Imaging Agent Effectively Detects, Localizes Tumors in Cushing’s Syndrome

Wannachalee T, et al. Clin Endocrinol. 2019;doi:10.1111/cen.14008.
May 20, 2019

A radioactive diagnostic agent for PET imaging effectively localized primary tumors or metastases in most adults with ectopic Cushing’s syndrome, leading to changes in clinical management for 64% of patients, according to findings from a retrospective study published in Clinical Endocrinology.

As Endocrine Today previously reported, the FDA approved the first kit for the preparation of gallium Ga-68 dotatate injection (Netspot, Advanced Accelerator Applications USA Inc.), a radioactive diagnostic agent for PET scan imaging, in June 2016. The radioactive probe is designed to help locate tumors in adult and pediatric patients with somatostatin receptor-positive neuroendocrine tumors. Ga-68 dotatate, a positron-emitting analogue of somatostatin, works by binding to the hormone.

In a retrospective review, Richard Auchus, MD, PhD, professor of pharmacology and internal medicine in the division of metabolism, endocrinology and diabetes at the University of Michigan, and colleagues analyzed data from 28 patients with ectopic Cushing’s syndrome who underwent imaging with gallium Ga-68 dotatate for identification of the primary tumor or follow-up between November 2016 and October 2018 (mean age, 50 years; 22 women). All imaging was completed at tertiary referral centers at Mayo Clinic, University of Michigan and The University of Texas MD Anderson Cancer Center. Researchers assessed patient demographics, imaging modalities, histopathological results and treatment data. Diagnosis of Cushing’s syndrome was confirmed by clinical and hormonal evaluation. The clinical impact of gallium Ga-68 dotatate was defined as the detection of primary ectopic Cushing’s syndrome or new metastatic foci, along with changes in clinical management.

Within the cohort, 17 patients underwent imaging with gallium Ga-68 dotatate for identification of the primary tumor and 11 underwent the imaging for follow-up. Researchers found that gallium Ga-68 dotatate identified suspected primary ectopic Cushing’s syndrome in 11 of 17 patients (65%), of which seven tumors were solitary and four were metastatic. Diagnosis was confirmed by pathology in eight of the 11 patients: Five patients had a bronchial neuroendocrine tumor, one patient had a thymic tumor, one had a pancreatic neuroendocrine tumor, and one metastatic neuroendocrine tumor was of unknown primary origin. One patient had a false positive scan, according to researchers.

Among the 11 patients with ectopic Cushing’s syndrome who underwent gallium Ga-68 dotatate imaging to assess disease burden or recurrence, the imaging led to changes in clinical management in seven cases (64%), according to researchers.

“Our study demonstrates the high sensitivity of [gallium Ga-68 dotatate] in the localization of [ectopic Cushing’s syndrome], for both occult primary tumors and metastatic lesions,” the researchers wrote. “Importantly, the use of [gallium Ga-68 dotatate] impacted clinical management in 64% of patients with [ectopic Cushing’s syndrome] overall.”

The researchers noted that the high cost and limited availability of PET/CT imaging might preclude the widespread use of gallium Ga-68 dotatate for imaging in patients with suspected ectopic Cushing’s syndrome, and that experience with the scans remains limited vs. other imaging studies.

“Nevertheless, combing the experience of three large referral centers, our study gathers the largest number of [patients with ectopic Cushing’s syndrome] imaged with [gallium Ga-68 dotatate] to date and provides a benchmark for the utility of this diagnostic modality for this rare but highly morbid condition,” the researchers wrote. – by Regina Schaffer

DisclosuresThe authors report no relevant financial disclosures.

From https://www.healio.com/endocrinology/adrenal/news/online/%7B69e458a8-e9a0-4567-a786-00868118b435%7D/imaging-agent-effectively-detects-localizes-tumors-in-cushings-syndrome

Metoclopramide Can Mask Adrenal Insufficiency After Gland Removal in BMAH Patients

Metoclopramide, a gastrointestinal medicine, can increase cortisol levels after unilateral adrenalectomy — the surgical removal of one adrenal gland — and conceal adrenal insufficiency in bilateral macronodular adrenal hyperplasia (BMAH) patients, a case report suggests.

The study, “Retention of aberrant cortisol secretion in a patient with bilateral macronodular adrenal hyperplasia after unilateral adrenalectomy,” was published in Therapeutics and Clinical Risk Management.

BMAH is a subtype of adrenal Cushing’s syndrome, characterized by the formation of nodules and enlargement of both adrenal glands.

In this condition, the production of cortisol does not depend on adrenocorticotropic hormone (ACTH) stimulation, as usually is the case. Instead, cortisol production is triggered by a variety of stimuli, such as maintaining an upright posture, eating mixed meals — those that contain fats, proteins, and carbohydrates — or exposure to certain substances.

A possible treatment for this condition is unilateral adrenalectomy. However, after the procedure, some patients cannot produce adequate amounts of cortisol. That makes it important for clinicians to closely monitor the changes in cortisol levels after surgery.

Metoclopramide, a medicine that alleviates gastrointestinal symptoms and is often used during the postoperative period, has been reported to increase the cortisol levels of BMAH patients. However, the effects of metoclopramide on BMAH patients who underwent unilateral adrenalectomy are not clear.

Researchers in Japan described the case of a 61-year-old postmenopausal woman whose levels of cortisol remained high after surgery due to metoclopramide ingestion.

The patient was first examined because she had experienced high blood pressure, abnormal lipid levels in the blood, and osteoporosis for ten years. She also was pre-obese.

She was given medication to control blood pressure with no results. The lab tests showed high serum cortisol and undetectable levels of ACTH, suggesting adrenal Cushing’s syndrome.

Patients who have increased cortisol levels, but low levels of ACTH, often have poor communication between the hypothalamus, the pituitary, and the adrenal glands. These three glands — together known as the HPA axis — control the levels of cortisol in healthy people.

Imaging of the adrenal glands revealed they were both enlarged and presented nodules. The patient’s cortisol levels peaked after taking metoclopramide, and her serum cortisol varied significantly during the day while ACTH remained undetectable. These results led to the BMAH diagnosis.

The doctors performed unilateral adrenalectomy to control cortisol levels. The surgery was successful, and the doctors reduced the dose of glucocorticoid replacement therapy on day 6.

Eight days after the surgery, however, the patient showed decreased levels of fasting serum cortisol, which indicated adrenal insufficiency — when the adrenal glands are unable to produce enough cortisol.

The doctors noticed that metoclopramide was causing an increase in serum cortisol levels, which made them appear normal and masked the adrenal insufficiency.

They stopped metoclopramide treatment and started replacement therapy (hydrocortisone) to control the adrenal insufficiency. The patient was discharged 10 days after the surgery.

The serum cortisol levels were monitored on days 72 and 109 after surgery, and they remained lower than average. Therefore she could not stop hydrocortisone treatment.

The levels of ACTH remained undetectable, suggesting that the communication between the HPA axis had not been restored.

“Habitual use of metoclopramide might suppress the hypothalamus and pituitary via negative feedback due to cortisol excess, and lead to a delayed recovery of the HPA axis,” the researchers said.

Meanwhile, the patient’s weight decreased, and high blood pressure was controlled.

“Detailed surveillance of aberrant cortisol secretion responses on a challenge with exogenous stimuli […] is clinically important in BMAH patients,” the study concluded. “Caution is thus required for assessing the actual status of the HPA axis.”

From https://cushingsdiseasenews.com/2019/05/07/metoclopramide-conceals-adrenal-insufficiency-after-gland-removal-bmah-patients-case-report/

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