Retrospective Cohort Study
Copyright ©The Author(s) 2023. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Oncol. Dec 15, 2023; 15(12): 2077-2092
Published online Dec 15, 2023. doi: 10.4251/wjgo.v15.i12.2077
Cohort study to assess geographical variation in cholangiocarcinoma treatment in England
Sophie Jose, Amy Zalin-Miller, Craig Knott, Lizz Paley, Daniela Tataru, Helen Morement, Mireille B Toledano, Shahid A Khan
Sophie Jose, Amy Zalin-Miller, Craig Knott, Health Data Analysis, Health Data Insight CIC, Cambridge CB21 5XE, United Kingdom
Sophie Jose, Amy Zalin-Miller, Craig Knott, Lizz Paley, Daniela Tataru, National Disease Registration Service, National Health Service England, London SE1 8UG, United Kingdom
Helen Morement, Department of Executive, AMMF-The Cholangiocarcinoma Charity, Essex CM24 1QW, United Kingdom
Mireille B Toledano, MRC Centre for Environment and Health, Imperial College London, London SW7 2BX, United Kingdom
Mireille B Toledano, Mohn Centre for Children's Health and Wellbeing, Imperial College London, London SW7 2BX, United Kingdom
Shahid A Khan, Liver Unit, Division of Digestive Diseases, Imperial College London, London SW7 2BX, United Kingdom
Author contributions: Jose S, Knott C, Khan SA, Morement H and Zalin-Miller A designed the study; Paley L and Toledano MB advised on the study design; Jose S, Zalin-Miller A and Knott C had full access to the underlying data in the study; all authors contributed to the interpretation of results; Jose S and Khan SA drafted the manuscript; Knott C, Morement H, Paley L, Tataru D, Toledano MB and Zalin-Miller A reviewed and revised the manuscript; all authors approved the final version of the manuscript had access to the study data and accept responsibility to submit for publication.
Supported by AMMF; National Disease Registration Service, National Health Service England.
Institutional review board statement: The study was reviewed and approved for publication by our Institutional Reviewer.
Informed consent statement: NHS England and has a special legal instruction to collect patient data without needing informed consent. This instruction is granted under section 254 of the Health and Social Care Act 2012.
Conflict-of-interest statement: Dr Jose reports grants from AMMF-The Cholangiocarcinoma Charity, during the conduct of the study.
Data sharing statement: The data that support the findings of this study are available from NHS England. Restrictions apply to the access and use of the data used to undertake this study. A data dictionary is available at https://digital.nhs.uk/ndrs/data/access-to-data.
STROBE statement: The authors have read the STROBE Statement-checklist of items, and the manuscript was prepared and revised according to the STROBE Statement-checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Sophie Jose, PhD, Senior Statistician, Health Data Analysis, Health Data Insight CIC, CPC4 Capital Park, Cambridge CB21 5XE, United Kingdom. sophie.jose@nhs.net
Received: August 7, 2023
Peer-review started: August 7, 2023
First decision: September 1, 2023
Revised: September 22, 2023
Accepted: October 30, 2023
Article in press: October 30, 2023
Published online: December 15, 2023
Processing time: 128 Days and 17.6 Hours
ARTICLE HIGHLIGHTS
Research background

Cholangiocarcinoma (CCA) is a cancer with poor survival outcomes that is increasing in incidence worldwide. In clinical practice there can be barriers to providing treatments that can improve outcomes for those with CCA. Potentially curative surgery is not an option for those diagnosed with advanced disease, which represents the majority of patients. Stent insertion to manage disease complications is a complex procedure requiring access to specialist expertise that is not routinely available in all areas. There are currently relatively few recommended systemic treatment options available that can prolong survival.

Research motivation

Due to the complexity of treating CCA, we hypothesise that there could be variation in the treatments received by CCA patients. Such variation could contribute to the poor outcomes experienced by CCA patients. There is very little data to evidence variation in the care and management of CCA in England, so research into this area is needed. Identifying variation that could point to inequality is the first step toward improving patient outcomes, leading to further research into understanding why this variation exists and ultimately improvement strategies to reduce these variations in care.

Research objectives

We aimed to investigate whether there was evidence of geographic variation in the proportion of CCA patients that received each of three main cancer-specific treatments: potentially curative surgery; systemic therapy amongst those that did not receive surgery; stent insertion amongst those that did not receive surgery.

Research methods

We conducted a retrospective cohort study including patients diagnosed with CCA from 2014-2017 in England. We used linear probability models to investigate geographic variation in the proportions of that received either potentially curative surgery, systemic therapy (in the absence of surgery) or stent insertion (in the absence of surgery) across Cancer Alliance areas in England, adjusting for potential confounders.

Research results

Half of CCA patients in England received none of the cancer treatments we investigated in this study. Only 12.4% received potentially curative surgery. Across all Cancer Alliance areas, the mean percentage-point difference from the population average [95% confidence interval (CI)] ranged from -3.96 (-6.34 to -1.59)% to 3.77 (0.54 o 6.99)% after adjustment for patient sociodemographic and clinical characteristics, showing statistically significant variation.

Amongst those who did not receive surgery, 19.9% received systemic therapy, with mean percentage-point difference from the population average [95%CI] ranging from -3.84 (-8.04 to 0.35)% to 9.28 (1.76 to 16.80)% across Cancer Alliances after adjustment. Stent insertion was received by 27.8%. Across Cancer Alliances, after adjustment for confounders, the mean percentage-point difference from population average [95%CI] ranged between -10.54 (-12.88 to -8.20)% and 13.64 (9.22 to 18.06)%, showing wide and statistically significant variation from the population average.

It is unknown whether the observed variation is evidence of inequality in access to treatment and differing clinical practice or can be explained by factors we were unable to account for in our analysis, such as patient choice and differences in the clinical case-mix of patients in these areas.

Research conclusions

We found statistically significant geographic variation in the proportions of CCA patients receiving surgery, systemic therapy and stent insertion across Cancer Alliance areas in England.

Research perspectives

Local detailed review of treatment pathways should be undertaken to understand in more detail why rates of treatment were low and whether the observed variation indicates disparities in access to care or differences in clinical practice. Greater understanding of why variation in care is present can support the development of future strategies to reduce unwarranted variation and improve outcomes.