Background: Recently a nationwide descriptive study documented a social inequality in survival after all major cancers in Denmark favouring patients with higher social position (SEP). Clinical factors as stage and treatment could not be accounted for due to the nature of data from the Danish Cancer Registry.
Aim: A summary of recent studies of factors mediating social inequality in survival after cancer in Denmark
Material and methods: We used nationwide clinical cancer databases to identify patients with cancer of the lung, head and neck, cervix and non-Hodgkin lymphoma (NHL) including detailed information on stage at diagnosis, histopathological characteristics, and treatment. From nationwide administrative registries we obtained data on SEP, comorbidity and vital status. We examined the association between SEP and stage at diagnosis by multivariate logistic regression models and further examined the role of stage, access to treatment and comorbidity in the associations between SEP and overall mortality by Cox proportional hazards models.
Results: A general pattern of reduced risk for advanced stage at diagnosis among high SEP patients was observed for all cancers investigated. I.e. patients with higher education had significantly reduced adjusted ORs of being diagnosed with advanced-stage lung cancer (OR, 0.92), NHL (OR, 0.85), cervix cancer (OR, 0.50) and NHC (OR, 0.78) compared to patients with short education. Advanced-stage at diagnosis explained part of the social inequality in survival, i.e. for NHL the confounder adjusted HR was reduced from 1.48 among short vs higher educated patients to 1.30 when adjusting for stage whereas adjusting for comorbidity and treatment did not influence the HRs.
Implications: The findings based on updated cancer populations will provide an overview of the contribution of stage at diagnosis, access to treatment and comorbidity to the social inequality in survival after cancer and might inform prioritize health care organization and future research projects.