Study population
We retrospectively reviewed the medical charts of patients who were diagnosed with HPSCC [removed for blind peer review] between April 2016 and April 2018. The enrolled patients were referred to the endoscopy center for diagnosis in [removed for blind peer review], where they underwent IEE screening of the upper gastrointestinal tract. The exclusion criteria for our study were as follows: Other head and neck cancers, hypopharyngeal cancer but not squamous cell carcinoma (SCC), recurrent or metastatic HPSCC cases, and patients who didn’t receive IEE due to compromised airways, tumor bleeding, or refusal. Patients who were newly diagnosed with HPSCC and underwent IEE screening during a primary staging work-up were defined as the newly-diagnosed (ND) group, and patients who had previously been treated for HPSCC and underwent IEE screening during their follow-up period were defined as the follow-up (FU) group. All patients provided written informed consent and the study design was approved by the hospital’ s institutional review board.