Colon Adjuvant Chemotherapy Based on Evaluation of Residual Disease

Inclusion Criteria: The patient must have an ECOG performance status of 0 or 1. Patients must have histologically/pathologically confirmed Stage IIB, IIC, or Stage III colon adenocarcinoma with R0 resection according to AJCC 8th edition criteria. No radiographic evidence of overt metastatic disease within 45 days prior to Step 1/Study entry (CT with IV contrast or MRI imaging is acceptable and must include chest, abdomen, and pelvis). The distal extent of the tumor must be greater than or equal to 12 cm from the anal verge on colonoscopy or above the peritoneal reflection as documented during surgery or on pathology specimen (i.e., excluding rectal adenocarcinomas warranting treatment with chemoradiation). The patient must have had an en bloc complete gross resection of tumor (curative resection). Patients who have had a two-stage surgical procedure, to first provide a decompressive colostomy and then in a later procedure to have the definitive surgical resection, are eligible. The resected tumor specimen and a blood specimen from patients with Stage IIB, IIC, or Stage III colon cancer must have central testing for ctDNA using the Signatera™ assay by Natera (after Step 1/Study entry and before Step2/Randomization). Patient must have sufficient tissue to meet protocol requirements. This blood specimen for the Signatera assay must be collected after surgery (and recommended at least 14 days post surgery). Tumor must be documented as microsatellite stable or have intact m…