Breast Cancer Coverage from Every Angle

Does Use of Dietary Supplements During Chemotherapy for Breast Cancer Improve Survival?

By: Dana A. Elya, MS, RD, CDN
Posted: Monday, January 27, 2020

According to the DELCaP study, a correlative to a phase III trial led by SWOG (S0221), the use of antioxidant supplements during chemotherapy for breast cancer, as well as iron and vitamin B12, may increase the risk of breast cancer recurrence and mortality. The associations between survival outcomes and the use of dietary supplements, both before and during chemotherapy, seem to be consistent with recommendations for caution. Christine B. Ambrosone, PhD, of Roswell Park Comprehensive Cancer Center, Buffalo, New York, and her colleagues published their findings in the Journal of Clinical Oncology.

“Short of a randomized trial of supplements in patients with cancer, the findings provide some empirical data for consideration when discussing with patients the use of dietary supplements during chemotherapy,” the authors concluded.

A total of 1,134 patients with breast cancer were randomly assigned to an intergroup metronomic trial of cyclophosphamide, doxorubicin, and paclitaxel. Patients were surveyed on their use of supplements at registration and during treatment. A landmark survival analysis was performed at 6 months.

Researchers identified that the use of any antioxidant supplement (vitamins A, C, and E; carotenoids; coenzyme Q10) both before and during treatment was associated with an increased hazard of recurrence (adjusted hazard ratio [HR] = 1.41) and, to a lesser extent, death (adjusted HR = 1.40).

Vitamin B12 use—both before and during chemotherapy—was associated with poorer disease-free survival (HR = 1.83) and overall survival (HR = 2.04). Iron supplementation during chemotherapy was associated with a greater recurrence during treatment (HR = 1.79) and with use both before and during chemotherapy (HR = 1.91).

Omega-3 fatty acid use, both before and during treatment, was found to be associated with disease-free survival (HR = 1.67) but not overall survival. Multivitamin use before, during, or at both time points was not associated with survival outcomes, nor was vitamin D use.

Disclosure: The authors’ disclosures can be found at

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