Corticotroph tumor progression after adrenalectomy in Cushing's Disease: A reappraisal of Nelson's Syndrome

Bilateral Testicular Tumors Resulting in Recurrent Cushing Disease After Bilateral Adrenalectomy

CONTEXT

Recurrence of hypercortisolism in patients after bilateral adrenalectomy for Cushing disease is extremely rare.

PATIENT

We present a 27-year-old man who previously underwent bilateral adrenalectomy for Cushing disease with complete clinical resolution. Cushingoid features recurred 12 years later, with bilateral testicular enlargement. Hormonal tests confirmed adrenocorticotropic hormone (ACTH)-dependent Cushing disease. Surgical resection of the testicular tumors led to clinical and biochemical remission.

DESIGN AND RESULTS

Gene expression analysis of the tumor tissue by quantitative polymerase chain reaction showed high expression of all key steroidogenic enzymes. Adrenocortical-specific genes were 5.1 × 105 (CYP11B1), 1.8 × 102 (CYP11B2), and 6.3 × 104 (MC2R) times higher than nonsteroidogenic fibroblast control. This correlated with urine steroid metabolome profiling showing 2 fivefold increases in the excretion of the metabolites of 11-deoxycortisol, 21-deoxycortisol, and total glucocorticoids. Leydig-specific genes were 4.3 × 101 (LHCGR) and 9.3 × 100 (HSD17B3) times higher than control, and urinary steroid profiling showed twofold increased excretion of the major androgen metabolites androsterone and etiocholanolone. These distinctly increased steroid metabolites were suppressed by dexamethasone but unresponsive to human chorionic gonadotropin stimulation, supporting the role of ACTH, but not luteinizing hormone, in regulating tumor-specific steroid excess.

CONCLUSION

We report bilateral testicular tumors occurring in a patient with recurrent Cushing disease 12 years after bilateral adrenalectomy. Using mRNA expression analysis and steroid metabolome profiling, the tumors demonstrated both adrenocortical and gonadal steroidogenic properties, similar to testicular adrenal rest tumors found in patients with congenital adrenal hyperplasia, suggesting the presence of pluripotent cells even in patients without congenital adrenal hyperplasia.

Characterizing and predicting the Nelson-Salassa syndrome

OBJECTIVE Nelson-Salassa syndrome (NSS) is a rare consequence of bilateral adrenalectomy (ADX) for refractory hypercortisolism due to Cushing disease (CD). Although classically defined by rapid growth of a large, invasive, adrenocorticotropin hormone (ACTH)-secreting pituitary tumor after bilateral ADX that causes cutaneous hyperpigmentation, visual disturbance, and high levels of ACTH, clinical experience suggests more variability. METHODS The authors conducted a retrospective chart review of all patients 18 years and older with a history of bilateral ADX for CD, adequate pituitary MRI, and at least 2 years of clinical follow-up. Statistical tests included Student's t-test, chi-square test, Fisher's exact test, multivariate analysis, and derived receiver operating characteristic curves. RESULTS Between 1956 and 2015, 302 patients underwent bilateral ADX for the treatment of hypercortisolism caused by CD; 88 had requisite imaging and follow-up (mean 16 years). Forty-seven patients (53%) had radiographic progression of pituitary disease and were diagnosed with NSS. Compared with patients who did not experience progression, those who developed NSS were significantly younger at the time of CD diagnosis (33 vs 44 years, p = 0.007) and at the time of bilateral ADX (35 vs 49 years, p = 0.007), had larger tumors at the time of CD diagnosis (6 mm vs 1 mm, p = 0.03), and were more likely to have undergone external-beam radiation therapy (EBRT, 43% vs 12%, p = 0.005). Among NSS patients, the mean tumor growth was 7 mm/yr (SE 6 mm/yr); the median tumor growth was 3 mm/yr. Prevalence of pathognomonic symptoms was low; the classic triad occurred in 9%, while hyperpigmentation without visual field deficit was observed in 23%, and 68% remained asymptomatic despite radiographic disease progression. NSS required treatment in 14 patients (30%). CONCLUSIONS NSS is a prevalent sequela of CD after bilateral ADX and affects more than 50% of patients. However, although radiological evidence of NSS is common, it is most often clinically indolent, with only a small minority of patients developing the more aggressive disease phenotype characterized by clinically meaningful symptoms and indications for treatment. Young age at the time of CD diagnosis or treatment with bilateral ADX, large tumor size at CD diagnosis, and EBRT are associated with progression to NSS and may be markers of aggressiveness.

STEREOTACTIC RADIATION THERAPY IN PITUITARY ADENOMAS, IS IT BETTER THAN CONVENTIONAL RADIATION THERAPY?

Pituitary radiotherapy (RT) has undergone important progress in the last decades due to the development of new stereotactic techniques which provide more precise tumour targeting with less overall radiation received by the adjacent brain structures. Pituitary surgery is usually first-line therapy in most patients with nonfunctioning (NFPA) and functioning adenomas (except for prolactinomas and large growth hormone (GH) secreting adenomas), while RT is used as second or third-line therapy. The benefits of RT (tumour volume control and, in functional tumours, decreased hormonal secretion) are hampered by the long latency of the effect and the potential side effects. This review presents the updates in the efficacy and safety of the new stereotactic radiation techniques in patients with NFPA, GH-, ACTH- or PRL-secreting pituitary adenomas.

Methods

A systematic review was performed using PubMed and articles/abstracts and reviews detailing RT in pituitary adenomas from 2000 to 2017 were included.

Results

Stereotactic radiosurgery (SRS) and fractionated stereotactic RT (FSRT) provide high rates of tumour control i.e. stable or decrease in tumour size, in all types of pituitary adenomas (median 92 - 98%) at 5 years. Endocrinological remission is however significantly lower: 44-52% in acromegaly, 54-64% in Cushing's disease and around 30% in prolactinomas at 5 years. The rate of new hypopituitarism varies from 10% to 50% at 5 years in all tumour types and as expected increases with the duration of follow-up (FU). The risk for other radiation-induced complications is usually low (0-5% for new visual deficits, cranial nerves damage or brain radionecrosis and extremely low for secondary brain tumours), however longer FU is needed to determine rates of secondary tumours. Notably, in acromegaly, there may be a higher risk for stroke with FSRT.

Conclusion

Stereotactic radiotherapy can be an effective treatment option for patients with persistent or recurrent pituitary adenomas after unsuccessful surgery (especially if residual tumour is enlarging) and/or resistance or unavailability of medical therapy. Comparison with conventional radiation therapy (CRT) is rather difficult, due to the substantial heterogeneity of the studies. In order to evaluate the potential brain-sparing effect of the new stereotactic techniques, suggested by the current data, long-term studies evaluating secondary morbidity and mortality are needed.

Currently used and investigational drugs for Cushing´s disease

INTRODUCTION

Cushing's disease (CD) is caused by a corticotroph adenoma of the pituitary gland that secretes excess adrenocorticotropic hormone (ACTH) causing increased morbidity and mortality. Surgery is the treatment of choice, but is not always successful. Alternatives include radiotherapy, adrenal surgery, and pharmaceutical therapy. The latter is increasingly gaining momentum due to the recent development of compounds that reduce hypercortisolaemia or its symptoms, acting through different mechanisms. Areas covered: In this article, the authors provide a complete overview of the treatment options for Cushing´s disease, including adrenal-directed, tumor-targeted, and peripheral therapies that are currently used or in development, and discuss their potential advantages and limitations. Expert opinion: Considering the lack of long-term remission in up to half of the patients after surgery, and the delayed response to radiotherapy along with potential side effects, there is a strong need for an effective pharmaceutical treatment. Pasireotide, mifepristone, ketoconazole and metyrapone have been approved by regulatory authorities but their use remains limited due to considerable costs and side effects. Research in this field has focused recently on the improvement of pre-existing drugs and the development of safe new ones. However, few approaches aim at targeting the source of the disease, the ACTH-secreting adenoma.

The risks of overlooking the diagnosis of secreting pituitary adenomas

Secreting pituitary adenomas that cause acromegaly and Cushing’s disease, as well as prolactinomas and thyrotroph adenomas, are uncommon, usually benign, slow-growing tumours. The rarity of these conditions means that their diagnosis is not familiar to most non-specialist physicians. Consequently, pituitary adenomas may be overlooked and remain untreated, and affected individuals may develop serious comorbidities that reduce their quality of life and life expectancy. Because many signs and symptoms of pituitary adenomas overlap with those of other, more common disorders, general practitioners and non-endocrinology specialists need to be aware of the “red flags” suggestive of these conditions. A long duration of active disease in patients with secreting pituitary adenomas is associated with an increased risk of comorbidities and reduced quality of life. Appropriate treatment can lead to disease remission, and, although some symptoms may persist in some patients, treatment usually reduces the incidence and severity of comorbidities and improves quality of life. Therefore, correct, early diagnosis and characterization of a pituitary adenoma is crucial for patients, to trigger timely, appropriate treatment and to optimize outcome. This article provides an overview of the epidemiology of hormonal syndromes associated with pituitary adenomas, discusses the difficulties of and considerations for their diagnosis, and reviews the comorbidities that may develop, but can be prevented, by accurate diagnosis and appropriate treatment. We hope this review will help general practitioners and non-endocrinology specialists to suspect secreting pituitary adenomas and refer patients to an endocrinologist for confirmation of the diagnosis and treatment.

Diagnostic criteria in invasive pituitary adenomas

Pituitary adenomas are benign pituitary primary tumors, the most frequent type of tumor in the pituitary fossa. An important part, around 1/3 of the pituitary adenomas manifests an aggressive behavior, growing faster and invading into parasellar areas (cavernous sinus, neural tissues and bones). Objectives: the first aim of this paper is to review the last findings about invasiveness diagnostic criteria, imagistic and biomarkers, which can be used in the classification of pituitary tumors and also to predict the probability of invasiveness, tumor recurrence and suspicion of malignancy. The second aim is to highlight the morphological and clinic types of invasive pituitary adenomas. Materials and methods: we performed a systematic review and analysis of the published articles, searching PubMed between January 1985 and December 2015. There were selected articles published in English, reviews and abstracts. During the advanced search type in PubMed, combinations of the following keywords were used: “pituitary adenoma”, “invasive”, “aggressive”, “biomarkers”, “classification”, “histological subtypes”, ‘”immunohistochemical markers”. Results: 215 articles were selected, regarding diagnostic, prognostic and therapeutic aspects. There were some histological subtypes of pituitary adenomas known as having an aggressive clinical behavior. Several biomarkers were identified as being associated with the invasive feature: proliferation markers (Ki-67 index, number of mitoses, p53 & p27 expression, microvascularization density, telomerase, topoisomerase 2 Alpha), matrix metalloproteinases, protein kinase C, cyclooxygenase-2, E-cadherin, transcription Factors, genetic alterations (PTTG gene, Galectin-3 protein/ LGALS3 gene), apoptosis markers. Based on their invasion and proliferation characteristics, pituitary tumors are proposed to be classified into five grades (1a, 1b, 2a, 2b, 3), the grade 2b tumor with high risk of recurrence being considered as tumor suspected of malignancy. Conclusions: Using a set of specific biological markers for invasive process, there is hope to establish an early diagnosis and prevention of invasive pituitary adenomas. Due to the fact that aggressive pituitary tumors are generally difficult to manage, unresponsive to therapy, quickly recurrent and associated with poor prognosis, the early diagnosis and the search for new therapeutic approaches is becoming mandatory. Instead of using “invasive” or “aggressive” adenoma, the term “tumor suspected of malignancy” would be used for more accuracy

Osilodrostat, a potent oral 11β-hydroxylase inhibitor: 22-week, prospective, Phase II study in Cushing's disease

PURPOSE

In a 10-week proof-of-concept study (LINC 1), the potent oral 11β-hydroxylase inhibitor osilodrostat (LCI699) normalized urinary free cortisol (UFC) in 11/12 patients with Cushing's disease. The current 22-week study (LINC 2; NCT01331239) further evaluated osilodrostat in patients with Cushing's disease.

METHODS

Phase II, open-label, prospective study of two patient cohorts. Follow-up cohort: 4/12 patients previously enrolled in LINC 1, offered re-enrollment if baseline mean UFC was above ULN. Expansion cohort: 15 newly enrolled patients with baseline UFC > 1.5 × ULN. In the follow-up cohort, patients initiated osilodrostat twice daily at the penultimate efficacious/tolerable dose in LINC 1; dose was adjusted as needed. In the expansion cohort, osilodrostat was initiated at 4 mg/day (10 mg/day if baseline UFC > 3 × ULN), with dose escalated every 2 weeks to 10, 20, 40, and 60 mg/day until UFC ≤ ULN. Main efficacy endpoint was the proportion of responders (UFC ≤ ULN or ≥50% decrease from baseline) at weeks 10 and 22.

RESULTS

Overall response rate was 89.5% (n/N = 17/19) at 10 weeks and 78.9% (n/N = 15/19) at 22 weeks; at week 22, all responding patients had UFC ≤ ULN. The most common AEs observed during osilodrostat treatment were nausea, diarrhea, asthenia, and adrenal insufficiency (n = 6 for each). New or worsening hirsutism (n = 2) and/or acne (n = 3) were reported among four female patients, all of whom had increased testosterone levels.

CONCLUSIONS

Osilodrostat treatment reduced UFC in all patients; 78.9% (n/N = 15/19) had normal UFC at week 22. Treatment with osilodrostat was generally well tolerated.

A critical reappraisal of bilateral adrenalectomy for ACTH-dependent Cushing's syndrome

OBJECTIVE

Our aim was to review short- and long-term outcomes of patients treated with bilateral adrenalectomy (BADx) in ACTH-dependent Cushing's syndrome.

METHODS

We reviewed the literature and analysed our experience with 53 patients treated with BADx since 1990 in our institution.

RESULTS

BADx is considered if ACTH-dependent Cushing's syndrome is refractory to other treatment modalities. In Cushing's disease (CD), BADx is mainly used as an ultima ratio after transsphenoidal surgery and medical therapies have failed. In these cases, the time span between the first diagnosis of CD and treatment with BADx is relatively long (median 44 months). In ectopic Cushing's syndrome, the time from diagnosis to BADx is shorter (median 2 months), and BADx is often performed as an emergency procedure because of life-threatening complications of severe hypercortisolism. In both situations, BADx is relatively safe (median surgical morbidity 15%; median surgical mortality 3%) and provides excellent control of hypercortisolism; Cushing's-associated signs and symptoms are rapidly corrected, and co-morbidities are stabilised. In CD, the quality of life following BADx is rapidly improving, and long-term mortality is low. Specific long-term complications include the development of adrenal crisis and Nelson's syndrome. In ectopic Cushing's syndrome, long-term mortality is high but is mostly dependent on the prognosis of the underlying malignant neuroendocrine tumour.

CONCLUSION

BADx is a relatively safe and highly effective treatment, and it provides adequate control of long-term co-morbidities associated with hypercortisolism.

Cushing's syndrome

Chronic exposure to excess glucorticoids results in diverse manifestations of Cushing's syndrome, including debilitating morbidities and increased mortality. Genetic and molecular mechanisms responsible for excess cortisol secretion by primary adrenal lesions and adrenocorticotropic hormone (ACTH) secretion from corticotroph or ectopic tumours have been identified. New biochemical and imaging diagnostic approaches and progress in surgical and radiotherapy techniques have improved the management of patients. The therapeutic goal is to normalise tissue exposure to cortisol to reverse increased morbidity and mortality. Optimum treatment consisting of selective and complete resection of the causative tumour is necessay to allow eventual normalisation of the hypothalamic-pituitary-adrenal axis, maintenance of pituitary function, and avoidance of tumour recurrence. The development of new drugs offers clinicians several choices to treat patients with residual cortisol excess. However, for patients affected by this challenging syndrome, the long-term effects and comorbidities associated with hypercortisolism need ongoing care.

Treatment of Cushing's Syndrome: An Endocrine Society Clinical Practice Guideline

OBJECTIVE

The objective is to formulate clinical practice guidelines for treating Cushing's syndrome.

PARTICIPANTS

Participants include an Endocrine Society-appointed Task Force of experts, a methodologist, and a medical writer. The European Society for Endocrinology co-sponsored the guideline.

EVIDENCE

The Task Force used the Grading of Recommendations, Assessment, Development, and Evaluation system to describe the strength of recommendations and the quality of evidence. The Task Force commissioned three systematic reviews and used the best available evidence from other published systematic reviews and individual studies.

CONSENSUS PROCESS

The Task Force achieved consensus through one group meeting, several conference calls, and numerous e-mail communications. Committees and members of The Endocrine Society and the European Society of Endocrinology reviewed and commented on preliminary drafts of these guidelines.

CONCLUSIONS

Treatment of Cushing's syndrome is essential to reduce mortality and associated comorbidities. Effective treatment includes the normalization of cortisol levels or action. It also includes the normalization of comorbidities via directly treating the cause of Cushing's syndrome and by adjunctive treatments (eg, antihypertensives). Surgical resection of the causal lesion(s) is generally the first-line approach. The choice of second-line treatments, including medication, bilateral adrenalectomy, and radiation therapy (for corticotrope tumors), must be individualized to each patient.

Re-examining Nelson's syndrome

PURPOSE OF REVIEW

Nelson's syndrome is a rare complication that can occur during the course of management of Cushing's disease. This article summarizes the recent literature on the diagnosis, monitoring and treatment of this potentially life-threatening outcome.

RECENT FINDINGS

Nelson's syndrome, with rising adrenocorticotropin hormone levels and corticotroph tumor progression on diagnostic imaging, can develop following treatment of refractory Cushing's disease with total bilateral adrenalectomy with/without radiotherapy. However, data showing that radiotherapy prevents Nelson's syndrome is inconsistent. In addition to the treatment of Nelson's syndrome with neurosurgery with/without adjuvant radiotherapy, selective somatostatin analogs and dopamine agonists, as well as other novel agents, have been used with increasing frequency in treating cases of Nelson's syndrome with limited benefit. The risk-benefit profile of each of these therapies is still not completely understood.

SUMMARY

Consensus guidelines on the evaluation and management of Nelson's syndrome are lacking. This article highlights areas in the surveillance of Cushing's disease patients, and diagnostic criteria and treatment regimens for Nelson's syndrome that require further research and review by experts in the field.

The Treatment of Cushing's Disease

Cushing's disease (CD), or pituitary-dependent Cushing's syndrome, is a severe endocrine disease caused by a corticotroph pituitary tumor and associated with increased morbidity and mortality. The first-line treatment for CD is pituitary surgery, which is followed by disease remission in around 78% and relapse in around 13% of patients during the 10-year period after surgery, so that nearly one third of patients experience in the long-term a failure of surgery and require an additional second-line treatment. Patients with persistent or recurrent CD require additional treatments, including pituitary radiotherapy, adrenal surgery, and/or medical therapy. Pituitary radiotherapy is effective in controlling cortisol excess in a large percentage of patients, but it is associated with a considerable risk of hypopituitarism. Adrenal surgery is followed by a rapid and definitive control of cortisol excess in nearly all patients, but it induces adrenal insufficiency. Medical therapy has recently acquired a more important role compared to the past, due to the recent employment of novel compounds able to control cortisol secretion or action. Currently, medical therapy is used as a presurgical treatment, particularly for severe disease; or as postsurgical treatment, in cases of failure or incomplete surgical tumor resection; or as bridging therapy before, during, and after radiotherapy while waiting for disease control; or, in selected cases, as primary therapy, mainly when surgery is not an option. The adrenal-directed drug ketoconazole is the most commonly used drug, mainly because of its rapid action, whereas the glucocorticoid receptor antagonist, mifepristone, is highly effective in controlling clinical comorbidities, mainly glucose intolerance, thus being a useful treatment for CD when it is associated with diabetes mellitus. Pituitary-directed drugs have the advantage of acting at the site responsible for CD, the pituitary tumor. Among this group of drugs, the dopamine agonist cabergoline and the somatostatin analog pasireotide result in disease remission in a consistent subgroup of patients with CD. Recently, pasireotide has been approved for the treatment of CD when surgery has failed or when surgery is not an option, and mifepristone has been approved for the treatment of Cushing's syndrome when associated with impairment of glucose metabolism in case of the lack of a surgical indication. Recent experience suggests that the combination of different drugs may be able to control cortisol excess in a great majority of patients with CD.

Emerging drugs for Cushing's disease

INTRODUCTION

Considering the effects of uncontrolled hypercortisolism on morbidity and mortality, there is a clear need for effective medical therapy for patients with Cushing's disease (CD). Therefore, the search for new medical effective tools remains active, and already promising results have been obtained.

AREAS COVERED

The importance of the design and conduct of trials to validate old drugs or to test new compounds is discussed. The results of the ongoing clinical trials, targeting the specific properties of drugs, such as ketoconazole, LCI699, mifepristone, etomidate and pasireotide, are also reported. The authors also emphasise the advantages and drawbacks of each particular drug, and the potential combined use of agents with complementary mechanisms of action.

EXPERT OPINION

CD is an excellent example of a situation where effective therapy is essential, but where the balance of risk and benefit must be carefully judged. Metyrapone is the drug of choice when rapid control of the hypercortisolaemia is required, ketoconazole represents a good second-line drug, although in the future LCI699 may be a better alternative. Mifepristone can also be used in the rare situation when previous drugs are inappropriate. Etomidate is useful where immediate parenteral action is required. For drugs working directly on the pituitary, cabergoline is occasionally effective and pasireotide can be attempted in patients with mild CD.

Cushing's syndrome: epidemiology and developments in disease management

Cushing’s syndrome is a rare disorder resulting from prolonged exposure to excess glucocorticoids. Early diagnosis and treatment of Cushing’s syndrome is associated with a decrease in morbidity and mortality. Clinical presentation can be highly variable, and establishing the diagnosis can often be difficult. Surgery (resection of the pituitary or ectopic source of adrenocorticotropic hormone, or unilateral or bilateral adrenalectomy) remains the optimal treatment in all forms of Cushing’s syndrome, but may not always lead to remission. Medical therapy (steroidogenesis inhibitors, agents that decrease adrenocorticotropic hormone levels or glucocorticoid receptor antagonists) and pituitary radiotherapy may be needed as an adjunct. A multidisciplinary approach, long-term follow-up, and treatment modalities customized to each individual are essential for optimal control of hypercortisolemia and management of comorbidities.

Update on radiation therapy in patients with Cushing's disease

INTRODUCTION

Radiation therapy is an important therapy for patients with Cushing's disease who are not in remission or relapse after transsphenoidal pituitary surgery and are not considered surgical candidates. The development of stereotactic radiation therapy, using gamma knife, linear accelerators or proton beam based methods, has enabled selective radiation delivery to the target while minimizing exposure of healthy tissues. In patients whose tumors are sufficiently distant from the optic apparatus, stereotactic radiation therapy can be delivered in a single session, a procedure termed radiosurgery, which significantly improves patient convenience.

METHODS

Original articles on radiation therapy in Cushing's disease, published during the past 12 months (2013-2014), were identified and pertinent data extracted.

RESULTS

Recent studies have reported on the outcomes of patients with Cushing's disease who received mostly stereotactic radiation therapy. While tumor control has been excellent, biochemical remission was less consistently achieved. Some studies suggested that stereotactic radiation may lead to biochemical remission faster than conventional radiation therapy. In addition, retrospective data have suggested that withdrawing medical therapy around the time stereotactic radiation therapy is administered might lead to a faster biochemical response. Regardless of the radiation therapy method, biochemical recurrences may develop and these patients are at long-term risk of developing anterior hypopituitarism and require lifelong periodic endocrine follow-up. Other, less frequent complications may include cranial neuropathies, secondary tumor formation or temporal lobe necrosis. It is plausible that complications may be less frequent after stereotactic radiation therapy, but this requires confirmation.

CONCLUSIONS

Radiation therapy is an effective second line therapy in patients with Cushing's disease. Ongoing refinements in delivery of radiation therapy are anticipated to lead to improved patient outcomes, but long-term follow-up data, including adequate control groups, are needed to fully investigate this possibility.

Bilateral adrenalectomy for Cushing's disease

PURPOSE

Review the indications, outcomes, and consequences of bilateral adrenalectomy (BLA) in patients with Cushing's disease.

METHODS

A literature review was performed.

RESULTS

The primary therapy for Cushing's disease is surgery, with medical therapy and radiation therapy relegated to an adjuvant role. BLA is indicated in cases of persistent disease following pituitary surgery or in situations where rapid normalization of hypercortisolism is required. When performed via the laparoscopic approach, BLA is associated with a significantly reduced morbidity compared to the traditional, open approach. Following BLA, patients are at risk for adrenal crisis and the concern of Nelson's syndrome. However, BLA leads to a rapid resolution of the signs and symptoms of CS and leads to an improved long-term quality of life.

CONCLUSION

BLA should be considered in the treatment algorithm for patients with persistent CD after failed pituitary surgery, especially in patients who have severe consequences of hypercortisolism or desire pregnancy.

Treatment of Cushing's disease: a mechanistic update

Cushing's disease (CD) is characterized by an ACTH-producing anterior corticotrope pituitary adenoma. If hypothalamus-pituitary-adrenal (HPA) axis physiology is disrupted, ACTH secretion increases, which in turn stimulates adrenocortical steroidogenesis and cortisol production. Medical treatment plays an important role for patients with persistent disease after surgery, for those in whom surgery is not feasible, or while awaiting effects of radiation. Multiple drugs, with different mechanisms of action and variable efficacy and tolerability for controlling the deleterious effects of chronic glucocorticoid excess, are available. The molecular basis and clinical data for centrally acting drugs, adrenal steroidogenesis inhibitors, and glucocorticoid receptor antagonists are reviewed, as are potential novel molecules and future possible targets for CD treatment. Although progress has been made in the understanding of specific corticotrope adenoma receptor physiology and recent clinical studies have detected improved effects with a combined medical therapy approach, there is a clear need for a more efficacious and better-tolerated medical therapy for patients with CD. A better understanding of the molecular mechanisms in CD and of HPA axis physiology should advance the development of new drugs in the future.

Changes in plasma ACTH levels and corticotroph tumor size in patients with Cushing's disease during long-term treatment with the glucocorticoid receptor antagonist mifepristone

CONTEXT

Pituitary effects of long-term therapy with mifepristone, a glucocorticoid receptor antagonist, in Cushing's disease (CD) patients are not well understood.

OBJECTIVE

Our objective was to report changes in ACTH and pituitary magnetic resonance imaging (MRI) findings during long-term use of mifepristone in CD patients.

DESIGN AND SETTING

The Study of the Efficacy and Safety of Mifepristone in the Treatment of Endogenous Cushing's Syndrome (SEISMIC) was a 24-week, open-label study of mifepristone, and its long-term extension (LTE) is a multicenter U.S. study.

PATIENTS

Forty-three CD patients (mean age 45.3 years) were enrolled in SEISMIC with 27 continuing into the LTE study.

INTERVENTIONS

Mifepristone (300-1200 mg) was administered once daily.

MAIN OUTCOME MEASURES

ACTH and pituitary MRI were assessed at baseline and at regular intervals during treatment.

RESULTS

A ≥2-fold increase in ACTH was observed in 72% of patients treated for a median duration of 11.3 months. The mean peak increase in ACTH was 2.76 ± 1.65-fold during SEISMIC, and mean ACTH concentrations remained stable during the LTE. ACTH was directly correlated with mifepristone dose and declined to near baseline levels after mifepristone discontinuation. Tumor regressed in 2 patients and progressed in 3 patients with macroadenomas. An additional microadenoma was identified after 25 months of treatment after a baseline tumor-negative MRI.

CONCLUSIONS

In the largest prospective study to date, long-term mifepristone treatment increased ACTH in approximately two-thirds of patients with CD. ACTH elevations were observed within the first few weeks of treatment, were dose-dependent, and generally remained stable over time. Corticotroph tumor progression and regression may occur over time, but patients may have significant increases in ACTH levels without evidence of tumor growth.

Nasally located ectopic ACTH-secreting pituitary adenoma (EAPA) causing Nelson's syndrome: diagnostic challenges

PURPOSE

We report the first case of an Ectopic adrenocorticotrophin (ACTH)-secreting pituitary adenoma (EAPA) located within the posterior nasal septum associated with Nelson's syndrome, which eluded diagnosis for over a decade. In this report, we explore the reasons for such diagnostic difficulty and suggest ways in which an earlier diagnosis may be made.

METHODS AND RESULTS

A 19 years old Lebanese man presented in 2000, with overt Cushing's syndrome confirmed with markedly elevated urine free cortisols and failed dexamethasone suppression tests. An unsuppressed ACTH and a possible 5 mm adenoma on MRI (Magnetic Resonance Imaging) pituitary suggested Cushing's disease. The patient underwent trans-sphenoidal surgery (TSS), but histology revealed normal pituitary tissue and Cushing's syndrome persisted. A repeat MRI pituitary showed no anomaly, and extensive investigations failed to locate an ectopic lesion. Subsequently a bilateral adrenalectomy was performed. Over the ensuing years, the patient developed Nelson's syndrome with hyperpigmentation and markedly elevated ACTH levels. Repeated high dose dexamethasone suppression tests, corticotrophin releasing hormone (CRH) tests, and CRH stimulated inferior petrosal sinus samplings (IPSS) suggested a pituitary origin of the ACTH. Two further TSS were unsuccessful. The pituitary was irradiated. Subsequent review of his previous MRIs revealed an enlarging mass within the posterior nasal septum, which was excised in 2011. The histology confirmed the diagnosis of an EAPA within the nasal septum.

CONCLUSION

Ectopic ACTH-secreting pituitary adenomas can occur not only along the developmental route of Rathke's pouch, but other aberrant locations giving a clinical and biochemical picture identical to Cushing's disease or Nelson's syndrome. Clinicians should suspect an EAPA, when a central ACTH source seems to be apparent with no obvious pituitary adenoma. A detailed MRI involving possible EAPA sites aids in locating these unusual lesions.

Managing Cushing's disease: the state of the art

Cushing's disease is a rare chronic disease caused by a pituitary adenoma, which leads to excess secretion of adrenocorticotropic hormone (ACTH). The over-production of ACTH leads to hyperstimulation of the adrenal glands and a chronic excess of cortisol, resulting in the signs and symptoms of a severe clinical state (Cushing's syndrome) that leads to significant morbidity, negative impacts on the patient's quality of life, and, if untreated, increased mortality. The management of patients with Cushing's disease is complicated by the heterogeneity of the condition, with signs and symptoms that overlap with those of other diseases, and high subclinical incidence rates. Controversies surrounding the tests used for screening and identifying patients with Cushing's disease add to the challenge of patient management. Surgical intervention to remove the adenoma is the first-line treatment for patients with Cushing's disease, but medical therapies are useful in patients who relapse or are unsuitable for surgery. The recent introduction of pasireotide, the first pituitary-directed medical therapy, expands the number of treatment options available for patients with Cushing's disease. This state-of-the-art review aims to provide an overview of the most recent scientific research and clinical information regarding Cushing's disease. Continuing research into improving the diagnosis and treatment of Cushing's disease will help to optimize patient management.

Characterization of persistent and recurrent Cushing's disease

A case of possible recurrent Cushing's disease (CD) is presented and data on current definitions of CD remission, persistence, and recurrence are reviewed. While prevailing guidelines recommend the use of serum cortisol in the first post-operative week for defining initial remission and predicting sustained remission, with the use of 24 h urinary free cortisol measurements if serum cortisol values are equivocal, there is debate as to which methods and thresholds best define CD remission and predict successful outcomes. Other methods used to define remission (and hence persistence and recurrence) include restoration of cortisol suppression after dexamethasone and physiologic diurnal cortisol rhythm as measured by midnight salivary free cortisol. However, the number and degree of abnormal test results needed to define recurrence, and the determination of which biochemical test has more significance when there are discrepancies between markers is inconsistent among studies. Further inquiry is warranted to examine if patients in apparent CD remission who have subtle hypothalamic pituitary adrenal (HPA) axis abnormalities represent distinctive remission subtypes versus mild or early recurrence. Additional investigation could also explore the degree to which these HPA axis abnormalities, such as alterations in cortisol circadian rhythm or partial resistance to dexamethasone, are associated with persistence of CD morbidities, including neuropsychiatric impairments, alterations in body composition, and cardiovascular risk.

Favorable long-term outcomes of bilateral adrenalectomy in Cushing's disease

OBJECTIVE

Bilateral adrenalectomy (BADX) is an important treatment option for patients with Cushing's syndrome (CS). Our aim is to analyze the long-term outcomes, surgical, biochemical, and clinical as well as morbidity and mortality, of patients who underwent BADX.

DESIGN

A total of 50 patients who underwent BADX since 1990 in two German centers were identified. Of them, 34 patients had Cushing's disease (CD), nine ectopic CS (ECS), and seven ACTH-independent bilateral adrenal hyperplasia (BAH).

METHODS

Standardized follow-up examination was performed in 36 patients with a minimum follow-up time of 6 months after BADX and a median follow-up time of 11 years.

RESULTS

Surgical morbidity and mortality were 6 and 4% respectively. All patients were found to be in remission after BADX. Almost all Cushing's-specific comorbidities except for psychiatric diseases improved significantly. Health-related quality of life remained impaired in 45.0% of female and 16.7% of male patients compared with a healthy population. The median number of adrenal crises per 100 patient-years was four. Nelson tumor occurred in 24% of CD patients after a median time span of 51 months. Long-term mortality after 10 years was high in ECS (44%) compared with CD (3%) and BAH (14%).

CONCLUSIONS

BADX is an effective and relatively safe treatment option especially in patients with CD. The majority of patients experience considerable improvement of Cushing's symptoms.

[Cushing syndrome: Physiopathology, etiology and principles of therapy]

The most frequent cause of Cushing's syndrome is iatrogenic, as Cushing's syndrome is the unavoidable consequence of long-term glucocorticoid treatment using more than 7.5 mg prednisone per day. The most frequent cause of endogenous Cushing's syndrome is Cushing's disease (CD), which is an ACTH dependent hypercortisolism linked to a pituitary corticotroph adenoma. This adenoma is often very small, its diagnosis may require bilateral inferior petrosal sinus sampling and the first line treatment of CD is transsphenoidal surgery by an expert neurosurgeon. The second line treatments include drugs that can act either on the pituitary adenoma or on adrenal steroidogenesis, pituitary radiotherapy or bilateral adrenalectomy. Ectopic ACTH dependent Cushing's syndrome is linked either to poorly differentiated endocrine tumors with a very poor prognosis, such as small cell lung cancer, or to well differentiated endocrine tumors, such as bronchial carcinoid tumors, which have a good prognosis when treated by surgery, but may be very difficult to localize. Adrenal Cushing's syndromes, which are independent of pituitary ACTH secretion, include adrenal cortex carcinoma, which requires abdominal surgery with extended adrenalectomy by an expert surgeon, adrenal adenoma which is treated by laparoscopic unilateral adrenalectomy and bilateral macronodular hyperplasia, whose surgical treatment may require unilateral or bilateral adrenalectomy. Treatment of Cushing's syndrome generally leads to spectacular clinical results, which must not hide the fact that the reversibility of some signs is actually incomplete. This underlines the need for a timely multidisciplinary management of the patients by an expert team.

Efficacy of medical treatment in Cushing's disease: a systematic review

OBJECTIVE

Reported rates of response to medical therapies used in Cushing's disease (CD) vary widely. The aim of this review is to analyse systematically the efficacy of medical therapies for CD and to assess the strength of the supporting evidence.

METHODS

Systematic PubMed searches identified studies of medical treatment in CD. The GRADE criteria were imposed to assess the strength of evidence supporting each medication.

RESULTS

Fifteen studies were included. Ten studies specifically reported response rates for patients with CD. Pasireotide was the only treatment to be assessed in a randomized trial and was supported by a 'moderate' level of evidence. Response rates with pasireotide from three prospective studies were 17-29%. The remaining medications were supported by a 'low' or 'very low' level of evidence. The highest response rates were reported in small retrospective studies of metyrapone (75%, one study) and mitotane (72%, one study). Response rates were 25-50% for cabergoline (four studies) and 45% for ketoconazole (one study). Among studies that included patients with other forms of Cushing's syndrome, response rates were 53-88% for ketoconazole (three studies), 70% for mitotane (one study), 57% for metyrapone (one study) and 38-60% for mifepristone. Again, all of these medications are supported by a 'low' level of evidence.

CONCLUSIONS

There is a paucity of high-quality studies of medical therapy in CD, with only one medication achieving a 'moderate' level of evidence. Caution should be employed when comparing efficacy rates owing to the variability in study design and quality.

[Cushing's disease with negative imaging in adults]

In more than one third of patients with Cushing's disease, pituitary MRI does not identify a microadenoma. The diagnostic approach should be as rigorous as possible in patients with ACTH-dependent Cushing's syndrome, to obtain a definitive diagnosis. Improved pituitary MRI techniques, including dynamic sequences, optimal T1-weighted spin-echo MRI protocol, MRI technique of spoiled gradient recalled acquisition in the steady state, and using a 3-tesla magnet, improved the tumor detection rate, parallel to the performance of endocrine dynamic tests (CRH stimulation, desmopressin stimulation and high-dose dexamethasone suppression tests). When a pituitary tumor is not convincingly identified, inferior petrosal sinus sampling remains the gold standard for diagnosis, and recently, new approaches (simultaneous prolactin measurement) could improve its sensitivity and specificity. Transsphenoidal surgery is the first-line treatment, with remission rates similar to those of patients with preoperative positive MRI. However, medical therapies play an important role after surgical failure or in a search for the onset of a visible tumor, especially with development of new drugs targeting the pituitary gland.

Effect of stereotactic radiosurgery before bilateral adrenalectomy for Cushing's disease on the incidence of Nelson's syndrome

Object

Nelson's syndrome (NS) is a significant and frequent risk for patients with Cushing's disease (CD) who undergo bilateral adrenalectomy. A recent study has shown tumor progression in 47% of patients at risk for NS. The authors sought to define the rate of NS in patients who were treated with Gamma Knife stereotactic radiosurgery (GK SRS) prior to bilateral adrenalectomy.

Methods

Consecutive patients with CD who were treated with GK SRS after pituitary surgery but before bilateral adrenalectomy were included. Serial MRI sequences were analyzed to evaluate for pituitary tumor growth. Clinical evaluations were performed to screen for NS. Follow-up for adrenocorticotropic hormone levels and hormone studies of other pituitary axes was performed.

Results

Twenty consecutive patients were followed with neuroimaging and clinically for a median of 5.4 years (range 0.6–12 years). One patient (5%) developed pituitary tumor growth consistent with NS 9 months after adrenalectomy. By Kaplan-Meier analysis, progression-free survival was 94.7% at 1, 3, and 7 years. No predisposing factors were identified for the tumor progression. Two patients developed new pituitary dysfunction and no patient developed cranial neuropathy or visual deficit after GK SRS.

Conclusions

These findings suggest that GK SRS not only serves a role as second-line therapy for CD, but that it also provides prophylaxis for NS when used before bilateral adrenalectomy.

A new therapeutic approach in the medical treatment of Cushing's syndrome: glucocorticoid receptor blockade with mifepristone

OBJECTIVE

Cushing's syndrome (CS) is a serious endocrine disorder caused by prolonged exposure to high cortisol levels. Initial treatment of this condition is dependent upon the cause, but is generally surgical. For patients whose hypercortisolism is not cured by surgery, medical therapy is often required. Drugs that have typically been used for CS medical therapy act by decreasing cortisol levels. Mifepristone is a glucocorticoid receptor antagonist now available for use in patients with CS. Unlike other agents, mifepristone does not decrease cortisol levels, but directly antagonizes its effects. Our objective is to review the pharmacology and clinical use of this novel agent and to discuss detailed guidance on the management of CS patients treated with mifepristone.

METHODS

We review the literature regarding mifepristone use in CS and recently published clinical trial data. Detailed information related to clinical assessment of mifepristone use, potential drug interactions, drug initiation and dose titration, and monitoring of drug tolerability are provided.

RESULTS

Clinical trial data have shown that mifepristone improves glycemic control and blood pressure, causes weight loss and a decrease in waist circumference, lessens depression, and improves overall wellbeing. However, adverse effects include adrenal insufficiency, hypokalemia, and endometrial thickening with vaginal bleeding. These findings are supported by the earlier literature case reports.

CONCLUSION

This article provides a review of the pharmacology and clinical use of mifepristone in Cushing's syndrome, as well as detailed guidance on the management of patients treated with this novel agent.

Nelson's syndrome presenting as bilateral oculomotor palsy

Nelson's syndrome refers to a clinical spectrum arising from progressive enlargement of pituitary adenoma and elevated adrenocorticotrophic hormone after total bilateral adrenalectomy for Cushing's disease comprising of hyperpigmentation, visual field defects which can be life threatening. We report here a 50-year male presenting with rapid onset of Nelson's syndrome with an unusual finding of bilateral oculomotor palsy mistakenly treated as ocular myasthenia.

Medical management of Cushing's disease

Cushing's disease (CD), caused by excess adrenocorticotropin secretion from tumorous pituitary corticotrophs, is associated with substantial morbidity and mortality. The primary, definitive therapy for patients with CD is selective pituitary adenomectomy, generally performed via a transsphenoidal approach. Medical therapy has an important adjunctive role in the management of patients with CD, including preoperative patient preparation in patients with severe disease, and temporizing management of hypercortisolism while awaiting the effects of radiation therapy to occur in patients who are not in remission postoperatively. Medical therapy can also be used in patients with hypercortisolism of unclear origin or in the few patients who decline or are unfit for surgery. Available medical options for patients with CD include centrally acting agents (cabergoline and pasireotide), steroidogenesis inhibitors (ketoconazole, metyrapone, mitotane and etomidate) and a glucocorticoid receptor antagonist (mifepristone). Pasireotide and mifepristone have been recently granted regulatory approval in some countries for use in patients with CD, whereas other medications are used "off label" in this patient population. As clinical trials using comparator agents have not been reported, the choice between different medications is based on patient characteristics and preference. Despite impressive advances in pharmacotherapy for patients with CD, much remains to be done. The long term efficacy and safety of medical therapies for hypercortisolism need to be evaluated and the role of combination therapy must be further characterized. As the pathogenesis of CD becomes better understood at the molecular level, it is likely that novel, targeted medical therapies will be developed to treat CD.

Mifepristone: is there a place in the treatment of Cushing's disease?

The purpose was to review the use of mifepristone in the treatment of Cushing's syndrome (CS) in the context of other recently published studies. We review the use of mifepristone, as published in the recent Study of the Efficacy and Safety of Mifepristone in the Treatment of Endogenous Cushing's Syndrome (SEISMIC). We also review the multiple case reports and case series of mifepristone use in CS. A review of other medications used in the treatment of Cushing's disease (CD), including pasireotide and cabergoline also provides context for the discussion of the role of mifepristone in the treatment of CD. The results show that the treatment of CD has been primarily surgical with medical therapy reserved for adjuvant therapy when primary treatment fails or other therapies require time for optimal efficacy. Two recent large prospective studies, using pasireotide and mifepristone provide new clinical insights to the medical treatment of CD in particular. Mifepristone has been used to treat excessive cortisol production by blocking the action of cortisol at the level of the glucocorticoid receptor. Until recently, the majority of clinical experience with mifepristone on the treatment of excess cortisol was derived from case reports and small case series. Based on the SEISMIC study, mifepristone was FDA approved for hyperglycemia associated with CS. In conclusion the role of mifepristone in the treatment of CD remains one of adjuvant therapy. Its place among other choices for medical therapy has yet to be firmly established and an evidenced-based approach toward the use of novel medications in the treatment of CD has not been made. Selection of medication depends on drug approval and availability in individual countries and requires cautious assessment of potential adverse effects, consideration of patient comorbidities, and efficacy.

Approach to the Cushing's disease patient with persistent/recurrent hypercortisolism after pituitary surgery

Although it is the ideal treatment, pituitary surgery is not always successful, and success is not always lasting. Close surveillance, clinical and biological, will detect immediate failure or late recurrence. The reason must be thoroughly explored with the somewhat dogmatic rule that the patient should be offered the best surgery in expert hands, and a repeat surgical attempt must be systematically discussed. When repeat pituitary surgery is not indicated or has failed, then comes the difficult task to choose between a number of options directed toward different targets: directly suppress tumor ACTH by pituitary radiotherapy (conventional or stereotaxic) or with medications (somatostatin analog such as pasireotide, or dopaminergic drug such as cabergoline), directly suppress adrenocortical activity with medications (inhibitors of adrenal steroidogenesis such as ketoconazole or metyrapone, or the adrenolytic Lysodren), or by surgery (bilateral adrenalectomy), and finally oppose peripheral cortisol action with the antiglucocorticoid mifepristone. No single option is ideal, able to provide at the same time a high success rate and a rapid onset of action, to restore a normal pituitary adrenal axis, and to have good tolerability. Close follow-up and thorough evaluation of the cortisolic status will eventually dictate a switch in treatment options and/or combination strategies over time. The tumor status and its possible oncogenic threat, the severity of the hypercortisolism, and the patient perspectives (wish of fertility) are among the major parameters that can help a multidisciplinary approach toward the best option.

Medical management of persistent and recurrent cushing disease

Recent evidence supports the notion that the incidence of Cushing disease is higher than previously thought. Transphenoidal surgery, in the hands of experienced neurosurgeons, is currently considered the first-line treatment of choice. However, an examination of remission and recurrence rates in long-term follow-up studies reveals that potentially up to 40% to 50% of patients could require additional treatment. If left untreated, the resultant morbidity and mortality are high. Successful clinical management of patients with Cushing disease remains a challenge. The development of new therapeutic agents has been eagerly anticipated. This article discusses the results of currently available and promising new therapeutic agents used to treat this challenging disease.

Medical management of Cushing's syndrome

Cushing's syndrome is a debilitating endocrine disorder which results from hypercortisolemia. While endogenous Cushing's syndrome can be caused by an adrenocorticotrophic hormone (ACTH)-dependent or ACTH-independent mechanism, it is most often a result of excess secretion of ACTH by a corticotroph adenoma (Cushing's disease). Untreated hypercortisolemia causes significant morbidity and increased mortality due to its metabolic effects including hypertension, osteoporosis, obesity, dyslipidemia, osteoporosis and glucose intolerance. Although primary therapy is surgical, a substantial portion of patients will go on to require second-line therapies including repeat surgery, radiotherapy or drug therapy. While medical therapy for Cushing's syndrome has been limited, several new agents are being investigated. This aim of this review is to analyze and present the available options for medical management of Cushing's syndrome as well as review potential new therapies and their role in the treatment of this disorder.

Leksell Gamma Knife : An Effective Non Invasive Treatment for Rare Case of Nelson's Syndrome

Nelson's syndrome nowadays a rare entity results from an adrenocorticotropin (ACTH)-secreting pituitary adenoma in patients with refractory Cushing's disease after a therapeutic bilateral adrenal gland removal. We report a case of 25 year old female with cushing's disease who was initially managed with medical treatment, but in view of severe persistent hyper cortisol state was subjected to bilateral adrenalectomy following which she developed Nelson's syndrome after a gap of six years, which was difficult to diagnose because of limited investigations available. Patient was managed with stereotactic radiosurgery (gamma knife surgery).

Efficiency and tolerance of mitotane in Cushing's disease in 76 patients from a single center

CONTEXT

Alternatives to transsphenoidal pituitary surgery may be required in Cushing's disease (CD) as a first- or second-line treatment. Mitotane is a potent anti-cortisolic drug but has been rarely investigated in the treatment of CD.

OBJECTIVE

Evaluation of the efficacy and tolerance of mitotane in CD patients.

DESIGN AND SETTING

Retrospective analysis of 76 patients treated with mitotane from 219 patients diagnosed with CD between 1993 and 2009 in a single center.

MAIN OUTCOME MEASURE

Remission was defined as normalization of 24-h urinary free cortisol (24-h-UFC).

RESULTS

Remission was achieved in 48 (72%) of the 67 long-term treated patients, after a median time of 6.7 (5.2-8.2) months. Mean plasma mitotane concentration at the time of remission was 10.5 ± 8.9 mg/l, with a mean daily dose of 2.6 ± 1.1 g. A negative linear relationship was observed between plasma mitotane concentration and 24-h-UFC (P<0.0001). Seventeen of 24 (71%) patients with durable remission subsequently experienced recurrence, after a median time of 13.2 (5.0-67.9) months. At the time of treatment discontinuation, ACTH concentration was statistically associated with a lower recurrence probability (hazard ratios 0.57 (0.32-1.00), P=0.05). Intolerance leading to treatment discontinuation occurred in 19 patients (29%). A pituitary adenoma became identifiable during mitotane treatment in 12 (25%) of the 48 patients with initial negative pituitary imaging allowing subsequent transsphenoidal surgery.

CONCLUSION

Mitotane is useful at different stages of CD. Mitotane dose adjustment based on plasma concentration monitoring and side effects could control hypercortisolism in the majority of CD patients.

Medical management of Cushing's disease: what is the future?

Cushing's disease (CD) is caused by a corticotroph, adrenocorticotropic-hormone (ACTH)-secreting pituitary adenoma resulting in significant morbidity and mortality. Transsphenoidal surgery is the initial treatment of choice in almost all cases. Remission rates for microadenomas are good at 65-90 % (with an experienced neurosurgeon) but remission rates are much lower for macroadenomas. However, even after postoperative remission, recurrence rates are high and can be seen up to decades after an initial diagnosis. Repeat surgery or radiation can be useful in these cases, although both have clear limitations with respect to efficacy and/or side effects. Hence, there is a clear unmet need for an effective medical treatment. Currently, most drugs act by inhibiting steroidogenesis in the adrenal glands. Most is known about the effects of ketoconazole and metyrapone. While effective, access to ketoconazole and metyrapone is limited in many countries, experience with long-term use is limited, and side effects can be significant. Recent studies have suggested a role for a pituitary-directed therapy with new multireceptor ligand somatostatin analogs (e.g., pasireotide, recently approved in Europe for treatment of CD), second-generation dopamine agonists, or a combination of both. Mifepristone (a glucocorticoid receptor antagonist) is another promising drug, recently approved by the FDA for treatment of hyperglycemia associated with Cushing's syndrome. We review available medical treatments for CD with a focus on the two most recent compounds referenced above. Our aim is to expand awareness of current research, and the possibilities afforded by available medical treatments for this mesmerizing, but often frightful disease.

The burden of Cushing's disease: clinical and health-related quality of life aspects

OBJECTIVE

Cushing's disease (CD) is a rare endocrine disorder characterized by excess secretion of ACTH due to a pituitary adenoma. Current treatment options are limited and may pose additional risks. A literature review was conducted to assess the holistic burden of CD.

DESIGN

Studies published in English were evaluated to address questions regarding the epidemiology of CD, time to diagnosis, health-related quality of life (HRQoL), treatment outcomes, mortality, prevalence of comorbidities at diagnosis, and reversibility of comorbidities following the treatment.

METHODS

a two-stage literature search was performed in Medline, EMBASE, and Science Citation Index, using keywords related to the epidemiology, treatment, and outcomes of CD: i) articles published from 2000 to 2012 were identified and ii) an additional hand search (all years) was conducted on the basis of bibliography of identified articles.

RESULTS

At the time of diagnosis, 58-85% of patients have hypertension, 32-41% are obese, 20-47% have diabetes mellitus, 50-81% have major depression, 31-50% have osteoporosis, and 38-71% have dyslipidemia. Remission rates following transsphenoidal surgery (TSS) are high when performed by expert pituitary surgeons (rates of 65-90%), but the potential for relapse remains (rates of 5-36%). Although some complications can be partially reversed, time to reversal can take years. The HRQoL of patients with CD also remains severely compromised after remission.

CONCLUSIONS

These findings highlight the significant burden associated with CD. As current treatment options may not fully reverse the burden of chronic hypercortisolism, there is a need for both improved diagnostic tools to reduce the time to diagnosis and effective therapy, particularly a targeted medical therapy.

Cushing's disease

Cushing’s disease, or pituitary ACTH dependent Cushing’s syndrome, is a rare disease responsible for increased morbidity and mortality. Signs and symptoms of hypercortisolism are usually non specific: obesity, signs of protein wasting, increased blood pressure, variable levels of hirsutism. Diagnosis is frequently difficult, and requires a strict algorithm. First-line treatment is based on transsphenoidal surgery, which cures 80% of ACTH-secreting microadenomas. The rate of remission is lower in macroadenomas. Other therapeutic modalities including anticortisolic drugs, radiation techniques or bilateral adrenalectomy will thus be necessary to avoid long-term risks (metabolic syndrome, osteoporosis, cardiovascular disease) of hypercortisolism. This review summarizes potential pathophysiological mechanisms, diagnostic approaches, and therapies.

Mifepristone, a glucocorticoid receptor antagonist, produces clinical and metabolic benefits in patients with Cushing's syndrome

CONTEXT

Cushing's syndrome (CS) is a disorder associated with significant morbidity and mortality due to prolonged exposure to high cortisol concentrations.

OBJECTIVE

Our objective was to evaluate the safety and efficacy of mifepristone, a glucocorticoid receptor antagonist, in endogenous CS.

DESIGN AND SETTING

We conducted a 24-wk multicenter, open-label trial after failed multimodality therapy at 14 U.S. academic medical centers and three private research centers.

PARTICIPANTS

Participants included 50 adults with endogenous CS associated with type 2 diabetes mellitus/impaired glucose tolerance (C-DM) or a diagnosis of hypertension alone (C-HT).

INTERVENTION

Mifepristone was administered at doses of 300-1200 mg daily.

MAIN OUTCOME MEASURES

We evaluated change in area under the curve for glucose on 2-h oral glucose test for C-DM and change in diastolic blood pressure from baseline to wk 24 for C-HT.

RESULTS

In the C-DM cohort, an area under the curve for glucose (AUC(glucose)) response was seen in 60% of patients (P < 0.0001). Mean ± sd glycated hemoglobin (HbA1c) decreased from 7.43 ± 1.52% to 6.29 ± 0.99% (P < 0.001); fasting plasma glucose decreased from 149.0 ± 75.7 mg/dl (8.3 ± 4.1 mmol/liter) to 104.7 ± 37.5 mg/dl (5.8 ± 2.1 mmol/liter, P < 0.03). In C-HT cohort, a diastolic blood pressure response was seen in 38% of patients (P < 0.05). Mean weight change was -5.7 ± 7.4% (P < 0.001) with waist circumference decrease of -6.78 ± 5.8 cm (P < 0.001) in women and -8.44 ± 5.9 cm (P < 0.001) in men. Overall, 87% (P < 0.0001) had significant improvement in clinical status. Insulin resistance, depression, cognition, and quality of life also improved. Common adverse events were fatigue, nausea, headache, low potassium, arthralgia, vomiting, edema, and endometrial thickening in women.

CONCLUSIONS

Mifepristone produced significant clinical and metabolic improvement in patients with CS with an acceptable risk-benefit profile during 6 months of treatment.

[Recent progress in the treatment of Cushing's disease]

Transsphenoidal surgery, possibly through the endoscopic approach, remains the first line treatment. Opposing cortisol action with mifepristone proved efficacious in some individual cases but but with major monitoring difficulties. Combined treatment with three anticortisolic drugs (metyrapone, ketokonazole, O,p'DDD) is particularly attractive in severe cases. The Nelson's syndrome has been revisited, and the corticotroph tumor progression should rather be cautiously assessed after bilateral adrenalectomy. Two molecules potentially act directly to suppress the ACTH secretion by the corticotroph adenoma: agonists of the D2 Dopamine receptor and of the somatostatin receptor type 5. Their efficacy remains modest (20 to 30% of the patients actually normalize urinary cortisol). Pituitary radiotherapy can be efficiently performed by stereotaxic approach.

Treatment Options in Cushing's Disease

Endogenous Cushing’s syndrome is a grave disease that requires a multidisciplinary and individualized treatment approach for each patient. Approximately 80% of all patients harbour a corticotroph pituitary adenoma (Cushing’s disease) with excessive secretion of adrenocorticotropin-hormone (ACTH) and, consecutively, cortisol. The goals of treatment include normalization of hormone excess, long-term disease control and the reversal of comorbidities caused by the underlying pathology. The treatment of choice is neurosurgical tumour removal of the pituitary adenoma. Second-line treatments include medical therapy, bilateral adrenalectomy and radiation therapy. Drug treatment modalities target at the hypothalamic/pituitary level, the adrenal gland and at the glucocorticoid receptor level and are commonly used in patients in whom surgery has failed. Bilateral adrenalectomy is the second-line treatment for persistent hypercortisolism that offers immediate control of hypercortisolism. However, this treatment option requires a careful individualized evaluation, since it has the disadvantage of permanent hypoadrenalism which requires lifelong glucocorticoid and mineralocorticoid replacement therapy and bears the risk of developing Nelson’s syndrome. Although there are some very promising medical therapy options it clearly remains a second-line treatment option. However, there are numerous circumstances where medical management of CD is indicated. Medical therapy is frequently used in cases with severe hypercortisolism before surgery in order to control the metabolic effects and help reduce the anestesiological risk. Additionally, it can help to bridge the time gap until radiotherapy takes effect. The aim of this review is to analyze and present current treatment options in Cushing’s disease.