Patients with low serum vitamin D levels prior to initial treatment for follicular lymphoma (FL) have poorer outcomes than those with higher vitamin D levels, a study of two independent cohorts showed..
“We are the first to our knowledge to report a strong association between low vitamin D levels, an easily measured and modifiable lifestyle factor, and FL outcomes in two independent cohorts,” wrote Jennifer L. Kelly, Ph.D., of the Wilmot Cancer Center at the University of Rochester (N.Y.) and her colleagues.
“Together with the accumulating evidence to support the relevance of vitamin D in other lymphoma subtypes, these findings warrant further investigation,” they wrote (J. Clin. Oncol. 2015 Mar. 30 [doi:10.1200/JCO.2014.57.5092]).
The SWOG clinical trial evaluated treatment with CHOP plus an anti-CD20 antibody, and the LYSA trial assessed CHOP plus rituximab in previously untreated patients with follicular lymphoma. Serum vitamin D levels were measured prior to treatment in 183 patients from SWOG and 240 from LYSA.
After a median 5.4 years, 81 patients (44%) in the SWOG cohort had disease progression, and those deficient in vitamin D had significantly inferior progression-free survival (adjusted hazard ratio, 1.97; P = .023) and overall survival (adjusted HR, 4.16; P = .002). After a median follow up of 6.6 years in the LYSA cohort, 112 patients (47%) had disease progression, and vitamin D–deficient patients had inferior progression-free and overall survival, although these findings were not significant (adjusted HR, 1.50; P = .095; and adjusted HR, 1.92; P = .192, respectively).
The two international populations had different serum vitamin D level distributions, which precludes identifying an optimal vitamin D level regarding follicular lymphoma prognosis. For the SWOG cohort, at the threshold of 25-hydroxvitamin D level less than 20 ng/mL, 15% of patients were deficient. For the LYSA cohort, at 25(OH)D < 10 ng/mL, 25% of patients were deficient. The threshold may differ between geographic regions and ethnic groups.
The study was limited by the small number of patients eligible for inclusion, and given the prolonged natural history of FL, there were relatively few events within the follow-up period. The strength of the findings lies in the similarity of observations between the two independent cohorts, which were beginning the common initial follicular lymphoma treatment of CHOP chemotherapy plus an antibody, the investigators said.
“In Europe and the United States, the most common presentation of FL is low tumor burden, where a period of observation without active treatment is often considered. On the basis of our results, a study of vitamin D supplementation for patients with insufficiency could be considered. At present, this should only be done in the context of a clinical trial,” Dr. Kelly and her associates wrote.
Dr. Kelly reported having no disclosures. Many of her coauthors reported ties to several industry sources.
