Interobserver variation among pathologists for delineation of tumor on H&E-sections of laryngeal and hypopharyngeal carcinoma. How good is the gold standard?

in tumor delineation studies for radiotherapy, histopathology is used for validation purposes [1–7]. Validation of tumor delineation is a complex procedure and relatively few studies have been performed in the research field of head-and-neck cancer [3,5,8]. in these studies, whole mount sections of laryngectomy specimens were obtained. The tumor was delineated by a pathologist and used to validate various imaging modalities, e.g. computed tomography (CT), magnetic resonance imaging (MRi), and positron emission tomography (PET) for their ability to distinguish tumor tissue. For the interpretation of validation studies, the variation of tumor outline on histopathology is crucial, as it is used as gold standard for tumor delineation in clinical imaging studies as currently performed by our institute [3,5,9]. However, a study on the reproducibility of tumor outline is missing. The aim of this study is to determine the variation of tumor delineation among pathologists on H&E-sections for laryngeal and hypopharyngeal carcinoma to quantify the uncertainties in the gold standard in the context of imaging validation studies for laryngeal and hypopharyngeal carcinoma.