Elective nodal irradiation mitigates local and systemic immunity generated by combination radiation and immunotherapy in head and neck tumors

• Published in: Nature communications Vol. 13; no. 1; pp. 7015 - 18
• Main Authors: Darragh, Laurel B, Gadwa, Jacob, Pham, Tiffany T, Van Court, Benjamin, Neupert, Brooke, Olimpo, Nicholas A, Nguyen, Khoa, Nguyen, Diemmy, Knitz, Michael W, Hoen, Maureen, Corbo, Sophia, Joshi, Molishree, Zhuang, Yonghua, Amann, Maria, Wang, Xiao-Jing, Dow, Steven, Kedl, Ross M, Samedi, Von, Boss, Mary-Keara, Karam, Sana D
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 16.11.2022; Nature Publishing Group UK; Nature Portfolio
• Subjects: Antigens; Cancer; Combined Modality Therapy; Epitopes; Head & neck cancer; Head and neck carcinoma; Head and Neck Neoplasms - radiotherapy; Humans; Immune response; Immune system; Immunity; Immunotherapy; Irradiation; Lymph Node Excision; Lymph nodes; Lymphocytes; Lymphocytes T; Metastases; Priming; Radiation; Radiation therapy; Regional development; Sentinel Lymph Node; Squamous cell carcinoma; Tumors
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-022-34676-w

In the setting of conventional radiation therapy, even when combined with immunotherapy, head and neck cancer often recurs locally and regionally. Elective nodal irradiation (ENI) is commonly employed to decrease regional recurrence. Given our developing understanding that immune cells are radio-sensitive, and that T cell priming occurs in the draining lymph nodes (DLNs), we hypothesize that radiation therapy directed at the primary tumor only will increase the effectiveness of immunotherapies. We find that ENI increases local, distant, and metastatic tumor growth. Multi-compartmental analysis of the primary/distant tumor, the DLNs, and the blood shows that ENI decreases the immune response systemically. Additionally, we find that ENI decreases antigen-specific T cells and epitope spreading. Treating the primary tumor with radiation and immunotherapy, however, fails to reduce regional recurrence, but this is reversed by either concurrent sentinel lymph node resection or irradiation. Our data support using lymphatic sparing radiation therapy for head and neck cancer.