Vitamin and mineral supplement use is thought to be common among the 10 million adults in the United States who have been diagnosed with cancer.
However, well-conducted studies of this topic are sparse.
The biologic effects of supplement use among cancer survivors are not well established and not necessarily beneficial.
|68% of physicians are unaware of supplement use among their cancer patients|
|Journal of Clinical Oncology|
Drs Christine Velicer and Cornelia Ulrich from Washington, USA presented a systematic summary of 32 studies published between 1999 and 2006.
The studies evaluated vitamin and mineral supplement use among adult cancer patients and survivors in the USA.
Supplement use is widespread among cancer patients and longer-term survivors.
In studies combining different cancer sites, the team found that 64% to 81% of survivors reported using any vitamin or mineral supplements.
The researchers noted that 26% to 77% of survivors reported using any multivitamins.
In contrast, approximately 50% of adults in the USA use dietary supplements, and 33% use multivitamin/multimineral supplements.
Between 14% and 32% of survivors initiate supplement use after diagnosis, and use differs by cancer site.
Higher level of education and female sex emerged as factors most consistently associated with supplement use.
The team found up to 68% of physicians are unaware of supplement use among their cancer patients.
Drs Velicer and Ulrich concluded, "These results highlight the need for further studies of the association between dietary supplement use and cancer treatment toxicity."
"Recurrence, survival, and quality of life to support evidence-based clinical guidelines for dietary supplement use among cancer patients and longer-term survivors."