Vitamin D Supplementation and Survival in Metastatic Colorectal Cancer

ABSTRACT

Background: Some studies have demonstrated that higher baseline plasma levels of 25-hydroxivitamin D [25(OH)D] are associated with a significant reduction in colorectal cancer (CRC) incidence. Patients with metastatic CRC (mCRC) tend to be vitamin D insufficient, but the effect of vitamin D on the survival of mCRC patients still remains uncertain. In this study, we evaluated the association between cholecalciferol 2,000 IU daily supplementation and survival of mCRC patients. Methods: Seventy-two patients with mCRC were included. Seventy-one patients with 25(OH)D levels <75 nmol/l were randomized to receive standard chemotherapy or standard chemotherapy with cholecalciferol 2,000 IU daily. The primary endpoint was overall survival (OS) and the secondary endpoint was progression-free survival (PFS). The follow-up period was 46 mo. Results: All but one patient (98.6%) was vitamin D insufficient. There was no statistically significant difference in OS or PFS between those who received vitamin D supplements and controls. Conclusions: The majority of patients with mCRC are vitamin D insufficient at the time of diagnosis. In our study, adding 2,000 IU of cholecalciferol daily for 2 yr to standard chemotherapy did not show any benefit in OS or PFS.

Acknowledgments

The authors wish to thank Aleksandra Žmegač Horvat for language editing the manuscript.

Additional information

Funding

This study was conducted at the University Hospital Centre Zagreb as part of the project “The role of predictive and prognostic molecular markers in cancer treatment” (project number 108-1080058-0047), supported by the Ministry of Science and Education of the Republic of Croatia.