Evaluating CD103 intratumoral immune cell abundance and PD-L1 CPS in primary tumors versus lymph nodes in Human papillomavirus associated oropharyngeal Cancer.

[BACKGROUND] CD103 intratumoral immune cell (ITIC) abundance in Human Papillomavirus associated Oropharyngeal Cancer (HPVOPC) primary tumors in patients treated with chemoradiation conveys an excellent prognosis, but data is lacking for nodal expression and surgical cohorts. High programmed death-ligand 1 (PD-L1) expression predicts immunotherapy response, but its prognostic significance and correlation with CD103 expression in HPVOPC is unknown.

[METHODS] Immunohistochemistry to evaluate CD103 ITIC abundance > 30 % and PD-L1 Combined Positive Score (CPS) > 20 % in primary tumors and lymph nodes in 114 surgically treated HPVOPC patients. Findings were correlated with clinicopathological and outcome data.

[RESULTS] High CD103 ITIC abundance (>30 %) in 14.5 % of primary tumors (16/110) and 14.3 % (11/77) of lymph nodes. High PD-L1 CPS (>20 %) in 38.3 % (41/107) of primaries, and 36.3 % (28/77) of nodes. Discordant rates between primaries and nodes for CD103 ITIC and PD-L1 CPS were 15 % and 29 % respectively. 5-year failure free survival (FFS) was 100 % and 83 % in patients with high and low CD103 ITIC abundance primary tumors, (95 % CI: 72-91; p = 0.161). 5-year FFS was 98 % and 79 % (p = 0.033) in patients with high and low PD-L1 CPS primary tumors. Lymph node CD103 ITIC abundance and PD-L1 CPS did not appear to be prognostic for survival.

[CONCLUSIONS] This study highlights the discordance in CD103 ITIC and PD-L1 expression between primaries and nodes, favorable results in high CD103 ITIC abundance HPVOPC in a surgical cohort consistent with outcomes in chemoradiation cohorts, and promising results suggesting that high PD-L1 CPS in HPVOPC also identifies patients with an excellent prognosis.