Calcitonin in a chronoepidemiologic perspective.

Calcitonin seasonal (circannual) variations in apparently healthy women and in women suffering from breast cancer in different evolutive-TNM-stage, were studied. Annual values are higher in patients with breast cancer, but there is no correlation with metastases. A significant calcitonin circannual rhythm with acrophase in winter was detectable in controls but not in breast cancer patients. The circannual rhythm obliteration could be a predictive signal of disease and not only metastatic disease.