Prognosis following the use of complementary and alternative medicine in women diagnosed with breast cancer.

Objective: The purpose of this study was to assess whether CAM use affected breast cancer prognosis in those who did not receive systemic therapy.

Design: Secondary data analysis of baseline/survey data from the Women's Healthy Eating and Living (WHEL) study. 2562 breast cancer survivors participating in the study completed baseline assessments and a CAM use questionnaire. Cox regression models were conducted to evaluate the use of CAM modalities and dietary supplements on time to an additional breast cancer event (mean follow-up=7.3 years).

Setting: A US-based multi-site randomized dietary trial.

Outcome: Time to additional breast cancer events.

Results: The women who did not receive any systemic treatment had a higher risk for time to additional breast cancer events (HR=1.9, 95% CI: 1.32, 2.73) and for all-cause mortality (HR=1.7, 95% CI: 1.06, 2.73) compared to those who had received systemic treatment. Among 177 women who did not receive systemic treatment, CAM use was not significantly related to additional breast cancer events. There were no significant differences between high supplement users (≥3 formulations per day) and low supplement users in either risk for additional breast cancer events.

Conclusion: The risk for an additional breast cancer event and/or death was higher for those who did not receive any systemic treatments; the use of dietary supplements or CAM therapies did not change this risk. This indicates that complementary and alternative therapies did not alter the outcome of breast cancer and should not be used in place of standard treatment.