From the Guidelines
Clinicians should not use vitamin D to prevent colorectal neoplasia, including recurrence, as the current evidence does not support its effectiveness. The most recent and highest quality study, a 2021 clinical practice update on chemoprevention for colorectal neoplasia, recommends against the use of vitamin D for this purpose 1. This recommendation is based on the lack of strong evidence supporting the use of vitamin D in preventing colorectal cancer recurrence.
While some observational studies suggest that higher vitamin D levels may be associated with better survival outcomes and lower recurrence rates in colorectal cancer patients, the evidence is not conclusive 1. A 2011 meta-analysis found a modest decrease in CRC risk comparing individuals with highest to lowest vitamin D intakes, but this finding is not sufficient to support the use of vitamin D supplementation for preventing colorectal cancer recurrence 1.
The Women’s Health Initiative randomized placebo-controlled trial, which investigated the combination of calcium and vitamin D on CRC incidence, found no effect on CRC incidence 1. Additionally, the Institute of Medicine has concluded that the data supporting a role for vitamin D in cancer prevention are not conclusive 1.
Therefore, the use of vitamin D supplementation for preventing colorectal cancer recurrence is not recommended, and patients should discuss their individual needs and risks with their oncologist as part of their overall cancer survivorship plan. Key considerations include:
- The lack of strong evidence supporting the use of vitamin D for preventing colorectal cancer recurrence
- The potential risks of high-dose vitamin D supplementation, such as hypercalcemia
- The need for individualized assessment and management of vitamin D levels and supplementation needs.
From the Research
Effect of Vitamin D on Colorectal Cancer Recurrence
- The relationship between vitamin D and colorectal cancer (CRC) recurrence has been investigated in several studies 2, 3, 4, 5, 6.
- A meta-analysis of 21 eligible studies found that vitamin D use was inversely associated with the incidence of CRC [OR = 0.87, (0.82-0.92)] and potentially improved the long-term survival of CRC patients [HR = 0.91, (0.83-0.98)] 4.
- Another meta-analysis of randomised controlled trials found a 30% reduction in adverse CRC outcomes with vitamin D supplementation (n = 815, HR = 0.70; 95% CI: 0.48-0.93) 5.
- Epidemiological evidence suggests that higher circulating 25(OH)D concentrations are associated with lower CRC risk and improved survival outcomes 3, 6.
- Some studies have found that vitamin D supplementation may have a beneficial effect on CRC survival outcomes, particularly in patients with CRC at outset 5.
- However, further well-designed, adequately powered RCTs are needed to fully evaluate the benefit of supplementation in augmenting 'real-life' follow-up and adjuvant chemotherapy regimens, as well as determining optimal dosing 5.
Vitamin D and CRC Survival
- A systematic review and meta-analysis found that vitamin D supplementation was associated with improved overall survival (OS) in CRC patients [HR = 0.91, (0.83-0.98)] 4.
- Another study found that higher postdiagnosis circulating 25(OH)D levels were associated with improved overall and CRC-specific survival in patients with CRC of all stages 6.
- Meta-analyses of observational studies have confirmed significant protective associations against overall and CRC-specific mortality, as well as significant dose-response relationships 6.
Ongoing Research
- Several ongoing trials are investigating the role of vitamin D and physical activity as adjunct treatments after a CRC diagnosis, including the phase II trial comparing high-dose vitamin D3 versus standard dose and the phase I-II trial comparing customized oral doses of vitamin D3 titrated to raise serum 25(OH)D levels to 80 to 100 ng/mL versus 2000 IU/d 6.
- The results of these trials will provide more definitive answers about the role of vitamin D in the treatment of CRC and pave the way for more conclusive phase III trials 6.