Theoretical underpinning

The essence of cancer burden is that it can be seen as a social dynamic, which can be explained with relevant theories and models. The findings of this thesis have been theorised inductively, which means the analytical exploration has been data-grounded, rather than theory-dictated. In this thesis, every finding was underpinned by a suitable theoretical framework.

This theorising stage was not straightforward, but rather a reflexive process and the relevant theory was selected based on compelling arguments of the researchers. As a result of the response to reviewers’ comments (the peer review process), however, the theoretical perspective was excluded from some of the papers in order to address the reviewers’ comments. In this thesis, three inductively generated theories were adopted: social conflict theory (Study 1), stress-coping theory (Studies 2-4) and portfolio theory perspectives (Study 5). The following section outlines the reasons for selecting those theories.

1.11.1 Social conflict theory

One of the studies (Study 1) was performed to examine the national level cancer outcomes in terms of trends, determinants and inequality over the last three decades, through the prism of social conflict theory (Marx and Engels, 1848), which was used to explain the phenomenon of socioeconomic inequality as a driving force behind cancer outcomes. Social conflict theorists

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argue that social classification emanates in a society from the conflict between and amongst social groups. In the mid-19th century Karl Marx was one of the principal social theorists who claimed that the attributes of the capitalist economy underpin upper-class domination of the socio-economic stratum (Marx, 1887). One of the striking themes in social conflict theory is that socioeconomic inequality is magnified owing to inequalities in age, race, wealth, gender, and geographical distribution. In this research (Study 1), social conflict theory fits into two dimensions. First, Australia has significant geographical differentiation, which indicates a deep divide among people in different localities in terms of their social capital, income, wealth, and class.

This might generate systematic social conflict between the ‘haves’ and ‘have nots’. Second, urban patients can more easily access health care services than those in remote areas. Other researchers have also used this theory to study different dimensions of social and health service provision (Sage Editors, 1957; Azar and Farah, 1981; Cornfield, 1991; Scambler, 2001; Hammack et al., 2018).

1.11.2 Stress-coping theory

The theoretical framework of stress-coping theory was designed by Lazarus and colleagues (Lazarus and Folkman, 1984; Lazarus, 1999) to investigate which antecedent factors may be aligned with long-term cancer health status burden (Study 2), chronic comorbid conditions (Study 3), and productivity-related work disability (Study 4). The longitudinal study perspective was underpinned by a stress-coping theory in order to determine if it could predict long-term health status burden (Dunn et al., 2013), chronic comorbid conditions (Hermsen et al., 2016), and work-related disability (Martz and Livneh, 2007; Livneh, 2015) over an extended period. They investigated individuals who faced the burden of life-threatening cancer and examined the magnitude of the cancer burden associated with its initial appraisal as well as their ability to manage the secondary stage of treatment and progression. In terms of secondary appraisal, individuals reconsidered their health status based on the magnitude of the burden (as either more or less). The theory of stress-coping is that the burden which extends over an extended period of

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time adversely affects health outcomes, including cancer outcomes (Lazarus, 1999). Furthermore, the theory holds that the magnitude of burden related to the disease is contextual, meaning that it involves a transaction between the individual and the management of disease, and it is a process, meaning that it changes over time.

To examine the longitudinal effects of the model, it is hypothesised that several antecedent variables (e.g., individual characteristics, social factors, and disease-related factors), measured at the symptom-level, might predict outcome factors (appraisal of disease with comorbidities, course of treatment, caregiving, life condition, uncertainty, disability). Moreover, the combination of factors (e.g., antecedent and outcomes) was assumed to predict patients’

health burden. In this context, the stress-coping theory fits with two adaptive tasks common across situations that threaten physical well-being managing the burden of disease and coping with a changing reality.

1.11.3 Portfolio theory

Portfolio theory, as applied in health economics, highlights the trade-offs that exist between the returns on investment in healthcare interventions or programs (e.g., cancer vaccination) and the risk associated with the outcomes (both costs and effects) (Markowitz, 1952). This theory also suggests a means to improve the risk-return characteristics of investments in healthcare interventions or programs (e.g., cancer vaccination) through change when costs and outcomes are uncertain. The foundation of this theory is based on the potential assumption that the investment proportions are not subject to uncertainty and that the budget can be invested in healthcare interventions or programs. Furthermore, a portfolio approach allows one to evaluate a combination of healthcare interventions or associated programs, focusing on their returns (e.g., health benefits) and risk related to outcomes. While various methods have been suggested for incorporating risk in the evaluation of costs and outcomes in health economic evaluations (Zivin and Bridges, 2002), these techniques remain dependent on the specification of a threshold incremental cost-effectiveness ratio for decision-making from the health

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system and societal perspectives. In this thesis, Study 5 is underpinned by the essence of Portfolio theory, whereas previous researchers have employed this theory to study healthcare interventions through economic evaluation approaches (Zivin and Bridges, 2002; Sendi et al., 2003, 2004; Bridges and Terris, 2004; Gafni, 2006).