Colon Adjuvant Chemotherapy Based on Evaluation of Residual Disease

- Absolute neutrophil count (ANC) must be greater than or equal to 1500/mm3;

- Platelet count must be greater than or equal to 100,000/mm3; and

- Hemoglobin must be greater than or equal to 9 g/dL. Adequate hepatic function within 28 days before study entry defined as follows:

- total bilirubin must be less than or equal to ULN (upper limit of normal) for the lab and

- alkaline phosphatase must be less than 2.5 x ULN for the lab; and

- AST and ALT must be less than 2.5 x ULN for the lab. Adequate renal function within 28 days before study entry defined as serum creatinine less than or equal to 1.5 x ULN for the lab or measured or calculated creatinine clearance greater than or equal to 50 mL/min using the Cockroft-Gault formula for patients with creatinine levels greater than 1.5 x ULN for the lab. For Women Creatinine Clearance (mL/min) = (140 - age) x weight (kg) x 0.85 72 x serum creatinine (mg/dL) For Men Creatinine Clearance (mL/min) = (140 - age) x weight (kg) 72 x serum creatinine (mg/dL) HIV-infected patients on effective anti-retroviral therapy with undetectable viral load within 6 months are eligible for this trial. Pregnancy test (urine or serum according to institutional standard) done within 14 days before study entry must be negative (for women of childbearing potential only). Patients receiving a coumarin-derivative anticoagulant must agree to weekly monitoring of INR if they are randomized to Arm 1 or Arm 3 and receive capecitabine. Eligibility Criteria for Cohort A Arm-2 patients on Second Randomization Patient must have developed a ctDNA +ve assay during serial monitoring. Patient's willingness to be re-randomized affirmed. The patient must continue to have an ECOG performance status of 0 or 1. No radiographic evidence of overt metastatic disease. Pregnancy test (urine or serum according to institutional standard) done within 14 days before study entry must be negative (for women of childbearing potential only). Adequate hematologic function within 28 days before randomization defined as follows:

- Absolute neutrophil count (ANC) must be greater than or equal to 1500/mm3;

- Platelet count must be greater than or equal to 100,000/mm3; and

- Hemoglobin must be greater than or equal to 9 g/dL. Adequate hepatic function within 28 days before randomization defined as follows:

- total bilirubin must be less than or equal to ULN (upper limit of normal) for the lab and

- alkaline phosphatase must be less than 2.5 x ULN for the lab; and

- AST and ALT must be less than 2.5 x ULN for the lab. Adequate renal function within 28 days before randomization defined as serum creatinine less than or equal to 1.5 x ULN for the lab or measured or calculated creatinine clearance greater than or equal to 50 mL/min using the Cockroft-Gault formula for patients with creatinine levels greater than 1.5 x ULN for the lab. For Women Creatinine Clearance (mL/min) = (140 - age) x weight (kg) x 0.85 72 x serum creatinine (mg/dL) For Men Creatinine Clearance (mL/min) = (140 - age) x weight (kg) 72 x serum creatinine (mg/dL)