April 25 (ANI): Though there is no evidence that antioxidant supplements interfere with the therapeutic effects of chemotherapy agents, according to a recent systematic review the supplements may help increase survival rates during the treatment.

This conclusion has important implications for patients whose oncologists discourage the use of antioxidant supplements during treatment. Until now, their concern has been that these supplements may counteract the tumor-shrinking abilities of the chemotherapy.

“This review demonstrates that there is no scientific support for the blanket objection to using antioxidants during chemotherapy. In addition, it also appears that these supplements may help mitigate the side effects of chemotherapy,” said Keith I. Block, MD, lead author of the study and Medical Director of the Block Center for Integrative Cancer Treatment.

“This is significant because it increases the likelihood that patients will be able to complete their treatment,” he added.

“This study, along with the evolving understanding of antioxidant-chemotherapy interactions, suggests that the previously held beliefs about interference do not pertain to clinical treatment,” co-author Dr. Robert Newman, Professor of Cancer Medicine at M. D. Anderson Cancer Center said.

Out of the 845 studies that were analyzed, 19 met all evaluation criteria. These included the use of randomized trials with a control group, and the reporting of treatment response (tumor shrinkage) and survival data. The 1,554 patients represented had a variety of cancer types, and most had advanced or relapsed disease. Some of the antioxidants used in the trials included glutathione, vitamin A, vitamin C, vitamin E, ellagic acid, selenium and beta carotene.

The authors noted that reducing side effects may help patients avoid having to cut back on their chemotherapy dosing, interrupt scheduled treatments, or abandon treatment altogether.

This in turn, is likely to favorably impact treatment outcomes. A recent study of a group of colon cancer patients indicated that those who completed their full prescribed schedules of chemotherapy had survival rates nearly double those of patients who abandoned their chemotherapy treatment prematurely.

This new study encourages further exploration of the potential importance of antioxidant supplements as a means of improving cancer survival.

The study is available in the May, 2007 issue of the peer-reviewed journal Cancer Treatment Reviews. (ANI)