Due to its higher concentration in the blood and longer half-life calcidiol, the intermediate metabolite of vitamin D, is used as the main marker for determining vitamin D levels in the body. The relationship between serum calcidiol levels and cancer was first demonstrated in colorectal cancer (CRC), and subsequent studies have shown a link between low calcidiol levels and a higher risk and poor prognosis not only for CRC but also for breast, prostate, lung, bladder, gastric, and hematological cancers. However, clinical studies related to CRC have not provided strong evidence that vitamin D supplementation reduces cancer risk or positively impacts disease progression or prognosis. This study suggests that administration of calcitriol, the active form of vitamin D, may be more advantageous than vitamin D supplementation in CRC. It also points to the limitations of calcitriol in pharmaceutical applications. Therefore, appropriately designed and innovative carrier platforms could enhance the utilization of calcitriol for both vitamin D deficiency/insufficiency and its anti-cancer effects.
Sinem Tunçer (Sat,) studied this question.