This study is testing a new way to decide treatment after surgery for certain colon cancer patients. It uses something called *minimal residual disease* (MRD) which is detected by looking for small pieces of tumor DNA, called circulating tumor DNA (ctDNA), in the blood. The study focuses on patients with specific types of early-stage colon cancer. **Key Points:** - The study lasts up to 5 years with regular check-ups, including MRD tests every 3 months and scans every 6 months for 3 years. - Participants will be divided into groups based on their MRD status after surgery to receive different types of follow-up treatments. - Both men and women need to use birth control during the study and for 3 months after to ensure safety. Eligible participants must be between 18 and 70 years old, have had successful surgery, and not have received previous treatments like chemotherapy. This study is important to see if MRD status can help decide who needs more or less treatment after surgery.