The respective parts of incidence and lethality in socioeconomic differences in cancer mortality. An analysis of the French network Cancer registries (FRANCIM) data

Joséphine Bryere,The French Network Of Cancer Registries (Francim) ,Laure Tron,Guy Launoy,Gwenn Menvielle

doi:10.1186/s12939-019-1087-y

Abstract

BackgroundTo determine relevant public health actions and to guide intervention priorities, it is of great importance to assess the relative contribution of incidence and lethality to social inequalities in cancer mortality.MethodsThe study population comprised 185,518 cases of cancer diagnosed between 2006 and 2009 recorded in the French registries. Survival was known for each patient (endpoint: 30/06/2013). Deprivation was assessed using the European Deprivation Index. We studied the influence of deprivation on mortality, incidence and lethality rates and quantified the respective proportions of incidence and lethality in social inequalities in mortality by calculating attributable deaths.ResultsFor cancers with social inequalities both in incidence and lethality, excess mortality in deprived was mainly caused by social inequalities in incidence (e.g. men lung cancer: 87% of excess deaths in the deprived caused by inequalities in incidence). Proportions were more balanced for some cancer sites (e.g. cervical cancer: 56% incidence, 44% lethality). For cancer sites with a higher incidence in the least deprived (e.g. breast cancer), the excess-lethality in deprived leads entirely the higher mortality among the deprived.ConclusionsMost of the excess mortality in deprived is due to the excess incidence of tobacco-dependent cancers and the excess lethality of screenable cancers.

Highlights

To determine relevant public health actions and to guide intervention priorities, it is of great importance to assess the relative contribution of incidence and lethality to social inequalities in cancer mortality
The objective of this study was to measure for each cancer site, the proportion of deaths caused by excess incidence and the proportion of deaths caused by excess lethality in the total number of excess deaths among the deprived
We were able to evaluate for each cancer site the number of excess deaths associated with deprivation and attributable to either the excess incidence or the excess lethality

Summary

Introduction

To determine relevant public health actions and to guide intervention priorities, it is of great importance to assess the relative contribution of incidence and lethality to social inequalities in cancer mortality. Social inequalities in cancer mortality have been observed worldwide in the last 40 years for most cancer sites [1,2,3,4,5]. This situation has occurred in many countries over time and is even increasing in some [2, 3]. It is crucial to elucidate the mechanisms that create health inequalities in order to establish adequate public health policies. Such mechanisms are numerous and have an impact on a wide range. Several recent studies have attempted to measure social inequalities in incidence, on one hand [1, 12,13,14,15] and the social inequalities in lethality, on the other [1, 16,17,18] and some have tried to quantify the human burden by calculating the excess cases for incidence [19] and the potential gain in life-years for lethality [20, 21].

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