Can vitamin D supplements prevent relapse in non-small-cell lung cancer?

This study looked at the effect of vitamin D supplements at preventing relapse in non-small-cell lung cancer (NSCLC). The authors concluded that vitamin D supplements might have the potential for improving survival in patients with early-stage lung adenocarcinoma. 
 

Current therapy for early-stage NSCLC involves surgery followed by chemotherapy. Relapse rates are high, however. There is evidence that good vitamin D levels are associated with better survival in patients with early-stage NSCLC. While vitamin D is obtained naturally in the body from sunlight and diet, it can also be obtained by supplements. It is unclear if vitamin D supplements can improve outcomes for these patients.

The trial included 144 patients with NSCLC. They were randomly assigned to be treated with vitamin D supplements (72 patients) or placebo (a substance with no effect on the body; 72 patients). The average follow-up period was 3.3 years. The authors examined relapse-free survival (RFS, time from beginning trial to relapse or death) and overall survival (OS, time from beginning trial until death). 

Overall, there was no difference in 5-year RFS and OS between both groups. 

However, patients with early-stage adenocarcinoma had a 77% better RFS and an 87% better OS when treated with vitamin D supplements compared to patients in the placebo group. 

The authors concluded that vitamin D supplements may improve survival of patients with early-stage adenocarcinoma with low vitamin D levels. 

The number of patients in the trial was very low. Most of these patients were early stage and there is therefore very little information regarding late stage NSCLC.