Abstract 4207: Systematic review and meta-analysis of cancer incidence after blood transfusion in the general population
Authors: Oh Youjin , Lee Soowon , Bok Sebin , Jung Chan Mi , Hong Ilene , Chung Liam , Lee Jeeyeon , Chae Young Kwang 
Published: April 2023

Abstract
Background: The impact of blood transfusion on cancer survival and mortality has been widely studied. However, few studies have investigated its relationship with cancer incidence. This is the first systematic review and meta-analysis evaluating the correlation between blood transfusion and cancer incidence.
Methods: Five studies were identified through Pubmed, Embase, and Cochrane library. Four cohort studies and one case-control study (N = 3,048,906) were included. Over seventy percent were female (N =2,167,580), and about thirty-one percent (N = 956,522) were transfused. Meta-analysis was conducted between blood transfusion and cancer incidence. Subgroup analyses were performed by cancer types, follow-up period, and units of transfused blood. We pooled available risk estimates, which were adjusted for confounding factors, including age and sex, were pooled.
Results: Overall cancer risk increased statistically significantly in people who received transfusion compared to the population that did not (1.70, 95% CI, 1.30 to 2.10). The result was consistent regardless of time intervals from transfusion or units of transfused blood. Cancer incidences in all solid tumors, except breast, thyroid, and uterine cancer, were higher in blood transfusion recipients (Table 1). The elevated risk of stomach, bladder, and kidney cancer was sustained for up to fifteen years. Furthermore, lung cancer, liver cancer, and non-Hodgkin lymphoma risk remained high among the blood transfusions group even after fifteen years. The three types of cancer with the highest incidence following transfusion were leukemia, stomach cancer, and liver cancer.
Conclusions: Blood transfusion increases the risk of cancer in transfusion recipients. The impact of blood transfusion on cancer development varies depending on the cancer type and the time from transfusion. Further prospective studies are warranted to validate the findings and investigate the underlying mechanism.
The pooled risk of cancer according to cancer types, units of transfusion, and time from transfusion Risk* (95% CI) Total &lt; 5 yrs 5-15 yrs ≧ 15 yrs All cancer types 1.70 (1.30 - 2.10) 1.89 (1.13 - 2.65) 1.18 (0.97 - 1.40) 1.10 (1.06 - 1.14) Leukemia 2.79 (2.00 - 3.57) 4.07 (2.72 - 5.42) 1.15 (1.04 - 1.27) 0.91 (0.66 - 1.16) Non Hodgkin lymphoma 1.94 (1.49 - 2.40) 2.66 (1.82 - 3.50) 1.43 (0.89 - 1.98) 1.23 (1.00 - 1.46) Stomach 2.37 (1.70 - 3.04) 2.37 (1.70 - 3.04) 1.13 (1.03 - 1.23) 1.17 (0.91 - 1.43) Liver 2.25 (1.67 - 2.84) 2.80 (1.80 - 3.80) 1.67 (1.48 - 1.86) 2.54 (1.85 - 3.23) Colon 2.34 (1.62 - 3.05) 3.49 (1.90 - 5.08) 1.02 (0.96 - 1.08) 1.05 (0.90 - 1.20) Pancreas 1.85 (1.36 - 2.34) 2.37 (1.50 - 3.24) 1.19 (0.72 - 1.66) 1.28 (0.97 - 1.59) Rectum 1.40 (1.06 - 1.75) 1.71 (1.04 - 2.39) 0.98 (0.91 - 1.05) 1.00 (0.81 - 1.19) Lung 1.49 (1.21 - 1.77) 1.71 (1.18 - 2.23) 1.24 (1.17 - 1.30) 1.27 (1.09 - 1.45) Kidney 2.27 (1.63 - 2.90) 3.30 (1.89 - 4.17) 1.15 (1.03 - 1.27) 1.39 (0.70 - 2.08) Bladder 1.40 (1.12 - 1.68) 1.56 (1.06 - 2.06) 1.19 (1.11 - 1.27) 1.35 (0.15 - 2.54) Breast 0.96 (0.84 - 1.09) 1.06 (0.91 - 1.22) 0.95 (0.90 - 1.00) 1.12 (1.03 - 1.21) Uterus 1.02 (0.84 - 1.19) 1.13 (0.85 - 1.25) 0.81 (0.46 - 1.16) 1.00 (0.78 - 1.22) Thyroid 1.16 (0.91 - 1.41) 1.32 (0.87 - 1.77) 0.92 (0.70 - 1.14) 1.12 (0.64 - 1.78) 1-2 units ≧ 3 units All cancer types 1.53 (1.15 - 1.90) 1.93 (1.39 - 2.48) *Risk is pooled from odds ratio, hazard ratio, relative risk, and standardized incidence ratio.Abbreviations: CI=Confidence Interval
Citation Format: Youjin Oh, Soowon Lee, Sebin Bok, Chan Mi Jung, Ilene Hong, Liam Chung, Jeeyeon Lee, Young Kwang Chae. Systematic review and meta-analysis of cancer incidence after blood transfusion in the general population. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4207.