Cholecalciferol in Improving Survival in Patients With Newly Diagnosed Cancer With Vitamin D Insufficiency

Inclusion Criteria: * Newly diagnosed aggressive lymphoma or CLL/small lymphocytic lymphoma (SLL) that meets disease specific criteria below: * Study 1 - Aggressive lymphoma * Newly diagnosed de-novo DLBCL or primary mediastinal B-cell lymphoma that will be treated with an anthracycline-containing regimen (rituximab-cyclophosphamide, doxorubicin hydrochloride, prednisone \[R-CHOP\] or equivalent); patients with composite lymphomas can also be enrolled as long as they have large cell component and will be treated with an anthracycline; in addition, patients with "B cell lymphoma, unclassifiable, with features intermediate between diffuse large B cell lymphoma and Burkitt lymphoma" or post-transplant DLBCL are also eligible as long as they meet other criteria; patients with typical Burkitt lymphoma are not eligible * NOTE: patients can be enrolled up through day 1 of cycle 3 of therapy; the patient is permitted to participate in any other therapeutic therapy for their disease as long as it does not concern vitamin D; patients can begin their chemotherapy while awaiting vitamin D results and treatment arm assignment or * Newly diagnosed untreated peripheral T-cell non-Hodgkin lymphoma (NHL) that will be treated with chemotherapy; NOTE: patients can be enrolled up through day 1 of cycle 3 of therapy; this includes the following disease types: * Peripheral T cell lymphoma, unspecified * Anaplastic large cell lymphoma (T and null cell type) * Extranodal NK/T…