Review of supplement use among US cancer patients

Many of the 10 million cancer patients in the US are taking nutritional supplements, but an accurate assessment of the frequency is not well appreciated.

In the February 1, 2008 issue of the Journal of Clinical Oncology, Christine Velicer and Cornelia Ulrich report a systematic review of supplement use among US cancer patients. Prostate cancer patients are among the lowest users of supplements.

A total of 32 studies published between 1999 and 2006 met the criteria for review of prevalence of vitamin and mineral supplement use among patients undergoing active cancer treatment. The review revealed that a range of 64% to 81% of survivors reported any vitamin or mineral supplement use and 26% to 77% reported using any vitamins. Nine studies reported use among breast cancer survivors, and use of any vitamins or minerals was 67%-87% and multivitamin use was 57%-62%. The increase in use after breast cancer diagnosis was up to 32%. Complimentary and alternative medicine (CAM) use was associated with younger age, higher education, greater physical activity and psychosocial factors. Use of any vitamins was 38%-43% for colorectal cancer patients and 60% for lung cancer patients.

In comparison, use of any vitamins among prostate cancer patients was 26%-35% and multivitamin use ranged from 13%-23%. Megavitamin use was 4%-24%. CAM use for prostate cancer patients was associated with higher education and higher income, but not cancer stage. Age and ethnicity were not clearly associated. In one study, 15% of patients undergoing radiotherapy used high-dose vitamins, but the treating physicians actually estimated that less than 5% were using them. After a diagnosis of prostate cancer, 15% of patients began using CAM (57% were already using CAM) but only 51% informed their physicians. In one study 20% of patients reported that their treating urologist or radiotherapist never raised the issue of CAM use with them.

The authors point out that while some therapies such as St. John's wort may interfere with drug metabolism, a great understanding of the effects and utilization of CAM among cancer patients is needed. At the very least, physicians should gather intake about CAM use among their patients.