A recent study, presented during the 2015 American Society of Cancer Oncology (ASCO) Gastrointestinal Cancers Symposium, San Francisco, has shown that metastatic colorectal cancer (mCRC) patients who had high levels of vitamin D before initiating treatment survived longer than those with lower levels of this vitamin.
This Dana-Farber Cancer Institute-conducted study analyzed data from over 1,000 mCRC patients who participated in a Phase 3 clinical trial assessing chemotherapy combined with biological therapies for the treatment of this malignancy.
“This is the largest study that has been undertaken of metastatic colorectal cancer patients and vitamin D,” study lead author, Kimmie Ng, MD, MPH, a medical oncologist at Dana-Farber, said in a news release. “It’s further supportive of the potential benefits of maintaining sufficient levels of vitamin D in improving patient survival times.”
During the study, the team measured the levels of 25-hydroxyvitamin D, a substance that is produced by the liver as a consequence of vitamin D intake, which varied between 8 ng/mL (lowest group) to 27.5 ng/mL (highest group). Median vitamin D level among patients was of 17.2 ng/mL, which is considered a low value, since according to guidelines from the Endocrine Society, vitamin D deficiency occurs when a patient has less that 20 ng/mL in their blood.
The results demonstrated that patients who had high levels of vitamin D survived a median of 32.6 months more when compared to 24.5 months for patients with low vitamin D levels. Furthermore, increased vitamin D levels were also associated with a longer time to disease progression.
Because researchers did not verify if there was a biological cause-and-effect connection between high vitamin D levels and prolonged survival, it is still early to advise vitamin D intake as an adjuvant therapy for colon cancer. However, the research team is currently conducting studies to understand this relation.
High levels of vitamin D can be a consequence of a balanced and healthy lifestyle due to adequate nutrition and physical activity. As such, the team assessed for lifestyle variables including diet, obesity, and physical exercise intensity. The researchers noted that, even after accounting for all these variables, the link between high vitamin D levels and increased survival were still maintained.