Abstract
BACKGROUND: The usage of complementary and alternative medicine (CAM) is widespread among cancer patients. While reasons for and aims of using CAM have been evaluated in many studies, less is known about whether patients' concepts of how and why cancer develops has an influence on the choice of the CAM method. METHODS: We pooled the data from all studies of our working group containing questions on lay etiological concepts and CAM usage and reanalyzed them with respect to the associations between these parameters. RESULTS: The pooled dataset from 12 studies included 4792 patients. A third (1645 patients) reported using CAM. Most often used were supplements (55.9%), relaxation techniques (43.6%), and homeopathy (37.9%). Regarding perceived causes, patients most often marked stress (35.4%) followed by genes (31.9%). While all lay etiological beliefs were highly significantly associated with usage of CAM in general, there was no association between single lay etiological concepts and types of CAM used. Yet, in a network analysis, we found two associations: one comprising trauma, mistletoe, genes, and nutritional supplements, the other yoga, vitamin C, nutritional supplements, and TCM herbs. In the correlation heatmap, one cluster comprises etiological concepts of personality, immune system and trauma, and two clusters of CAM methods emerged: one comprising praying, yoga, meditation, and relaxation procedures, the other nutritional supplements, selenium, vitamins A and C. CONCLUSION: While physicians are trained to derive treatment strategies from etiological concepts, lay people choosing CAM do not follow these rules, which may point to other needs of patients addressed by CAM.