Contents lists available at ScienceDirect Cancer Epidemiology journal homepage: www.elsevier.com/locate/canep Peri-operative blood transfusion for resected colon cancer: Practice patterns and outcomes in a population-based study Sunil V. Patel a,b, ⁎ , Kelly E. Brennan c , Sulaiman Nanji a,b , Safiya Karim a,c , Shaila Merchant a,b , Christopher M. Booth a,c a Department of Oncology, Queen’s University, Kingston, Canada b Department of Surgery, Queen’s University, Kingston, Canada c Division of Cancer Care and Epidemiology, Queen’s University Cancer Research Institute, Canada ARTICLE INFO Keywords: Colon cancer Blood transfusion Overall survival Cancer specific survival ABSTRACT Background & objectives: Literature suggests that peri-operative blood transfusion among patients with resected colon cancer may be associated with inferior long-term survival. The study objective was to characterize this association in our population. Methods: This is a retrospective cohort study using the population-based Ontario Cancer Registry (2002–2008). Pathology reports were obtained for a 25% random sample of all cases and constituted the study population. Log binomial regression was used to identify factors associated with transfusion. Cox proportional hazards model explored the association between transfusion and cancer specific survival (CSS) and overall survival (OS). Results: The study population included 7198 patients: 18% stage I, 36% stage II, 40% stage III, and 6% stage IV. Twenty-eight percent of patients were transfused. Factors independently associated with transfusion included advanced age (p < 0.001), female sex (p < 0.001), greater comorbidity (p < 0.001), more advanced disease (p < 0.001) and open surgical resection (p < 0.001). Transfusion was associated with inferior CSS (HR 1.51, 95% CI 1.38–1.65) and OS (HR 1.52, 95% CI 1.41–1.63), after adjusting for important confounders. Conclusions: Peri-operative transfusion rates among patients with colon cancer have decreased over time. Transfusion is associated with inferior long-term CSS and OS. 1. Introduction Colorectal cancer is the third most common newly diagnosed cancer in Ontario, Canada and is responsible for the second highest proportion of cancer deaths in this province [1]. Patients undergoing surgery for colon cancer are transfused fre- quently [2]. Population level studies appear to show large variations in the rates of transfusion by surgeon (2–59%) and institution (3–33%) [3]. Blood transfusion was noted to have immunologic effects in renal transplant patients in a number of early reports [4]. Shortly thereafter, concerns were raised regarding the potential negative association be- tween blood transfusion and colorectal cancer survival [5]. Since these earlier publications, a number of studies have assessed the long term effects of blood transfusion on colorectal cancer survival. A Cochrane review [6] included 36 studies published over a 20 year period (1985–2001) and found that red blood cell (RBC) transfusion was as- sociated with an increased risk of cancer recurrence. This review included a large number of studies with significant heterogeneity, limited sample size, and many of the included studies did not adjust for comorbidities, disease stage or other pathologic risk features. Most of the included publications were conducted prior to the standardization and use of modern 5-Fluorucil based chemotherapy regimens. The objective of this paper was to describe transfusion rates among patients with resected colon cancer in routine practice, identify factors associated with transfusion and evaluate the association between transfusion and long-term survival. 2. Methods 2.1. Study design and population This is a retrospective population-based cohort study to describe the effect of peri-operative red blood cell transfusion in colon cancer pa- tients in the province of Ontario, Canada. Ontario (population 13.5 million) has a single-payer universal health care system. Patients with http://dx.doi.org/10.1016/j.canep.2017.10.006 Received 3 May 2017; Accepted 7 October 2017 ⁎ Corresponding author. Department of Surgery, Kingston General Hospital, 76 Stuart Street, Kingston, ON K7L 2V7, Canada. E-mail address: patels2@kgh.kari.net (S.V. Patel). Cancer Epidemiology 51 (2017) 35–40 1877-7821/ © 2017 Elsevier Ltd. All rights reserved. MARK