br From the Department of Surgery and Cancer Imperial Colleg
From the Department of Surgery and Cancer, Imperial College London,
Londona; the Molecular and Clinical Sciences Institute,b and Population
Health Research Institute,c St George’s University of London, London; the
Department of Molecular Medicine and Surgery, Karolinska Institutet, Stock-
holmd; and the Division of Cancer Studies, King’s College London, London.e
S.R.M. is an NIHR Clinical Trials Fellow (NIHR Clinical Trial Fellowship: NIHR-CTF-2015-04-09). The views expressed in this publication are those of the authors and not necessarily those of the NIHR, NHS, or the Department of Health.
Author conflict of interest: none.
Additional material for this article may be found online at www.jvascsurg.org. Correspondence: Sheraz R. Markar, PhD, MA, MSc, MRCS, Department of Sur-gery and Cancer, St Mary’s Hospital, Imperial College London, 10th Floor, QEQM Building, London W2 1NY, United Kingdom (e-mail: [email protected]
The editors and reviewers of this article have no relevant financial relationships to disclose per the JVS policy that requires reviewers to decline review of any manuscript for which they may have a conflict of interest.
mortality for EVAR compared with open repair, with sug-gestions that this may be partly attributable to an increased late cancer burden after exposure to external radiation from the procedure or stent surveillance with computed tomography (CT).6,7 Visualization for EVAR is dependent on fluoroscopy, which exposes the patient to radiation.8-11 Many patients are also followed up with regular CT scans
after EVAR, entailing additional lifetime radiation expo-sure.12,13 Use of radiation to treat breast cancer and lym-
phoma has been shown to increase the incidence of secondary cancers (eg, esophageal cancer), with an often poor long-term prognosis.14,15 The long-term oncologic effects of radiation exposure both during and after EVAR remain unclear from the limited available literature.8,10-12
This study examined the Cycloheximide that EVAR and associated CT surveillance of endografts lead to an increased risk of abdominal cancer within the radiation field compared with open AAA repair.
Design. This was a population-based and nationwide English cohort study, including all patients older than 50 years who received an AAA repair between April 1, 2005, and March 31, 2013. Patients who underwent EVAR, under both elective and emergency settings, were compared with those having undergone open AAA repair regarding cancer risk. Permissions for the
Journal of Vascular Surgery
comparison of anonymized administrative data were obtained from the National Information Governance Board for Health and Social Care in England. Institutional Review Board approval was sought per the principles outlined in the Declaration of Helsinki.
Data sources. Data were derived from the Hospital Episode Statistics (HES) database.16 This is a record-based system that collects patient-level data from all National Health Service (NHS) hospitals in England. It captures all patients treated in public sector hospitals and the minority of patients treated in privately funded institutions. All patients older than 50 years in the HES data set who received an AAA repair, under elective and emergency settings, between April 1, 2005, and March 31, 2013, were included in the study. Given the design of the study, formal informed consent was not required at a patient level.
HES data use International Classification of Diseases, Tenth Revision diagnostic codes and OPCS Classifica-tion of Interventions and Procedures version 4 proce-dural codes. A list of codes and the algorithm used to identify patients with AAA have been previously pub-lished.17,18 Patients are given a unique HES identifier that allows all of their hospital admissions to be tracked throughout the data set. The data set therefore allows individual follow-up and linkage to data regarding new diagnosis of cancer and out-of-hospital death, which differentiates it from other administrative data sets in which admissions are treated as unrelated entities and cannot be linked to population data for long-term mortality. Thus, patients were tracked through the HES database using their unique HES iden-tifier to provide data about diagnosis of cancer. Linking HES data with data from the Office for National Statis-tics identified long-term mortality. The process of data linkage was performed centrally using a unique patient NHS number, which permits linkage of data between patient data sets.