Vitamin D insufficiency
most severe in people with advanced cancer
More than three-quarters of cancer patients
have insufficient levels of vitamin D (25-hydroxy-vitamin D) and
the lowest levels are associated with more advanced cancer, according
to a study presented on October 2, 2011, at the 53rd Annual Meeting
of the American Society for Radiation Oncology (ASTRO).
"Until recently, studies have not investigated whether vitamin
D has an impact on the prognosis or course of cancer. Researchers
are just starting to examine how vitamin D may impact specific features
of cancer, such as the stage or extent of tumor spread, prognosis,
recurrence or relapse of disease, and even sub-types of cancer,"
Thomas Churilla, lead author of the study and a medical student
at the Commonwealth Medical College, Scranton, Pa., said.
Researchers sought to determine the vitamin D levels of patients
at Northeast Radiation Oncology Center in Dunmore, Pa., a community
oncology practice, and to see if vitamin D levels were related to
any specific aspects of cancer. The study involved 160 patients
with a median age of 64 years and a 1:1 ratio of men to women. The
five most common primary diagnoses were breast, prostate, lung,
thyroid and colorectal cancer. A total of 77 percent of patients
had vitamin D concentrations either deficient (less than 20 ng/mL)
or sub-optimal (20-30 ng/mL). The median serum vitamin D level was
23.5 ng/mL. Regardless of the age or sex of the patient, levels
of vitamin D were below the median predicted for advanced stage
disease in the patient group.
Patients who were found to be vitamin D deficient were administered
replacement therapy, increasing serum D levels by an average of
14.9 ng/mL. Investigators will be analyzing if vitamin D supplementation
had an impact on aspects of treatment or survival in the long-term.
"The benefits of vitamin D outside of improving bone health
are controversial, yet there are various levels of evidence to support
that vitamin D has a role in either the prevention or the prediction
of outcome of cancer," Churilla said. "Further study is
needed to continue to understand the relationship between vitamin
D and cancer."
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