Esophageal Squamous Cell Cancer Surveillance With Cytosponge

Inclusion Criteria: Patients with esophageal squamous cell cancer (ESCC): * Patients ≥18 years of with adequate performance status for endoscopy * Newly diagnosed ESCC suitable for endoscopic or oncological treatment (Rth/Chth) * Patients currently undergoing oncological treatment (Rth/Chth) * Consent to provide tissue samples for the study * Dysphagia grade ≤2 (able to swallow mixed foods and tablets) Patients at high risk for ESCC: * Patients ≥18 years of age with adequate performance status for endoscopy * Prior definitive treatment for head and neck cancer (cancer of the oral cavity, hypopharyngeal cancer, laryngeal carcinoma) and at least 12 months post-therapy (both Rth, Chth, and combination treatment) * Prior definitive endoscopic treatment for early ESCC in the past (at least 6 months since completion) * Consent to provide tissue samples for the study * Dysphagia grade ≤2 Exclusion Criteria (for both groups of patients): * Patients currently on anticoagulant treatment (warfarin, acenocoumarol) with no possibility of stopping / modification * Dysphagia grade ≥3 (able to swallow only liquid foods) * History of myocardial infarction or other cardiovascular event within 6 months of enrolment * Neurological diseases associated with impaired swallowing * Patients in long-term care or institutional care (physical, psycho-social disorders, intellectual disability).