Vitamin D is associated with improved survival outcomes of patients with advanced colorectal cancer

This study investigated the association between vitamin D blood levels and survival outcomes in patients with metastatic colorectal cancer (mCRC). Researchers suggested that higher levels of vitamin D in the blood were associated with better survival.

CRC is the third most common cancer in the US. Among CRC patients, only 39% are diagnosed in early stages with a survival rate of 90%. The survival rate for mCRC (spread to other parts of the body) decreases to 14%. 

Vitamin D is a nutrient found in some foods. It also increases during sun exposure. It is needed for good health and to maintain strong bones. Prior studies showed that this vitamin has anti-cancer effects and that CRC patients tend to have lower levels of it. It has been suggested that higher vitamin D levels are associated with improved survival in CRC patients. However, the role of vitamin D on the survival of patients with mCRC remains unknown.

This study included information about 1041 patients with mCRC. Overall survival (OS; time from treatment and death by any cause) and progression-free survival (PFS; time from treatment to cancer progression) were measured. A vitamin D sample in the blood was taken at study entry. 

At the start of the study, 63% of patients had a very low level (less than 20 ng/mL) of vitamin D. Another 31% of patients had insufficient vitamin D levels (between 20 and 30 ng/ml). Higher vitamin D levels were associated with an improved OS and PFS. Patients with 24ng/mL or more had a 34% improvement in the odds of a better OS and 19% of a better PFS.

This study concluded that higher blood levels of vitamin D were associated with improved OS and PFS in patients with mCRC.

This study only measured the levels of vitamin D once. The effect of changes in levels (vitamin D supplementation) on survival was not studied. Further studies are necessary.