Addition of Antibiotics to Upfront Treatment Regimen for Colorectal Cancer

Inclusion Criteria: * Diagnosis of stage IV colorectal cancer * Measurable disease by Response evaluation criteria in solid tumors (RECIST) 1.1 criteria * Planned first-line treatment with a 5FU-based doublet chemotherapy regimen for colon cancer, specifics of the regimen at the discretion of the treating physician Note: Patients who have received adjuvant therapy \>6 months prior are eligible * Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0-2 * Absolute neutrophil count (ANC) ≥1,500 cells/μL * Platelet count ≥100,000 cells/μL * Hemoglobin ≥8 g/dL Note: The use of transfusion or other intervention to achieve hemoglobin ≥8 g/dL is acceptable. * Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤2.5 × upper limit of normal (ULN) Note: Patients with documented liver metastases: AST and ALT ≤5 × ULN * Serum creatinine ≤1.5 x ULN or calculated creatinine clearance ≥40 mL/min using the Cockcroft-Gault equation: (140 - age) × body weight/plasma creatinine × 72 (× 0.85 if female) * Radiographically measurable disease by RECIST 1.1 * Nonpregnant and not actively breastfeeding * Sexually active patients of childbearing potential and their partners must agree to use medically acceptable form of contraception, per treating investigator, throughout the study Patients should continue to use medically acceptable methods of contraception after study treatment ends, following the guidance for their specific chemotherapy regimen. Childbearing potential …