Common Cushing’s Treatment, Somatostatin Analogs, May Sometimes Worsen Disease Course
Doctors often prescribe somatostatin analogs to manage the hormonal imbalance that characterizes Cushing’s syndrome. However, in rare situations these medicines have paradoxically made patients worse than better.
This recently happened with a 48-year-old Spanish woman whose Cushing’s syndrome was caused by an adrenal gland tumor that was producing excess adrenocorticotropic hormone (ACTH). Her case was recently reported in the study “Ectopic Cushing’s syndrome: Paradoxical effect of somatostatin analogs,” and published in the journal Endocrinología, Diabetes y Nutrición.
Cushing’s syndrome occurs when the body produces too much cortisol. This can happen for many reasons, including an oversupply of ACTH, the hormone responsible for cortisol production, due to a tumor in the pituitary gland.
But sometimes, tumors growing elsewhere can also produce ACTH. This feature, known as ectopic ACTH secretion (EAS), may also cause ACTH-dependent Cushing’s syndrome.
Two-thirds of EAS tumors are located in the thorax, and 8 to 15 percent are in the abdominal cavity. Only 5 percent of EAS tumors are located in the adrenal gland, and up to 15 percent of EAS tumors are never detected.
Doctors usually use cortisol synthesis inhibitors such as ketoconazole or Metopirone (metyrapone) to control EAS, due to their efficacy and safety profiles. But somatostatin analogs (SSAs) such as Somatuline (lanreotide) have also been used to treat these tumors. However, these drugs produce mixed results.
The woman in the case study, reported by researchers at the University Hospital Vall d’Hebron in Barcelona, Spain, had an EAS tumor on the adrenal gland. She experienced s life-threatening cortisol and ACTH increase after receiving high-dose Somatuline.
The patient had been recently diagnosed with hypertension, and complained of intense fatigue, muscular weakness, easy bruising and an absence of menstruation. Laboratory analysis revealed that she had triple the normal levels of free cortisol in the urine, elevated levels of plasma cortisol, and high ACTH levels. In addition, her cortisol levels remained unchanged after receiving dexamethasone. The patient was therefore diagnosed with ACTH-dependent Cushing syndrome.
To determine the origin of her high cortisol levels, the team conducted magnetic resonance imaging (MRI). They found no tumors on the most common places, including the pituitary gland, neck, thorax or abdomen. However, additional evaluation detected a small alteration on the left adrenal gland, suggesting that was the source of ectopic ACTH production.
The team initiated treatment with 120 mg of Somatuline, but a week later, her condition had worsened and become life-threatening. Doctors started Ketoconazole treatment immediately, three times daily. The affected adrenal gland was surgically removed, and tissue analysis confirmed the diagnosis. The patient’s clinical condition improved significantly over the follow-up period.
“We highlight the need to be aware of this rare presentation of EAS, and we remark the difficulties of EAS diagnosis and treatment,” researchers wrote.
The team could not rule out the possibility that the patient’s clinical development was due to the natural course of the disease. However, they believe “she had a paradoxical response on the basis of her dramatical worsening just after the SSAs administration, associated to an important rise in ACTH and UFC levels.”
For that reason, researchers think a new version of SSAs, such as Signifor (pasireotide) — which has improved receptor affinity — could provide better therapeutic response.