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 eligible
  * Age ≥ 18 years
  * ECOG performance status ≤ 2
  * Absolute neutrophil count (ANC) ≥ 1,000/mm\^3
  * Platelet count ≥ 100,000/mm\^3
  * Total bilirubin ≤ 3 x upper limit of normal (ULN)
  * AST (SGOT)/ALT (SGPT) ≤ 5 x upper limit of normal (ULN)
  * Calc. creatinine clearance ≥ 30 mL/min
  * Not pregnant and not nursing, because this study involves agents that have known genotoxic, mutagenic and teratogenic effects. Therefore, for women of childbearing potential only, a negative pregnancy test done ≤ 30 days prior to registration is required
  * Patients with treated brain metastases are eligible if follow-up brain imaging after CNS-directed therapy shows no evidence of progression
  * Patients with known HIV infection are eligible if receiving effective anti-retroviral therapy with undetectable viral load within 6 months prior to registration
  * Patients with known chronic hepatitis B virus (HBV) infection are eligible if HBV DNA is undetectable when measured within 6 months prior to registration
  * Patients with a known history of hepatitis C virus (HCV) infection are eligible if HCV RNA is undetectable when measured at least 12 weeks after completion of antiviral therapy
  * Patients with known history or current symptoms of cardiac disease are eligible if the New York Heart Association Functional Classification is class I or II
  * Patients with a known history of congenital long QT syndrome are ineligible
  * Patients with known DPD deficiency are ineligible
* \* NON-PATIENT (ONCOLOGY PHYSICIAN OR ONCOLOGY ADVANCED PRACTICE PROVIDER ELIGIBILITY:

  * The non-patient provider participant is a medical oncologist or oncology advanced practice provider with responsibility for signing and making necessary modifications to chemotherapy orders for a subject assigned to the intervention arm (Arm B). Non-patient participants may not be enrolled more than once over the course of the study
  * The non-patient participant must be proficient in the English language
  * The non-patient participant must be age 21 years or older