Effect of selenium on the immunocompetence of patients with head and neck cancer and on adoptive immunotherapy of early and established lesions.

Supplementation with 200 microg/day of sodium selenite during therapy for squamous cell carcinoma (SQCC) of the head and neck, e.g., surgery, radiation, or surgery and radiation, resulted in a significantly enhanced cell-mediated immune responsiveness. The enhanced responsiveness was evident during therapy and following conclusion of therapy. In contrast, patients in the placebo arm of the study showed a decline in immune responsiveness during therapy. The results from studies on mice inoculated with SQCC cells expressing the receptor for interleukin-2 (IL-2) and supplemented with Se (2.00 ppm) indicated that Se significantly retards the clinical appearance of tumors; peritumoral injections of 2,000 IU of IL-2 resulted in 50% reduction in the size of established tumors and 72% of early tumors. The combined data suggested that local immunotherapy with IL-2 in hosts supplemented with Se may represent an effective modality of treatment for the prevention of recurrences at the site of conventionally treated primary tumors.