Lung cancer remains the leading cause of cancer-related death in France with 5-year net survival of 20% (46,363 new diagnoses and 33,000 estimated deaths in 2018) [1], [2]. The prognosis depends mainly on stage at diagnosis and histological subtype, and diagnosing patients at a non-advanced stage has become a mainstay of lung cancer prevention and control strategies.

Understanding the determinants behind disparities in stage at diagnosis may improve the targeting of interventions on patients at higher risk. In the past decade, evidence has accumulated about demographic and socio-economic inequalities for several lung cancer outcomes. In particular, prior studies have shown an impact of demographic variables such as sex, age or place of residence on stage at diagnosis [3], [4], [5]. Furthermore, poor socio-economic status has been identified as increasing the risk of lung cancer incidence and mortality [6], [7]. Although some studies suggest that this determinant may not significantly impact the stage at diagnosis, this hypothesis remains under discussion [4], [8], [9], [10].

The impact of socio-demographic factors on stage at diagnosis may vary between countries, depending on population characteristics and public health policies. The French health care system ensures universal coverage for healthcare through public health insurance funds [11]. It can therefore be assumed that there are no financial barriers to accessing health services and that sociological and geographical differences should play only a marginal role in lung cancer outcomes. Nonetheless, data related to such influences are very limited in France.

Inequalities in access to early cancer diagnosis may result in limited effective management options and consequently lead to differences in survival [12]. Research aimed at improved understanding of such disparities in outcomes and access to care should be a key priority in the management of lung cancer, while taking into account the specificities of histological subtypes. The objective of this retrospective cohort registry-based study is therefore to identify the socio-demographic factors associated with stage at diagnosis of lung cancer over a 12-year period in a region of south-western France.