapy is also recommended.