Can Serum Levels of Vitamin D at Diagnosis Predict Breast Cancer Prognosis?
Posted: Thursday, July 29, 2021
Song Yao, PhD, of Roswell Park Comprehensive Cancer Center, Buffalo, New York, and colleagues conducted a study to evaluate the relationship between serum levels of vitamin D and breast cancer outcomes. During the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 10510), these researchers reported their findings from a large observational cohort of breast cancer survivors, indicating sufficient vitamin D levels at the time of diagnosis may be associated with improved prognosis.
The levels of 25-hydroxyvitamin D at the time of breast cancer diagnosis were measured in serum samples collected from 3,995 women who were enrolled in the Pathways Study. Follow-up data were provided for a median of 9.6 years.
The strongest determinants of higher 25-hydroxyvitamin D levels seemed to be vitamin D supplement use, lower body mass index (BMI), and self-reported White race. The polygenic score was found to be significantly associated with the levels of 25-hydroxyvitamin D; however, it explained just 0.3% of the variance.
Even after the investigators controlled for various covariates, patients with sufficient levels of vitamin D had significantly better survival outcomes than those with deficient levels (overall survival: hazard ratio = 0.73; breast cancer–specific survival: hazard ratio = 0.78; recurrence-free survival: hazard ratio = 0.79; invasive disease–free survival: hazard ratio = 0.82). The investigators noted that associations seemed to be similar by estrogen receptor status; the strongest associations were found to be among patients with a more advanced stage of disease and those who had underweight or normal BMI. Black patients had the lowest levels of 25-hydroxyvitamin D, which may have contributed to their poorer survival compared with White patients. After 25-hydroxyvitamin D levels were added to the Cox model of overall survival, the hazard ratio associated with Black versus White race was lowered from 2.03 to 1.79.
Disclosure: Dr. Yao reported no conflicts of interest. For full disclosures of the other study authors, visit coi.asco.org.
