Randomized trial of antioxidant vitamins to prevent acute adverse effects of radiation therapy in head and neck cancer patients.
OBJECTIVE
Many cancer patients take antioxidant vitamin supplements with the hope of improving the outcome of conventional therapies and of reducing the adverse effects of these treatments. A randomized trial was conducted to determine whether supplementation with antioxidant vitamins could reduce the occurrence and severity of acute adverse effects of radiation therapy and improve quality of life without compromising treatment efficacy.


METHODS
We conducted a randomized, double-blind, placebo-controlled trial among 540 head and neck cancer patients treated with radiation therapy. Patients were randomly assigned into two arms. The supplementation with alpha-tocopherol (400 IU/d) and beta-carotene (30 mg/d) or placebos was administered during radiation therapy and for 3 years thereafter. During the course of the trial, supplementation with beta-carotene was discontinued because of ethical concerns.


RESULTS
Patients randomly assigned in the supplement arm tended to have less severe acute adverse effects during radiation therapy (odds ratio [OR], 0.72; 95% CI, 0.52 to 1.02). The reduction was statistically significant when the supplementation combined alpha-tocopherol and beta-carotene for adverse effects to the larynx (OR, 0.38; 95% CI, 0.21 to 0.71) and overall at any site (OR, 0.38; 95% CI, 0.20 to 0.74). Quality of life was not improved by the supplementation. The rate of local recurrence of the head and neck tumor tended to be higher in the supplement arm of the trial (hazard ratio, 1.37; 95% CI, 0.93 to 2.02).


CONCLUSIONS
Supplementation with high doses of alpha-tocopherol and beta-carotene during radiation therapy could reduce the severity of treatment adverse effects. However, this trial suggests that use of high doses of antioxidants as adjuvant therapy might compromise radiation treatment efficacy.
Bairati
Isabelle
I
Laval University Cancer Research Center, CHUQ-HDQ, 11, Cote du Palais, Quebec, G1R 2J6 Canada.
Meyer
François
F
Gélinas
Michel
M
Fortin
André
A
Nabid
Abdenour
A
Brochet
François
F
Mercier
Jean-Philippe
JP
Têtu
Bernard
B
Harel
François
F
Abdous
Belkacem
B
Vigneault
Eric
E
Vass
Sylvie
S
Del Vecchio
Pierre
P
Roy
Jean
J
D000208:Acute Disease; D000704:Analysis of Variance; D000975:Antioxidants / Q000627:therapeutic use*; D016009:Chi-Square Distribution; D004311:Double-Blind Method; D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011788:Quality of Life; D011832:Radiation Injuries / Q000517:prevention & control*; D016019:Survival Analysis; D024502:alpha-Tocopherol / Q000627:therapeutic use*; D019207:beta Carotene / Q000627:therapeutic use*
D000975:Antioxidants; D019207:beta Carotene; D024502:alpha-Tocopherol