Novel Strategy for Early Detection of Esophageal Squamous Cell Carcinoma

Inclusion Criteria: ESCC Cases (Group 1): * Male or female \>= 18 years of age at screening visit. * Patients are currently seen for clinical care at Muhimbili National Hospital (MNH)-Upanga or at MNH-Mloganzila. * Patient meets one of the following two criteria- * Patients with a confirmed diagnosis of ESCC as evidenced by histological confirmation OR * Patient planned to undergo EGD with biopsy for suspected ESCC based upon any one of the following clinical criteria: (1) findings on computed tomography (CT) scan; (2) findings on barium swallow; (3) findings on endoscopy without biopsy confirmation, (4) symptoms of dysphagia and/or odynophagia without an alternative explanation for these symptoms. * Patient must be able to swallow liquid (Ogilvie's score \< 3). * Patients must be well enough to participate in a 20-minute interview or have a close relative who is able to do so on their behalf. * Patients must be willing to be contacted either in person or via phone 7-10 days following administration of the 'EsophaCap' sponge device. * Native of Tanzania. * Written informed consent (and assent when applicable) obtained from subject or subject's legal representative and ability for subject to comply with the requirements of the study. Non-ESCC study participants (Group 2): * Male or female ≥ 18 years of age at screening visit. * Patients are currently seen for clinical care at MNH-Upanga or at MNH-Mloganzila. * Patient is scheduled to undergo EGD for a suspected non-malignant condition with no symptoms concerning for esophageal cancer (i.e. dysphagia or odynophagia). * Patient must be able to swallow liquid (Ogilvie's score \< 3). * Patients must be well enough to participate in a 20-minute interview or have a close relative who is able to do so on their behalf. * Patients must be willing to be contacted either in person or via phone 7-10 days following administration of the 'EsophaCap' sponge device. * Native of Tanzania. * Written informed consent (and assent when applicable) obtained from participant or participant's legal representative and ability for subject to comply with the requirements of the study. Exclusion Criteria: ESCC Cases (Group 1): * Known pregnancy during participation in the study. * Presence of a condition or abnormality that in the opinion of the Investigator would compromise the safety of the patient or the quality of the data. * Clinical instability (i.e. hypotension or a recent cardiovascular event). * Any history of upper gastrointestinal bleeding within the past 3 months (including reported history of hematemesis and/or melena). * Diagnosis of peptic ulcer disease within the last 3 months. * Known history of esophageal varices. * Patients taking anticoagulation or antiplatelet therapy/medication (warfarin, clopidogrel, aspirin, heparin or enoxaparin) for high-risk conditions. * Patients with an active extra-esophageal malignancy (not currently in remission). * Patient with a known history of a non-malignant esophageal stricture. * Patients with esophageal stents currently in place. * Patients with a history of radiation therapy to the head, neck, any part of the gastrointestinal tract (including esophagus) or thorax. * Patients who have previously received chemotherapy in the last 12 months * Patients with any history of major surgery for esophageal cancer (e.g. esophageal bypass, esophagectomy, etc.). * Patients who have a known history of or clinical symptoms concerning for tracheoesophageal fistula (aspiration history, severe cough) * Patients with a known history of small bowel obstruction * Patients with a history of bleeding complications during esophageal biopsy. * Patients with any history of a head and neck malignancy. * Patients with a known bleeding disorder * Patients with known thrombocytopenia (less than 50,000 platelets per microliter) * Individuals who are not permanent residents or natives of Tanzania. * Inability to follow instructions. * Unable to provide informed consent. Non-ESCC study participants (Group 2): * Known pregnancy during participation in the study. * Presence of a condition or abnormality that in the opinion of the Investigator would compromise the safety of the patient or the quality of the data. * Clinical instability (i.e. hypotension or a recent cardiovascular event). * Any history of upper gastrointestinal bleeding within the past 3 months (including reported history of hematemesis and/or melena). * Diagnosis of peptic ulcer disease within the last 3 months. * Known history of esophageal varices. * Patients taking anticoagulation or antiplatelet therapy/medication (warfarin, clopidogrel, aspirin, heparin or enoxaparin) for high-risk conditions. * Patients with an active extra-esophageal malignancy (not currently in remission) or any history of a non-cutaneous malignancy diagnosed within the previous five years. * Patient with a known history of esophageal strictures disabling passage of the capsule. * Patient with esophageal stents currently in place. * Patients with a history of radiation therapy to the head, neck, any part of the gastrointestinal tract (including esophagus) or thorax. * Patients with a known history of small bowel obstruction * Patients with a known bleeding disorder * Patients with known thrombocytopenia (less than 50,000 platelets per microliter) * Individuals who are not permanent residents or natives of Tanzania. * Allergy to iodine * Presence of goiter. * Inability to follow instructions. * Unable to provide informed consent