# Sociodemographic and Health-Service Precursors of Local-Stage Lung Cancer Diagnosis: A Population-Based Study in New South Wales, Australia

## TL;DR

This study identifies factors like CT scans and being female that predict early-stage lung cancer diagnosis, helping improve screening strategies.

## Contribution

The study uses population-level data linkage to identify predictors of early-stage lung cancer diagnosis, highlighting CT scans and gender as key factors.

## Key findings

- CT scans of the lung and being female were the main predictors of local-stage lung cancer diagnosis.
- Age, GP consultations, and residence in a major city were associated with having CT scans.
- Linking cancer registry and census data reveals pathways to early diagnosis relevant for screening planning.

## Abstract

Lung cancer is a major health problem. It ranks fifth among cancers most commonly reported to Australian cancer registries and is the leading cause of cancer death in Australia. Five-year relative survival for lung cancer is about 68% for local stage at diagnosis compared with less than 5% for metastatic stage. Diagnosis at an early stage improves survival, but only about 20% of lung cancers were found at a local stage. The aim of this study was to examine the socio-demographic associations with medicated health conditions, general practitioner consultations, and computed tomography (CT) scans of the lung as precursor predictors to lung cancer diagnosis at a local stage. Multivariate structural equation modelling suggested CT scans of the lung and being female were main predictors. This study shows the breadth of evidence that can be obtained from linking person-level data population-wide. By identifying at-risk population subgroups, the research can inform the design and implementation of lung cancer screening initiatives for maximum benefit and optimal cost-effectiveness.

Aims: To investigate sociodemographic associations with medicated health conditions, general practitioner (GP) contacts, and computed tomography (CT) scans of the lung, as 12-month precursors of diagnosis of lung cancer at a local stage (cancers localized to the primary site of bronchus and lung). Methods: Cancer Registry data for New South Wales (NSW) adults diagnosed with lung cancer (ICD-10 C33-34) since the Census of August 2016 (n = 6160) were linked at person level with census and other administrative data. These included residents diagnosed with lung cancer from September 2016 to December 2018. Structural equation modelling indicated adjusted measures of associations with lung cancer, including adjusted odds ratios (aORs), in stepped analyses. Results: The first part of the multivariate modelling showed age, major city residence, and other sociodemographic characteristics that were associated with numbers of medicated conditions. The second part showed the numbers of medicated conditions and other sociodemographic characteristics that were associated with the number of GP consultations. The third part of the modelling showed the numbers of GP consultations and other sociodemographic characteristics that were associated with having CT lung scans. Modelling showed that having CT scans and being female were the main predictors of lung cancer diagnosis at a local stage, with aORs of 2.30, 95%CI 2.01–2.63 and 1.39, and 95%CI 1.23–1.58, respectively. The modelling also showed age, GP consultations, residence in a major city, and other sociodemographic characteristics to be associated with having CT scans. Conclusions: The findings of the study indicate the main precursors of lung cancer diagnosis at a local stage after multivariate adjustment. Irrespective of causal significance, results reveal population-wide characteristics for targeting screening for early detection. They demonstrate the potential value of person-level linkage of cancer-registry data with census and other administrative data for this purpose. Our study of linked cancer-registry and census data revealed broad descriptive features of pathways to early diagnosis of relevance to service screening and planning.