A Clinically Translatable Immune-based Classification of HPV-associated Head and Neck Cancer with Implications for Biomarker-Driven Treatment Deintensification and Immunotherapy

PurposeHuman papillomavirus-associated (HPV+) head and neck squamous cell carcinoma (HNSCC) is the fastest rising cancer in North America. There is significant interest in treatment de-escalation for these patients given the generally favourable prognosis. However, 15-30% of patients recur after primary treatment, reflecting a need for improved risk-stratification tools. We sought to develop a molecular test to predict the survival of patients with newly diagnosed HPV+ HNSCC. MethodsWe created a prognostic score (UWO3) that was successfully validated in six independent cohorts comprising 906 patients, including blinded retrospective and prospective external validations. Transcriptomic data from two aggressive radiation de-escalation cohorts were used to assess the ability of UWO3 to identify patients who recur. Multivariate Cox models were used to assess the associations between the UWO3 immune class and outcomes. ResultsA three-gene immune score classified patients into three immune classes (immune rich, mixed, or immune desert) and was strongly associated with disease-free survival in six datasets, including large retrospective and prospective datasets. Pooled analysis demonstrated that the immune rich group had superior disease-free survival at 5 years to the immune desert (HR= 9.0, 95% CI 3.2-25.5, P=3.6x10-5) and mixed (HR=6.4, 95%CI 2.2-18.7, P=0.006) groups after adjusting for age, sex, smoking status, and AJCC8 clinical stage. Finally, UWO3 was able to identify patients from two treatment de-escalation cohorts who remain disease-free after aggressive de-escalation to 30 Gy radiation. ConclusionsThe UWO3 immune score could enable biomarker-driven clinical decision-making for patients with HPV+ HNSCC based on robust outcome prediction across six independent cohorts. The superior survival of immune rich patients supports de-intensification strategies, while the inferior outcomes of the immune desert patients suggest the potential for intensification and/or immunotherapy. Prospective de-escalation and intensification clinical trials are currently being planned.