Use of Complementary and Alternative Medicine in the Management of Breast Cancer.

Importance: Innovations in both the surgical and medical management of breast cancer over the past few decades have led to reductions in treatment-related morbidity and increases in overall survival. Despite these advancements in traditional therapies, including surgery, chemotherapy, radiation, endocrine therapy, and immunotherapy, a subset of patients continues to choose complementary and alternative medicine (CAM). Objective: To describe the association of CAM with survival in patients with breast cancer. Design, Setting, and Participants: This cohort study analyzed data from the National Cancer Database on female patients diagnosed with breast cancer from 2011 through 2021. Survival time was compared among patients who received traditional treatment, traditional treatment and CAM, and no treatment. Data were analyzed from May 2025 to December 2025. Exposure: Complementary or alternative treatment, defined in the NCDB as treatment administered by nonmedical personnel. Main Outcomes and Measures: The primary outcome was 5-year survival. Unadjusted 5-year survival was assessed by Kaplan-Meier analysis, and adjusted survival was assessed with a Cox proportional hazards model controlled for age, race and ethnicity, Charlson Comorbidity index, insurance type, facility type, region, year of diagnosis, cancer stage, and income. Results: Of 2 169 202 female patients with breast cancer identified, 2 157 219 (median [IQR] age, 62 [52-71] years) were included in the sample. A total of 2 106 665 patients (97.6%) received traditional therapy, 273 (<0.1%) received CAM alone, 568 (<0.1%) received a combination of CAM and traditional therapies, and 49 713 (2.3%) received no treatment. Compared with patients treated with traditional therapies, those treated with CAM alone (adjusted hazard ratio [AHR], 3.67; 95% CI, 3.03-4.44; P < .001) or no treatment (AHR, 3.53; 95% CI, 3.48-3.58; P < .001) had the highest risks for mortality. Patients who received a combination of traditional therapies and CAM were less likely to receive endocrine therapy (eg, 40.7% vs 65.2% in stage II; P < .001) and radiation (59.5% vs 36.6% in stage II; P < .001) compared with patients treated exclusively with traditional therapies. Receipt of a combination of traditional therapies and CAM was associated with a higher mortality compared with being treated exclusively with traditional therapy (AHR, 1.45; 95% CI, 1.22-1.72; P < .001). Conclusions and Relevance: In this cohort study of data from female patients with breast cancer included in the NCDB, the use of CAM instead of traditional therapies was uncommon but was associated with a reduction in survival time. Further study is warranted.