Chemotherapy lowers levels of antioxidants and micronutrients

Children undergoing chemotherapy for acute lymphoblastic leukemia (ALL) have significant changes in their antioxidant and micronutrient status which are related to their treatment outcomes, according to the results of a novel prospective study.

The findings suggest that eating certain fruits and vegetables could ameliorate some of the negative effects of chemotherapy. The study will be published December 27, 2004 in the online edition of Pediatric Blood & Cancer, and will be available via Wiley InterScience. The study will also appear in a future print issue of the journal.

ALL is the most common form of childhood cancer. Sufferers are treated with chemotherapy, which is associated with the production of free radicals. Certain vitamins and antioxidants are thought to improve the side effects of chemotherapy and boost the immune system, although this association had never been studied in children with cancer.

To address this lack of information, researchers led by Kara M. Kelly, M.D. of Columbia University, sought to assess the effects of chemotherapy on antioxidant status in children with ALL. They also planned to compare antioxidant status and oxidative stress with treatment outcomes.

The researchers studied 103 children newly diagnosed with ALL. They collected blood samples from each child at the time of diagnosis, after 28 days of interim maintenance therapy (3 to 4 months after diagnosis) and after 28 days of delayed intensification therapy (6 to 7 months after diagnosis.) They analyzed the blood for levels of ascorbic acid, vitamins A and E, carotenoids, cholesterol and triglycerides. They also measured Oxygen Radical Absorbance capacity (ORAC) and oxidative damage in mononuclear cells in blood and bone marrow. They compared the results to each patient's response to therapy, quality of life, and disease status.

In general, the researchers found that over the course of the children's treatment, their oxidative stress increased while their antioxidant levels decreased. They noted that varying levels of each antioxidant at the different time points often related to how each is stored and utilized in the body.

They also found that antioxidant status was associated with treatment-related side effects. Patients with higher concentrations of vitamins A, E, total carotenoids, ORAC and 8-oxo-dG had fewer adverse outcomes, such as infections and toxicity. However, higher levels of vitamin E/TL and ORAC were associated with greater risk of negative side effects. The authors suggest this may not be a true finding, but a result of the small sample size and the multiple comparisons performed. "Before a recommendation for nutrient supplementation can be made," they suggest, "further research needs to be done to elucidate the relationship between plasma antioxidants and side effects of chemotherapy."

Other study limitations include the selection criteria for deficiency states. The authors suggest that children with leukemia may require more antioxidants due to the increase in free radicals from chemotherapy.

"Findings in this study suggest that children may benefit from an increase in their intake of fruits and vegetables in order to increase their plasma carotenoid and perhaps flavanoid concentrations," the authors conclude. "This may be protective against treatment-related side effects in children with ALL."

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