Stereotactic Radiosurgery for Cushing Disease: Results of an International, Multicenter Study

Cushing's Syndrome in the Elderly

Management of Cushing's syndrome (CS) can be particularly challenging in older patients, compared with younger individuals, due to the lack of several clinical features associated with cortisol excess along with a greater burden of associated comorbidities. Moreover, the interpretation of diagnostic tests could be influenced by age-related physiological changes in cortisol secretion. While mortality is higher and quality of life is more impaired in the elderly with CS as compared with the younger, there is currently no agreement on the most effective therapeutic options in aged individuals, and safety data concerning medical treatment are scanty. In this review, we summarize the current knowledge about age-related differences in CS etiology, clinical presentation, treatment, and outcomes and describe the potential underlying mechanisms.

Stereotactic radiosurgery for nonfunctioning pituitary tumor: A multicenter study of new pituitary hormone deficiency

BACKGROUND

Stereotactic radiosurgery (SRS) is used to treat recurrent or residual nonfunctioning pituitary neuroendocrine tumors (NFPA). The objective of the study was to assess imaging and development of new pituitary hormone deficiency.

METHODS

Patients treated with single-session SRS for a NFPA were included in this retrospective, multicenter study. Tumor control and new pituitary dysfunction were evaluated using Cox analysis and Kaplan-Meier curves.

RESULTS

A total of 869 patients (male 476 [54.8%], median age at SRS 52.5 years [Interquartile range (IQR): 18.9]) were treated using a median margin dose of 14Gy (IQR: 4) for a median tumor volume of 3.4 cc (IQR: 4.3). With a median radiological follow-up of 3.7 years (IQR: 4.8), volumetric tumor reduction occurred in 451 patients (51.9%), stability in 364 (41.9%) and 54 patients (6.2%) showed tumor progression.The probability of tumor control was 95.5% (95% Confidence Interval [CI]: 93.8-97.3) and 88.8% (95%CI: 85.2-92.5) at 5 and 10 years, respectively. A margin dose >14 Gy was associated with tumor control (Hazard Ratio [HR]:0.33, 95% CI: 0.18-0.60, P < 0.001). The probability of new hypopituitarism was 9.9% (95% CI: 7.3-12.5) and 15.3% (95% CI: 11-19.4) at 5 and 10 years, respectively. A maximum point dose >10 Gy in the pituitary stalk was associated with new pituitary hormone deficiency (HR: 3.47, 95% CI: 1.95-6.19). The cumulative probability of new cortisol, thyroid, gonadotroph, and growth hormone deficiency was 8% (95% CI: 3.9-11.9), 8.3% (95% CI: 3.9-12.5), 3.5% (95% CI: 1.7-5.2), and 4.7% (95% CI: 1.9-7.4), respectively at 10 years.

CONCLUSIONS

SRS provides long-term tumor control with a 15.3% risk of hypopituitarism at 10 years.

Silent Corticotroph Staining Pituitary Neuroendocrine Tumors: Prognostic Significance in Radiosurgery

BACKGROUND AND OBJECTIVES

There is conflicting evidence on the significance of adrenocorticotrophic hormone (ACTH) staining in the prognosis of nonfunctioning pituitary neuroendocrine tumors (NFpitNETs). The objective of this study was to define the effect of ACTH immunostaining on clinical and radiographic outcomes of stereotactic radiosurgery (SRS) for NFpitNETs.

METHODS

This retrospective, multicenter study included patients managed with SRS for NFpitNET residuals. The patients were divided into 2 cohorts: (1) silent corticotroph (SC) for NFpitNETs with positive ACTH immunostaining and (2) non-SC NFpitNETs. Rates of local tumor control and the incidence of post-treatment pituitary and neurological dysfunction were documented. Factors associated with radiological and clinical outcomes were also analyzed.

RESULTS

The cohort included 535 patients from 14 centers with 84 (15.7%) patients harboring silent corticotroph NFpitNETs (SCs). At last follow-up, local tumor progression occurred in 11.9% of patients in the SC compared with 8.1% of patients in the non-SC cohort (P = .27). No statistically significant difference was noted in new-onset hypopituitarism rates (10.7% vs 15.4%, P = .25) or visual deficits (3.6% vs 1.1%, P = .088) between the 2 cohorts at last follow-up. When controlling for residual tumor volume, maximum dose, and patient age and sex, positive ACTH immunostaining did not have a significant correlation with local tumor progression (hazard ratio = 1.69, 95% CI = 0.8-3.61, P = .17).

CONCLUSION

In contemporary radiosurgical practice with a single fraction dose of 8-25 Gy (median 15 Gy), ACTH immunostaining in NFpitNETs did not appear to confer a significantly reduced rate of local tumor control after SRS.

Clinical Spectrum of USP8 Pathogenic Variants in Cushing's Disease

Cushing's disease (CD) is a life-threatening condition with a challenging diagnostic process and scarce treatment options. CD is caused by usually benign adrenocorticotrophic hormone (ACTH)-secreting pituitary neuroendocrine tumors (PitNETs), known as corticotropinomas. These tumors are predominantly of sporadic origin, and usually derive from the monoclonal expansion of a mutated cell. Somatic activating variants located within a hotspot of the USP8 gene are present in 11-62% of corticotropinomas, making USP8 the most frequent genetic driver of corticotroph neoplasia. In contrast, other somatic defects such as those affecting the glucocorticoid receptor gene (NR3C1), the BRAF oncogene, the deubiquitinase-encoding gene USP48, and TP53 are infrequent. Moreover, patients with familial tumor syndromes, such as multiple endocrine neoplasia, familial isolated pituitary adenoma, and DICER1 rarely develop corticotropinomas. One of the main molecular alterations in USP8-driven tumors is an overactivation of the epidermal growth factor receptor (EGFR) signaling pathway, which induces ACTH production. Hotspot USP8 variants lead to persistent EGFR overexpression, thereby perpetuating the hyper-synthesis of ACTH. More importantly, they condition a characteristic transcriptomic signature that might be useful for the clinical prognosis of patients with CD. Nevertheless, the clinical phenotype associated with USP8 variants is less well defined. Hereby we discuss the current knowledge on the molecular pathogenesis and clinical picture associated with USP8 hotspot variants. We focus on the potential significance of the USP8 mutational status for the design of tailored clinical strategies in CD.

An individualized approach to the management of Cushing disease

Cushing disease caused by an adrenocorticotropic hormone (ACTH)-secreting pituitary corticotroph adenoma leads to hypercortisolaemia with high mortality due to metabolic, cardiovascular, immunological, neurocognitive, haematological and infectious conditions. The disorder is challenging to diagnose because of its common and heterogenous presenting features and the biochemical pitfalls of testing levels of hormones in the hypothalamic-pituitary-adrenal axis. Several late-night salivary cortisol and 24-h urinary free cortisol tests are usually required as well as serum levels of cortisol after a dexamethasone suppression test. MRI might only identify an adenoma in 60-75% of patients and many adenomas are small. Therefore, inferior petrosal sinus sampling remains the gold standard for confirmation of ACTH secretion from a pituitary source. Initial treatment is usually transsphenoidal adenoma resection, but preoperative medical therapy is increasingly being used in some countries and regions. Other management approaches are required if Cushing disease persists or recurs following surgery, including medications to modulate ACTH or block cortisol secretion or actions, pituitary radiation, and/or bilateral adrenalectomy. All patients require lifelong surveillance for persistent comorbidities, clinical and biochemical recurrence, and treatment-related adverse effects (including development of treatment-associated hypopituitarism). In this Review, we discuss challenges in the management of Cushing disease in adults and provide information to guide clinicians when planning an integrated and individualized approach for each patient.

Gamma Knife Radiosurgery for Cushing's Disease: Evaluation of Biological Effective Dose from a Single-Center Experience

Objective: Gamma knife radiosurgery (GKRS) has served as an adjunctive treatment in Cushing's disease (CD) for decades and has become a vital part of therapy in the management of CD. Biological effective dose (BED) is a radiobiological parameter with time correction, considering the cellular deoxyribonucleic acid repairment. We aimed to investigate the safety and efficacy of GKRS for CD and evaluate the association of BED and treatment outcome. Methods: A cohort study of 31 patients with CD received GKRS in West China Hospital between June 2010 and December 2021. Endocrine remission was defined as normalization of 24 h urinary free cortisol (UFC) or serum cortisol ≤ 50 nmol/L after a 1 mg dexamethasone suppression test. Result: The mean age was 38.6 years old, and females accounted for 77.4%. GKRS was the initial treatment for 21 patients (67.7%), and 32.3% of patients underwent GKRS after surgery due to residual disease and recurrence. The mean endocrine follow-up duration was 22 months. The median marginal dose was 28.0 Gy, and the median BED was 221.5 Gy_2.47. Fourteen patients (45.1%) experienced control of hypercortisolism in the absence of pharmacological treatment, and the median duration to remission was 20.0 months. The cumulative rates of endocrine remission at 1, 2, and 3 years after GKRS were 18.9%, 55.3%, and 72.21%, respectively. The total complication rate was 25.8%, and the mean duration from GKRS to hypopituitary was 17.5 months. The new hypopituitary rate at 1, 2, and 3 years were 7.1%, 30.3%, and 48.4%, respectively. A high BED level (BED > 205 Gy_2.47) was associated with better endocrine remission than a low BED level (BED ≤ 205 Gy_2.47), while no significant differences were found between the BED level and hypopituitarism. Conclusions: GKRS was a second-line therapeutic option for CD with satisfactory safety and efficacy. BED should be considered during GKRS treatment planning, and optimization of BED is a potentially impactful avenue toward improving the efficacy of GKRS.

Pituitary Adenomas: Classification, Clinical Evaluation and Management

Pituitary adenomas are one of the most common brain tumors. They represent approximately 18% of all intracranial, and around 95% of sellar neoplasms. In recent years, our understanding of the pathophysiology and the behavior of these lesions has led to better control and higher curative rates. The treatment decision is largely dependent on type of the adenoma, clinical presentation, and the size of the lesion. In addition, incidental pituitary lesions add uncertainty in the decision-making process, especially for pituitary adenomas that can be medically managed. When surgery is indicated, the endoscopic endonasal transsphenoidal approach is the technique of choice, but open standard craniotomy approaches can also be the option in selected cases. The following chapter will review the classification, clinical presentation, pathophysiology, diagnostic work-up, selection of surgical approach, and treatment complications in pituitary adenomas.

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.

Role of radiosurgery in the treatment of Cushing's disease

Radiotherapy is a useful adjuvant treatment for patients with Cushing's disease that is not cured by surgery. In particular, Gamma Knife radiosurgery (GKRS) has been increasingly used worldwide as the preferred radiation technique in patients with persistent or recurrent Cushing's disease. The most widely accepted criterion for hormonal remission after GKRS is normalization of urinary free cortisol (UFC) levels. When a clear biological target is not identified, irradiation of the whole pituitary gland can be considered. The 5-year probability of remission is 65%-75%. Normalization of hypercortisolism usually occurs within 3 years from GKRS treatment and control of tumor growth is optimal, approaching more than 90%. No clear predictor of a favorable outcome has emerged up to now, except for the experience of the treating team. In the largest series, development of partial or complete hypopituitarism occurred between 15% and 36%. Severe side effects of GKRS, such as optic neuropathy and oculomotor palsy, are uncommon but have been documented in patients previously exposed to radiation. Recurrence of disease has been reported in as high as 16%-18% of the patients who achieved normalization of UFC levels in the two largest series, whereas smaller series did not describe late failure of GKRS. The reason for this discrepancy is unclear, as is the relationship between hormonal and tumoral recurrence. Another unresolved issue is whether treatment with adrenal blocking drugs can jeopardize the results of GKRS. GKRS is an effective second-line treatment in patients with Cushing's disease not cured by surgery. Hypopituitarism is the most frequent side effect of GKRS, whereas severe neurologic complications are uncommon in radiation-naïve patients.

Course of Cushing`s disease and treatment outcomes in correlation with pituitary MRI in children

BACKGROUND

Cushing's disease (CD) is a rare disorder of a persistent cortisol excess caused by ACTH-secreting pituitary tumor (corticotropinoma). Transsphenoidal surgery (TSS) is a treatment of choice for СD, which effectiveness range is from 70 to 90%. Recurrence rate after successful treatment is about 25%. If surgical treatment is unsuccessful or recurrence appear, radiation treatment is the next therapeutic option, which effectiveness range is also 90%, but the hypopituitarism rate as side effect of treatment is higher. Preoperative predictors of remission and recurrence are still unexplored what leads to further investigations.

AIM

Analysis of remission and recurrence rates of pediatric CD after successful treatment according to preoperative MRI and therapeutic option.

MATERIALS AND METHODS

We conducted a retrospective analysis of 90 pediatric patients with CD who were observed between 1992 and 2020 at the Endocrinology Research Centre.

RESULTS

The most common clinical symptoms of CD were weight gain [94%] and growth retardation [72%]. Pituitary tumor was detected on radiological imaging in 53/90 patients [59%], there were no signs of visible adenoma in 37/90 of patients [41%]. 63 of 90 patients underwent TSS (70%), 27 patients underwent radiosurgery (30%). Remission rate after TSS was 71% [45/63], after radiosurgery - 85% [23/27]. There were no significant differences in remission rates after radical treatment according to preoperative MRI results (P=0.21 after TSS and P=0.87 after radiosurgery, х2 analysis). Recurrence after successful treatment was diagnosed in 10 patients. There were no significant differences in time to recurrence according to preoperative MRI results (P=0.055, х2 analysis). Time to recurrence was statistically different after TSS compared to radiosurgery (P=0.007, Kaplan-Meier analysis) and in the group with developed adrenal insufficiency in the early postoperative period (P=0.04, Kaplan-Meier analysis). Analysis of side effect of treatment showed that the frequency of growth hormone and gonadotrophin deficiency was statistically higher after radiosurgery (р&lt;0.01, Kruskel-Wallis ANOVA test). Diabetes insipidus was diagnosed only after TSS.

CONCLUSION

Results of our study didn`t allow to use MRI-results as predictor of effectiveness treatment in pediatric CD. Therapeutic option has an impact on time to recurrence, not on recurrence rates. The frequency of growth hormone and gonadotrophin deficiency was statistically higher after radiosurgery compared to TSS. Further studies are needed to identify predictors of remission and recurrence in CD.&gt;&lt; 0.01, Kruskel-Wallis ANOVA test). Diabetes insipidus was diagnosed only after TSS.

CONCLUSION

Results of our study didn`t allow to use MRI-results as predictor of effectiveness treatment in pediatric CD. Therapeutic option has an impact on time to recurrence, not on recurrence rates. The frequency of growth hormone and gonadotrophin deficiency was statistically higher after radiosurgery compared to TSS. Further studies are needed to identify predictors of remission and recurrence in CD.

Pituitary adenomas

Pituitary adenomas produce a complex collection of disorders. Some are incidental findings. Some distort local anatomical structures which can lead to disorders of vision or hormone production. Some produce excesses of hormones which can be either life threatening or clinically distressing. The management requires the expertise of a variety of experts who plan together. No single treatment is universally successful in controlling these conditions. Medical, biochemical, surgical and radiosurgical management can all have parts to play. Coordinate co-operation between specialists will provide patients with the best available treatment.

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.

Modern LINAC-based radiotherapy is safe and effective in the treatment of secretory and non-secretory pituitary adenomas

OBJECTIVE

Adjuvant radiotherapy (RT) can help achieve local tumor control (LC) and reduce hormonal overexpression for pituitary adenomas (PAs). Prior reports involved Gamma Knife or older LINAC techniques. We report on long-term outcomes for modern LINAC RT.

METHODS

Institutional retrospective review of LINAC RT for PAs with minimum 3 years MRI follow-up. Hormonal control defined as biochemical remission in absence of medications targeting hormone excess LC defined using RECIST on surveillance MRIs. Progression Free Survival (PFS) defined as time alive with LC and without return of or worsening hormonal excess from secretory PA. Kaplan-Meier method and Cox proportional hazard models used.

RESULTS

From 2003-2017, 140 patients with PAs (94 non-secretory, 46 secretory) were treated with LINAC RT (105 fractionated, 35 radiosurgery) with mFU of 5.35 years. Techniques included fixed gantry IMRT (51.4%), DCA (9.3%), and VMAT (39.3%). PFS at 5-years was 95.3% for secretory tumors and 94.8% for non-secretory tumors. Worse PFS associated with larger PTV on MVA (HR 2.87, 95% CI 1.01 - 8.21, p=0.049). Hormonal control at 5 years was 50.0% and associated with higher dose to the tumor (HR 1.05, 95% CI 1.02 -1.09, p=0.005) and number of surgeries (HR 1.74, 95% CI 1.05-2.89, p=0.032). Patients requiring any pituitary hormone replacement increased from 57.9% to 70.0% after radiotherapy.

CONCLUSION

Modern LINAC RT for patients with PAs was safe and effective for hormonal control and LC. Notably, no difference in LC was noted for functional versus non-functional tumors possibly due to higher total dose and daily image guidance.

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.

Gamma Knife Radiosurgery for Pituitary Tumors: A Systematic Review and Meta-Analysis

Simple Summary

Pituitary tumors represent approximately 10–15% of all brain neoplasms. Gamma Knife, the most commonly used stereotactic radiosurgery technique worldwide, plays an important role in the treatment of several pituitary neoplasm. It is currently used in cases of residual or recurrent tumors after surgery or as primary treatment when surgery is contraindicated. Its goals are long-term tumor control, preservation of visual function, and, for secreting pituitary adenomas, endocrine remission. Several retrospective case-series (level of evidence IV) on Gamma Knife for pituitary tumors have been published describing encouraging outcomes; only one systematic review and meta-analysis on non-functioning pituitary adenoma has been recently reported. We provide a systematic review of the literature and meta-analysis from the last two decades on Gamma Knife radiosurgery for several pituitary tumors with the aim of describing and confirming safety and effectiveness of this technique.

Abstract

To describe and evaluate outcomes of Gamma Knife radiosurgery (GK) for the treatment of pituitary tumors over the past twenty years, a systematic review and meta-analysis according to PRISMA statement was performed. Articles counting more than 30 patients were included. A weighted random effects models was used to calculate pooled outcome estimates. From 459 abstract reviews, 52 retrospective studies were included. Among them, 18 reported on non-functioning pituitary adenomas (NFPA), 13 on growth hormone (GH)-secreting adenomas, six on adrenocorticotropic hormone (ACTH)-secreting adenomas, four on prolactin hormone (PRL)-secreting adenomas, and 11 on craniopharyngiomas. Overall tumor control and five-year progression free survival (PFS) estimate after one GK procedure for NFPA was 93% (95% CI 89–97%) and 95% (95% CI 91–99%), respectively. In case of secreting pituitary adenomas, overall remission (cure without need for medication) estimates were 45% (95% CI 35–54%) for GH-secreting adenomas, 64% (95% CI 0.52–0.75%) for ACTH-secreting adenomas and 34% (95% CI: 19–48%) for PRL-secreting adenomas. The pooled analysis for overall tumor control and five-year PFS estimate after GK for craniopharyngioma was 74% (95% CI 67–81%) and 70% (95% CI: 64–76%), respectively. This meta-analysis confirms and quantifies safety and effectiveness of GK for pituitary tumors.

Stereotactic radiosurgery before bilateral adrenalectomy is associated with lowered risk of Nelson's syndrome in refractory Cushing's disease patients

BACKGROUND

Nelson's syndrome is a rare but challenging sequelae of Cushing's disease (CD) after bilateral adrenalectomy (BLA). We sought to determine if stereotactic radiosurgery (SRS) of residual pituitary adenoma performed before BLA can decrease the risk of Nelson's syndrome.

METHODS

Consecutive patients with CD who underwent BLA after non-curative resection of ACTH secreting pituitary adenoma and had at least one follow-up visit after BLA were studied. Nelson's syndrome was diagnosed based on the combination of rising ACTH levels, increasing volume of the pituitary adenoma and/or hyperpigmentation.

RESULTS

Fifty patients underwent BLA for refractory CD, and 43 patients (7 men and 36 women) had at least one follow-up visit after BAL. Median endocrine, imaging, and clinical follow-up were 66 months, 69 months, and 80 months, respectively. Nine patients (22%) were diagnosed with the Nelson's syndrome at median time after BLA at 24 months (range: 0.6-119.4 months). SRS before BLA was associated with reduced risk of the Nelson's syndrome (HR = 0.126; 95%CI [0.022-0.714], p=0.019), while elevated ACTH level within 6 months after BLA was associated with increased risk for the Nelson's syndrome (HR = 9.053; 95%CI [2.076-39.472], p=0.003).

CONCLUSIONS

SRS before BLA can reduce the risk for the Nelson's syndrome in refractory CD patients requiring BLA and should be considered before proceeding to BLA. Elevated ACTH concentration within 6 months after BLA is associated with greater risk of the Nelsons' syndrome. When no prior SRS is administered, those with a high ACTH level shortly after BLA may benefit from early SRS.

Mifepristone as Bridge or Adjunct Therapy in the Management of Challenging Cushing Disease Cases

Establishing a definitive diagnosis of Cushing disease (CD), given its clinical and biochemical heterogeneity, initiating effective treatment to control the effects of hypercortisolism, and managing recurrence are challenging disease aspects to address. Mifepristone is a competitive glucocorticoid receptor antagonist that is approved in the US by the Food and Drug Administration to control hyperglycemia secondary to endogenous hypercortisolism (Cushing syndrome) in patients who have glucose intolerance or type 2 diabetes mellitus and have failed surgery or are not candidates for surgery. Herein, we describe 6 patients with CD who received mifepristone as adjunct/bridge therapy in the following clinical settings: to assess clinical benefits of treatment for suspected recurrent disease, to control hypercortisolism preoperatively for severe disease, to control hypercortisolism during the COVID-19 pandemic, and to provide adjunctive treatment to radiation therapy. The patients were treated at multiple medical practice settings. Mifepristone treatment in each of the described cases was associated with clinical improvements, including improvements in overall glycemia, hypertension, and weight loss. In addition, in one case where biochemical and radiological evidence of disease recurrence was uncertain, clinical improvement with mifepristone pointed toward likely disease recurrence. Adverse events associated with mifepristone reported in the 6 cases were consistent with those previously reported in the pivotal trial and included cortisol withdrawal symptoms, antiprogesterone effects (vaginal bleeding), hypothyroidism (treated with levothyroxine), and hypokalemia (treated with spironolactone). These cases show how mifepristone can potentially be utilized as a therapeutic trial in equivocal cases of CD recurrence; as a presurgical treatment strategy, particularly during the COVID-19 pandemic; and as bridge therapy, while awaiting the effects of radiation.

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.

Early versus late Gamma Knife radiosurgery for Cushing's disease after prior resection: results of an international, multicenter study

OBJECTIVE

The optimal time to perform stereotactic radiosurgery after incomplete resection of adrenocorticotropic hormone (ACTH)-producing pituitary adenoma in patients with Cushing's disease (CD) remains unclear. In patients with persistent CD after resection of ACTH-producing pituitary adenoma, the authors evaluated the association of the interval between resection and Gamma Knife radiosurgery (GKRS) with outcomes.

METHODS

Pooled data from 10 institutions participating in the International Radiosurgery Research Foundation were used in this study.

RESULTS

Data from 255 patients with a mean follow-up of 65.59 ± 49.01 months (mean ± SD) were analyzed. Seventy-seven patients (30%) underwent GKRS within 3 months; 46 (18%) from 4 to 6 months; 34 (13%) from 7 to 12 months; and 98 (38%) at > 12 months after the resection. Actuarial endocrine remission rates were higher in patients who underwent GKRS ≤ 3 months than when treatment was > 3 months after the resection (78% and 65%, respectively; p = 0.017). Endocrine remission rates were lower in patients who underwent GKRS at > 12 months versus ≤ 12 months after the resection (57% vs 76%, respectively; p = 0.006). In multivariate Cox regression analyses adjusted for clinical and treatment characteristics, early GKRS was associated with increased probability of endocrine remission (hazard ratio [HR] 1.518, 95% CI 1.039-2.218; p = 0.031), whereas late GKRS (HR 0.641, 95% CI 0.448-0.919; p = 0.015) was associated with reduced probability of endocrine remission. The incidence of some degree of new pituitary deficiency (p = 0.922), new visual deficits (p = 0.740), and other cranial nerve deficits (p = 0.610) was not significantly related to time from resection to GKRS.

CONCLUSIONS

Early GKRS is associated with an improved endocrine remission rate, whereas later GKRS is associated with a lower rate of endocrine remission after pituitary adenoma resection. Early GKRS should be considered for patients with CD after incomplete pituitary adenoma resection.

Outcomes of Cushing's disease following Gamma Knife radiosurgery: effect of a center's growing experience and era of treatment

OBJECTIVE

Stereotactic radiosurgery (SRS) is used for the management of residual or recurrent Cushing's disease (CD). Increasing experience and technological advancements of Gamma Knife radiosurgery (GKRS) systems can impact the outcomes of CD patients. The authors evaluated the association of their center's growing experience and the era in which GKRS was performed with treatment success and adverse events in patients with CD.

METHODS

The authors studied consecutive patients with CD treated with GKRS at the University of Virginia since installation of the first Gamma Knife system in March 1989 through August 2019. They compared endocrine remission and complication rates between patients treated before 2000 (early cohort) and those who were treated in 2000 and later (contemporary cohort).

RESULTS

One hundred thirty-four patients with CD underwent GKRS during the study period: 55 patients (41%) comprised the early cohort, and 79 patients (59%) comprised the contemporary cohort. The contemporary cohort, compared with the early cohort, had a significantly greater treatment volume, radiation prescription dose, maximal dose to the optic chiasm, and number of isocenters, and they more often had cavernous sinus involvement. Endocrine remission rates were higher in the contemporary cohort when compared with the early cohort (82% vs 66%, respectively; p = 0.01). In a Cox regression analysis adjusted for demographic, clinical, and SRS characteristics, the contemporary GKRS cohort had a higher probability of endocrine remission than the early cohort (HR 1.987, 95% CI 1.234-3.199; p = 0.005). The tumor control rate, incidence of cranial nerve neuropathy, and new anterior pituitary deficiency were similar between the two groups.

CONCLUSIONS

Technological advancements over the years and growing center experience were important factors for improved endocrine remission rates in patients with CD. Technological aspects and results of contemporary Gamma Knife systems should be considered when counseling patients, planning treatment, and reporting treatment results. Studies exploring the learning curve for GKRS are warranted.

Aggressive Cushing's Disease: Molecular Pathology and Its Therapeutic Approach

Cushing's disease is a syndromic pathological condition caused by adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas (ACTHomas) mediated by hypercortisolemia. It may have a severe clinical course, including infection, psychiatric disorders, hypercoagulability, and metabolic abnormalities, despite the generally small, nonaggressive nature of the tumors. Up to 20% of ACTHomas show aggressive behavior, which is related to poor surgical outcomes, postsurgical recurrence, serious clinical course, and high mortality. Although several gene variants have been identified in both germline and somatic changes in Cushing's disease, the pathophysiology of aggressive ACTHomas is poorly understood. In this review, we focused on the aggressiveness of ACTHomas, its pathology, the current status of medical therapy, and future prospects. Crooke's cell adenoma (CCA), Nelson syndrome, and corticotroph pituitary carcinoma are representative refractory pituitary tumors that secrete superphysiological ACTH. Although clinically asymptomatic, silent corticotroph adenoma is an aggressive ACTH-producing pituitary adenoma. In this review, we summarize the current understanding of the pathophysiology of aggressive ACTHomas, including these tumors, from a molecular point of view based on genetic, pathological, and experimental evidence. The treatment of aggressive ACTHomas is clinically challenging and usually resistant to standard treatment, including surgery, radiotherapy, and established medical therapy (e.g., pasireotide and cabergoline). Temozolomide is the most prescribed pharmaceutical treatment for these tumors. Reports have shown that several treatments for patients with refractory ACTHomas include chemotherapy, such as cyclohexyl-chloroethyl-nitrosourea combined with 5-fluorouracil, or targeted therapies against several molecules including vascular endothelial growth factor receptor, cytotoxic T lymphocyte antigen 4, programmed cell death protein 1 (PD-1), and ligand for PD-1. Genetic and experimental evidence indicates that some possible therapeutic candidates are expected, such as epidermal growth factor receptor tyrosine kinase inhibitor, cyclin-dependent kinase inhibitor, and BRAF inhibitor. The development of novel treatment options for aggressive ACTHomas is an emerging task.

Treatment of Aggressive Pituitary Adenomas: A Case-Based Narrative Review

Management of aggressive pituitary adenomas is challenging due to a paucity of rigorous evidence supporting available treatment approaches. Recent guidelines emphasize the need to maximize standard therapies as well as the use of temozolomide and radiation therapy to treat disease recurrence. However, often these adenomas continue to progress over time, necessitating the use of additional targeted therapies which also impact quality of life and long-term outcomes. In this review, we present 9 cases of aggressive pituitary adenomas to illustrate the importance of a multidisciplinary, individualized approach. The timing and rationale for surgery, radiation therapy, temozolomide, somatostatin receptor ligands, and EGFR, VEGF, and mTOR inhibitors in each case are discussed within the context of evidence-based guidelines and clarify strategies for implementing an individualized approach in the management of these difficult-to-treat-adenomas.

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.

Management of patients with persistent or recurrent Cushing's disease after initial pituitary surgery

INTRODUCTION

Treatment options for persistent and recurrent Cushing's disease (CD) include an individualized approach for repeat surgery, medical treatment, radiation therapy (RT), and bilateral adrenalectomy (BLA).

AREAS COVERED

In this expert opinion perspective, the authors review the latest treatment(s) for persistent/recurrent CD. A PubMed search was undertaken (English articles through May 2020) and relevant articles discussed. Repeat pituitary surgery should be considered in most patients with proven hypercortisolism; there is potential for cure with low risk of major complications. Medical therapy is valuable either alone, while awaiting the effects of RT, or in preparation for BLA. Medical therapy includes steroidogenesis inhibitors, agents that act at the pituitary or glucocorticoid receptor level, and novel agents in development. Radiation therapy has been used successfully to treat CD, but hypopituitarism risk and delayed efficacy (improved with radiosurgery) are major drawbacks. Laparoscopic BLA is safe and effective in patients with severe, difficult-to-manage hypercortisolism, but long-term follow-up is required as corticotroph tumor progression can develop.

EXPERT OPINION

Treatment of persistent/recurrent CD is challenging. Most patients require >1 therapy to achieve long-lasting remission. There is currently no ideal single treatment option that provides high and rapid efficacy, low adverse effects, and preserves normal pituitary-adrenal axis function.

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.

Gamma knife radiosurgery in patients with Cushing's disease: Comparison of aggressive pituitary corticotroph tumor versus corticotroph adenoma

Aggressive pituitary corticotroph tumors causing Cushing's disease are rare, and there is limited data about their clinical management. Here, we aimed to report our long-term experience with gamma knife radiosurgery (GKRS) as adjuvant treatment in patients with residual or recurrent pituitary corticotroph tumors. This retrospective study included 45 adult patients (M/F, 7/38; mean age, 40.2 ± 13.1 years) with residual tumor or recurrence after initially successful surgical resection. Single-session GKRS was performed in all patients. Tumors with a Ki-67 value higher than 3 % and radiologic invasion to surrounding tissues were classified as aggressive tumor group. Clinical, hormonal and radiological findings were compared between the aggressive (n = 10) and non-aggressive adenoma (n = 35) groups. Following GKRS, tumor volumes were significantly reduced in both groups. The mean time to hormonal remission in the non-aggressive group was significantly shorter than in the aggressive group (23.5 ± 6.3 vs 33.0 ± 5.0 month, respectively, p < 0.05). New-onset hypopituitarism was identified in only seven patients (15 %) after GKRS in the whole cohort. The present study introduces several essential findings about aggressive corticotroph tumors. First, aggressive behavior tends to occur more frequently in male subjects. Second, time to GKRS was significantly shorter in the aggressive group. Moreover, a tumor volume ≥2 cm³ may be associated with clinical aggressiveness in corticotroph tumors. In conclusion, we suggest that early adjuvant GKRS is an effective treatment option in aggressive pituitary corticotroph tumors.

Efficacy and Safety of Stereotactic Radiotherapy in Cushing's Disease: A Single Center Experience

OBJECTIVE

To determine the efficacy and safety of stereotactic radiotherapy (RT) in patients with Cushing's disease (CD).

METHODS

The study included 38 patients [31 patients who received gamma knife radiosurgery (GKS) and 7 patients who received cyberknife hypofractionated RT (HFRT)] with CD. Hormonal remission was considered if the patient had suppressed cortisol levels after low dose dexamethasone, normal 24-hour urinary free cortisol (UFC), and lack or regression of clinical features.

RESULTS

Biochemical control after RT was observed in 52.6% of the patients with CD and median time to hormonal remission was 15 months. Tumor size control was obtained in all of the patients. There was no significant relationship between remission rate and laboratory, radiological and pathological variables except for preoperative UFC. Remission rate was higher in patients with lower preoperative UFC. Time to remission increased in parallel to postoperative cortisol and 1mg DST level. Although medical therapy before RT did not affect the rate of- and time to remission, medical therapy after RT prolonged the time to hormonal remission.

CONCLUSION

In this current single center experience, postoperative cortisol and 1mg DST levels were found as the determinants of time to remission. Although medical therapy before RT did not affect the rate of- and time to remission, medical therapy after RT prolonged the time to biochemical control . This latter finding might suggest a radioprotective effect of cortisol lowering medication use on peri-RT period.

Radiation techniques in aggressive pituitary tumours and carcinomas

Defining the role of radiation techniques in treatment of aggressive pituitary tumours and carcinomas is a difficult task: indeed, studies reported in the literature on this topic can probably be counted on the fingers of one hand. To try to better define these roles, it is thus necessary to extrapolate based on anti-secretory and anti-tumor efficacy reported in studies on non-selected pituitary tumours, regardless of their pathological status and intrinsic aggressiveness. Generally, radiation techniques are delivered as part of a multimodal treatment, usually with the primary aim of controlling tumor volume. Side-effects need to be divided into short and long-term, also depending on the overall prognosis of the tumour, since hypopituitarism will likely appear in the majority of patients, extra-pituitary side-effects, which have been reported after a significant delay after the procedure, can only be considered in patients with less aggressive pituitary tumours. In this review, we will first detail the different modalities of radiation techniques and the inherent limits of each technique depending on the volume and the localization of the tumour. We will then discuss the anti-tumour and anti-secretory efficacy of radiation techniques in aggressive pituitary tumors, either as a single treatment or as part of a multimodal treatment. Finally we will discuss the technique-specific side-effects.

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 syndrome - Disease monitoring: Recurrence, surveillance with biomarkers or imaging studies

Pituitary surgery is the first-line treatment for patients with Cushing's disease. For patients who are not considered candidates for pituitary surgery, pituitary radiation and bilateral adrenalectomy are further treatment alternatives. Not all patients are cured with pituitary surgery, and a substantial number of patients develop recurrence, sometimes many years after an apparently successful treatment. The same applies to patients treated with radiotherapy. Far from all patients are cured, and in many cases the disease recurs. Bilateral adrenalectomy, although always curative, causes chronic adrenal insufficiency and the remaining pituitary tumour can continue to grow and cause symptoms due to pressure on adjacent tissues, a phenomenon called Nelson's syndrome. In this paper the rate of recurrence of hypercortisolism, as well as the rate of development of Nelson's syndrome, following treatment of patients with Cushing's syndrome, will be reviewed. The aim of the paper is also to summarize clinical and biochemical factors that are associated with recurrence of hypercortisolism and how the patients should be monitored following treatment.

Stereotactic Radiosurgery for Acromegaly: An International Multicenter Retrospective Cohort Study

BACKGROUND

Stereotactic radiosurgery (SRS) is a treatment option for persistent or recurrent acromegaly secondary to a growth hormone secreting pituitary adenoma, but its efficacy is inadequately defined.

OBJECTIVE

To assess, in a multicenter, retrospective cohort study, the outcomes of SRS for acromegaly and determine predictors.

METHODS

We pooled and analyzed data from 10 participating institutions of the International Gamma Knife Research Foundation for patients with acromegaly who underwent SRS with endocrine follow-up of ≥6 mo.

RESULTS

The study cohort comprised 371 patients with a mean endocrine follow-up of 79 mo. IGF-1 lowering medications were held in 56% of patients who were on pre-SRS medical therapy. The mean SRS treatment volume and margin dose were 3.0 cm3 and 24.2 Gy, respectively. The actuarial rates of initial and durable endocrine remission at 10 yr were 69% and 59%, respectively. The mean time to durable remission after SRS was 38 mo. Biochemical relapse after initial remission occurred in 9%, with a mean time to recurrence of 17 mo. Cessation of IGF-1 lowering medication prior to SRS was the only independent predictor of durable remission (P = .01). Adverse radiation effects included the development of ≥1 new endocrinopathy in 26% and ≥1 cranial neuropathy in 4%.

CONCLUSION

SRS is a definitive treatment option for patients with persistent or recurrent acromegaly after surgical resection. There appears to be a statistical association between the cessation of IGF-1 lowering medications prior to SRS and durable remission.

Benign Intracranial Lesions - Radiotherapy: An Overview of Treatment Options, Indications and Therapeutic Results

BACKGROUND

Radiation Therapy (RT) is an established treatment option for benign intracranial lesions. The aim of this study is to display an update on the role of RT concerning the most frequent benign brain lesions and tumors.

METHODS

Published articles about RT and meningiomas, Vestibular Schwannomas (VSs), Pituitary Adenomas (PAs), Arteriovenous Malformations (AVMs) and craniopharyngiomas were reviewed and extracted data were used.

RESULTS

In meningiomas RT is applied as an adjuvant therapy, in case of patientrefusing surgery or in unresectable tumors. The available techniques are External Beam RT (EBRT) and stereotactic ones such as Stereotactic Radiosurgery (SRS), Fractionated Stereotactic RT (FSRT), Intensity Modulated RT (IMRT) and proton-beam therapy. The same indications are considered in PAs, in which SRS and FSRT achieve excellent tumor control rate (92-100%), acceptable hormone remission rates (>50%) and decreased Adverse Radiation Effects (AREs). Upon tumor growth or neurological deterioration, RT emerges as alone or adjuvant treatment against VSs, with SRS, FSRT, EBRT or protonbeam therapy presenting excellent tumor control growth (>90%), facial nerve (84-100%), trigeminal nerve (74-99%) and hearing (>50%) preservation. SRS poses an effective treatment modality of certain AVMs, demonstrating a 3-year obliteration rate of 80%. Lastly, a combination of microsurgery and RT presents equal local control and 5-year survival rate (>90%) but improved toxicity profile compared to total resection in case of craniopharyngiomas.

CONCLUSION

RT comprises an effective treatment modality of benign brain and intracranial lesions. By minimizing its AREs with optimal use, RT projects as a potent tool against such diseases.

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.

Current management of Cushing's disease

Cushing's disease (CD) is caused by a pituitary tumour that secretes adrenocorticotropin (ACTH) autonomously, leading to excess cortisol secretion from the adrenal glands. The condition is associated with increased morbidity and mortality that can be mitigated by treatments that result in sustained endocrine remission. Transsphenoidal pituitary surgery (TSS) remains the mainstay of treatment for CD but requires considerable neurosurgical expertise and experience in order to optimize patient outcomes. Up to 90% of patients with microadenomas (tumour below 1 cm in largest diameter) and 65% of patients with macroadenomas (tumour at or above 1 cm in greatest diameter) achieve endocrine remission after TSS by an experienced surgeon. Patients who are not in remission postoperatively or those who relapse may benefit from undergoing a second pituitary operation. Alternatively, radiation therapy to the sella with interim medical therapy, or bilateral adrenalectomy, can be effective as definitive treatments of CD. Medical therapy is currently adjunctive in most patients with CD and is generally prescribed to patients who are about to receive radiation therapy and will be awaiting its salutary effects to occur. Available treatment options include steroidogenesis inhibitors, centrally acting agents and glucocorticoid receptor antagonists. Several novel agents are in clinical trials and may eventually constitute additional treatment options for this serious condition.

Management of Nonfunctioning Recurrent Pituitary Adenomas

Pituitary adenomas are typically slow-growing benign tumors. However, 50% to 60% of tumors progress following subtotal resection and up to 30% recur after apparent complete resection. Options for treatment of recurrent pituitary adenomas include repeat surgical resection, radiation therapy, and systemic therapies. There is no consensus approach for the management of recurrent pituitary adenomas. This article reviews the natural history of recurrent adenomas and emerging biomarkers predictive of clinical behavior as well as the outcomes associated with the various treatment modalities for these challenging tumors, with an emphasis on the surgical treatment.

Upfront Gamma Knife radiosurgery for Cushing's disease and acromegaly: a multicenter, international study

OBJECTIVE

Gamma Knife radiosurgery (GKS) is typically used after failed resection in patients with Cushing's disease (CD) and acromegaly. Little is known about the upfront role of GKS for patients with CD and acromegaly. In this study, the authors examine the outcome of upfront GKS for patients with these functioning adenomas.

METHODS

An international group of 7 Gamma Knife centers sent pooled data from 46 patients (21 with CD and 25 with acromegaly) undergoing upfront GKS to the coordinating center of the study for analysis. Diagnosis was established on the basis of clinical, endocrine, and radiological studies. All patients were treated on a common radiosurgical platform and longitudinally followed for tumor control, endocrine remission, and hypopituitarism. Patients received a tumor median margin dose of 25 Gy (range 12-40.0 Gy) at a median isodose of 50%.

RESULTS

The median endocrine follow-up was 69.5 months (range 9-246 months). Endocrine remission was achieved in 51% of the entire cohort, with 28% remission in acromegaly and 81% remission for those with CD at the 5-year interval. Patients with CD achieved remission earlier as compared to those with acromegaly (p = 0.0005). In patients post-GKS, the pituitary adenoma remained stable (39%) or reduced (61%) in size. Hypopituitarism occurred in 9 patients (19.6%), and 1 (2.2%) developed third cranial nerve (CN III) palsy. Eight patients needed further intervention, including repeat GKS in 6 and transsphenoidal surgery in 2.

CONCLUSIONS

Upfront GKS resulted in good tumor control as well as a low rate of adverse radiation effects in the whole group. Patients with CD achieved a faster and far better remission rate after upfront GKS in comparison to patients with acromegaly. GKS can be considered as an upfront treatment in carefully selected patients with CD who are unwilling or unable to undergo resection, but it has a more limited role in acromegaly.

Current and novel practice of stereotactic radiosurgery

Stereotactic radiosurgery emerged as a neurosurgical discipline in order to utilize energy for the manipulation of brain or nerve tissue, with the goal of minimal access and safe and effective care of a spectrum of neurosurgical disorders. Perhaps no other branch of neurosurgery has been so disruptive across the entire discipline of brain tumor care, treatment of vascular disorders, and management of functional problems. Radiosurgery is mainstream, supported by thousands of peer-reviewed outcomes reports. This article reviews current practice with a focus on challenges, emerging trends, and areas of investigation.

Radiotherapy as a tool for the treatment of Cushing's disease

Treatment of Cushing's disease (CD) is one of the most challenging tasks in endocrinology. The first-line treatment, transsphenoidal pituitary surgery, is associated with a high failure rate and a high prevalence of recurrence. Re-operation is associated with an even higher rate of a failure and recurrence. There are three main second-line treatments for CD - pituitary radiation therapy (RT), bilateral adrenalectomy and chronic cortisol-lowering medical treatment. All these treatments have their limitations. While bilateral adrenalectomy provides permanent cure of the hypercortisolism in all patients, the unavoidable chronic adrenal insufficiency and the risk of development of Nelson syndrome are of concern. Chronic cortisol-lowering medical treatment is not efficient in all patients and side effects are often a limiting factor. RT is efficient for approximately two-thirds of all patients with CD. However, the high prevalence of pituitary insufficiency is of concern as well as potential optic nerve damage, development of cerebrovascular disease and secondary brain tumours. Thus, when it comes to decide appropriate treatment for patients with CD, who have either failed to achieve remission with pituitary surgery, or patients with recurrence, the pros and cons of all second-line treatment options must be considered.

Functioning Pituitary Adenomas - Current Treatment Options and Emerging Medical Therapies

Pituitary adenomas are benign tumours comprising approximately 16% of all primary cranial neoplasms. Functioning pituitary adenomas (prolactinomas, somatotroph, corticotroph, thyrotroph and rarely gonadotroph adenomas) cause complex clinical syndromes and require prompt treatment to reduce associated morbidity and mortality. Treatment approaches include transsphenoidal surgery, medical therapy and radiation. Medical therapy is the primary therapy for prolactinomas, and surgery by a skilled neurosurgeon is the first-line approach for other functioning pituitary adenomas. A multimodal treatment is frequently necessary to achieve biochemical and clinical control, especially, when surgery is not curative or when medical therapy fails. Several emerging, novel, medical treatments for acromegaly, Cushing's disease and prolactinomas are in phase II and III clinical trials and may become effective additions to the current drug armamentarium. The availability of various management options will allow an individualised treatment approach based on the unique tumour type, clinical situation and patient preference.

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.

Outcomes After Gamma Knife Stereotactic Radiosurgery in Pediatric Patients with Cushing Disease or Acromegaly: A Multi-Institutional Study

OBJECTIVE

Pituitary adenomas comprise about 3% of all intracranial tumors in pediatric patients. This study examines the role of stereotactic radiosurgery in the management of pediatric acromegaly or patients with Cushing disease (CD).

METHODS

From an international consortium, we retrospectively collected treatment and outcome data on pediatric adrenocorticotrophic hormone and growth hormone-secreting pituitary adenomas treated with Gamma Knife radiosurgery (GKRS). There were a total of 36 patients including 24 with CD and 12 with acromegaly. The data were analyzed to assess outcomes including tumor control, endocrine remission, and adverse effects. Statistical analysis was performed to determine correlation between clinical/treatment parameters and outcomes.

RESULTS

At the last follow-up after GKRS, endocrine remission rates for CD and acromegaly were 80% and 42%, respectively. Tumor control was achieved in 87.5% of patients with CD and in 42% of patients with acromegaly. New pituitary hormone deficiency occurred in 7 of the 36 patients at a median time of 18 months after GKRS (range, 12-81 months). The predictive factors for endocrine remission were age <15 years (P = 0.015) and margin dose (P = 0.042). The median endocrine follow-up was 63.7 months (range, 7-246 months).

CONCLUSIONS

GKRS affords reasonable rates of endocrine remission and tumor control in most pediatric patients with functioning adenomas. The most common post-GKRS complication was hypopituitarism, although this occurred in only a few patients. Given the larger at-risk period for pediatric patients, further study is required to evaluate for delayed recurrences and hypopituitarism.

The role of Crooke's changes in recurrence and remission after gamma knife radiosurgery

PURPOSE

The objective of this study is to evaluate the role of Crooke's changes (CC) in normal the peri-tumoral anterior pituitary gland, in patients with Cushing's disease (CD) with a histopathological confirmed corticotroph adenoma, and determine if there is any difference in the recurrence and remission rates in CD patients after treatment with Gamma Knife Radiosurgery (GKRS).

METHODS

All patients treated with GKRS for CD from 2005 to 2016 at our institution were identified. Patients had a confirmed adrenocorticotropic (ACTH)-secreting adenoma, i.e. corticotroph adenoma, and normal pituitary gland included in the surgical specimen, and specimens were stained with hematoxylin and eosin and also immunostaining for cytokeratin and ACTH. Statistical analyses were performed in a total of 61 patients who met the inclusion criteria. Additionally, we analyzed 20 patients in each group, with and without CC, after they were matched in a propensity score fashion.

RESULTS

Endocrine remission defined as, a normal 24 h urine free cortisol while off suppressive medication, occurred in 48 patients (78.7%), with 76.9% in those with CC and 81.8% in those without CC. There was no statistical significant difference between the two groups in regarding remission (p = 0.312) or recurrence (p = 0.659) in either the unmatched or matched cohorts.

CONCLUSION

The presence or absence of CC in normal pituitary gland does not appear to confer a lower rate of remission or a higher rate of recurrence after GKRS. Patients with pituitary corticotroph adenomas that present with CC features may be well served by Stereotactic radiosurgery (SRS).

The Treatment of Refractory Pituitary Adenomas

Refractory pituitary adenomas (PAs) are defined as aggressive-invasive PAs characterized by a high Ki-67 index, rapid growth, frequent recurrence, and resistance to conventional treatments. It is notoriously difficult to manage refractory PAs because the efficacy of current therapeutic options is limited. The purpose of this review is to address currently employed and promising therapeutic strategies for the treatment of refractory PAs. Except for prolactinomas, neurosurgery is the first-line option, but most refractory PAs often recur or re-grow after initial surgery and require further treatments. Medical therapy, radiotherapy and re-operation are explored when surgery has failed to completely resect tumors; however, refractory PAs are usually resistant to these treatments. As a salvage treatment, temozolomide (TMZ) has shown promising results and is currently used for all types of refractory PAs. However, not all refractory PAs are responsive to TMZ treatment, and some of these PAs are resistant to TMZ. Although targeted therapies such as vascular endothelial growth factor, epidermal growth factor and mTOR inhibitors have also been used to treat refractory PAs, the effectiveness of these targeted therapies is still not known due to a lack of data from randomized prospective trials. As a novel therapeutic method, cancer immunotherapy is a promising strategy for the treatment of refractory PAs, but further preclinical research and clinical trials are needed to assess the efficacy of this new approach. In summary, early identification and a multidisciplinary approach are required to treat refractory PAs.