Adjuvant Chemotherapy in High Risk Stage II Colon Cancer

* Benefit of adjuvant chemotherapy after curative surgery for stage II Colon Cancer is still debated. Several high-risk features may help to stratify stage II cancer patients into groups that will truly benefit from adjuvant chemotherapy. However, those factors are rather subjective, and no specific trial has been designed to answer the high-risk stage II colon cancer question directly. * Immunoscore® Colon, an in vitro diagnostic test, which quantifies the density of CD3+ and CD8+ T lymphocyte populations in the center the tumor (CT) and its invasive margin (IM) using immunohistochemistry and automated image analysis. Immunoscore® has been extensively validated as a prognostic biomarker in early stage CC patients. This unique diagnostic assay measuring host immune response at the tumor site may inform the decision to administer adjuvant chemotherapy in resected Stage II and III CC patients. * This randomized trial is studying how observation compares to adjuvant chemotherapy (investigator's choice) in stage II colon cancer patients with high-risk features and High-Immunoscore®. The trial would represent a unique opportunity to classify stage II CC patients based on their tumor microenvironment with the aim to provide efficient patient stratification to improve clinical care.