Journal of Clinical Oncology, 2005 ASCO Annual Meeting Proceedings.
Vol 23, No 16S (June 1 Supplement), 2005: 3017
© 2005 American Society of Clinical Oncology

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Abstract

Phase III trial of antioxidant vitamins to prevent acute side effects of radiation therapy in head and neck cancer (HNC) patients

Laval Univ Cancer Research Ctr, Quebec City, PQ, Canada; Ctr Hospitalier Univ de Montréal, Montréal, PQ, Canada; Ctr Hospitalier Univ de Sherbrooke, Sherbrooke, PQ, Canada; Ctr Hospitalier de la Sagamie, Saguenay, PQ, Canada

3017

Background: Many cancer patients take antioxidant vitamins in the hope of improving the outcome of therapies and of reducing treatments side effects. We conducted a randomized trial to determine whether a supplementation with antioxidant vitamins could reduce the occurrence and severity of acute side effects of radiation therapy (ASERT) and improve quality of life without compromising treatment efficacy (second objective of the trial). Methods: This randomized, double-blind, placebo-controlled trial was conducted among 540 stage I or II HNC patients treated by radiation therapy. The supplementation with alpha tocopherol (400 IU/day) and beta carotene (30 mg/day) or placebos was given during radiation therapy and for 3 years thereafter. From October, 1994 to June, 2000, 273 and 267 patients were randomized in the supplement and the placebo arms, respectively. This study population provided 91% power to detect a 50% reduction in the frequency of grade 3 and 4 ASERT in the supplement arm with two-sided =0.05. In 1996, beta carotene was discontinued after recommendation of the trial’s ethical and safety monitoring committee. Ordinal logistic regression was used to estimate the cumulative odds ratios (OR) associated with ASERT one grade higher, with their 95% confidence intervals (CI). Cox proportional hazard model was used to estimate the hazard ratio of local recurrence. No interim analysis was conducted. Results: Patients in the supplement arm had less severe ASERT during radiation therapy (OR=0.72, 95% CI: 0.52–1.02). The reduction was statistically significant when the supplementation combined alpha tocopherol and beta carotene (OR=0.38, 95% CI: 0.20–0.74). Overall, quality of life was not improved by the supplementation. The rate of local recurrence of the HNC tended to be higher in the supplement arm: HR=1.37, 95% CI: 0.93- 2.02. Conclusions: Supplementation with high doses of alpha tocopherol and beta carotene during radiation therapy could reduce the severity of ASERT. However, high doses of antioxidants as adjuvant therapy might compromise radiation treatment efficacy.

No significant financial relationships to disclose.

Abstract presentation from the 2005 ASCO Annual Meeting