title: Vitamin supplement use during breast cancer treatment and survival: a prospective cohort study.
abstract: BACKGROUND
  Antioxidants may protect normal cells from the oxidative damage that occurs during radiotherapy and certain chemotherapy regimens; however, the same mechanism could protect tumor cells and potentially reduce effectiveness of cancer treatments. We evaluated the association of vitamin supplement use in the first 6 months after breast cancer diagnosis and during cancer treatment with total mortality and recurrence.
  
  
  METHODS
  We conducted a population-based prospective cohort study of 4,877 women aged 20 to 75 years diagnosed with invasive breast cancer in Shanghai, China, between March 2002 and April 2006. Women were interviewed approximately 6 months after diagnosis and followed up by in-person interviews and record linkage with the vital statistics registry.
  
  
  RESULTS
  During a mean follow-up of 4.1 years, 444 deaths and 532 recurrences occurred. Vitamin use shortly after breast cancer diagnosis was associated with reduced mortality and recurrence risk, adjusted for multiple lifestyle factors, sociodemographics, and known clinical prognostic factors. Women who used antioxidants (vitamin E, vitamin C, multivitamins) had 18% reduced mortality risk (HR = 0.82, 95% CI: 0.65-1.02) and 22% reduced recurrence risk (HR = 0.78, 95% CI: 0.63-0.95). The inverse association was found regardless of whether vitamin use was concurrent or nonconcurrent with chemotherapy, but was present only among patients who did not receive radiotherapy.
  
  
  CONCLUSIONS
  Vitamin supplement use in the first 6 months after breast cancer diagnosis may be associated with reduced risk of mortality and recurrence.
  
  
  CONCLUSIONS
  Our results do not support the current recommendation that breast cancer patients should avoid use of vitamin supplements.
authors.affiliation: Division of Epidemiology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37203, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Nechuta
authors.forename: Wei
authors.initials: W
authors.lastname: Lu
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
authors.forename: Ying
authors.initials: Y
authors.lastname: Zheng
authors.forename: Kai
authors.initials: K
authors.lastname: Gu
authors.forename: Hui
authors.initials: H
authors.lastname: Cai
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.forename: Xiao Ou
authors.initials: XO
authors.lastname: Shu
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000401:mortality* / Q000628:therapy; D018270:Carcinoma, Ductal, Breast / Q000401:mortality* / Q000628:therapy; D015331:Cohort Studies; D019587:Dietary Supplements / Q000706:statistics & numerical data*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D015996:Survival Rate; D014807:Vitamin D / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D014807:Vitamin D