- In digestive tract cancer, vitamin D3 supplementation offers no risk reduction for relapse or death from any cause.
- Post hoc age-adjusted analysis did show benefit for relapse-free survival, but not OS.
Why this matters
- 2 randomized trials involving vitamin D3 have yielded conflicting results, with 1 showing no protective benefit against colorectal cancer from 400 IU/day of vitamin D3 and another showing benefit with 1100 IU/day.
- This trial involved 2000 IU/day for secondary prevention.
- 5-year relapse-free survival: 77% with supplementation vs 69% with placebo.
- HR for relapse or death: 0.76 (P=.18).
- OS: 82% vs 81%.
- HR for death: 0.95 (P=.83).
- Among those with vitamin D, 20-40 ng/mL:
- HR for relapse or death with supplementation vs placebo: 0.46 (P=.02; P=.04 for interaction).
- Fracture rates: 1.3% with supplementation vs 3.4% without.
- Urinary stones: 0.9% with supplementation vs 0% without.
- Randomized, double-blind, placebo-controlled trial of 251 patients with gastric cancer taking vitamin D3 supplement (2000 IU/day) vs 166 in placebo group.
- Primary outcome: relapse-free survival to relapse or death.
- Funding: Ministry of Education, Culture, Sports, Science, and Technology, Japan; others.
- A mix of cancers included.