Use of vitamin supplements may reduce the risk of recurrence and death in women with breast cancer, two new studies suggest.
These studies contrast with some previous studies, which suggested that antioxidants may protect cancer cells during radiotherapy and chemotherapy, thus reducing the effectiveness of treatment.
In a prospective cohort study, Xiao-Ou Shu, MD, PhD, of Vanderbilt University School of Medicine, Nashville, Tennessee, and associates evaluated the relationship between use of vitamin supplements in the first 6 months after diagnosis of breast cancer and total mortality and disease recurrence in 4877 Chinese women aged 20 to 75 years.
The findings, reported in online December 21 in Cancer Epidemiology, Biomarkers, & Prevention, showed that use of vitamin supplements shortly after breast cancer diagnosis was associated with reduced mortality and disease recurrence. Antioxidants had the greatest effect. Women who used vitamin E, vitamin C, or multivitamins had an 18% reduced risk of death and a 22% lower risk of recurrence.
A study reported by Heather Greenlee, ND, PhD, at the San Antonio Breast Cancer Symposium in December, also showed beneficial effects in breast cancer patients who used multivitamins. In this study, however, the benefits were limited to those who took minerals as well as multivitamins.
Of 2239 women diagnosed with a first primary early-stage breast cancer, 44 % reported that they had taken multivitamins with minerals for at least 12 months during the 5 years before the diagnosis of breast cancer, and 60% said they used multivitamins and minerals for at least a year after diagnosis.
Women who had continually taken multivitamins with minerals before their diagnosis and continued afterward were 31% less likely to have a disease recurrence than women who had never taken multivitamins with minerals. They were also 47% less likely to die of breast cancer and 27% less likely to die of any cause. Use of multivitamins without minerals did not confer consistent benefits.