DPYD Pharmacogenomics and Fluoropyrimidine (FP) Dose-Adjustment

Who May Qualify: - Diagnosis of cancer in either the adjuvant or metastatic setting requiring initial therapy with 5-FU or Capecitabine. - DPYD testing performed by a CLIA-certified laboratory (i.e., Guardant 360 or Caris blood testing for genomic profiling, DPYD testing by the Mayo Clinic or other certified laboratory) with results available before starting chemotherapy. - DPYD testing results falling into one of the following cohorts for first-line therapy with a fluoropyridine: - Study Cohort: Patients with one DPYD variant in one gene (heterozygotes). - Control Arm: Patients with normal or wild-type DPYD genes, for comparison, will be treated at the usual 100% dose. --FOLFOX regimen (N=50) - You should be able to carry out daily activities with 0 level of ability (ECOG 0)-2. - Measurable disease or non-measurable disease allowed, including adjuvant 5-FU-based regimens. Who Should NOT Join This Trial: - Patients for whom 5-FU or Capecitabine therapy is contraindicated or not deemed appropriate in the judgment of the treating physician. - Patients with two DPYD variants (homozygous deletions or non-functional genetic variants, or double heterozygotes with two different abnormalities) should not receive 5-FU or Capecitabine and are therefore excluded from the study. - Pregnant Women and Children Always talk to your doctor about whether this trial is right for you.