Preliminary studies on melatonin in the treatment of myelodysplastic syndromes following cancer chemotherapy.

Experimental studies have suggested that the pineal hormone melatonin, in addition to its documented antineoplastic action, plays a role in the physiological regulation of blood cell proliferation. Based on these data, we evaluated the clinical effects of melatonin therapy in patients with myelodysplastic syndrome (MDS) secondary to cancer chemotherapy for primary neoplasms. The study was carried out on six patients, and melatonin was given orally at a dose of 20 mg/daily, following a schedule prepared to reproduce the circadian rhythm of the pineal hormone. A transient improvement in platelet and neutrophil count was achieved in two of five patients with thrombocytopenia and in two of four patients with neutropenia before therapy, respectively, while no effect was seen on hemoglobin concentration. Mean survival time was 12.5 months, and a long survival, greater than 30 months, was achieved in two of six patients. These preliminary results seem to suggest that melatonin may have a role in the treatment of MDS induced by previous cancer chemotherapy.