What this trial measures

• Risk of residual disease and/or recurrent disease5 years

  Residual disease analysis will be limited to patients who underwent surgery (in addition to endoscopic resection). Participants will be evaluable if they undergo adequate pathological assessment of the resected specimen.Adequate assessment is defined as histopathological evaluation of all relevant tissue specimens with a documented report. Participants with incomplete or inadequate pathological assessments will be considered inevaluable. Risk of residual disease will be estimated using the Kaplan-Meier method and reported with 95% confidence intervals. Local recurrence is defined by the reappearance of disease at or near the primary site. The date of diagnosis and anatomical site of recurrence will be documented. Distant recurrence is defined by disease spread to sites distant from the primary lesion. The date of diagnosis and specific sites involved will be documented.