Intervention-generated inequalities in lung cancer care

Abstract

Lung cancer survival is poorer in more socio-economically deprived patient groups. It has been suggested that socio-economic inequalities in receipt of, and time to, treatment may contribute to inequalities in cancer outcome. Unintended variations in outcome that result from the way that interventions are organised and delivered have been described as intervention-generated inequalities. The aim of this thesis was to determine if there are socio-economic inequalities in lung cancer care and, if so, to identify where on the pathway of care these inequalities might occur: looking at receipt of treatment; referral, diagnostic and treatment time intervals; and survival. A systematic review and meta-analysis was conducted in order to examine the published evidence for socio-economic inequalities in lung cancer treatment. A secondary analysis of cancer registry data for 65,210 patients diagnosed between 1999-2010 with a primary diagnosis of lung cancer [ICD10 C33 and C34], linked to Hospital Episode Statistics and lung cancer audit data, was conducted. Logistic regression was used to examine the likelihood of receipt of treatment; of receiving timely referral, diagnosis and treatment within guidelines; and of being alive two years after diagnosis, by socio-economic position [SEP]. Cox regression was used to assess the likelihood of early referral, diagnosis and treatment and hazard of death, by SEP. Socio-economic inequalities in receipt of lung cancer surgery and chemotherapy, but not radiotherapy, were found in the systematic review and meta-analysis, and in the linked-data analysis. Socio-economic inequalities in the GP referral to first hospital appointment time interval were identified. Socio-economic inequalities in survival from lung cancer were statistically explained by socio-economic inequalities in receipt of treatment, but not by inequalities in timeliness of referral and treatment, in this cohort. However high levels of missing stage, performance status and co-morbidity data were a limitation. Research into the unexplained variance in treatment rates is required in order to develop interventions that address socio-economic inequalities in receipt of treatment and reduce socio-economic inequalities in survival.