Immune evasion is a critical process in carcinogenesis. Downregulation of host defense mechanisms and enhanced regulatory and tolerance pathways allow for tumors to grow unchecked by the immune system. In head and neck squamous cell carcinoma (HNSCC), there is growing interest in the use of immunomodulatory therapy to treat disease, particularly in the recurrent or metastatic setting. However, there is a relative paucity of data regarding the immunophenotype of recurrent HNSCC or immune biomarkers that may be associated with increased survival. Variability in the tumor immune microenvironment and immune markers may be a critical factor in determining tumor response to treatment, particularly in regards to newer immunomodulatory therapies. Thus, a multi-institutional collaboration has been established to analyze the association of immune biomarkers with patient outcomes and to understand the changes that occur in the tumor immune microenvironment after disease recurrence.
A collaborative project across multiple institutions in the United States was initiated to pool patients with recurrent HNSCC between 2010-2015. Patients were eligible for inclusion if they underwent radiation or chemoradiation for HNSCC, had recurrence of this tumor after treatment, and had pathologic specimens available for examination both before and after treatment. Demographic, tumor staging, treatment details, and survival outcomes were collected on all patients. Immunohistochemical analysis of tumor immune biomarker expression was performed, and correlated to outcome data.
Patient identification and specimen collection is currently ongoing. Preliminary results indicate that changes in immune biomarker such PD-L1 within the tumor microenvironment are observed in the recurrent HNSCC setting and may correlate with survival.
Changes in the tumor immune microenvironment may be a key determinant of HNSCC tumor recurrence and patient outcomes in the recurrent setting. Characterization of immune biomarkers in recurrent HNSCC may provide insight into the role of the immune system in regulating tumor growth. Furthermore, these data may aid in selecting patients most likely to benefit from various immunomodulatory therapies, and may point the way to new therapeutic targets.