Assessment of endpoint definitions in recurrent and metastatic mucosal head and neck squamous cell carcinoma trials: Head and Neck Cancer International Group consensus recommendations

Transparent and precise endpoint definitions are a critical aspect of clinical trial conduct and reporting, and are used to communicate the benefit of an intervention. Previous studies have identified inconsistencies in endpoint definitions in oncological clinical trials. Here, the Head Neck Cancer International Group reports endpoint definitions from trial published between 2008-2021 in phase 3 trials or trials considered potentially practice-changing in the recurrent metastatic setting for patients with mucosal head and neck squamous cell carcinoma. We identify significant and global heterogeneity in endpoint definitions which potentially undermines the interpretation of results and development of future studies. We demonstrate how fundamental components of even seemingly incontrovertible endpoints such as overall survival varies widely, highlighting an urgent need for increased rigor in reporting and harmonisation of endpoint reporting.