Is there a role for melatonin in the treatment of neoplastic cachexia?

It is known that neoplastic cachexia shows metabolic characteristics different from other common causes of malnutrition, and that it is mainly due to an abnormal secretion of TNF, whose levels are often high in patients with advanced neoplasia. Previous clinical studies have suggested that the pineal hormone melatonin (MLT), which plays an essential role in the neuroendocrine regulation of biological systems, may improve the clinical status of advanced cancer patients and inhibit TNF secretion. To investigate the relationship between MLT, TNF and cancer-related weight loss, 100 untreatable metastatic solid tumour patients entered this study to receive either supportive care alone, or supportive care plus MLT (20 mg/day orally in the evening). Patients were observed for 3 months, and were considered evaluable when they were observed for at least 2 months. There were 86 evaluable patients, the other 14 patients having died from rapid progression of disease. The per cent of weight loss greater than 10% was significantly higher in patients treated by supportive care alone than in those concomitantly treated by MLT, with no difference in food intake (P < 0.01). Mean serum levels of TNF progressively increased in the supportive care group, but to levels that were not significantly different from pretreatment values. In contrast, TNF mean concentrations significantly decreased (P < 0.05) in patients concomitantly treated by MLT. These results suggest that the pineal hormone MLT may be effective in the treatment of the neoplastic cachexia by decreasing TNF blood concentrations.