A Study to Evaluate the Effect of Vitamin D on PFS in Indolent Non-Hodgkin’s Lymphoma

Inclusion Criteria:

Each of the following criteria must be met in order for a patient to be considered eligible for registration:

Biopsy proven (with hematopathology review at one of the participating sites to confirm correct histology in accordance with World Health Organization) indolent lymphoma to include the following diagnoses:

Grade 1, 2, or 3a follicular lymphoma
Small lymphocytic lymphoma (CLL excluded)
Marginal zone lymphoma (nodal or splenic)
Mucosal-associated lymphoid tissue
Measurable disease defined by Lugano criteria
No prior anti-lymphoma systemic therapy; prior radiation therapy allowed
Age 18 or over
Ann Arbor stages II, III or IV

Patients with follicular lymphoma must have PET FDG-avid lymphoma and fulfill Low tumor burden by Groupe D'Etude des Lymphomes Folliculaires (GELF) criteria:

No mass > 7 cm
< 3 distinct masses of greater than 3 cm
No B symptoms
No splenomegaly > 16 cm by computed tomography (CT) scan
No risk of vital organ compression
No leukemic phase > 5000/µl circulating lymphocytes (except for in patients with splenic marginal zone diagnosis)
No cytopenias (platelets < 100,000/µl, hemoglobin < 10 g/dl, or absolute neutrophil count < 1500/µl)

Exclusion Criteria:

The following criteria will prevent inclusion of an inappropriate subject into the trial:

Osteoporosis requiring prescription treatment
Known symptomatic primary hyperparathyroidism
Hypercalcemia defined as above the institutional normal range (corrected for albumin when albumin levels are below normal)
History of calcium-related kidney stones
Creatinine > 1.5X above upper limit of normal
Women who are known to be pregnant or who plan to become pregnant while on rituximab treatment