Supplement of Vitamin D for early-stage Chronic Lymphocytic Leukemia Patients is Associated with a Longer Time to first Treatment.

Low levels of vitamin D are associated with a shorter time to first treatment (TTFT) and inferior overall survival in patients with Chronic Lymphocytic leukemia. But whether vitamin D supplement affects the clinical course of CLL patients, remains an open question. In the current study, we aimed to retrospectively explore the clinical benefit of Vitamin D supplement, or one of its analogues, on TTFT and treatment-free survival (TFS) in a large cohort of patients with asymptomatic CLL, who were under watch and wait approach. Among the 3,474 patients included in the study, 931 patients (26.8%) received either vitamin D supplement or its analogue, for a minimum of 6 months. We found that vitamin D supplement was statistically significant for longer TTFT in the young cohort (age<=65) and was associated with a longer TFS for all ages (p-value=0.004). Among non-vitamin D users, the median TFS was found to be 84 months, while among vitamin D supplement users the median TFS extended to 169 months. In conclusion, our long-term retrospective study demonstrates that the administration of vitamin D to patients with CLL in a watch and wait active surveillance is significantly associated with a longer treatment free survival (in any age) and a longer time to first treatment among young patients (age<=65). A prospective clinical trial is needed to validate results.