Paradoxical effect of somatostatin analogues on the ectopic secretion of corticotropin in two cases of small cell lung carcinoma.

We investigated 2 patients affected with Cushing's syndrome due to the ectopic production of adrenocorticotropic hormone (ACTH) by a small cell lung carcinoma. In the 2 patients, the long-acting somatostatin analogue octreotide (100 micrograms, subcutaneously) induced a paradoxical increase in plasma ACTH and cortisol levels. In 1 patient, lanreotide, a new somatostatin analogue in a slow-release formulation (30 mg, intramuscularly), induced a similar rise in ACTH and cortisol secretion. To our knowledge, such a response has not been previously reported. Further use of somatostatin analogues in ectopic ACTH-producing tumors, especially lung tumors, requires preliminary evaluation of their therapeutic efficacy by a short test with somatostatin analogue.