Neuroendocrine alterations in lung cancer patients.

Background: A number of qualitative and quantitative changes in hormonal secretion pattern have been found in subjects suffering from neoplastic disease. The aim of this study was to evaluate the presence of alterations in neuro-endocrine system function and in the pattern of endocrine secretion in patients with lung cancer.

Methods: Cortisol, melatonin, growth hormone (GH), insulin-like growth factor I (IGF-I), thyrotropin-releasing hormone (TRH), thyroid-stimulating-hormone (TSH), and free thyroxine (FT4) serum levels were measured on blood samples collected every four hours for 24 hours from ten healthy old subjects aged 65-79 years (mean age +/- s.e. 67.28 +/- 3.11) and from ten subjects suffering from untreated non small cell lung cancer aged 65-78 years (mean age +/- s.e. 68.57 +/- 1.81). Areas under the curve and mean diurnal and nocturnal levels were compared and the presence of circadian rhythmicity was evaluated.

Results: When hormone levels were expressed as area under the curve GH levels were higher (p=0.004) and IGF-I levels were lower (p=0.006) in patients with lung cancer than in normal subjects. The evaluation of melatonin/cortisol ratio in all subjects showed a significant difference between the control group and the group of cancer patients (p<0.05). When we compared mean diurnal levels (mean of 06.00-10.00-14.00h) GH levels were higher (p<0.0001) and IGF I levels were lower (p<0.0001) in cancer patients; when we compared mean nocturnal levels (mean of 18.00-22.00-02.00h) cortisol (p=0.03), TRH (p=0.02), and GH (p=0.001) levels were higher in cancer patients, while melatonin (p=0.04), TSH (p=0.04) and IGF I (p<0.0001) levels were higher in control subjects. A clear circadian rhythm was validated for time related changes of cortisol, melatonin, TRH, TSH and GH in control subjects and for time related changes of melatonin in cancer patients.

Conclusion: These data suggest that lung cancer patients show alterations of hormone secretion and neuroendocrine system function.