Frequency of Abnormalities of Cortisol Secretion and Water Metabolism in Patients With Small Cell Carcinoma of the Lung and Other Malignancies

Abstract

Previous studies have suggested that ectopic production of adrenocorticotropic hormone (ACTH) or antidiuretic hormone (ADH) may occur commonly in patients with small cell carcinoma of the lung (SCCL) and that evidence of such production may be elicited only by provocative tests of water excretion and adrenal function. We studied 28 patients with SCCL and 29 patients with other cancers. Adrenal function, assessed by measuring the 8 am plasma cortisol, the 8 am to 4 pm diurnal variation in plasma cortisol, and the suppressibility of the 8 am plasma cortisol following administration of 1 mg of dexamethasone, was found to be abnormal in 28.5, 71, and 25 percent, respectively, of the patients with SCCL, compared with 18, 65, and 29.5 percent in patients with other types of cancer (P greater than 0.3). The possibility of ectopic ADH secretion was assessed by a standard water loading test, which showed excretion impairment in 60 percent of patients with SCCL and 68 percent of patients with other cancers (P greater than 0.9). Neither the stage of neoplastic disease, sites of metastatic deposits, nor performance status of the patients correlated with abnormalities of water and cortisol metabolism, indicating that such abnormalities are common in patients with all types of cancer. These data do not suggest that subclinical disturbances of adrenal function or water excretion are characteristic of any histologic type of cancer. The precise mechanism(s) underlying these abnormalities are unknown.