Vitamin E May Have Adverse Effects in Head, Neck Cancer Patients

QUEBEC--A multicenter, double blind intervention trial examining the impact of antioxidant supplementation on subjects with head or neck cancer undergoing radiation showed varying effects on tumor recurrence, according to a study published in the Journal of the National Cancer Institute (JNCI, 97, 7:481-8, 2005). Coordinated by researchers from the Universite Laval, the study involved 540 patients with stage I or II head and neck cancer treated by radiation therapy. Patients received either 400 IU/d alpha-tocopherol with 30 mg/d beta-carotene or placebo starting on the first day of radiation therapy and continuing for three years after the end of radiation therapy.

One year into the trial, beta-carotene supplementation was suspended after the release of the CARET lung cancer study results, which suggested the carotenoid increased the risk of cancer. The remaining patients received alpha-tocopherol or placebo only. After a median follow-up of more than four years, second primary cancers and recurrences of the first tumor were diagnosed in 113 and 119 participants, respectively. Compared with patients taking placebo, those on vitamin E had a higher rate of first cancer recurrence and development of second primary cancers during the supplementation period, but a lower rate after supplementation was discontinued.

The authors noted the patient population was at high risk of second primary cancer and cautioned that the study results should not be generalized to individuals in the general population who are at low risk of a first primary cancer. "Nevertheless, our results suggest that caution should be advised regarding the use of high-dose alpha-tocopherol supplements for cancer prevention," they concluded.