T1 Colorectal Cancer After Local Excision: Decision Between Surgery and Active Surveillance (T1LDA Trial)

The goal of this two-arm clinical trial is to compare additional surgery with active surveillance in patients with high-risk pT1 colorectal cancer after local excision. The main questions it aims to answer are Does additional surgery result in lower rates of distant or extraluminal recurrence compared with active surveillance? How do the two treatment strategies differ in survival, complications, quality of life, and treatment-related costs? Participants will be randomly assigned to either additional surgery or active surveillance. Patients assigned to the surgery group will undergo standard preoperative assessment followed by additional surgery. Following surgery, patients will undergo surveillance according to the predefined follow-up protocol. Patients assigned to the active surveillance group will not receive any additional treatment. They will undergo surveillance according to a more intensive predefined follow-up protocol.