Telomere Length in Predicting Toxicity in Older Patients With Stage III-IV Colorectal Cancer Undergoing Chemotherapy

Inclusion Criteria: * Both men and women of all races and ethnic groups are eligible for this trial * Patients must have histologically or cytologically confirmed adenocarcinoma of the colon or rectum that is stage III or IV and has not been treated with systemic chemotherapy (biopsy of metastatic site not required if primary tumor biopsied and clinical scenario is consistent with metastatic disease) * Patients must be deemed eligible for systemic chemotherapy with FOLFOX6 +/- bevacizumab at full standard doses * For patient with metastatic disease, previous adjuvant chemotherapy is allowed as long it was completed at least 12 months prior to study enrollment and did not include oxaliplatin * Prior radiation therapy is allowed but must have been completed \>= 4 weeks prior to study entry * Eastern Cooperative Oncology Group (ECOG) performance status \< 2 * Leukocytes \>= 3,000/mcL * Absolute neutrophil count \>= 1,500/mcL * Platelets \>= 100,000/mcL * Total bilirubin within normal institutional limits * Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase \[SGOT\])/alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase \[SGPT\]) =\< 2.5 X institutional upper limit of normal * Creatinine within normal institutional limits, or creatinine clearance \>= 50 mL/min/1.73 m\^2 for patients with creatinine levels above institutional normal * Patients must demonstrate ability to understand and the willingness to sign a written informed consent docum…