Vitamin D3 2000 IU/day for Neurotoxicity

Many patients with cancer that are treated with a drug called oxaliplatin. This drug is used with other drugs to treat cancer. The drug can cause problems with the nerves in the hands and feet called peripheral neuropathy (a side effect of the drug). Peripheral neuropathy may make the hands and feet feel like they are tingling, have a burning feeling, and can cause pain. Almost all patients who receive oxaliplatin as part of their cancer treatment have peripheral neuropathy. Patients who do have this side effect usually have to take a lower dose of or stop taking the oxaliplatin even if the drug is helping their cancer. So far there is not a lot of information about how to make this side effect better or help it go away completely. There is some information that low levels of Vitamin D in the blood might be linked to problems or diseases of the nervous system like multiple sclerosis or Parkinson's Disease. It is even thought that Vitamin D may help protect the cells in the nervous system. Because of this information, researchers want to see if giving patients Vitamin D while they are receiving the drug oxaliplatin to see if it helps prevent the side effect peripheral neuropathy. Patients taking oxaliplatin who want to be in this study will take one Vitamin D capsule each day while they take oxaliplatin. Being in this study will not affect how the patient's cancer is treated. There are blood tests in the study to check Vitamin D levels and for a protein called nerve growth factor (NGF). The study team will carefully monitor the patients for any signs of oxaliplatin-related neurologic toxicity during the study.