Recent publications

2024

Longitudinal record linkage in Sub-Saharan Africa countries: Recommendations for healthcare research.
June 22 2024
by Wende Safari
BACKGROUND: The use of unique national personal identification numbers (PIN) for linkage of medical records across health facilities and population-based studies is limited in sub-Saharan Africa (SSA) countries. The disintegration of healthcare research with different participant identifiers creates methodological challenges in linking data from multiple sources to answer a diverse range of policy-relevant, clinical, administrative, and research questions. This commentary aims to provide recommendations for improved linkage of health services data in SSA for healthcare research.

Extended excess hazard models for spatially dependent survival data.
March 6, 2024
by Manuela Quaresma
BACKGROUND: We propose a flexible parametric class of spatial excess hazard models (along with inference tools), named “Relative Survival Spatial General Hazard,” that allows for the inclusion of fixed and spatial effects in both time-level and hazard-level components. We illustrate the performance of the proposed model using an extensive simulation study, and provide guidelines about the interplay of sample size, censoring, and model misspecification. We present a case study using real data from colon cancer patients in England. This case study illustrates how a spatial model can be used to identify geographical areas with low cancer survival, as well as how to summarize such a model through marginal survival quantities and spatial effects.

On variance estimation of the inverse probability-of-treatment weighting estimator: A tutorial for different types of propensity score weights.
April 15, 2024
by Andriana Kostouraki
BACKGROUND: We present a comprehensive tutorial to obtain unbiased variance estimates, by proposing and applying a unifying formula for different types of PS weights (ATE, ATT, matching and overlap weights). This can be derived either via the linearization approach or M-estimation. Extensive R code is provided along with the corresponding large-sample theory. We perform simulation studies to illustrate the behavior of the estimators under different treatment and outcome prevalences and demonstrate appropriate behavior of the analytical variance estimator. We also use a reproducible analysis of observational lung cancer data as an illustrative example, estimating the effect of receiving a PET-CT scan on the receipt of surgery.

Older

• Inequalities in cancer care in England: from diagnosis to treatment
  October 1, 2024 by A Exarchakou
  Cancer is among the leading causes of death and morbidity worldwide. Although it is a disease that predominantly affects older people, cancer incidence is increasing among adolescents and young adults. In the UK, cancer outcomes have been historically lagging behind other comparable countries and wide geographical and socio-economic inequalities have been observed within the country. […]
• Immortal-time bias in older vs younger age groups: a simulation study with application to a population-based cohort of patients with colon cancer.
  September 8, 2023 by Sophie Pilleron
  BACKGROUND: In observational studies, the risk of immortal-time bias (ITB) increases with the likelihood of early death, itself increasing with age. We investigated how age impacts the magnitude of ITB when estimating the effect of surgery on 1-year overall survival (OS) in patients with Stage IV colon cancer aged 50-74 and 75-84 in England. METHODS: […]
• Monitoring multidimensional aspects of quality of life after cancer immunotherapy: protocol for the international multicentre, observational QUALITOP cohort study.
  May 11, 2023 by Petra C Vinke
  INTRODUCTION: Immunotherapies, such as immune checkpoint inhibitors and chimeric antigen receptor T-cell therapy, have significantly improved the clinical outcomes of various malignancies. However, they also cause immune-related adverse events (irAEs) that can be challenging to predict, prevent and treat. Although they likely interact with health-related quality of life (HRQoL), most existing evidence on this topic […]
• Socioeconomic status and its relation with breast cancer recurrence and survival in young women in the Netherlands.
  July 25, 2022 by Marissa C van Maaren
  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
• Socioeconomic gaps over time in colorectal cancer survival in England: flexible parametric survival analysis.
  May 24, 2022 by Mari Kajiwara Saito
  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 retrospective cohort study using the National […]
• Cardiovascular diseases among diffuse large B-cell lymphoma long-term survivors in Asia: a multistate model study.
  January 31, 2022 by SF Lee
  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 from a population-wide electronic […]
• An investigation of cancer survival inequalities associated with individual-level socio-economic status, area-level deprivation, and contextual effects, in a cancer patient cohort in England and Wales.
  January 31, 2022 by Fiona C Ingleby
  BACKGROUND: People living in more deprived areas of high-income countries have lower cancer survival than those in less deprived areas. However, associations between individual-level socio-economic circumstances and cancer survival are relatively poorly understood. Moreover, few studies have addressed contextual effects, where associations between individual-level socio-economic status and cancer survival vary depending on area-based deprivation. METHODS: […]
• Statistical approaches for monitoring early cancer diagnosis in England
  January 10, 2022 by P Muller
  Background: Increasing early-stage diagnosis is a priority of health policy in England. Numerous interventions to effect improvements were implemented during 2008-2013, including symptom awareness campaigns and bowel cancer screening. There were also structural changes to health services, with smaller increases in health spending from 2010 and a reorganisation in 2013. An analysis of early diagnosis […]
• Association between multimorbidity and socioeconomic deprivation on short-term mortality among patients with diffuse large B-cell or follicular lymphoma in England: a nationwide cohort study.
  January 8, 2022 by Matthew James Smith
  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 and 2013. We linked the English population-based […]
• Do presenting symptoms, use of pre-diagnostic endoscopy and risk of emergency cancer diagnosis vary by comorbidity burden and type in patients with colorectal cancer?
  December 7, 2021 by Sara Benitez Majano
  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 patients (2011-2015), and multivariate quantile and logistic regression, we examined variations […]