High levels of vitamin in blood double the likelihood of survival
In a previous study Cedric F. Garland, DrPH, professor in the Department of Family and Preventive Medicine and colleagues showed that low vitamin D levels were linked to a high risk of premenopausal breast cancer. This researchers promoted this new meta-analysis that examined whether serum 25-hydroxyvitamin D [25(OH)D] at diagnosis is associated with longer survival of patients with breast cancer.
Dr. Garland and colleagues performed a statistical analysis of five studies of 25-hydroxyvitamin D obtained at the time of patient diagnosis and their follow-up for an average of nine years. Combined, the studies included 4,443 breast cancer patients.
The results showed higher serum concentrations of 25(OH)D were associated with lower case-fatality rates after diagnosis of breast cancer.
The high serum group had an average level of 30 nanograms per milliliter (ng/ml) of 25-hydroxyvitamin D in their blood. The low group averaged 17 ng/ml. The average level in patients with breast cancer in the United States is 17 ng/ml.
Patients in the highest quintile of 25(OH)D had approximately half the death rate from breast cancer as those in the lowest.
In their conclusion the researchers write “High serum 25(OH)D was associated with lower mortality from breast cancer. Serum 25(OH)D in all patients with breast cancer should be restored to the normal range (30-80 ng/ml), with appropriate monitoring. Clinical or field studies should be initiated to confirm that this association was not due to reverse causation.”
According to Dr. Heather Hofflich, DO, FACE, UC San Diego associate professor in the Department of Medicine and co-author “"The study has implications for including vitamin D as an adjuvant to conventional breast cancer therapy.”
Dr. Garland comments “Vitamin D metabolites increase communication between cells by switching on a protein that blocks aggressive cell division.” “As long as vitamin D receptors are present tumor growth is prevented and kept from expanding its blood supply. Vitamin D receptors are not lost until a tumor is very advanced. This is the reason for better survival in patients whose vitamin D blood levels are high.”
Dr. Garland recommended randomized controlled clinical trials to confirm the findings but suggested physicians consider adding vitamin D into a breast cancer patient’s standard care now and then closely monitor the patient.
In closing he comments “There is no compelling reason to wait for further studies to incorporate vitamin D supplements into standard care regimens since a safe dose of vitamin D needed to achieve high serum levels above 30 nanograms per milliliter has already been established,”
A 2011 meta-analysis by Garland and colleagues estimated that a serum level of 50 ng/ml is associated with 50 percent lower risk of breast cancer. While there are some variations in absorption, those who consume 4,000 International Units (IU) per day of vitamin D from food or a supplement normally would reach a serum level of 50 ng/ml. Garland urged patients to ask their health care provider to measure their levels before substantially increasing vitamin D intake.
This new study appears in the March issue of Anticancer Research.