Abstract 5768: Peripartum blood transfusions are associated with increased risk of cancer: A national retrospective cohort study

Background: The effect of blood transfusions on the risk of developing primary cancer remains unclear, especially when administered in the peripartum period. Methods: We conducted a retrospective cohort study of 270,529 pregnant women who delivered between January 1, 2007 and December 31, 2009, with data obtained from three national databases in South Korea. From this cohort, we identified 4,569 patients who received peripartum blood transfusions. We calculated hazard ratios (HRs) for new diagnoses of cancer, and adjusted them for relevant clinical factors using a Cox proportional hazards model. Results: During follow-up, patients who received peripartum transfusions had an increased risk of developing cancer, with an adjusted HR of 1.16 (95% confidence interval [CI], 1.01-1.34). This risk was significant only among patients who received 3 or more units of blood, with an adjusted HR of 1.40 (95% CI, 1.10-1.79). Increased risk after transfusions were seen with brain, lung, ovarian, and gallbladder cancers. The difference in cancer risk between the transfusion and no-transfusion groups remained significant during both the first (1.34% vs 1.10%, p Conclusion: Receipt of 3 or more blood transfusions in the peripartum period was associated with a significantly increased risk of developing cancer. Citation Format: Young Kwang Chae, Michael S. Oh, Misuk Lee, Sukjoo Cho, Jonghanne Park, Geum Joon Cho. Peripartum blood transfusions are associated with increased risk of cancer: A national retrospective cohort study [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5768.