The role of stereotactic radiosurgery in the multimodal management of growth hormone–secreting pituitary adenomas

Phosphoproteome profiling revealed abnormally phosphorylated AMPK and ATF2 involved in glucose metabolism and tumorigenesis of GH-PAs

PURPOSE

Protein phosphorylation plays a key role in tumorigenesis and progression. However, little is known about the phosphoproteome profiles of growth hormone-secreting pituitary adenomas (GH-PAs). The aim of this study was to identify critical biomarkers and signaling pathways that might play important roles in GH-PAs and may, therefore, represent potential therapeutic targets.

METHODS

The differential phosphoprotein expression patterns involved in GH-PAs were investigated by nano-LC-MS/MS in a group of samples. The phosphoprotein expression data were analyzed by bioinformatics. The expression levels of the candidate phosphorylated AMPK (ser496) and ATF2 (ser112) were validated by Western blot analysis in another group of samples.

RESULTS

A total of 1213 phosphorylated protein sites corresponding to 667 proteins were significantly different between GH-PAs and healthy pituitary glands. Among these phosphorylated sites, 871 exhibited lower levels of phosphorylation in GH-PAs. Moreover, 140 novel phosphosites corresponding to 93 proteins were differentially phosphorylated between GH-PAs and healthy pituitary glands, 101 of which showed decreased phosphorylation in GH-PAs. The majority of differentially expressed phosphorylated proteins were significantly enriched in glycolysis and the AMPK signaling pathway in GH-PAs. The AMPK signaling pathway was demonstrated to be inhibited in GH-PAs by pathway activity analysis (z score = - 2.324). Notably, the phosphorylated levels of AMPK (ser496) and ATF2 (ser112) were significantly lower in GH-PAs than in healthy pituitary glands.

CONCLUSION

These findings suggest that decreased phosphorylation of the AMPK/ATF2 pathway may be critical for glucose metabolism and tumorigenesis in GH-PAs.

[Modern Management of Pituitary Adenomas - Current State of Diagnosis, Treatment and Follow-Up]

Modern Management of Pituitary Adenomas - Current State of Diagnosis, Treatment and Follow-Up Abstract. Pituitary adenomas (PA) are benign neoplasms originating from parenchymal cells of the anterior pituitary. Tumor mass effect can cause headaches, visual deficits by compression of the optic chiasm, and partial or complete hypopituitarism. Hormone secreting PA can cause several forms of specific syndromes such as Cushing's disease or acromegaly depending on the type of hormone. Endoscopic transsphenoidal resection is the preferred treatment option for most symptomatic or growing PA. Nowadays techniques like high definition intraoperative MRI can assist the surgeon in his goal of maximal safe resection. An exception are prolactinomas which can usually be treated medically with dopamine agonists. Therapy of PA is complex and should be managed in a high-volume center with an interdisciplinary team approach including neurosurgeons and endocrinologists.

Reoperation for growth hormone-secreting pituitary adenomas: report on an endonasal endoscopic series with a systematic review and meta-analysis of the literature

OBJECTIVE Surgery is generally the first-line therapy for acromegaly. For patients with residual or recurrent tumors, several treatment options exist, including repeat surgery, medical therapy, and radiation. Reoperation for recurrent acromegaly has been associated with poor results, with hormonal control usually achieved in fewer than 50% of cases. Extended endonasal endoscopic approaches (EEAs) may potentially improve the results of reoperation for acromegaly by providing increased visibility and maneuverability in parasellar areas. METHODS A database of all patients treated in the authors' center between July 2004 and February 2016 was reviewed. Cases involving patients with acromegaly secondary to growth hormone (GH)-secreting adenomas who underwent EEA were selected for chart review and divided into 2 groups: first-time surgery and reoperation. Disease control was defined by 2010 guidelines. Clinical and radiological characteristics and outcome data were extracted. A systematic review was done through a MEDLINE database search (2000-2016) to identify studies on the surgical treatment of acromegaly. Using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, the included studies were reviewed for surgical approach, tumor size, cavernous sinus invasion, disease control, and complications. Cases were divided into reoperation or first-time surgery for comparative analysis. RESULTS A total of 44 patients from the authors' institution were included in this study. Of these patients, 2 underwent both first-time surgery and reoperation during the study period and were therefore included in both groups. Thus data from 46 surgical cases were analyzed (35 first-time operations and 11 reoperations). The mean length of follow-up was 70 months (range 6-150 months). The mean size of the reoperated tumors was 14.8 ± 10.0 mm (5 micro- and 6 macroadenomas). The patients' mean age at the time of surgery was younger in the reoperation group than in the first-time surgery group (34.3 ± 12.8 years vs 49.1 ± 15.7 years, p = 0.007) and the mean preoperative GH level was also lower (7.7 ± 13.1 μg/L vs 25.6 ± 36.8 μg/L, p = 0.04). There was no statistically significant difference in disease control rates between the reoperation (7 [63.6%] of 11) and first-time surgery (25 [71.4%] of 33) groups (p = 0.71). Univariate analysis showed that older age, smaller tumor size, lower preoperative GH level, lower preoperative IGF-I level, and absence of cavernous sinus invasion were associated with higher chances of disease control in the first-time surgery group, whereas only absence of cavernous sinus invasion was associated with disease control in the reoperation group (p = 0.01). There was 1 case (9%) of transient diabetes insipidus and hypogonadism and 1 (9%) postoperative nasal infection after reoperation. The systematic review retrieved 29 papers with 161 reoperation and 2189 first-time surgery cases. Overall disease control for reoperation was 46.8% (95% CI 20%-74%) versus 56.4% (95% CI 49%-63%) for first-time operation. Reoperation and first-time surgery had similar control rates for microadenomas (73.6% [95% CI 32%-98%] vs 77.6% [95% CI 68%-85%]); however, reoperation was associated with substantially lower control rates for macroadenomas (27.5% [95% CI 5%-57%] vs 54.3% [95% CI 45%-62%]) and tumors invading the cavernous sinus (14.7% [95% CI 4%-29%] vs 38.5% [95% CI 27%-50%]). CONCLUSIONS Reoperative EEA for acromegaly had results similar to those for first-time surgery and rates of control for macroadenomas that were better than historical rates. Cavernous sinus invasion continues to be a negative prognostic indicator for disease control; however, results with EEA show improvement compared with results reported in the prior literature.

Cytomorphology of metastatic pituitary carcinoma to the bone

Metastatic pituitary carcinoma to bone is rare. In this report, we present a case of a 59-year-old female with recurrent pituitary adenoma of the sparsely granulated somatotroph subtype with metastasis to a few bony sites 10 years later. Needle core biopsy (NCB) with touch preparations was performed on a 5 mm lesion in left ilium. Diff-Quik stained NCB touch preparation slides showed a few loosely cohesive epithelial polygonal cells that were arranged in nests or acini, or singly, had scant vacuolated cytoplasm and eccentrically located round nuclei (plasmacytoid) with slight nuclear pleomorphism, fine granular chromatin, conspicuous nucleoli, and smooth nuclear membrane. Trilineage hematopoietic cells of bone marrow were also appreciated in the background. H&E stained core sections showed fragments of bone and bone marrow with nests of bland epithelial cells with similar cytomorphology as seen in NCB touch preparation slides. The tumor cells were immunoreactive for juxtanuclear dot-like staining of pan-cytokeratin (CAM 5.2 and AE1/AE3) (a specific feature), neuroendocrine markers (CD56, synaptophysin, and chromogranin. Additionally, scattered cells were immunoreactive for growth hormone. Molecular test showed that tumor cells were negative for the promoter methylation of O-6-Methylguanine-DNA Methyltransferase (MGMT). Final diagnosis of metastatic pituitary carcinoma was rendered. Morphology of metastatic pituitary carcinoma, its differential, clinical presentation and treatment were discussed. Diagn. Cytopathol. 2017;45:645-650. © 2017 Wiley Periodicals, Inc.

Management of aggressive growth hormone secreting pituitary adenomas

Aggressive GH-secreting pituitary adenomas (GHPAs) represent an important clinical problem in patients with acromegaly. Surgical therapy, although often the mainstay of treatment for GHPAs, is less effective in aggressive GHPAs due to their invasive and destructive growth patterns, and their proclivity for infrasellar invasion. Medical therapies for GHPAs, including somatostatin analogues and GH receptor antagonists, are becoming increasingly important adjuncts to surgical intervention. Stereotactic radiosurgery serves as an important fallback therapy for tumors that cannot be cured with surgery and medications. Data suggests that patients with aggressive and refractory GHPAs are best treated at dedicated tertiary pituitary centers with multidisciplinary teams of neuroendocrinologists, neurosurgeons, radiation oncologists and other specialists who routinely provide advanced care to GHPA patients. Future research will help clarify the defining features of "aggressive" and "atypical" PAs, likely based on tumor behavior, preoperative imaging characteristics, histopathological characteristics, and molecular markers.

Advancing Treatment of Pituitary Adenomas through Targeted Molecular Therapies: The Acromegaly and Cushing Disease Paradigms

The current treatment of pituitary adenomas requires a balance of conservative management, surgical resection, and in select tumor types, molecular therapy. Acromegaly treatment is an evolving field where our understanding of molecular targets and drug therapies has improved treatment options for patients with excess growth hormone levels. We highlight the use of molecular therapies in this disease process and advances in this field, which may represent a paradigm shift for the future of pituitary adenoma treatment.

60 YEARS OF NEUROENDOCRINOLOGY: Acromegaly

Acromegaly (ACM) is a chronic, progressive disorder caused by the persistent hypersecretion of GH, in the vast majority of cases secreted by a pituitary adenoma. The consequent increase in IGF1 (a GH-induced liver protein) is responsible for most clinical features and for the systemic complications associated with increased mortality. The clinical diagnosis, based on symptoms related to GH excess or the presence of a pituitary mass, is often delayed many years because of the slow progression of the disease. Initial testing relies on measuring the serum IGF1 concentration. The oral glucose tolerance test with concomitant GH measurement is the gold-standard diagnostic test. The therapeutic options for ACM are surgery, medical treatment, and radiotherapy (RT). The outcome of surgery is very good for microadenomas (80-90% cure rate), but at least half of the macroadenomas (most frequently encountered in ACM patients) are not cured surgically. Somatostatin analogs are mainly indicated after surgical failure. Currently their routine use as primary therapy is not recommended. Dopamine agonists are useful in a minority of cases. Pegvisomant is indicated for patients refractory to surgery and other medical treatments. RT is employed sparingly, in cases of persistent disease activity despite other treatments, due to its long-term side effects. With complex, combined treatment, at least three-quarters of the cases are controlled according to current criteria. With proper control of the disease, the specific complications are partially improved and the mortality rate is close to that of the background population.

Surgical outcomes using a medial-to-lateral endonasal endoscopic approach to pituitary adenomas invading the cavernous sinus

OBJECT

This study details the extent of resection and complications associated with endonasal endoscopic surgery for pituitary tumors invading the cavernous sinus (CS) using a moderately aggressive approach to maximize extent of resection through the medial CS wall while minimizing the risk of cranial neuropathy and blood loss. Tumor in the medial CS was aggressively pursued while tumor in the lateral CS was debulked in preparation for radiosurgery.

METHODS

A prospective surgical database of consecutive endonasal pituitary surgeries with verified CS invasion on intraoperative visual inspection was reviewed. The extent of resection as a whole and within the CS was assessed by an independent neuroradiologist using pre- and postoperative Knosp-Steiner (KS) categorization and volumetrics of the respective MR images. The extent of resection and clinical outcomes were compared for medial (KS 1-2) and lateral (KS 3-4) lesions.

RESULTS

Thirty-six consecutive patients with pituitary adenomas involving the CS who had surgery via an endonasal endoscopic approach were identified. The extent of resection was 84.6% for KS 1-2 and 66.6% for KS 3-4 (p = 0.04). The rate of gross-total resection was 53.8% for KS 1-2 and 8.7% for KS 3-4 (p = 0.0006). Six patients (16.7%) had preoperative cranial neuropathies, and all 6 had subjective improvement after surgery. Surgical complications included 2 transient postoperative cranial neuropathies (5.6%), 1 postoperative CSF leak (2.8%), 1 reoperation for mucocele (2.8%), and 1 infection (2.8%).

CONCLUSIONS

The endoscopic endonasal "medial-to-lateral" approach permits safe debulking of tumors in the medial and lateral CS. Although rates of gross-total resection are moderate, particularly in the lateral CS, the risk of permanent cranial neuropathy is extremely low and there is a high chance of improvement of preexisting deficits. This approach can also facilitate targeting for postoperative radiosurgery.

Gamma knife in the treatment of pituitary adenomas: results of a single center

INTRODUCTION

Gamma Knife (GK) radiosurgery for pituitary adenomas can offer a means of tumor and biologic control with acceptable risk and low complication rates.

METHODS

Retrospective review of all the patients treated at our center with GK for pituitary adenomas from Nov 2003 to June 2011.

RESULTS

We treated a total of 86 patients. Ten were lost to follow-up. Mean follow was 32.8 months. There were 21 (24.4%) growth hormone secreting adenomas (GH), 8 (9.3%) prolactinomas (PRL), 8 (9.3%) adrenocorticotropic hormone secreting (ACTH) adenomas, 2 (2.3%) follicle stimulating hormone/luteinizing hormone secreting (FSH/LH) adenomas, and 47 (54.7%) null cell pituitary adenomas that were treated. Average maximum tumor diameter and volume was 2.21cm and 5.41cm³, respectively. The average dose to the 50% isodose line was 14.2 Gy and 23.6 Gy for secreting and non-secreting adenomas respectively. Mean maximal optic nerve dose was 8.87 Gy. Local control rate was 75 of 76 (98.7%), for those with followup. Thirty-three (43.4%) patients experienced arrest of tumor growth, while 42 (55.2%) patients experienced tumor regression. Of the 39 patients with secreting pituitary tumors, 6 were lost to follow-up. Improved endocrine status occurred in 16 (50.0%), while 14 (43.8%) demonstrated stability of hormone status on continued pre-operative medical management. Permanent complications included: panhypopituitarism (4), hypothyroidism (4), hypocortisolemia (1), diabetes insipidus (1), apoplexy (1), visual field defect (2), and diplopia (1).

CONCLUSIONS

Gamma Knife radiosurgery is a safe and effective means of achieving tumor growth control and endocrine remission/stability in pituitary adenomas.

Orbital metastasis of pituitary growth hormone secreting carcinoma causing lateral gaze palsy

Background:

Although pituitary adenoma is one of the most common intracranial tumors, it rarely progresses secondarily into a metastatic carcinoma. Commonalities in reported cases include subtotal resection at presentation, treatment with radiation therapy, and delayed metastatic progression. Pathologic descriptions of these lesions are varying and inconsistent.

Case Description:

A 52-year-old male was diagnosed with acromegaly and pituitary tumor in 1996. He underwent four subtotal resections and five courses of stereotactic radiosurgery over 14 years. He developed left eye lateral gaze palsy, and was found to have a distant orbital metastasis with involvement of the left lateral rectus and lateral orbital wall. He underwent left orbital craniotomy via eyebrow incision for resection of this lesion. Pathologic evaluation showed a markedly elevated Ki67 level of 30%.

Conclusion:

While overall incidence of metastatic progression of pituitary adenoma after radiotherapy appears to be low, it appears to be a possible complication, and could be more likely in patients receiving multiple doses of radiotherapy. Our review of reported cases showed that 45/46 (97.8%) of patients developing carcinoma had prior radiation exposure. These patients may also have more aggressive pathologic characteristics of their lesions.

Role of gamma knife radiosurgery in the management of pituitary adenomas and craniopharyngiomas

INTRODUCTION

Radical microsurgical removal of pituitary adenomas (PAs) and craniopharyngiomas (CPHs) is often difficult. In such cases radiosurgery can be used as a second-line treatment option.

MATERIALS AND METHODS

Our series included 436 PAs and 164 CPHs. The majority of patients had large or giant tumors and were treated with microsurgery. Additionally, between June 2008 and August 2011, a total of 29 PAs and 10 CPHs underwent radiosurgery using Leksell Gamma Knife PerfeXion. At the time of treatment the volume of the PAs varied from 0.6 to 26.0 cm3 (mean 5.9 cm3) and that of the CPHs from 0.19 to 17.0 cm3 (mean 6.6 cm3). The marginal doses ranged from 12 to 15 Gy (mean 14.5 Gy) for nonsecreting PAs, from 22 to 25 Gy (mean 24 Gy) for hormone-secreting PAs, and from 8 to 14 Gy (mean 11 Gy) for CPHs.

RESULTS

The postoperative mortality rates after surgical removal of PAs via the transspenoidal approach and craniotomy were 2.4 % and 8.0 %, respectively, whereas after surgery for CPH it was 5.9 %. No major complications were noted in our limited number of patients after radiosurgical treatment. Taking into consideration only cases with radiological follow-up of at least 12 months, shrinkage of the tumor was demonstrated in 5 of 11 patients with a PA and in 4 out of 6 patients with a CPH.

CONCLUSION

Radiosurgery is safe and effective second-line management option in cases of recurrent or residual PA or CPH. Occasionally, it can be applied even as a primary treatment in selected patients.

Management options for persistent postoperative acromegaly

This article presents management options for the patient with acromegaly after noncurative surgery. The current evidence for repeat surgery, adjuvant medical therapy with somatostatin analogues, dopamine agonists, the growth hormone receptor antagonist pegvisomant, combination medical therapy, and radiotherapy in the context of persistent postoperative disease are summarized. The relative advantages and disadvantages of each of these treatment modalities are explored, and a general treatment algorithm that integrates these modalities is proposed.

Gamma knife radiosurgery for acromegaly

Acromegaly is debilitating disease occasionally refractory to surgical and medical treatment. Stereotactic radiosurgery, and in particular Gamma Knife surgery (GKS), has proven to be an effective noninvasive adjunct to traditional treatments, leading to disease remission in a substantial proportion of patients. Such remission holds the promise of eliminating the need for expensive medications, along with side effects, as well as sparing patients the damaging sequelae of uncontrolled acromegaly. Numerous studies of radiosurgical treatments for acromegaly have been carried out. These illustrate an overall remission rate over 40%. Morbidity from radiosurgery is infrequent but can include cranial nerve palsies and hypopituitarism. Overall, stereotactic radiosurgery is a promising therapy for patients with acromegaly and deserves further study to refine its role in the treatment of affected patients.

Surgery and radiosurgery for acromegaly: a review of indications, operative techniques, outcomes, and complications

Among multimodality treatments for acromegaly, the goals of surgical intervention are to balance maximal tumor resection while preserving normal pituitary function and maintaining patient safety. The resection of growth hormone-(GH-) secreting pituitary adenomas in the hands of experienced surgeons results in hormonal remission in 50-70% of patients. Acromegalic patients often have medical comorbidities and anatomical variations complicating anesthesia and surgical management. Despite these challenges, complications such as CSF leak or new hypopituitarism following surgery remain uncommon. Over the past decade, endoscopic approaches to pituitary tumors have improved visualization and facilitated identification of additional tumor using angled telescopes. Patients with persistent acromegaly following surgery require continued medical and/or radiation-based interventions. The adjunctive use of stereotactic radiosurgery offers hormonal remission in 40-50% of patients. In this article, the current preoperative evaluation, indications for surgery, surgical approaches, role of radiosurgery, complications, and remission criteria following operative resection of GH adenomas are reviewed.

Nelfinavir induces radiation sensitization in pituitary adenoma cells

Pituitary adenomas with local invasion and high secretory activity remain a therapeutic challenge. The HIV protease inhibitor nelfinavir is a radiosensitizer in multiple tumor models. We tested nelfinavir as a radiosensitizer in pituitary adenoma cells in vitro and in vivo. We examined the effect of nelfinavir with radiation on in vitro cell viability, clonogenic survival, apoptosis, prolactin secretion, cell cycle distribution, and the PI3K-AKT-mTOR pathway. We evaluated tumor growth delay and confirmed nelfinavir's effect on the PI3K-AKT-mTOR pathway in a hind-flank model. Nelfinavir sensitized pituitary adenoma cells to ionizing radiation as shown by viability assays and clonogenic assay with an enhancement ratio of 1.2 (p < 0.05). There is increased apoptotic cell death, as determined by annexin-V expression and cleaved caspase-3 levels. Nelfinavir does not affect prolactin secretion or cell cycle distribution. In vivo, untreated tumors reached 4-fold volume in 12 days, 17 days with nelfinavir treatment, 27 days with radiation 6 Gy, and 41 days with nelfinavir plus radiation (one-way ANOVA p < 0.001). Decreased phospho-S6 on Western blotting in vitro and immunohistochemistry in vivo demonstrated nelfinavir inhibition of the PI3K-AKT-mTOR pathway. Our data suggests a promising combination therapy with nelfinavir plus radiation in pituitary adenomas, which should be investigated in clinical studies.