Individual and contextual deprivation: Association with cancer outcomes and implications for cancer policy

Lead Research Organisation: London Sch of Hygiene and Trop Medicine
Department Name: Epidemiology and Population Health

Abstract

In the UK, people who reside within more income-deprived areas live a shorter period of time after a diagnosis of cancer compared to people living in less income-deprived areas. At least part of these inequalities in cancer survival are due to inequalities in cancer care, even considering differential patient and tumour factors such as stage at diagnosis. The specific mechanisms by which area-based deprivation levels lead to poorer individual health outcomes within the context of a universal healthcare system, free at the point of use, are not well understood. These analyses will enable, for the first time, the examination of how an individual patient's socio-economic status is associated with poorer cancer survival in England, and will demonstrate how these associations might be modified by the level of deprivation in the small area within which the patient resides.
Our aim is to perform an in-depth study of the association between the individual patient's deprivation and cancer survival, considering in particular how this is influenced by their socio-economic context, whether it varies over time since diagnosis and whether it has changed over calendar time. We will focus on three indicators of deprivation: income, education and occupation. We will first examine the correlation between individual and area deprivation, by each of these indicators, and then secondly describe the association between individual deprivation and survival. Third, we will assess whether the association between individual deprivation and patients' survival is modified by area deprivation; that is, whether equally deprived individuals in different areas fare better, or worse, according to the socio-economic context of the area within which they live. Finally we will gain the insights of patients, carers, and healthcare professionals on these data, and communicate these to cancer policy makers.
We will use data from the ONS Longitudinal Study, which contains individual deprivation information on 1% of individuals in England present at each national census since 1971. The ONS-LS is linked to Cancer Registry data so that information on all diagnoses of invasive cancer amongst cohort members can be examined. These data will be further linked to the Indices of Multiple Deprivation (IMD) defined at the Lower Super Output Area (LSOA, mean population 1,500) to obtain area-based measures of deprivation. We will fit regression models for the excess mortality hazard (EMH) in order to examine how cancer survival varies with individual deprivation status. The EMH represents the mortality hazard that is observed among cancer patients, taking into account each patient's expected mortality. We will construct life tables stratified by individual deprivation, using the ONS-LS mortality and population data, in order to account as accurately as possible for this background mortality. We will assess whether these associations are modified according to the ecological level of deprivation through the use of interaction terms. We will examine time-dependent associations between individual deprivation and the EMH using flexible functions, and will account for the correlation between observations coming from the same small area through a shared random-effect (defined at LSOA level).
The results will allow us to determine the degree of correspondence between individual and area deprivation for cancer patients; to assess how individual deprivation (income, education or occupation) is associated with cancer-specific mortality; and to quantify if and how these associations are modified according to area deprivation, as well as how these associations vary by the time since diagnosis. During the final phases of the project we will seek the insights of patients, carers and healthcare professionals upon our findings. These will then be directly shared with policy makers in a half-day workshop, so that future policies aimed at reducing socio-economic inequalities are more targeted.

Planned Impact

Our research has the potential to have an impact on individual cancer patients who do not experience the full benefit of the cancer services available to them simply because of their deprivation status. In the medium to long-term, we anticipate that these analyses will inform new policies which lead to higher survival for more deprived groups of patients, greater equality in cancer outcomes for patients across the social spectrum, and improved cancer survival at the national level.
This ultimate long-term impact of our results will be brought about by an intermediate impact upon key UK policy makers. We propose to seek the insights of patients, carers and healthcare professionals upon our results and subsequently communicate these directly to UK cancer policy makers.
This will be done via three specific activities which will engage three key groups of stakeholders:

* UK cancer policy makers
Improvements to outcomes for individual patients from more deprived areas will only occur if policies designed to reach them are effective and appropriately directed. Our research will have a direct impact on this because it will result in a new understanding of underlying mechanisms which will be communicated directly to the UK's key cancer policy makers. Through a half-day workshop held during the final phases of the grant we will provide these stakeholders with the opportunity to discuss the interpretation and implications of our findings, as well as the patient, carer and healthcare professional perspective on them. Ultimately this will lead to them being better equipped to implement or tailor interventions which are more effective at reducing inequalities in cancer outcomes in the UK.

* National Cancer Research Institute (NCRI) Consumer Forum
The patient perspective on our research findings is key to gaining a better understanding as to the potential reasons for differences in the way patients from different social groups access and interact with cancer services. Via direct engagement with the NCRI Consumer Forum members we will gain patient and carer insights on our results which will be fed into the half-day workshop with UK cancer policy makers described above.

* Healthcare professionals
The mechanisms by which social inequalities in cancer outcomes arise are potentially at work across the whole cancer pathway. In an online interactive webinar, we will present our findings to a range of healthcare professionals selected from across the cancer pathway in order to gain their expert input on the results. These discussions will be recorded, summarised and key themes fed into the half-day workshop with UK cancer policy makers described above.

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