March is National Colorectal Cancer Awareness Month. Of the cancers that can affect both men and women, colorectal cancer is the second leading cause of cancer, responsible for more than 50,000 deaths each year in the United States.
Individuals can reduce their risk of developing colorectal cancer by taking preventative action:
- Get screened. People between the ages of 50 and 75 should get screened for colorectal cancer on a regular basis. Screening helps prevent colorectal cancer by detecting precancerous abnormal growths to be removed. The earlier cancer is detected, the more effective treatment will be.
- Be physically active.
- Maintain a healthy weight.
- Do not drink excessive amounts of alcohol.
- Do not smoke.
In addition, research shows maintaining a healthy vitamin D status is related to a reduced risk for colorectal cancer and increased survival rates for those already affected by colorectal cancer.
A recent study was conducted in order to confirm or reject the findings from various studies that show high vitamin D status is associated with survival outcomes in colorectal patients.
The researchers measured the vitamin D status of 143 colorectal cancer patients with 215 liver metastases. Colorectal liver metastases, or secondary liver cancer, occurs when a malignant growth develops in the liver after originating in the colon or rectum. All patients underwent radiofrequency ablation. Radiofrequency ablation is a medical procedure in which the tumor is removed using heat generated from an alternating current. The patients’ median age was 68 years.
The researchers wanted to assess the influence of vitamin D levels on overall survival and time to recurrence. Here is what they found:
- Survival rate was 91.4%, 46.5% and 42.2% at 1, 4 and 5 years, respectively.
- Median survival was 65 months if vitamin D levels were above 20 ng/ml compared to 34 months if vitamin D levels were 20 ng/ml or below (p < 0.001).
- Median time to recurrence was 50 months for patients with vitamin D levels above 20 ng/ml and 24 months for vitamin D levels of 20 ng/ml or below (p < 0.001).
- Nodule size and vitamin D levels acted as significant predictors of both overall survival and time to recurrence after adjusting for confounding variables.
The researchers concluded,
“Our study provides support for the use of 25-hydroxyvitamin D as a new predictor of outcome for colorectal liver metastases patients.”
This study indicates that vitamin D status is associated with overall survival of patients with colorectal cancer. However, the study design was incapable of proving causation, meaning the study was unable to show whether vitamin D supplementation increases survival in colorectal liver metastases patients. Thus, clinical trials assessing the efficacy of vitamin D supplementation on colorectal cancer outcomes are warranted.
While such studies are clearly warranted, how are they going to get past an ethics committee? To conduct a meaningful RCT, a deficient placebo group would have to be identified and not treated for their vitamin D deficiency. Would that be ethical, given the above results?
Tovey, A. & Cannell, JJ. Colorectal Cancer Awareness Month: Recent research finds high vitamin D status linked to longer survival among colorectal liver metastases patients. The Vitamin D Council Blog & Newsletter, March, 2016.
Facciorusso, A. et al. Prognostic role of 25-hydroxyvitamin d in patients with liver metastases from colorectal cancer treated with radiofrequency ablation. Journal of Gastroenterology and Hepatology, 2016.