Epidemiologic studies suggest that low dietary intakes and low plasma concentrations of antioxidant vitamins and minerals are associated with increased risks of cancer, especially for epidermoid tumors. Patients with stage I or II head and neck cancer have a good prognosis, with a 5-year relative survival of 60% to 90%, depending of the tumor site. However, the benefit of treatment is often compromised by the occurrence of second primary cancers, which develop in 20% of patients during the first 5 years after diagnosis. We conducted a randomized chemoprevention trial among patients with head and neck cancer treated by radiation therapy to determine whether supplementation combining two antioxidants, alpha-tocopherol and beta-carotene, could reduce the incidence of second primary cancers in this patient population (primary objective of the trial). This study was conducted with funds from the NCIC (#008176,004738,013211) and was completed.