Anorexia, serum zinc, and immunologic response in small cell lung cancer patients receiving chemotherapy and prophylactic cranial radiotherapy.

Anorexia is a major clinical problem for patients with certain types of cancer. The specific mechanisms that result in this spontaneous decline in food intake remain unknown. In noncancer populations, zinc has been shown to play a role in maintaining normal appetite, taste acuity, and immunocompetence. One purpose of this prospective, longitudinal study of cachexia in ten males with small cell lung carcinoma was to determine if anorexia (caloric intake), perceived taste changes, zinc intake, and impaired cellular immunity were associated with serum zinc concentrations. The average daily caloric intake declined 490 kcal from time of diagnosis to seven months after diagnosis (mean caloric intake = 72% of RDA). Daily zinc intake ranged from 6.5 to 25.4 mg over the seven months. During this period, the mean serum zinc concentrations, although low (71 micrograms/dl), remained within the normal range. The average weight declined from 81.7 to 74.1 kg. There was no identifiable pattern of perceived taste changes; most of the perceived changes were recorded during the period coinciding with prophylactic cranial radiation. At the initial testing, four of nine subjects were anergic to a battery of skin test antigens (mumps, candida, tuberculin purified protein derivative). The only subject who remained responsive to two antigens throughout the study remained alive at 12 months. Caloric intake was inadequate to maintain weight. While zinc intake was low, low normal serum zinc concentrations were maintained; thus in this sample, serum zinc does not appear to be the anorexigenic factor.