High-Dose Cholecalciferol in Treating Patients Receiving Combination Chemotherapy and Bevacizumab as First-Line Therapy For Metastatic Colorectal Cancer

This phase II trial is studying how well giving high-dose cholecalciferol works in treating patients receiving combination chemotherapy and bevacizumab as first-line therapy for metastatic colorectal cancer. Cholecalciferol during treatment may delay the development of colorectal cancer. Drugs used in chemotherapy, such as leucovorin calcium, fluorouracil, and oxaliplatin, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Monoclonal antibodies, such as bevacizumab, can block tumor growth in different ways. Some block the ability of tumor cells to grow and spread. Others find tumor cells and help kill them or carry tumor-killing substances to them. Bevacizumab may also stop the growth of tumor cells by blocking blood flow to the tumor. Giving cholecalciferol together with combination chemotherapy and monoclonal antibody therapy may be an effective treatment for colorectal cancer