Studying the PAGODA Algorithm for Chemotherapy Dose Changes to Prevent Unplanned Treatment Delays

Inclusion Criteria: * \* REGISTRATION ELIGIBILITY CRITERIA (STEP 1) * Histologic confirmation of invasive cancer that is confirmed or suspected to arise from the gastrointestinal (GI) tract * Any stage for which FOLFOX-based chemotherapy is a clinically-indicated, standard-of-care treatment (adjuvant, neoadjuvant, or first-line chemotherapy) * Eligible primary tumor sites include the esophagus, gastroesophageal junction, stomach, small intestine, ampulla of Vater, appendix, colon, rectum, and cancers of unknown primary with suspected GI origin * Prior systemic therapy for GI cancer (other than cycle 1 of FOLFOX-based chemotherapy) is not allowed. Prior radiation-sensitizing chemotherapy is permitted * The planned duration of FOLFOX-based chemotherapy must be at least four cycles (1 cycle = 14 days) * Cycle 1, day 1 of FOLFOX-based chemotherapy must be completed 1 to 8 days prior to registration * Cycle 1, day 1 of FOLFOX-based chemotherapy must include minimum ordered doses of oxaliplatin (≥ 65 mg/m\^2) and infusional 5-FU (2400 mg/m\^2/46 hours). Use of the 5-FU bolus is at the discretion of the treating physician * Patients who require primary prophylactic white blood cell growth factor with cycle 1 of FOLFOX chemotherapy due to high risk for fever and neutropenia are not eligible * History of hypersensitivity reaction to oxaliplatin or other platinum-based drugs, to fluorouracil, or to leucovorin, and the excipients in their formulations are not eligibl…