Using vitamin supplements soon after a diagnosis of breast cancer may decrease cancer mortality and recurrence

   Researchers at Vanderbilt University School of Medicine in Nashville and from the Shanghai Center for Disease Control and Prevention have discovered that vitamin supplement use during the first six months following a diagnosis of breast cancer is associated with a reduced risk of disease recurrence and death compared to non-supplement users. 

     The study included 4,877 Chinese women with invasive breast cancer enrolled in the Shanghai Breast Cancer Survival Study.  Participants were limited to those who underwent surgery for their tumors and for whom the current diagnosis of breast cancer was their first. Interviews conducted an average of 6.5 months after diagnosis provided information on the use of vitamin supplements during treatment. 

     During a 4.1 year average follow-up period, 532 participants had a recurrence of their breast cancer, 389 participants died from breast cancer and 55 from other causes.  Use of a multiple-vitamin was associated with a lower risk of breast cancer recurrence or death over the follow-up period with an 18% reduced mortality risk and a 22% reduced recurrence risk. Those who used vitamin C for more than 3 months had a 38 percent lower risk of recurrence and a 44 percent lower risk of dying than those who did not report using the vitamin, and for vitamin E use over 3 months, the risk of recurrence and death were 48 and 43 percent lower. 

    “There is a widespread concern that the use of antioxidant supplements during cancer treatment may protect tumor cells from the oxidative damage induced by cancer therapies, thereby reducing the effectiveness of treatment and increasing risk of mortality,” the authors write.  “We found no evidence that vitamin use during the first six months following diagnosis had a detrimental effect on breast cancer outcomes.” Our results do not support the current recommendation that breast cancer patients should avoid the use of vitamin supplements. The study is published online ahead of print in the December 21, 2010 edition of the journal Cancer Epidemiology, Biomarkers & Prevention.