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Antioxidant Vitamins C and E Increase Survival Rate of Breast Cancer Patients Undergoing Treatment

 Abstracted by Tatjana Djakovic, BS, from “Vitamin Supplement Use During Breast Cancer Treatment and Survival: a Prospective Cohort Study” in the Cancer Epidemiology Biomarkers and Prevention. January 4, 2010

Breast cancer is a major concern of all women, because about 1 in 8 women in the United States will develop breast cancer over the course of her lifetime. (1) The risk factors include family history, inherited gene mutations, lifestyle, and environmental factors. (2) The treatment varies in individuals, based on the stage and type of breast cancer, but the main treatments includes chemo and radiation therapy. (3)

It has been recommended by oncologists to avoid taking supplemental antioxidant vitamins, such as vitamins C, E, and multivitamins while having chemo and radiation therapy. (3). These vitamins keep harmful particles called free radicals from forming and damaging DNA of cells. Radiation therapy works in part by creating free radicals that are focused on cancer cells in order to eliminate them. (4) Therefore, it is believed taking vitamins that neutralize free radicals will interfere with treatment of breast cancer.

There have only been 5 studies to confirm this theory and 4 involved less than 55 patients and did not have a concurrent control group. (5) In the main study that supported this view, it was found that the higher risk of death while taking vitamins and undergoing treatment was limited to patients who smoked during radiation therapy. (6)

In the first large prospective cohort (observational) study of vitamin use in conjunction with cancer treatment, researchers found that vitamin supplements, especially C, E or multivitamins, are safe to use while undergoing treatment, and even increase the chance of survival. (5) The recent study included 4,877 Chinese women who were observed for a period of about 4.1 years after initial diagnosis. The vitamin use among participants varied, but approximately 85% used up to 400 mg per day of vitamin C, and approximately 99% used up to 400 mg per day of vitamin E.

The researchers found that the women who were taking vitamins C, E, or a multivitamin had an 18% increase in survival rate, and a 22% reduced risk of recurrence of breast cancer. The increase in survival was seen in women who used the vitamins for a longer duration after diagnosis. Use of vitamin C (400 mg daily) had a 44% increase in survival rate and use of vitamin E (400 mg daily) had a 48% increase in survival rate while undergoing chemotherapy when used for longer than three months. In addition, it was found that use of vitamin antioxidants did not increase the risk of mortality among breast cancer patients undergoing radiation therapy. (5)

References:

1. “Breast Cancer Statistics” http://www.breastcancer.org/symptoms/understand_bc/statistics.jsp
2. Weinberg, Robert A. The biology of cancer. New York: Garland Science, 2007. Print.
3. “Vitamins and Treatment”- http://www.breastcancer.org/treatment/radiation/ext_expect/vitamins.jsp
4. “Radiation Therapy”- http://www.cancer.gov/cancertopics/factsheet/Therapy/radiation
5. Nechuta S, Lu W., Chen Z, et al. Vitamin Supplement Use During Breast Cancer Treatment and Survival: a Prospective Cohort Study” in the Cancer Epidemiol Biomarkers Prev. December 21, 2010.
6. Meyer F, Bairati I, Fortin A, et. al. Interaction between antioxidant vitamin supplementation and cigarette smoking during radiation therapy in relation to long-term affects on recurrence and mortality: a randomized trial among head and neck cancer patients. Int J Cancer 2008; 122: 1679-83.