Cushing’s Syndrome Eludes Treatment Paradigm or Standard Approach to Care

Results of two systematic reviews indicate that while surgery is the preferred treatment, many patients present with contraindications without an accepted management paradigm leaving clinicians to follow a patient-centric approach to care.

With commentary by Eliza B. Geer, MD

Cushing’s syndrome may arise from an endogenous glucocorticoid excess is either adrenocorticotropic hormone (ACTH)-dependent or ACTH-independent; each variation has numerous underlying causes, including pituitary tumor, adrenal tumor, or other unknown causes.

Although rare, ectopic Cushing’s syndrome results from a non-pituitary ACTH-producing source. Cushing’s disease, a type of Cushing’s syndrome, affects an estimated 1.2 to 2.4 million people each year, and is caused by an ACTH-secreting pituitary adenoma.1

While surgery is preferred for treatment of Cushing's syndrome many patients need a medical approach instead.

Gaining insights into treatment preferences and efficacy for Cushing’s syndrome were the focus of two separate systematic reviews and meta-analyses, both published in the journal, Pituitary: one regarding medical treatments for Cushing’s syndrome,2 and the other comparing endoscopic versus microscopic transsphenoidal surgery for Cushing’s disease.3

Assessing Medical Management of Cushing’s Syndrome

The meta-analysis examining medical care of individuals with Cushing’s syndrome encompassed 1520 total patients across 35 studies, most of whom had Cushing’s disease.2 However, only 2 of the 35 studies were randomized trials, highlighting the lack of and clear need for controlled clinical trials on medical therapies for Cushing’s syndrome.

Surgery is typically first-line treatment—whether transsphenoidal pituitary adenomectomy for Cushing’s disease,4 removal of the ACTH-producing tumor in ectopic Cushing’s syndrome or adrenalectomy in ACTH-independent Cushing’s syndrome.5

However, many patients require medical therapy owing to contraindications for surgery, for recurrent disease, or to control cortisol secretion prior to surgery or radiotherapy. Results of the meta-analysis reflected wide-ranging normalization of cortisol levels depending upon the agent used– from 35.7% for cabergoline to nearly 82% for mitotane in Cushing’s disease.2 Combination therapy (medications used either together or sequentially) was shown to increase effectiveness in normalizing cortisol levels.2

In an interview with EndocrineWeb, Eliza B. Geer, MD, medical director of the Multidisciplinary Pituitary and Skull Base Tumor Center at Memorial Sloan Kettering Cancer Center in New York City, noted that most medical therapies for Cushing’s syndrome are used off-label (in the US), and thus may lack clinical trial efficacy and safety data; consequently, this review provides useful information for treatment selection. However, Dr. Geer said there was substantial diversity of treatments reviewed in this paper – including tumor-directed therapies, cortisol synthesis inhibitors, an adrenolytic therapy, and a receptor blocker, used alone or in combination.

Further, treatments used in the studies addressed a range of Cushing’s etiologies and reflected heterogeneous study designs (for example follow-up ranged from 2 weeks to 11.5 years).2  As such, she said, “findings provided by this review should be viewed in the context of a broader clinical understanding of Cushing’s treatment.”

Specifically, Dr. Geer said, “Dr. Broersen’s analysis found that efficacy of medical therapy was improved by prior radiotherapy. But we know that radiotherapy is recommended on an individualized basis in only a fraction of Cushing’s patients, depending on tumor behavior and treatment history. Also, the fact that mitotane was shown here to have the highest efficacy of all therapies does not make this the appropriate treatment for all, or even most, Cushing’s patients; mitotane is adrenolytic and has a high rate of significant adverse effects.”

Too Many Questions Persist, Necessitating Focus on Attaining Management Paradigm

Dr. Geer also highlighted the need for answers to basic questions when investigating Cushing’s treatments: How do we define ‘successful’ treatment? What goals of care can patients expect? Which cortisol measurements and cut-offs can be used? How do we define clinical remission—resolution of which symptoms and comorbidities? She said Cushing’s syndrome is one of the most challenging endocrine diseases to treat because of the lack of an accepted, universal treatment or management paradigm.

Treatment is often multimodal and always multidisciplinary, with patient-specific decision trees that must consider many factors, including goals of care, treatment history, disease etiology and severity, tumor behavior, and individual responses to medical therapies, she told EndocrineWeb.

She concluded, “While Broersen et al’s study provides a useful review of available medical therapies, it reinforces something we already know about the treatment of Cushing’s: Expertise is required.”

Pituitary surgery is first-line treatment for Cushing’s disease. Currently, there are two main techniques for transsphenoidal pituitary surgery: microscopic and endoscopic. The operating microscope provides three-dimensional vision and may be advantageous in identifying small tumors; the broader field of vision afforded by the endoscope may be advantageous for complete resection of large tumors.3  Generally, despite an absence of studies directly comparing relative remission and complication rates between microscopic versus endoscopic approaches, most surgical centers choose to use one or the other; few have both.3

Examining the Surgical Options to Manage Cushing’s Disease

The second systematic review is the first to compare remission and recurrence rates, and mortality after microscopic versus endoscopic transsphenoidal pituitary surgery for Cushing’s disease.3 The review included 97 studies of 6695 patients: 5711 individuals having the microscopic procedure and 984 undergoing endoscopic surgery.

Results of the meta-analysis found no clear difference between the two techniques in overall remission (80%) or recurrence (10%).3 Short-term mortality for both techniques was < 0.5%. However, endoscopic surgery was associated with a greater occurrence of cerebrospinal fluid leak (12.9 vs 4.0%) but a lesser occurrence of transient diabetes insipidus (11.3 vs 21.7%).3

The authors reported a higher percentage of patients in remission (76.3 vs. 59.9%) and lower percentage recurrence rates (1.5 vs 17.0%) among patients undergoing endoscopic surgery for macroadenomas.3

When interviewed regarding the second meta-analysis,3 Dr. Geer said that the potential benefit of endoscopy over microscopy has been questioned for ACTH-secreting tumors specifically since most are microadenomas.

“With the caveat that few studies (four of the 97 reviewed) compared techniques directly, Broersen et al3 found that endoscopic surgery was associated with higher remission rates compared to microscopic surgery for large tumors, but the two techniques were comparable for small tumors,” said Dr. Geer, however, “one limitation of these data is the lack of standardized criteria to define diagnosis and remission of Cushing’s among the studies reviewed.”

Need for Consistency in Clinical Trials and Surgical Expertise

The study investigators concluded, “endoscopic surgery for patients with Cushing’s disease reaches comparable results for microadenomas, and probably better results for macroadenomas than microscopic surgery,” despite the greater learning curve associated with endoscopic surgery.3 As such, based on their findings, the authors concluded that “endoscopic surgery may thus be considered the current standard of care. Microscopic surgery can be used based on neurosurgeon’s preference.” They did not respond to EndocrineWeb for a request for comment.

As more neurosurgeons receiving training with the endoscope, the preferred technique for pituitary surgery is changing. Dr. Geer said, “Broersen’s review provides reassurance that the newer endoscopic technique is at least equal to the microscope for microadenomas and may be preferred for macroadenomas.”

“However, [conclusions based on the systematic review] do not change our role as endocrinologists treating Cushing’s disease, which is to refer, when indicated, to the available neurosurgeon with the most favorable outcomes and lowest rate of complications, both of which depend directly on level of experience with the procedure and the instrument being used, whether endoscope or microscope,” she said.

The authors had no financial conflicts to declare.

From https://www.endocrineweb.com/professional/cushings/cushings-syndrome-eludes-treatment-paradigm-standard-approach-care

Postsurgical treatment often necessary in persistent, recurrent Cushing’s disease

Nearly half of adults with Cushing’s disease that persists or recurs after surgical treatment require second and sometimes third therapeutic interventions, including pituitary surgical reintervention, radiotherapy, pharmacotherapy or bilateral adrenalectomy, study data from Mexico show.

Moisés Mercado, MD, FRCPC, of the ABC Hospital Neurological and Cancer Centers in Mexico City, and colleagues evaluated 84 adults (median age, 34 years; 77 women) with Cushing’s disease to determine the long-term efficacy of secondary interventions for persistent and recurrent Cushing’s disease. Median follow-up was 6.3 years.

Overall, 81 participants were primarily treated with transsphenoidal surgery. More than half experienced long-lasting remission (61.7%); disease remained active in 16%, who were diagnosed with persistent Cushing’s disease; and 22% experienced relapse after remission and were diagnosed with recurrent Cushing’s disease.

After the initial procedure, 18 participants required pituitary surgical reintervention, including 10 with recurrent and eight with persistent disease. Radiation therapy was administered to 14 participants, including two as primary therapy and 12 after failed pituitary surgery. Pharmacologic treatment with ketoconazole was prescribed for 15 participants at one point during the course of disease. Bilateral adrenalectomy was performed in 12 participants.

Pituitary surgical reintervention was the most commonly used secondary treatment (22.2%), followed by pharmacologic therapy with ketoconazole (16%), radiotherapy (14.8%) and bilateral adrenalectomy (14.8%). More than half of participants experienced early remissions after a second operation (66.6%) and radiotherapy (58.3%), whereas long-lasting remission was reached in only 33.3% of participants who underwent a second surgery and 41.6% of participants who underwent radiotherapy. Half of participants who underwent bilateral adrenalectomy were diagnosed with Nelson’s syndrome.

Overall, 88% of participants achieved remission, and disease was biochemically controlled with pharmacologic treatment in 9.5% of participants after their initial, secondary and third-line treatments.

“The efficacy of treatment alternatives for recurrent or persistent [Cushing’s disease] vary among patients, and often, more than one of these interventions is required in order to achieve a long-lasting remission,” the researchers wrote. – by Amber Cox

Disclosure: The researchers report no relevant financial disclosures.

From http://www.healio.com/endocrinology/adrenal/news/in-the-journals/%7B5519b312-5912-4c65-b2ed-2ece3f68e83f%7D/postsurgical-treatment-often-necessary-in-persistent-recurrent-cushings-disease

GH therapy increases fracture risk in patients previously treated for acromegaly

van Varsseveld NC, et al. Pituitary. 2016;doi:10.1007/s11102-016-0716-3.

Adult patients with severe growth hormone deficiency previously treated for acromegaly saw an increased fracture risk after 6 years of growth hormone replacement therapy, whereas those previously treated for Cushing’s disease did not experience the same risk, according to a recent observational study.

Nadege C. van Varsseveld, MD, of the department of internal medicine at VU University Medical Center in Amsterdam, and colleagues analyzed data from 1,028 patients with previous nonfunctioning pituitary adenoma (NFPA; n = 783), acromegaly (n = 65) and Cushing’s disease (n = 180), identified through the Dutch National Registry of Growth Hormone Treatment in Adults, a nationwide, long-term surveillance study in patients with severe GH deficiency. Data were collected biannually from medical records through 2009. Baseline DXA measurements were available for 414 patients; 71 (17.1%) had osteoporosis at one or more of the measured sites; 147 (35.5%) had osteopenia.

During a mean follow-up of 5.2 years, researchers found that 166 of patients with previous NFPA were prescribed osteoporosis medications (21.3%), as were 69 patients with previous Cushing’s disease (38.5%) and 22 patients with previous acromegaly (33.4%). During follow-up, 39 patients experienced fractures (3.8%; 32 experiencing one fracture), including 26 patients in the previous NFPA group, eight patients in the previous Cushing’s disease group and five patients in the previous acromegaly group. The median time between baseline and first fracture was 2.4 years (mean age, 59 years).

Researchers found that fracture risk did not differ between groups before 6 years’ follow-up. Fracture risk increased in patients with previous acromegaly after 6 years’ follow-up, but not for those with previous Cushing’s disease vs. patients with NFPA. Results persisted after adjustment for multiple factors, including sex, age, fracture history and the extent of pituitary insufficiency.

The researchers noted that patients with previous Cushing’s disease were younger and more often women and had a greater history of osteopenia or osteoporosis, whereas patients with acromegaly had a longer duration between tumor treatment and the start of GH therapy and were treated more often with radiotherapy.

“During active acromegaly, increased bone turnover has been observed, but reported effects on [bone mineral density] are heterogeneous,” the researchers wrote. “It is postulated that cortical BMD increases, whereas trabecular BMD decreases or remains unaffected.

“The increased fracture risk in the present study may be a long-term effect of impaired skeletal health due to previous GH excess, even though this was not reflected by an increased occurrence of osteopenia or osteoporosis in the medical history,” the researchers wrote. – by Regina Schaffer

Disclosure: One researcher reports receiving consultancy fees from Novartis and Pfizer.

From http://www.healio.com/endocrinology/hormone-therapy/news/online/%7B92a67ad7-3bd5-46f0-b999-0a8e3486edab%7D/gh-therapy-increases-fracture-risk-in-patients-previously-treated-for-acromegaly

Webinar on Management Options for Pituitary Tumors March 22

Dr. Andaluz will cover the full breadth of treatment options from managing endocrine function, surgical procedures (transsphenoidal, endoscopic, and keyhole approaches), radiotherapy / radiosurgery, and the importance of getting care at a multidisciplinary center.

Dr. Norberto Andaluz is a neurosurgeon with the Mayfield Clinic and University of Cincinnati Brain Tumor Center. He is also Associate Professor of Neurosurgery at the University of Cincinnati, Surgical Director of the Neuroscience Intensive Care Unit, and Director of Neurotrauma at the University of Cincinnati Neuroscience Institute. He specializes in the treatment of all disorders and diseases of the brain and spine, but in particular, traumatic brain injury, aneurysms, arteriovenous malformations (AVMs), intracerebral hemorrhage, stroke, carotid artery disease, moyamoya disease and brain tumors (with special training in skull base tumors like pituitary adenoma). Dr. Andaluz received his medical degree from Unversidad Nacional de Rosario in Argentina. He completed his residency in neurosurgery at Instituto de Neurología y Neurocirugía at Sanatorio Parque in Rosario, Argentina and earned a fellowship in cerebrovascular surgery from the University of Cincinnati. Professional memberships include the American Heart Association, Congress of Neurological Surgeons, National Neurotrauma Society, Neurocritical Care Society and North American Skull Base Society.

Register at http://pituitary.org/events/webinar-management-options-for-pituitary-tumors

The New Molecular Landscape of Cushing’s Disease

Silviu Sbiera#Timo Deutschbein#Isabel Weigand, Martin Reincke, Martin FassnachtcorrespondenceBruno Allolio
#These authors contributed equally to this work.
A few days after acceptance of this manuscript, Bruno Allolio passed away.

Cushing’s disease (CD) is caused by corticotropin-secreting pituitary adenomas and results in substantial morbidity and mortality. Its molecular basis has remained poorly understood until the past few years, when several proteins and genes [such as testicular orphan nuclear receptor 4 (TR4) and heat shock protein 90 (HSP90)] were found to play key roles in the disease. Most recently, mutations in the gene of ubiquitin-specific peptidase 8 (USP8) increasing its deubiquination activity were discovered in a high percentage of corticotroph adenomas. Here, we will discuss emerging insights in the molecular alterations that finally result in CD. The therapeutic potential of these findings needs to be carefully evaluated in the near future, hopefully resulting in new treatment options for this devastating disorder.

Trends

Transsphenoidal surgery and radiotherapy are the treatment of choice in CD. However, despite high initial remission rates, a significant percentage of patients relapse.

Owing to the poor understanding of the pathophysiology of CD, drug therapy is still limited and often only ameliorates the clinical manifestations through blocking of ACTH release or adrenal cortisol synthesis.

Recent research has identified several important proteins (e.g., EGFR, HSP90, TR4, and AVPR1b) whose deregulation is associated with CD and may therefore represent potential therapeutic targets.

Frequent, novel mutations in the USP8 gene that are associated with corticotroph pituitary adenomas were recently discovered that result in reduced EGFR degradation and increased POMC activation in vitro.

Keywords:

Cushing’s disease, pituitary, gene expression, epidermal growth factor receptor, ubiquitin-specific peptidase 8, 14-3-3 proteins

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