Original Article Access to radiotherapy and its association with cancer outcomes in a high-income country: Addressing the inequity in Canada Jessica Chan a,b,c,⇑ , Alfredo Polo b , Eduardo Zubizarreta b , Jean-Marc Bourque a,b,d , Timothy P Hanna e , Marc Gaudet a , Kristopher Dennis a , Michael Brundage e , Ben Slotman c , May Abdel-Wahab b a Division of Radiation Oncology, The Ottawa Hospital and the University of Ottawa, Canada; b Division of Human Health, International Atomic Energy Agency, Vienna, Austria; c Department of Radiation Oncology, Amsterdam UMC – Vrije University Medical Center, The Netherlands; d Institute of Cancer Policy, Kings College London, United Kingdom; and e Division of Cancer Care and Epidemiology, Cancer Research Institute at Queen’s University, Kingston, Canada article info Article history: Received 25 April 2019 Received in revised form 3 August 2019 Accepted 7 September 2019 Available online xxxx Keywords: Cancer Radiotherapy Access MIRs Mortality-to-incidence ratios abstract Background and purpose: Canada is a high-income country with universal healthcare. In international comparisons, its overall level of access to radiotherapy appears sufficient. However, challenges exist due to Canada’s large geographic area and small population density. The association between access and cancer outcomes nationally has not yet been described. Materials and methods: We quantified geographic accessibility for 2012 using the linear distance from each Canadian health region centroid to the nearest radiotherapy center. We used geospatial analytic techniques to detect clusters of age-standardized all-cancer mortality-to-incidence ratios (MIRs) across health regions, from 2010–2012. Global ordinary least squares (OLS) and geographically-weighted regression (GWR) were conducted to examine relationships between distance and MIR, adjusting for sociodemographic factors. Results: Median distance from health region centroid to nearest radiotherapy center was 101.73 km (range 1.14–2095.12). One cluster of worse outcomes (MIR range 0.45–0.88) involved most of northern Canada, with a second cluster of better outcomes (MIR range 0.40–0.41) in southern British Columbia. In both regression models, regions with longer distance to radiotherapy center (ß = 0.0001), increased smoking (ß = 0.002), and poorer food security (ß = –0.003) were significantly associated with worse out- comes (OLS R 2 = 0.70, GWR R 2 = 0.74). Distance remained independently associated with MIR for lung and colorectal cancer subgroups, but not breast and prostate. Conclusions: A clear north–south discordance in cancer outcomes exists in Canada, with poorer outcomes in the north, while radiotherapy centers are concentrated along the south. Increased distance to radio- therapy, along with other sociodemographic and health-system factors, are associated with poorer cancer outcomes. Our study could be replicated, particularly in other high-income countries, to help identify national patterns and regional disparities in access and outcomes. Ó 2019 Elsevier B.V. All rights reserved. Radiotherapy and Oncology xxx (2019) xxx–xxx Cancer is the leading cause of death and premature mortality in Canada [1]. Despite being a high-income country with a universal healthcare system, regional disparities in cancer outcomes persist. This may be related to poorer accessibility to cancer services, par- ticularly for low-income populations, those residing in rural and/or remote areas, the elderly, and new immigrants [2]. Indeed, dispar- ities in access to healthcare were recently highlighted by the Lan- cet Commission as one of Canada’s major challenges [3]. Radiotherapy is part of the Universal Health Coverage Package in many high-income countries, and is needed in more than half of all cases of cancer to cure localized disease, palliate symptoms, and control disease in incurable cancers [4,5]. Radiotherapy also has a population benefit on overall survival when optimally used [6]. An analysis of global radiotherapy capacity by the International Atomic Energy Agency (IAEA) in 2012 demonstrated that Canada was among the most well-resourced, with less than 500,000 people being served by one radiotherapy unit [7]. However, despite having enough radiotherapy capacity in the country as a whole, Canada’s large geographic area and small population density create unique challenges in providing equal geographic accessibility to this spe- cialized cancer treatment. Indeed, longer distance, or travel time, https://doi.org/10.1016/j.radonc.2019.09.009 0167-8140/Ó 2019 Elsevier B.V. All rights reserved. ⇑ Corresponding author at: Division of Radiation Oncology, The Ottawa Hospital and the University of Ottawa, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada. E-mail address: jchan207@uottawa.ca (J. Chan). Radiotherapy and Oncology xxx (xxxx) xxx Contents lists available at ScienceDirect Radiotherapy and Oncology journal homepage: www.thegreenjournal.com Please cite this article as: J. Chan, A. Polo, E. Zubizarreta et al., Access to radiotherapy and its association with cancer outcomes in a high-income country: Addressing the inequity in Canada, Radiotherapy and Oncology, https://doi.org/10.1016/j.radonc.2019.09.009