Abstract
BACKGROUND: Recent studies have suggested a correlation between ABO blood type and the effectiveness of immune checkpoint inhibitors. However, the relationship between ABO blood type and response to pembrolizumab monotherapy as first-line treatment for squamous cell carcinoma of the head and neck (SCCHN) remains unclear. METHOD: We retrospectively analyzed the patients who were treated with pembrolizumab as the first-line treatment for locally advanced, recurrent, or metastatic SCCHN between May 2020 and September 2024. RESULT: A total of 38 cases were analysed in this study. The ABO blood types of patients were as follows: 15 (39.5%) were type A, 9 (23.7%) were type B, 3 (7.9%) were type AB, and 11 (28.9%) were type O. Median Overall survival (OS) by blood type was 28.9 months for type A, 7.8 months for type B, 45.6 months for type O, and 21.4 months for type AB. The OS of B antigen-positive group (B group; B or AB) was significantly poorer than that of B antigen-negative group (non-B group; A or O) (7.8 months [95% CI, 3.0-16.4] vs. 28.9 months [95% CI, 10.7-45.6], p = 0.0022). Progression-free survival (PFS) was 2.6 (95% CI, 1.2-7.6) months vs. 7.2 (95% CI, 3.5-24.1) months (p = 0.06), overall response rate (ORR) was 25.0 vs. 46.2% (p = 0.29) and disease control rate (DCR) was 41.7 vs. 76.9% (p = 0.06), respectively. CONCLUSION: In this cohort, the presence of B antigen provides a significant disadvantage in terms of survival in patients using pembrolizumab for SCCHN.