Dietary supplements in patients with cancer: risks and key concepts, part 2.

Purpose: The risks and key concepts regarding the use of dietary supplements in patients with cancer are described.

Summary: There are six common characteristics of dietary supplements that must be addressed when used by patients with cancer. Clinicians must establish if the supplement is an antioxidant, is an anticoagulant or procoagulant, has immunosuppressive or immunomodulating properties, has hormonal properties, has known safety issues, and has known or theoretical drug interactions. These six characteristics of the dietary supplements commonly used by patients with cancer are reviewed to aid in the analysis of the scientific data and communication of the results with the patient or family members. A framework upon which clinicians can adequately help patients make informed decisions regarding the use of complimentary and alternative medicine and dietary supplements is also described. When evaluating the appropriateness of a supplement for use by a patient with cancer, clinicians must conduct a safety review (evaluate the six characteristics). If the supplement is considered safe, an efficacy review must be conducted, after which the clinicians can recommend the supplement's use, accept the patient's decision to use the supplement if no or inconclusive evidence exists, or discourage use if there is conclusive evidence supporting inefficacy. Available resources for locating information regarding dietary supplements are also discussed.

Conclusion: Counseling patients with cancer about dietary supplements requires a systematic thought process that considers the available theories and data, as well as the patients' views about the agents.