Dietary supplement usage by patients with cancer undergoing chemotherapy: Does prognosis or cancer symptoms predict usage?

Any interactions between chemotherapeutic drugs and dietary supplements (DS) are a concern for oncologists. This study sought to obtain pilot data about the prevalence of consumption of DS (which include vitamin/ mineral supplements [VS] and herbal supplements [HS]) among patients undergoing chemotherapy and to assess the relationship between DS consumption and both cancer prognosis and secondary cancer symptoms. In this pilot study, data on demographics, DS usage, presence of secondary cancer symptoms, and cancer diagnosis and stage were collected on 100 consecutive patients with gastrointestinal cancer and 40 with breast cancer who were receiving active chemotherapy from April 2004 to July 2004. Overall prevalence of DS consumption was 52.52% ± 8.3% (VS, 48.2% ± 8.31%; HS, 23.74% ± 7.07%). Of HS users, 42.42% ± 16.86% used multiple HS. Factors significantly associated with higher consumption of HS were female gender and presence of metastasis, fatigue, and cancer pain. No significant associations between consumption of DS or HS and age, cancer type, presence of pain, sleep problems, or sexual problems were seen. Approximately half of the patients undergoing chemotherapy in this pilot survey were using DS, including HS - which heralds the potential for drug-supplement interactions and warrants caution. Consumption of HS was greater among people having a higher cancer stage and symptoms such as fatigue or cancer pain; patients in these subgroups probably should be screened actively for DS use. Further studies are needed to confirm these results.