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The use of supplements during chemotherapy is controversial, partly due to the potential effect of antioxidants on reduced efficacy of chemotherapy-related cytotoxicity. We examined supplement use among breast cancer patients registered to a clinical trial (SWOG 0221) before diagnosis and during treatment. Patients ( n = 1,467) completed questionnaires regarding multivitamin and supplement use at trial registration (baseline) to capture use before diagnosis. Of these patients, 1,249 completed a 6-month followup questionnaire to capture use during treatment. We examined the use of vitamins C, D, E, B6, B12, folic acid, and calcium at these timepoints, as well as physician recommendations regarding supplement use. The use of vitamins C, E, folic acid, and calcium decreased during treatment, while the use of vitamin B6 increased. Five hundred seventy four patients (51 %) received no physician recommendations regarding supplement use. Among the remaining 49, 10 % were advised not to take multivitamins and/or supplements, 7 % were advised to use only multivitamins, and 32 % received recommendations to use multivitamins and/or supplements. Among patients who took vitamin C before diagnosis, those who were advised not to take supplements were >5 times more likely not to use of vitamin C during treatment than those not advised to stop use (OR = 5.27, 95 % CI 1.13-24.6). Previous non-users who were advised to take a multivitamin were nearly 5 times more likely to use multivitamins during treatment compared to those who received no recommendation (OR = 4.66, 95 % CI 2.10-10.3). In this clinical trial for high-risk breast cancer, supplement use generally decreased during treatment. Upon followup from the clinical trial, findings regarding supplement use and survival outcomes will better inform physician recommendations for patients on adjuvant chemotherapy. [ABSTRACT FROM AUTHOR]

Taxanes have resulted in improved survival for breast cancer patients, but often cause neurological toxicities. Identification of biomarkers related to toxicities could be important for dictating treatment regimen. We evaluated single nucleotide polymorphisms (SNPs) in the Fanconi Anemia (FA)/BRCA pathway in relation to grade 3/4 neurotoxicities in patients ( n = 888) from SWOG0221, a phase III adjuvant trial for breast cancer of 4 dose/schedules of cyclophosphamide (C), doxorubicin (A), and paclitaxel (T). In a separate cohort, we measured the correlation of significant FANCD2 SNPs with corresponding gene expression. For FANCD2, permutation testing revealed that 4 (out of 20) SNPs were significantly associated with an almost two-fold increased risk of toxicity. Two FANCD2 haplotypes were also associated with neurological toxicity, with odds ratios (OR) in the overall population of 1.8 (95% confidence interval (CI) 1.3, 2.5) and 1.7 (95% CI, 1.2, 2.4). Although numbers were small, an African-American-specific haplotype was associated with an almost 3-fold increase in risk of neurologic toxicity (OR = 2.84, 95% CI = 1.2, 6.9). Expression analyses revealed that significant FANCD2 SNPs were associated with FANCD2 expression levels ( P = 0.03). There were no associations between SNPs in BRCA1 and neurotoxicities. In this trial of CA+T for breast cancer, SNPs in FANCD2, but not in BRCA1, were associated with a 70-80% increase in the odds of grade 3/4 neurological toxicities and increased expression of the gene. If replicated, women with these genotypes should be closely monitored for toxicities and could be targeted for preventive measures or alternative therapeutic approaches. [ABSTRACT FROM AUTHOR]