Socioeconomic inequalities in the diagnosis and treatment of ovarian and colon cancer

Introduction
There are inequalities along the continuum of care among patients diagnosed with cancer. Previous research has investigated the pre-hospital experience. However, the research presented in this thesis aimed to evaluate the experience after a referral from primary care, known as the system interval, to understand how socioeconomic factors impact care pathways for patients with ovarian and colon cancer. The specific objectives were to evaluate socioeconomic inequalities in treatment and the time to diagnosis and treatment within the hospital setting.

Methods
Two systematic reviews evaluated the relationship between socioeconomic status, the treatments received, and the system interval among patients diagnosed with ovarian and colorectal cancer.
Two population-based studies used linked cancer registry data for all patients diagnosed with ovarian and colon cancer in 2016-2017 in England. Lasso logistic regression identified predictors of receipt of surgery and chemotherapy. The secondary care diagnostic interval methodology was used to calculate the time to diagnosis and treatment, analysed using quantile regression.

Results
The systematic reviews demonstrated unexplained socioeconomic inequalities in the receipt of surgery and chemotherapy but not radiotherapy. Meanwhile, there was inconsistent evidence for delays in the system interval. However, there were limitations across the included studies.
The data linkage studies demonstrated reduced odds of surgery and chemotherapy among patients from the most deprived areas. This was unexplained by differences in stage, comorbidity, and other factors. Patients from the most deprived areas also experienced longer system intervals.

Conclusions
Survival is worse for patients diagnosed with ovarian and colon cancer living in more deprived areas. Despite a universal healthcare system, there were unexplained inequalities in treatment and time to diagnosis and treatment; such disparities potentially contribute to this survival gap. Qualitative research of patients and clinicians conducted across various settings would provide a rich understanding of the complex factors that drive these inequalities.