The epidemiology of disparities in lung cancer in NSW: an exploration of intersecting populations

Lung cancer is the most common cause of cancer death in Australia, resulting in considerable disease burden. Despite being a poor prognosis disease, there are marked disparities in the incidence, treatment, survival and mortality for sub-populations. The lung cancer burden in NSW is higher among people residing in lower socioeconomic areas, people who live regionally and remotely and Aboriginal people. This thesis uses theoretical and empirical approaches used in the fields of both social and cancer epidemiology to comprehensively examine lung cancer sub-population disparities in NSW. It is the first examination of intersecting disparities for people with lung cancer in NSW. Through the development of a conceptual framework for addressing lung cancer disparities in the Australian context, it explores how previous research has estimated disparities in lung cancer incidence, treatment, survival and mortality and assesses the utility of the mortality to incidence ratio using already available data as a proxy measure for survival. Using linked data and existing data from a patterns of care study, lung cancer disparities are explored by Aboriginal status, socioeconomic area and geographic remoteness with focus on the intersections of these sub-populations. It comprises of three sections which together include seven sequential chapters. The first section (chapters 1 to 3) provides the theoretical background and empirical evidence to support the basis of and approach to estimating lung cancer disparities in NSW. A conceptual framework was developed, underpinned by theoretical models, through available literature that provides potential explanations for lung cancer disparities. It aims to clarify mediating pathways and describe the broad range of determinants of lung cancer disparities and their relationships. A systematic review was also conducted examining the range of metrics used to estimate lung cancer disparities in the international setting. Recommendations for empirical approaches to measuring lung cancer disparities have been developed. Additionally, the variations in empirical vii evidence seen across the literature highlighted the need for the development of comprehensive national recommendations for estimating comparative cancer disparities. The second section (chapters 4 to 6) provides empirical investigations of lung cancer disparities in NSW with aims to elucidate complex patterns that exist when considering multiple sub-populations by investigating associations between Indigenous status, socioeconomic disadvantage, and geographic remoteness. A data linkage study included 20,846 residents of NSW with a primary diagnosis of lung cancer reported to the NSW Central Cancer Registry between January 01, 2001 and December 31, 2007. Records were linked (using the NSW Centre for Record Health Linkage) to the Admitted Patients Data Collection and deaths data collections. Methods of addressing intersectionality, examining how gender, ethnicity, disadvantage and other factors work together to create inequity, using population-level data were applied to incidence, utilisation of evidence-based surgery, survival and mortality rates to assess Indigenous, socioeconomic and geographic disparities. Indigenous people had a standardised incidence rate ratio (IRR) of 1.96 (p<0.001) when adjusting for socioeconomic disadvantage and remoteness. However, when stratified by geographic remoteness, Indigenous people were almost eight times (IRR 7.70, p