Psychooncology and cancer progression-related alterations of pleasure-associated neurochemical system: Abnormal neuroendocrine response to apomorphine in advanced cancer patients.

OBJECTIVES: The clinical approach of the Psychooncology is generally limited to the investigation of the only psychological status of cancer patients, without taking into consideration the well demonstrated cancer progression-related psychoneuroendocrine alterations, namely consisting of a progressive decline in the pineal endocrine function and an anomalous activity of brain opioid system. The endocrine response to apomorphine, a dopaminergic agent, has been proven to reflect the dopaminergic sensitivity, which would be involved at least in part in pleasure-related neurochemical mechanisms. The present study was performed to analyze the endocrine response to apomorphine in metastatic cancer patients, as a preliminary approach to the investigation of pleasure-related neuroendocrine mechanisms in human neoplasms.

MATERIALS & METHODS: The study included 10 metastatic cancer male patients and 6 male volunteers as a control group. Apomorphine was given orally at 0.01 mg/kg body weight in the morning, and venous blood samples were collected before, and at 20, 60 and 120 minutes after apomorphine administration. The endocrine analysis consisted of the measurement of serum levels of GH, PRL and cortisol.

RESULTS: All cancer patients presented alterations involving one or more endocrine responses to apomorphine. GH and cortisol mean levels after apomorphine were significantly higher in controls than in cancer patients, whereas no substantial difference occurred in those of PRL.

CONCLUSIONS: This preliminary study, by showing an altered endocrine response to apomorphine in metastatic cancer patients, would suggest that cancer progression may be associated with an altered dopaminergic sensitivity. Because of the involvement of the dopaminergic system in pleasure-related neurochemical mechanisms, this finding would demonstrated that the decline in the perception of pleasure with cancer progression may depend not only on psychological factors, but also, at least in part, on psychochemical alterations occurring during the clinical course of the neoplastic disease.