Background Intervention-generated inequalities in health result from the way that health interventions are organised and delivered. There is some evidence that socio-economic inequalities in care may occur for some common cancers and treatment inequalities may contribute to socio-economic differences in survival. Although the incidence and outcome of lung cancer varies with socio-economic status (SES), it is not known whether socio-economic inequalities in treatment occur. We conducted a systematic review and meta-analysis of existing research on socio-economic inequalities in receipt of treatment for lung cancer.

Methods Systematic methods were used to identify relevant studies, assess study eligibility for inclusion and evaluate study quality. Cohort studies of adults with a primary diagnosis of lung cancer, published in peer-reviewed English language journals up to 2011, were examined. All studies reporting rates of receipt of any treatment for lung cancer according to a measure of SES were included in the review. Studies that reported odds ratios for receipt of treatment, adjusted for at least age and sex, were included in the meta-analysis. Subgroup analyses by healthcare system (universal healthcare system or insurance-based system), histology and stage were conducted.

Results From the initial 1345 studies identified, 46 studies were included in the review and 29 in the meta-analysis.

Socio-economic inequalities in receipt of lung cancer treatment were observed. Low SES was associated with a reduced likelihood of receiving any treatment (OR=0.79, CI (0.74 to 0.84) p<0.001), surgery (OR=0.71 (CI 0.65 to 0.77), p<0.001) and chemotherapy (OR=0.81 (CI 0.73 to 0.91), p<0.001), but not radiotherapy (OR=0.95 (CI 0.84 to 1.07), p=0.41), for lung cancer. The association was found in both insurance-based and universal healthcare systems and remained when stage and histology were taken into account for receipt of surgery.

Conclusion This systematic review and meta-analysis found that lung cancer patients living in more socio-economically deprived circumstances were less likely to receive any type of treatment, surgery and chemotherapy. These inequalities cannot be accounted for by socio-economic differences in stage at presentation or by type of healthcare system. Further investigation is required into the patient, clinician and system factors that may contribute to socio-economic inequalities in receipt of lung cancer care and how these inequalities may impact on survival, and also into how to reduce such inequalities.