Naturopathic Oncology for Advanced Cancers: Survival Outcomes from the Canadian/US Integrative Oncology Study

Background: Several traditional, complementary, and integrative therapies have been studied for their effect on cancer outcomes; however, few studies have evaluated naturopathic oncology in a real-world setting. We conducted an observational cohort study to evaluate whether consulting with a naturopathic doctor (ND) improves survival in people with advanced cancers. Methods: Participants with metastatic breast, metastatic colorectal, advanced ovarian, or advanced pancreatic cancer were recruited from 12 North American naturopathic clinics. The primary outcome was 5-year overall survival compared with a matched cohort from the Surveillance Epidemiology and End Results (SEER) registry. We additionally evaluated survival based on the number of ND visits and intravenous vitamin C (IVC), intravenous mistletoe, and hyperthermia treatments. Results: 400 participants were enrolled: 165 had breast cancer, 116 had colorectal cancer, 72 had ovarian cancer, and 47 had pancreatic cancer. A bootstrapped analysis showed no significant differences in 5-year survival compared with SEER (breast: median hazard ratio [HR] 1.10, 95% confidence interval [CI] 0.80–1.54; colorectal: median HR 0.95, 95% CI 0.68–1.31; ovarian: median HR 1.08, 95% CI 0.64–1.86; pancreatic: median HR 0.76, 95% CI 0.51–1.13). Higher survival odds were seen with increasing IVC treatments in breast cancer, and with increasing ND visits in all cancer types except ovarian. Conclusion: No survival benefits were seen in patients with advanced cancers who saw an ND compared with registry data. After controlling for survivorship bias, in general, the number of ND visits positively correlated with improved survival; however, the number of select naturopathic treatments did not. Findings should be interpreted with caution given study limitations.