High dose vitamin D supplementation may be associated with improved colorectal cancer outcomes

This study investigated if high-dose vitamin D combined with chemotherapy improves outcomes in patients with metastatic (spread to other parts of the body) colorectal cancer. Researchers suggested that high-dose vitamin D was associated with an improved chance of survival.

Vitamin D is associated with the intake of calcium and bone health. More recently, it has been associated with anti-tumor activity. Some studies even showed that vitamin D is associated with a decreased risk of colorectal cancer. It is also associated with improved survival among patients with the cancer. However, the role of this vitamin in patients with metastatic colorectal cancer is not clear.

This study included 139 patients with metastatic colorectal cancer. These patients received chemotherapy every 2 weeks and either standard or high-dose vitamin D daily until disease progression. Progression-free survival (PFS; time from treatment to disease progression), overall survival and tumor response were measured. They were followed-up for an average of 22.9 months.

The average PFS was 13 months for the high-dose vitamin D group and 11 months for the standard group. Patients with high-dose had a 36% improvement in the odds of a better PFS.

No significant difference was seen in tumor response or overall survival between both groups.

The average Vitamin D levels at the start of the treatment was 16.1 ng/mL for high dose group and 18.7ng/mL for standard group. By the end of the treatment the high dose group had 34.8 ng/mL while the standard group had 18.7ng/mL. The most common side effect was neutropenia (24; decreased blood white cells) and hypertension (9; increased blood pressure).

This study concluded that high-dose vitamin D may increase PFS in patients with advanced colorectal cancer.

This study had a limited number of participants. Further larger studies are needed for more solid evidence.