Inclusion Criteria:  .-Age ≥ 18 years at the time of study entry  ECOG 0-1 Histologically documented high-risk stage II, stage III, or stage IV colorectal adenocarcinoma with no evidence of disease following definitive local therapy (including surgical resection or ablation) No radiographic evidence of disease by contrast enhanced CT chest/abdomen/pelvis Presence of detectable ctDNA mutation that matches mutations found in tumor tissue Completion of all standard of care adjuvant therapy Platelet count >50,000 Ability to give informed consent Ability to complete all questionnaires involved in study  Exclusion Criteria:  Concurrent malignancy under active treatment Known active gastrointestinal bleeding or peptic ulcer disease Known hypersensitivity to vitamin D or aspirin CrCl<30 mL/min within 30 days of starting the intervention Current usage of therapeutic anticoagulation (warfarin, Eliquis, Xarelto) Inability to safely participate in physical activity in the opinion of the treating oncologist Pregnant or nursing women Persistent hypercalcemia or conditions predisposing to hypercalcemia (i.e., hyperparathyroidism) Known symptomatic genitourinary stones