High dose conditioning (HDC) and adjunct haematopoietic stem cell transplantation (HSCT) is a widely used treatment for haematological malignancies. Due to an increased chemotherapy dosage, the treatment is accompanied by severe gastrotoxicity and prolonged bone marrow suppression. Patients are at risk of nutritional deterioration after the treatment but the prevalence of malnutrition is poorly documented amongst this patient group. However, long term survivors have reported persisting nutrition impact symptoms, suboptimal changes in body composition, and poorer quality of life.
This PhD research was conducted in two phases. Firstly, to identify the nutritional issues and adverse changes in nutrition-related outcomes amongst cancer patients treated with HSCT using validated measures including nutritional status, body composition, and quality of life (QoL). Secondly, to conduct an intervention that addresses persisting nutritional issues after hospitalisation and subsequently improve nutrition-related outcomes. For the scope of this PhD, the investigation targeted adult cancer patients undergoing HSCT only. The thesis is presented as a series of published and submitted research manuscripts (Chapter 3 to 6).
Chapter 1 is an overview of the literature summarizing the current evidence for the nutritional management of cancer patients treated with HSCT. A comprehensive range of related areas were examined (i.e., nutritional status, body composition, QoL and physical activity) with a focus on the treatment and post-treatment stages.
Chapter 2 describes the methods of the research studies undertaken including ethical considerations, population background, hypotheses, outcome measures, and methods of assessment. The data collection procedures are described in detail.
Chapter 3 is a published manuscript that presents the findings of Phase 1. At 100 days post-transplantation, adverse changes in body composition were not completely reversed. Patients were not identified as malnourished at a group level; however, a subgroup of patients may require nutritional support from dietitians to address persisting nutrition impact symptoms. Changes in nutrition-related outcomes, body composition, QoL, and physical activity level were interrelated.
Chapter 4 is a submitted manuscript that presents the main findings of Phase 2. This is a pilot randomized-controlled trial (RCT) and the first to examine a home-based, telephone-delivered nutrition and exercise intervention amongst cancer patients treated with autologous HSCT. Results suggested autologous HSCT patients provided with fortnightly telephone-delivered nutrition and exercise counselling after hospitalisation may experience less weight loss, better recovery in dietary intake and components of QoL than usual care patients who did not receive any intervention after hospitalisation. The findings warrant further investigation into the optimal frequency and intensity of a telephone-delivered nutrition and exercise intervention.
Chapter 5 is a published manuscript and a sub-study of Phase 2. Patient satisfaction with the clinical nutrition service delivered by an Accredited Practising Dietitian was examined amongst patients recruited in the RCT. Results demonstrated that patients were satisfied with the use of telephone-delivered clinical nutrition services as a form of follow-up care after hospitalisation. Further, patients who received three or more telephone calls were more satisfied than those with less frequent telephone calls.
Chapter 6 is a submitted manuscript and a sub-study of this PhD. The agreements of body composition parameters estimated by air-displacement plethysmography (ADP) and bioimpedance spectroscopy (BIS) before, and after HSCT were compared. Comparisons were made using the method of Bland-Altman and a clinically acceptable difference in lean body mass of ≤1kg. BIS may be an alternative method to ADP for assessing body composition changes at a group level; however, the agreement of absolute body composition was variable depending on the BIS algorithm used. The BIS algorithm adjusting for body mass index (BMI) is recommended amongst patients undergoing HSCT.
Chapter 7 provides a synthesis of the findings across the four manuscripts in this thesis. The research findings were discussed in the context of the existing literature and the theoretical model. The theoretical model is modified and finalized in this chapter based on the study findings.
Chapter 8 is the final chapter of the thesis. This chapter provides a summary on the novel aspects of the investigation, the strengths and limitations of the research, the challenges and experience gained, the recommendations for future research, and finally, the thesis conclusions.
In conclusion, this thesis provides new insight into the role of medical nutrition therapy in cancer supportive care for patients following HSCT. One in three patients may be malnourished after HDC and autologous HSCT. A subgroup of patients may experience persisting nutrition impact symptoms, suboptimal changes in body composition and adverse changes in QoL and functioning. Nutrition and exercise counselling are recommended following hospitalisation as ongoing support may benefit the recovery of dietary intake and minimise changes in body composition in the early phase of survivorship. A non-traditional method, for example telephone nutrition counselling, is an acceptable way to provide clinical nutrition services amongst HSCT patients after hospitalisation. When using BIS in place of ADP to assess body composition changes amongst patients undergoing HSCT, results of the BIS default setting should be adjusted for BMI. The potential benefit of ongoing nutrition and exercise counselling amongst allogeneic transplant patients and the cost-effectiveness of traditional face-to-face HSCT versus telephone-delivered counselling amongst HSCT survivors should be examined in future studies.