Impact of implementing stricter criteria for blood transfusion in patients with head and neck cancer undergoing free tissue transfer

Objective: Recent literature studying the impact of blood transfusion on outcomes in patients with head and neck cancer (HNC) have shown that blood transfusions are associated with increased risk of death and higher wound infection rates. The purpose of this study was to implement a lower transfusion threshold while comparing outcomes of free flap patients following initiation of a new transfusion guideline. Methods: A retrospective study of all patients at a tertiary care academic center who underwent free tissue transfer after HNC resection between July 17, 2007 and June 7, 2021. Transfusion criteria were adjusted in 2014; the hematocrit threshold to transfuse was incrementally reduced from 30% in 2007 to 21% in 2017. The main outcomes of interest were overall survival (OS) and recurrence free survival (RFS). Results: A total of 346 patients met the criteria for inclusion in the study. Groups 1 (less strict protocol - 30%) and 2 (stricter protocol - 21%) consisted of 171 and 175 patients, respectively. Fewer units of packed red cells were transfused per patient in group 2 (0.26 vs. 2.87 in group 1, p < .001). Group 1 was associated with worse OS (p = .01; hazard ratio [HR] = 1.7) and RFS (p < .001; HR = 2.5). Comparing only patients with SCC between the two groups also demonstrated poorer OS (p = .01; HR = 1.8) and RFS (p = .006; HR = 2.1) in group 1. Conclusion: In HNC patients undergoing free tissue transfer, stricter transfusion criteria with threshold hematocrit of 21% was associated with improved OS, RFS, and complication rates with no negative impact on free flap survival.