Integrative oncology: best of both worlds-theoretical, practical, and research issues.

More and more cancer patients use complementary therapies. As the majority of patients do not disclose their use of complementary therapies to their oncologists, they expose themselves to possible detrimental effects from the therapies due to drug interactions. To meet the needs of patients and health care professionals on valid information on complementary therapies, the collaborative research project "Competence Network Complementary Medicine in Oncology-KOKON", an interdisciplinary network for complementary medicine research in oncology, was established. Moreover, Integrative Oncology, a combination of conventional and evidenced-based complementary therapies delivered using a comprehensive approach, is now increasingly used in the United States and Europe. A variety of different Integrative Oncology models have been established worldwide including an expert-based model at the Kliniken Essen-Mitte, Essen, Germany and a patient-centered, evidenced-based approach at The University of Texas MD Anderson Cancer Center. Both models are briefly reviewed. More research is needed and Comparative Effectiveness Research that places strong emphasis on the comparison of different treatment options in usual care settings by including more heterogeneous patients, using less standardized treatment protocols, and measuring patient-centered outcomes would provide useful information for decision-making. To improve the quality of care and research in Integrative Oncology, sustainable financial models for Integrative Oncology and more funding for research are needed.