Bernard Rachet's research while affiliated with London School of Hygiene and Tropical Medicine and other places

Publications (321)

Article
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Life tables summarise a population’s mortality experience during a time period. Sex- and age-specific life tables are needed to compute various cancer survival measures. However, mortality rates vary according to socioeconomic status. We present sex- and age-specific life tables based on socioeconomic status at the census tract level in Spain durin...
Preprint
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Purpose: Treatment with any adjuvant chemotherapy for Stage III colon cancer has been shown to differ between groups. Few studies, however, explore variations in the type of adjuvant chemotherapy received, none of which from the UK. The aim of this study is to explore variation in the type of chemotherapy received by Stage III colon cancer patients...
Article
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Purpose System science offers a unique set of tools, including causal loop diagrams (CLDs), for stakeholders to better grasp the complexity of factors surrounding quality of life. Because the health-related quality of life (HRQoL) of cancer immunotherapy patients exists within an intricate system affected by and affecting many factors across multip...
Article
Introduction The burden of stomach cancer remains high, particularly among Asian countries. Although Japan is known to achieve high survival from stomach cancer, little is known regarding the survival trends for recent years and survival by subsite and stage. We report age-standardised 1-, 3-, 5- and 10-year net survival for patients diagnosed with...
Preprint
Approximate statistical inference via determination of the asymptotic distribution of a statistic is routinely used for inference in applied medical statistics (e.g. to estimate the standard error of the marginal or conditional risk ratio). One method for variance estimation is the classical Delta-method but there is a knowledge gap as this method...
Article
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Background Associations between socioeconomic status (SES) and breast cancer survival are most pronounced in young patients. We further investigated the relation between SES, subsequent recurrent events and mortality in breast cancer patients < 40 years. Using detailed data on all recurrences that occur between date of diagnosis of the primary tumo...
Article
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Background We modeled the clinical course of a cohort of diffuse large B-cell lymphoma (DLBCL) patients with no prior cardiovascular diseases (CVDs) using a multistate modeling framework. Patients and methods Data on 2600 patients with DLBCL diagnosed between 2000 and 2018 and had received chemotherapy with or without radiotherapy were obtained fr...
Article
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Background We aimed to investigate the impact of socio-economic inequalities in cancer survival in England on the Number of Life-Years Lost (NLYL) due to cancer. Methods We analysed 1.2 million patients diagnosed with one of the 23 most common cancers (92.3% of all incident cancers in England) between 2010 and 2014. Socio-economic deprivation of p...
Article
Lung cancer is one of the most important causes of morbidity and mortality globally, accounting for 12% of new cancers, and 18% of cancer deaths each year. Tobacco smoking is overwhelmingly the main cause of lung cancer, and also an important cause of other noncommunicable diseases (NCDs). Large-scale policies for tobacco control lead to significan...
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(1) Background: Socioeconomic inequalities of survival in patients with lymphoma persist, which may be explained by patients’ comorbidities. We aimed to assess the association between comorbidities and the survival of patients diagnosed with diffuse large B-cell (DLBCL) or follicular lymphoma (FL) in England accounting for other socio-demographic c...
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Background Cancer patients often have pre-existing comorbidities, which can influence timeliness of cancer diagnosis. We examined symptoms, investigations and emergency presentation (EP) risk among colorectal cancer (CRC) patients by comorbidity status. Methods Using linked cancer registration, primary care and hospital records of 4836 CRC patient...
Article
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Objectives We aimed to assess the association between multimorbidity and deprivation on short-term mortality among patients with diffuse large B-cell (DLBCL) and follicular lymphoma (FL) in England. Setting The association of multimorbidity and socioeconomic deprivation on survival among patients diagnosed with DLBCL and FL in England between 2005...
Article
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The main purpose of many medical studies is to estimate the effects of a treatment or exposure on an outcome. However, it is not always possible to randomize the study participants to a particular treatment, therefore observational study designs may be used. There are major challenges with observational studies; one of which is confounding. Control...
Article
Missing data is a common issue in epidemiological databases. Among the different ways of dealing with missing data, multiple imputation has become more available in common statistical software packages. However, the incompatibility between the imputation and substantive model, which can arise when the associations between variables in the substanti...
Article
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Background Marked geographical disparities in survival from colon cancer have been consistently described in England. Similar patterns have been observed within London, almost mimicking a microcosm of the country’s survival patterns. This evidence has suggested that the area of residence plays an important role in the survival from cancer. Methods...
Article
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Introduction Diagnostic delay is associated with lower chances of cancer survival. Underlying comorbidities are known to affect the timely diagnosis of cancer. Diffuse large B-cell (DLBCL) and follicular lymphomas (FL) are primarily diagnosed amongst older patients, who are more likely to have comorbidities. Characteristics of clinical commissionin...
Article
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Background Pancreatic cancer (PC) represents a substantial public health burden. Pancreatic cancer patients have very low survival due to the difficulty of identifying cancers early when the tumour is localised to the site of origin and treatable. Recent progress has been made in identifying biomarkers for PC in the blood and urine, but these canno...
Chapter
Comorbidity is considered to be a prognostic factor in cancer outcomes. The presence of comorbidity can be influential at different points on the cancer pathway, from the time leading up to the diagnosis of cancer to treatment options and ultimate prognosis once cancer has been diagnosed. Cancer patients of lower social or socioeconomic position ar...
Article
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Background Despite persistent reports of socioeconomic inequalities in colorectal cancer survival in England, the magnitude of survival differences has not been fully evaluated. Methods Patients diagnosed with colon cancer (n=68 169) and rectal cancer (n=38 267) in England (diagnosed between January 2010 and March 2013) were analysed as a retrospe...
Article
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This study aimed to evaluate the association between thyroid dysfunction and breast cancer risk. We included 239,436 females of the UK Biobank cohort. Information on thyroid dysfunction, personal and family medical history, medications, reproductive factors, lifestyle, and socioeconomic characteristics was retrieved from baseline self-reported data...
Article
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Introduction Delays in cancer diagnosis arose from the commencement of non-pharmaceutical interventions (NPI) introduced in the UK in March 2020 in response to the COVID-19 pandemic. Our earlier work predicted this will lead to approximately 3620 avoidable deaths for four major tumour types (breast, bowel, lung, and oesophageal cancer) in the next...
Article
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Background Patients living in more deprived localities have lower cancer survival in England, but the role of individual health status at diagnosis and the utilisation of primary health care in explaining these differentials has not been widely considered. We set out to evaluate whether pre-existing individual health status at diagnosis and primary...
Article
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Background Subsequent epidemic waves have already emerged in many countries and in the absence of highly effective preventive and curative options, the role of patient characteristics on the development of outcomes needs to be thoroughly examined, especially in middle-east countries where such epidemiological studies are lacking. There is a huge pr...
Article
Background A persistent socioeconomic gap in colon cancer survival is observed in England. Provision of cancer care may also vary by socioeconomic status (SES). We investigated population-based data to explore differential surgical care by SES. Methods We analysed a retrospective cohort of patients diagnosed with colon cancer in England (2010–2013...
Article
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We explored the role of socioeconomic inequalities in COVID-19 incidence among cancer patients during the first wave of the pandemic. We conducted a case-control study within the UK Biobank cohort linked to the COVID-19 tests results available from 16 March 2020 until 23 August 2020. The main exposure variable was socioeconomic status, assessed usi...
Preprint
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Background Socioeconomic inequalities of survival in patients with non–Hodgkin lymphoma (NHL) persists, which may be explained by patients’ comorbidities. We aimed to assess the association between co/multimorbidity and survival in patients diagnosed with Diffuse Large B-cell (DLBCL) or Follicular lymphoma (FL) in England accounting for other socio...
Article
Full-text available
In cancer epidemiology using population-based data, regression models for the excess mortality hazard is a useful method to estimate cancer survival and to describe the association between prognosis factors and excess mortality. This method requires expected mortality rates from general population life tables: each cancer patient is assigned an exp...
Preprint
The purpose of many health studies is to estimate the effect of an exposure on an outcome. It is not always ethical to assign an exposure to individuals in randomised controlled trials, instead observational data and appropriate study design must be used. There are major challenges with observational studies, one of which is confounding that can le...
Preprint
Full-text available
Background Subsequent epidemic waves have already emerged in some countries and in the absence of highly effective preventive and curative options, there is a need for detailed epidemiological examination of the role of patient characteristics on the development of outcomes. The objective of this study is to describe the probabilities of admission...
Article
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Despite a large choice of models, functional forms and types of effects, the selection of excess hazard models for prediction of population cancer survival is not widespread in the literature. We propose multi-model inference based on excess hazard model(s) selected using Akaike information criteria or Bayesian information criteria for prediction a...
Chapter
Cancer death has been Japan’s greatest public health enemy since the 1980s, after controlling infectious diseases, such as tuberculosis. Improvement in cancer survival due to the development of effective cancer treatment and the spread of screening for early detection of cancer has led to declining trends in cancer mortality. However, inequalities...
Article
Objective: Myeloma is primarily a disease of the elderly, but older patients experience poorer outcomes. Effective treatments may not be offered to older patients over fears about toxicity, particularly for those with comorbidities. We aimed to characterise the trend in survival disparity between older and younger patients and assess to what exten...
Article
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Patient and public involvement and engagement has become an essential element of health research, ensuring aims and outputs are worthwhile and relevant. However, research involving secondary data analyses does not present immediately obvious ways to involve patients and the public. Innovative approaches to ensure their involvement is meaningful and...
Article
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Belot A, Ndiaye A, Luque-Fernandez MA, et al. Clin Epidemiol. 2019;11:53–65. Page 57, Number of life years lost (NLYL) section, left column, the sentence “where the quantity 1–FP(t) can be replaced by SP(t), ie, the classical survival function using the population mortality rates λP” placed immediately after equation 14 indicates that the quantity...
Article
BACKGROUND: Pancreatic cancer (PC) represents a substantial public health burden. Pancreatic cancer patients have very low survival due to the difficulty of identifying cancers early when the tumour is localised to the site of origin and treatable. Recent progress has been made in identifying biomarkers for PC in the blood and urine, but these cann...
Article
Full-text available
Background Since a national lockdown was introduced across the UK in March, 2020, in response to the COVID-19 pandemic, cancer screening has been suspended, routine diagnostic work deferred, and only urgent symptomatic cases prioritised for diagnostic intervention. In this study, we estimated the impact of delays in diagnosis on cancer survival out...
Preprint
Full-text available
Background A persistent socioeconomic gap in colon cancer survival is observed in England. Provision of cancer care may also vary by socioeconomic status (SES). We investigated population-based data to explore differential care by SES. Methods We analysed a retrospective cohort of patients diagnosed with colon cancer in England (2010–2013) using t...
Article
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Acquiring real-world evidence is crucial to support health policy, but observational studies are prone to serious biases. An approach was recently proposed to overcome confounding and immortal-time biases within the emulated trial framework. This tutorial provides a step-by-step description of the design and analysis of emulated trials, as well as...
Article
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In population-based cancer studies, net survival is a crucial measure for population comparison purposes. However, alternative measures, namely the crude probability of death (CPr) and the number of life years lost (LYL) due to death according to different causes, are useful as complementary measures for reflecting different dimensions in terms of...
Article
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Background: The presence of comorbidity affects the care of cancer patients, many of whom are living with multiple comorbidities. The prevalence of cancer comorbidity, beyond summary metrics, is not well known. This study aims to estimate the prevalence of comorbid conditions among cancer patients in England, and describe the association between c...
Article
Background: The aim was to compare population-based survival for exocrine pancreatic cancer in England in the 23 regions covered by specialist centres. The centres were initiated in 2001, covering populations of 2-4 million. Methods: We examined incidence for adults diagnosed with a pancreatic exocrine cancer during 1995-2014 and age-standardise...
Article
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Background: Large and complex population-based cancer data are becoming broadly available, thanks to purposeful linkage between cancer registry data and health electronic records. Aiming at understanding the explanatory power of factors on cancer survival, the modelling and selection of variables need to be understood and exploited properly for im...
Article
Excess hazard models became the preferred modelling tool in population-based cancer survival research. In this setting, the model is commonly formulated as the additive decomposition of the overall hazard into two components: the excess hazard due to the cancer of interest and the population hazard due to all other causes of death. We introduce a f...
Article
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An earlier diagnosis is a key strategy for improving the outcomes of patients with cancer. However, achieving this goal can be challenging, particularly for the growing number of people with one or more chronic conditions (comorbidity/multimorbidity) at the time of diagnosis. Pre-existing chronic diseases might affect patient participation in cance...
Article
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In competing risks setting, we account for death according to a specific cause and the quantities of interest are usually the cause‐specific hazards (CSHs) and the cause‐specific cumulative probabilities. A cause‐specific cumulative probability can be obtained with a combination of the CSHs or via the subdistribution hazard. Here, we modeled the CS...
Article
In cancer epidemiology using population-based data, regression models for the excess mortality hazard is a useful method to estimate cancer survival and to describe the association between prognosis factors and excess mortality. This method requires expected mortality rates from general population life tables: each cancer patient is assigned an exp...
Conference Paper
Introduction En Angleterre, l’âge a un fort impact sur l’accès au traitement et les perspectives de rémission pour les patients atteints de cancer : ceux qui sont diagnostiqués avec un cancer du poumon non-à-petites-cellules (NSCLC) après 70 ans ont une probabilité de recevoir un traitement chirurgical réduite de 60 % par rapport aux patients de mo...
Article
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Background One in three colon cancers are diagnosed as an emergency, which is associated with worse cancer outcomes. Chronic conditions (comorbidities) affect large proportions of adults and they might influence the risk of emergency presentations (EP). Methods We aimed to evaluate the effect of specific pre-existing comorbidities on the risk of c...
Article
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Purpose: The ratio of cancer mortality and cancer incidence rates in a population has conventionally been used as an indicator of the completeness of cancer registration. More recently, the complement of the mortality-to-incidence ratio (1-M/I) has increasingly been presented as a surrogate for cancer survival. We discuss why this is mistaken in p...
Preprint
Full-text available
In cancer epidemiology using population-based data, regression models for the excess mortality hazard is a useful method to estimate cancer survival and to describe the association between prognosis factors and excess mortality. This method requires expected mortality rates from general population life tables: each cancer patient is assigned an exp...
Article
Full-text available
Background Completing mortality data by information on possible socioeconomic inequalities in mortality is crucial for policy planning. The aim of this study was to build deprivation-specific life tables using the Portuguese version of the European Deprivation Index (EDI) as a measure of area-level socioeconomic deprivation, and to evaluate mortali...
Article
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Objectives To identify opportunities for reducing emergency colon cancer diagnoses, we evaluated symptoms and benign diagnoses recorded before emergency presentations (EP). Methods Cohort of 5,745 colon cancers diagnosed in England 2005–2010, with individually linked cancer registry and primary care data for the 5‐year pre‐diagnostic period. Resu...
Article
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Background Breast cancer prognosis has dramatically improved over 40 years. There is, however, no proof of population ‘cure’. This research aimed to examine the pattern of long-term excess mortality due to breast cancer and evaluate its determinants in the context of cancer registry data. Methods We used data from the Geneva Cancer Registry to ide...
Article
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Survival data analysis results are usually communicated through the overall survival probability. Alternative measures provide additional insights and may help in communicating the results to a wider audience. We describe these alternative measures in two data settings, the overall survival setting and the relative survival setting, the latter corr...