Outcomes of Pituitary Radiation for Cushing's Disease

Cushing's syndrome

Endogenous Cushing's syndrome results from excess glucocorticoid secretion, which leads to a myriad of clinical manifestations, comorbidities, and increased mortality despite treatment. Molecular mechanisms and genetic alterations associated with different causes of Cushing's syndrome have been described in the last decade. Imaging modalities and biochemical testing have evolved; however, both the diagnosis and management of Cushing's syndrome remain challenging. Surgery is the preferred treatment for all causes, but medical therapy has markedly advanced, with new drug options becoming available. Nevertheless, several comorbidities remain even after patient remission, which can affect quality of life. Accurate and timely diagnosis and treatment are essential for mitigating chronic complications of excess glucocorticoids and improving patient quality of life. In this Seminar, we aim to update several important aspects of diagnosis, complications, and treatment of endogenous Cushing's syndrome of all causes.

Intensity-modulated radiotherapy for cushing's disease: single-center experience in 70 patients

Context

Intensity-modulated radiotherapy (IMRT) is a modern precision radiotherapy technique for the treatment of the pituitary adenoma.

Objective

Aim to investigate the efficacy and toxicity of IMRT in treating Cushing's Disease (CD).

Methods

70 of 115 patients with CD treated with IMRT at our institute from April 2012 to August 2021 were included in the study. The radiation doses were usually 45-50 Gy in 25 fractions. After IMRT, endocrine evaluations were performed every 6 months and magnetic resonance imaging (MRI) annually. Endocrine remission was defined as suppression of 1 mg dexamethasone test (DST) or normal 24-hour urinary free cortisol level (24hUFC). The outcome of endocrine remission, endocrine recurrence, tumor control and complications were retrieved from medical record.

Results

At a median follow-up time of 36.8 months, the endocrine remission rate at 1, 2, 3 and 5 years were 28.5%, 50.2%, 62.5% and 74.0%, respectively. The median time to remission was 24 months (95%CI: 14.0-34.0). Endocrine recurrence was found in 5 patients (13.5%) till the last follow-up. The recurrence-free rate at 1, 2, 3 and 5 years after endocrine remission was 98.2%, 93.9%, 88.7% and 88.7%, respectively. The tumor control rate was 98%. The overall incidence of new onset hypopituitarism was 22.9%, with hypothyroidism serving as the most common individual axis deficiency. Univariate analysis indicated that only higher Ki-67 index (P=0.044) was significant favorable factors for endocrine remission.

Conclusion

IMRT was a highly effective second-line therapy with low side effect profile for CD patients. Endocrine remission, tumor control and recurrence rates were comparable to previous reports on FRT and SRS.

Genetically engineered human pituitary corticotroph tumor organoids exhibit divergent responses to glucocorticoid receptor modulators

Cushing's disease (CD) is a serious endocrine disorder attributed to an adrenocorticotropic hormone (ACTH)-secreting pituitary neuroendocrine tumor (PitNET) that that subsequently leads to chronic hypercortisolemia. PitNET regression has been reported following treatment with the investigational selective glucocorticoid receptor (GR) modulator relacorilant, but the mechanisms behind that effect remain unknown. Human PitNET organoid models were generated from induced human pluripotent stem cells (iPSCs) or fresh tissue obtained from CD patient PitNETs (hPITOs). Genetically engineered iPSC derived organoids were used to model the development of corticotroph PitNETs expressing USP48 (iPSCUSP48) or USP8 (iPSCUSP8) somatic mutations. Organoids were treated with the GR antagonist mifepristone or the GR modulator relacorilant with or without somatostatin receptor (SSTR) agonists pasireotide or octreotide. In iPSCUSP48 and iPSCUSP8 cultures, mifepristone induced a predominant expression of SSTR2 with a concomitant increase in ACTH secretion and tumor cell proliferation. Relacorilant predominantly induced SSTR5 expression and tumor cell apoptosis with minimal ACTH induction. Hedgehog signaling mediated the induction of SSTR2 and SSTR5 in response to mifepristone and relacorilant. Relacorilant sensitized PitNET organoid responsiveness to pasireotide. Therefore, our study identified the potential therapeutic use of relacorilant in combination with somatostatin analogs and demonstrated the advantages of relacorilant over mifepristone, supporting its further development for use in the treatment of Cushing's disease patients.

Recurrent Cushing Disease: An Extensive Review on Pros and Cons of Different Therapeutic Approaches

OBJECTIVE

Recurrent Cushing disease (CD) is characterized by the reappearance of clinical and hormonal aspects of hypercortisolism that occur more than 6 months after an initial post-treatment remission.

METHODS

We performed a systematic review and meta-analysis to synthesize the evidence about remission and complication rates after transsphenoidal surgery (TSS) radiotherapy (RT) and medical therapy (MT) in recurrent CD patients. A quantitative systematic review was performed. Article selection was performed by searching MEDLINE (using PubMed), and Cochrane electronic bibliographic databases through 2020.

RESULTS

We noted 61 articles described therapeutic management of recurrent CD patients with representative outcome. A total of 723 patients received different therapeutic modality for their recurrent CD. The remission rates were 0.65 (95% confidence interval [CI] 0.60-0.70), 0.57 (95% CI 0.51-0.63), and 0.75 (95% CI 0.60-0.86) in the TSS, RT, and MT subgroups, respectively. The total remission rate after therapeutic approaches on recurrent CD patients was 0.64 (95% CI 0.60-0.68). A test for subgroup differences revealed there was a statistically significant difference between different subgroups (P = 0.01). The post hoc test showed that in comparison with RT, TSS (P = 0.0344) and MT (P = 0.0149) had a higher rate of remission. However, there was no statistically significant difference between separate therapeutic modalities in terms of complications including diabetes insipidus (P = 1.0) and hypopituitarism (P = 0.28).

CONCLUSIONS

Compared MT and TSS, RT has a statistically lower rate of remission. Although there is robust superiority of surgery over RT, interpretation of MT data must considered with caution due to the small number of included cases and wide CI range.

Development of Human Pituitary Neuroendocrine Tumor Organoids to Facilitate Effective Targeted Treatments of Cushing's Disease

(1) Background: Cushing's disease (CD) is a serious endocrine disorder caused by an adrenocorticotropic hormone (ACTH)-secreting pituitary neuroendocrine tumor (PitNET) that stimulates the adrenal glands to overproduce cortisol. Chronic exposure to excess cortisol has detrimental effects on health, including increased stroke rates, diabetes, obesity, cognitive impairment, anxiety, depression, and death. The first-line treatment for CD is pituitary surgery. Current surgical remission rates reported in only 56% of patients depending on several criteria. The lack of specificity, poor tolerability, and low efficacy of the subsequent second-line medical therapies make CD a medical therapeutic challenge. One major limitation that hinders the development of specific medical therapies is the lack of relevant human model systems that recapitulate the cellular composition of PitNET microenvironment. (2) Methods: human pituitary tumor tissue was harvested during transsphenoidal surgery from CD patients to generate organoids (hPITOs). (3) Results: hPITOs generated from corticotroph, lactotroph, gonadotroph, and somatotroph tumors exhibited morphological diversity among the organoid lines between individual patients and amongst subtypes. The similarity in cell lineages between the organoid line and the patient's tumor was validated by comparing the neuropathology report to the expression pattern of PitNET specific markers, using spectral flow cytometry and exome sequencing. A high-throughput drug screen demonstrated patient-specific drug responses of hPITOs amongst each tumor subtype. Generation of induced pluripotent stem cells (iPSCs) from a CD patient carrying germline mutation CDH23 exhibited dysregulated cell lineage commitment. (4) Conclusions: The human pituitary neuroendocrine tumor organoids represent a novel approach in how we model complex pathologies in CD patients, which will enable effective personalized medicine for these patients.

Role of Radiation in the treatment of Cushing Disease

In Cushing disease (CD), radiation therapy (RT) is mostly used in the adjuvant setting in patients who have failed transsphenoidal surgery or have recurrent CD. Stereotactic radiotherapy (SRT) is administered as either single or several sessions, and the most commonly used modalities include photon source (Gamma Knife, CyberKnife, and LINAC) or heavy particles (protons). In multicenter studies, Gamma Knife SRT can lead to biochemical control in 80%, with medial time to remission approximately 15 mos, and 70% recurrence free at 10 years. Conventional RT (CRT) consists of administration of small daily fractions over six weeks, with cumulative dose of 45-50 Gy. Biochemical control is achieved in up to 64% of patients with CRT. Choice of radiation modality includes convenience for patients (SRT is more convenient) and proximity to critical structures. Both forms of RT can result in hypopituitarism. RT remains an important modality for the treatment of patients with CD.

Update in Cushing disease: What the neurosurgeon has to KNOW, on behalf of the EANS skull base section

Introduction

Cushing's disease is a state of chronic and excessive cortisol levels caused by a pituitary adenoma

Research question

CD is a complex entity and often entails difficulties in its diagnosis and management. For that reason, there are still controversial points to that respect. The aim of this consensus paper of the skull base section of the EANS is to review the main aspects of the disease a neurosurgeon has to know and also to offer updated recommendations on the controversial aspects of its management.

Material and methods

PUBMED database was used to search the most pertinent articles published on the last 5 years related with the management of CD. A summary of literature evidence was proposed for discussion within the EANS skull base section and other international experts.

Results

This article represents the consensual opinion of the task force regarding optimal management and surgical strategy in CD

Discussion and conclusion

After discussion in the group several recommendations and suggestions were elaborated. Patients should be treated by an experienced multidisciplinary team. Accurate clinical, biochemical and radiological diagnosis is mandatory. The goal of treatment is the complete adenoma resection to achieve permanent remission. If this is not possible, the treatment aims to achieving eucortisolism. Radiation therapy is recommended to patients with CD when surgical options have been exhausted. All patients in remission should be tested all life-long.

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Modalities of management of Cushing disease and recommendations based on the literature and expert's opinion.

Consensus on diagnosis and management of Cushing's disease: a guideline update

Cushing's disease requires accurate diagnosis, careful treatment selection, and long-term management to optimise patient outcomes. The Pituitary Society convened a consensus workshop comprising more than 50 academic researchers and clinical experts to discuss the application of recent evidence to clinical practice. In advance of the virtual meeting, data from 2015 to present about screening and diagnosis; surgery, medical, and radiation therapy; and disease-related and treatment-related complications of Cushing's disease summarised in recorded lectures were reviewed by all participants. During the meeting, concise summaries of the recorded lectures were presented, followed by small group breakout discussions. Consensus opinions from each group were collated into a draft document, which was reviewed and approved by all participants. Recommendations regarding use of laboratory tests, imaging, and treatment options are presented, along with algorithms for diagnosis of Cushing's syndrome and management of Cushing's disease. Topics considered most important to address in future research are also identified.

Cushing's disease

Cushing's disease (CD) is the most prevalent cause of endogenous hypercortisolism. CD is responsible for multiple co-morbidities and increased mortality. Accurate and prompt diagnosis and optimal treatment are essential to improve the prognosis of CD. However, the diagnosis of CD is probably one of the most difficult in endocrinology and, therefore, diagnostic workup should be performed in an experienced center. Transsphenoidal surgery performed by an expert surgeon is the only therapeutic option that can offer definitive cure and remains the first-line treatment in most patients. Second-line treatments include pharmacotherapy, pituitary radiotherapy and bilateral adrenalectomy. The second-line therapeutic strategy is complex, must be individualized and performed in a multidisciplinary expert center. Symptomatic treatments of persisting co-morbidities after remission, which are responsible for increased mortality and impaired quality of life is an important part of medical management.

Updates in the outcomes of radiation therapy for Cushing's disease

External radiation therapy (RT) directed to the pituitary gland is generally recommended in patients with Cushing's disease (CD) as adjuvant to transsphenoidal surgery, among other second-line therapies offered to patients with residual or recurrent hypercortisolism (i.e., medical treatment, repeat surgery or bilateral adrenalectomy). RT is effective for the control of tumor growth, even in invasive tumors and in Nelson's syndrome. Progress in radiation stereotactic techniques lead to improved tumor targeting and radiation delivery, thus sparing the adjacent brain structures. Stereotactic RT is associated with a 55-65% rate of cortisol normalization after several months to a few years and potentially with a lower risk of long-term complications, compared with conventional RT. Cortisol-lowering medical therapy is recommended while awaiting the radiation effects. Hypopituitarism is the most frequent side-effect, damage to optic or cranial nerves or second brain tumors are rarely reported. This review presents the updates in the efficacy and safety of the stereotactic radiation techniques in CD patients. Practical points which should be considered by the clinician before recommending RT are also presented.

The role of reoperation after recurrence of Cushing's disease

Surgical failure or recurrence of Cushing's disease can be treated with medical therapy, radiotherapy, adrenalectomy, and/or repeat transsphenoidal surgery, all of which have their respective benefits and drawbacks. Redo transsphenoidal surgery has been shown to achieve at least short-term remission in about 40-80% of patients and is associated with low rates of morbidity and near-zero mortality, albeit higher rates of postoperative hypopituitarism, diabetes insipidus, and cerebrospinal fluid leak than initial resection. Despite this, recurrence may ensue in 50% of patients. When selecting patient candidates for reoperation, many predictors of postoperative outcomes have been proposed including imaging characteristics, histopathological staining, intraoperative tumor visualization, and tumor size, however no single predictor consistently predicts outcomes. Redo transsphenoidal surgery should be performed by an experienced pituitary surgeon and patients should be followed at a tertiary care center by a multidisciplinary team consisting of an experienced endocrinologist and neurosurgeon to monitor closely for remission and recurrence.

Recurrence after pituitary surgery in adult Cushing's disease: a systematic review on diagnosis and treatment

PURPOSE

Recurrence after pituitary surgery in Cushing's disease (CD) is a common problem ranging from 5% (minimum) to 50% (maximum) after initially successful surgery, respectively. In this review, we give an overview of the current literature regarding prevalence, diagnosis, and therapeutic options of recurrent CD.

METHODS

We systematically screened the literature regarding recurrent and persistent Cushing's disease using the MESH term Cushing's disease and recurrence. Of 717 results in PubMed, all manuscripts in English and German published between 1980 and April 2020 were screened. Case reports, comments, publications focusing on pediatric CD or CD in veterinary disciplines or studies with very small sample size (patient number < 10) were excluded. Also, papers on CD in pregnancy were not included in this review.

RESULTS AND CONCLUSIONS

Because of the high incidence of recurrence in CD, annual clinical and biochemical follow-up is paramount. 50% of recurrences occur during the first 50 months after first surgery. In case of recurrence, treatment options include second surgery, pituitary radiation, targeted medical therapy to control hypercortisolism, and bilateral adrenalectomy. Success rates of all these treatment options vary between 25 (some of the medical therapy) and 100% (bilateral adrenalectomy). All treatment options have specific advantages, limitations, and side effects. Therefore, treatment decisions have to be individualized according to the specific needs of the patient.

Persistent Cushing's Disease after Transsphenoidal Surgery: Challenges and Solutions

Transsphenoidal surgery remains the primary treatment for Cushing's disease (CD). However, despite the vast improvements in pituitary surgery, successful treatment of CD remains a great challenge. Although selective transsphenoidal removal of the pituitary tumor is a safe and effective procedure, the disease persists in around 22% of CD patients due to incomplete tumor resection. The persistence of hypercortisolism after pituitary surgery may also be the consequence of a misdiagnosis, as can occur in case of ectopic ACTH secretion or pseudo-Cushing. Considering the elevated mortality and morbidity characterizing the disease, a multidisciplinary approach is needed to minimize potential pitfalls occurring during the diagnosis, avoid surgical failure and provide the best care in those patients who have undergone unsuccessful surgery. In this review, we analyze the factors that could predict remission or persistence of CD after pituitary surgery and revise the therapeutic options in case of surgical failure.

Cushing's syndrome: Treatment and new therapeutic approaches

Overt Cushing's syndrome is a severe condition responsible for multiple comorbidities and increased mortality. Effective treatment is essential to reduce mortality, improve comorbidities and long-term quality of life. Surgical resection of the causal lesion(s) is generally the first-line and most effective treatment to normalize cortisol secretion. Adjunctive symptomatic treatments of co-morbidities are often necessary both during the active phase of the disease and for persisting co-morbidities after cessation of hypercortisolism. Second-line treatments include various pharmacological treatments, bilateral adrenalectomy, and radiotherapy of corticotroph tumors. The choice of these treatments is complex, must be performed in a multidisciplinary expert team to be individualized for each patient, and use a shared decision-making approach.

Cushing's Disease

In patients with Cushing's disease (CD), prompt diagnosis and treatment are essential for favorable long-term outcomes, although this remains a challenging task. The differential diagnosis of CD is still difficult in some patients, even with an organized stepwise diagnostic approach. Moreover, despite the use of high-resolution magnetic resonance imaging (MRI) combined with advanced fine sequences, some tumors remain invisible. Surgery, using various surgical approaches for safe maximum tumor removal, still remains the first-line treatment for most patients with CD. Persistent or recurrent CD after unsuccessful surgery requires further treatment, including repeat surgery, medical therapy, radiotherapy, or sometimes, bilateral adrenalectomy. These treatments have their own advantages and disadvantages. However, the most important thing is that this complex disease should be managed by a multidisciplinary team with collaborating experts. In addition, a personalized and individual-based approach is paramount to achieve high success rates while minimizing the occurrence of adverse events and improving the patients' quality of life. Finally, the recent new insights into the pathophysiology of CD at the molecular level are highly anticipated to lead to the introduction of more accurate diagnostic tests and efficacious therapies for this devastating disease in the near future.

Therapeutic options after surgical failure in Cushing's disease: A critical review

Cushing's disease (CD) is the most common etiology of Cushing's syndrome (CD) due to corticotroph pituitary adenoma, which are in most cases small (80-90% microadenomas) and in about 40% cannot be visualized on imaging of the sella. First-line treatment for CD is transsphenoidal surgery (TSS) with the aim of complete adenoma removal and preservation of pituitary gland function. As complete adenoma resection is not always possible, surgical failure is a common problem. This can be the case either due to persistent hypercortisolism after first TSS or recurrence of hypercortisolism after initially achieving remission. For these scenarios exist several therapeutic options with their inherent characteristics, which will be covered by this review.