Any recurrence of the symptoms that a patient initially presented with or new symptoms (outlined in section 2.1) in the treated region should be thoroughly investigated as clinically indicated. Less commonly, the team providing surveillance in the post-treatment period may detect asymptomatic recurrence, often as a progressive mass or mucosal changes. Any new or unexplained clinical finding related to the treated area should be investigated as clinically indicated to determine if recurrent disease is present, especially when the potential to deliver additional treatment with curative intent exists.