Transsphenoidal adenomectomy for growth hormone-secreting pituitary adenomas in acromegaly: outcome analysis and determinants of failure

The Prognostic-Based Approach in Growth Hormone-Secreting Pituitary Neuroendocrine Tumors (PitNET): Tertiary Reference Center, Single Senior Surgeon, and Long-Term Follow-Up

Postoperative deserved outcomes in acromegalic patients are to normalize serum insulin-like growth factor (IGF-1), reduce the tumoral mass effect, improve systemic comorbidities, and reverse metabolic alterations. Pituitary neuroendocrine tumors (PitNET) are characterized to present a heterogeneous behavior, and growth hormone (GH)-secreting PitNET is not an exception. Promptly determining which patients are affected by more aggressive tumors is essential to guide the optimal postoperative decision-making process [prognostic-based approach]. From 2006 to 2019, 394 patients affected by PitNET were intervened via endoscopic endonasal transsphenoidal approach by the same senior surgeon. A total of 44 patients that met the criteria to be diagnosed as acromegalic and were followed up at least for 24 months (median of 66 months (26-156) were included in the present study. Multiple predictive variables [age, gender, preoperative GH and IGF-1 levels, maximal tumor diameter, Hardy's and Knosp's grade, MRI. T2-weighted tumor intensity, cytokeratin expression pattern, and clinicopathological classification] were evaluated through uni- and multivariate statistical analysis. Sparse probability of long-term remission was related to younger age, higher preoperative GH and- or IGF-1, group 2b of the clinicopathological classification, and sparsely granulated cytokeratin expression pattern. Augmented recurrence risk was related to elevated preoperative GH levels, tumor MRI T2-weighted hyperintensity, and sparsely granulated cytokeratin expression pattern. Finally, elevated risk for reintervention was related to group 2b of the clinicopathological classification, Knosp's grade IV, and tumor MRI T2-weighted hyperintensity. In this study, the authors determined younger age, higher preoperative GH and- or IGF-1 levels, group 2b of the clinicopathological classification, Knosp's grade IV, MRI T2-weighted tumor hyperintensity and sparsely granulated cytokeratin expression pattern are related to worse postoperative outcomes in long-term follow-up patients affected with GH-secreting PitNET.

Predictors of postoperative biochemical remission in acromegaly

PURPOSE

Acromegaly is a rare neuroendocrine condition that can lead to significant morbidity. Despite China's vast population size, studies on acromegaly remain sparse. This study aimed to investigate the clinical characteristics and predictors of biochemical remission after surgery for acromegaly using the China Acromegaly Patient Association (CAPA) database.

METHODS

A retrospective nationwide study was conducted using patient-reported data from CAPA database between 1998 and 2018. The principal component analysis (PCA) and logistic regression analysis were employed to determine independent predictors of biochemical remission at 3 months in patients after surgery.

RESULTS

Of the 546 surgical cases (mean age: 36.8 years; 59.5% females), macroadenomas and invasive tumors (Knosp score 3-4) were 83.9% and 64.1%, respectively. Ninety-five percent of patients were treated with endonasal surgery and 36.8% exhibited biochemical remission at 3-months postoperatively. The following independent predictors of biochemical remission were identified: preoperative growth hormone (GH) levels between 12 and 28 μg/L [odds ratio (OR) = 0.58; 95% confidence interval (CI), 0.37-0.92; p = 0.021], preoperative GH levels > 28 μg/L (OR = 0.55; 95% CI, 0.34-0.88; p = 0.013), macroadenoma (OR = 0.56; 95% CI, 0.32-0.96; p = 0.034), giant adenomas (OR = 0.14; 95% CI, 0.05-0.38; p < 0.001), Knosp score 3-4 (OR = 0.37; 95% CI, 0.24-0.57; p < 0.001), and preoperative medication usage (OR = 2.32; 95% CI, 1.46-3.70; p < 0.001).

CONCLUSIONS

In this nationwide study spanning over two decades, we highlight that higher preoperative GH levels, large tumor size, and greater extent of tumor invasiveness are associated with a lower likelihood of biochemical remission at 3-months after surgery, while preoperative medical therapy increases the chance of remission.

Predictive model of surgical remission in acromegaly: age, presurgical GH levels and Knosp grade as the best predictors of surgical remission

PURPOSE

To identify presurgical clinical, hormonal and radiological variables associated with surgical remission in acromegaly and develop a predictive model for surgical remission.

METHODS

Ambispective study of acromegaly surgical patients followed in two Spanish tertiary hospitals. Patients operated by the same neurosurgeon by endonasal endoscopic transsphenoidal approach (n = 49) were included to develop the predictive model, and patients operated by other neurosurgeons (n = 37) were used for external validation of the predictive model. The predictive model was developed with a multivariate logistic regression model based on the 2000 criteria.

RESULTS

86 acromegalic patients were included. 49 patients, 83.7% with macroadenomas and 32.7% with Knosp grade > 2, were included for the development of the predictive model. The overall rate of surgical remission with the 2000 criteria was 73.5% and 51.0% with the 2010 criteria. Using the 2000 criteria, variables associated with surgical remission were: older age (OR = 1.1, p = 0.001), lower basal presurgical GH levels (OR = 0.9, p = 0.003), Knosp 0-2 (OR = 34.1, p < 0.0001) and lower maximum pituitary adenoma diameter (OR = 0.9, p = 0.019). The model with the best diagnostic accuracy to predict surgical remission combined age, Knosp 0-2 and presurgical GH levels (AIC = 29.7, AUC = 0.95) with a sensitivity of 93.8% and a specificity of 75.0%. The estimated loss of prediction with the external validation (n = 37) was 4.2%.

CONCLUSION

The predictive model with the best diagnosis accuracy for surgical remission combined age, Knosp 0-2 and presurgical GH levels, with a sensitivity of 93.8% and a specificity of 75.0%. This model could be very useful to select candidates to preoperative medical treatment and planning the follow-up.

Prognostic factors of biochemical remission after transsphenoidal surgery for acromegaly: a structured review

PURPOSE

Biochemical control is the main determinant of survival, clinical manifestations and comorbidities in acromegaly. Transsphenoidal selective adenomectomy (TSA) is the initial treatment of choice with reported biochemical remission rates varying between 32 and 85%. Understanding the limiting factors is essential for identification of patients who require medical treatment.

METHODS

We reviewed the English literature published in Medline/Pubmed until Dec 31, 2019 to identify eligible studies that described outcomes of TSA as primary therapy and performed analyses to determine the main predictors of remission.

RESULTS

Most publications reported single-institution, retrospective studies. The following preoperative parameters were consistently associated with lower remission rates: cavernous sinus invasion by imaging, larger tumor size and higher GH levels. Young age and preoperative IGF-1 levels were predictive in some studies. When controlled for covariates, the best single preoperative predictor was cavernous sinus invasion, followed by preoperative GH levels. Conversely, low GH level in the first few days postoperatively was a robust predictor of durable remission. The influence of tumor histology (sparsely granular pattern, co-expression of prolactin and proliferation markers) on surgical remission remains to be established. Few studies developed predictive models that yielded much higher predictive values than individual parameters.

CONCLUSION

Surgical outcome prognostication systems could be further generated by machine learning algorithms in order to support development and implementation of personalized care in patients with acromegaly.

A follow-up study on outcomes of endoscopic transsphenoidal approach for acromegaly

OBJECTIVE

A thorough follow-up study in which the same clinic presents the change in the surgical outcomes of acromegaly over the years, is still lacking in the endoscopic era. In this study, we intended to evaluate the clinical characteristics, radiological features, surgical and late remission rates of newly diagnosed acromegaly patients treated in our clinic between 2014 and 2019 in order to delineate the surgical remission status according to radiological, microscopic, and hormonal features. As a follow-up to our initial report, we also aimed to display the change of surgical remission rates over time in a tertiary center.

METHODS

A total of newly diagnosed 106 patients with acromegaly, who underwent endoscopic endonasal trans-sphenoidal approach (EETSA) in the last five years were retrospectively analyzed and presented in this study. Medical records were reviewed in clinical, biochemical, pathological, and radiological aspects to assess the relationship of preoperative patient characteristics with surgical remissions.

RESULTS

The percentages of the giant pituitary adenomas (≥4 cm), adenomas with suprasellar extension and adenomas with surgically proven invasion of the cavernous sinus in the present series were 13%, 34%, and 20%, respectively. Gross total resection was achieved in 80% of the patients. Surgical remission and late remission rates were 66% and 86%, respectively. Nine (9.4%) patients in our current report had postoperative transient diabetes insipidus. The mean follow-up period in this series was 36.1 ± 18.1 (range 12-59) months.

CONCLUSION

The presented surgical results are considerably better than our published initial series of acromegaly patients operated in the same clinic between 2007 and 2014. The improvement in surgical remission rate support a positive surgical volume - remission rate relationship for acromegaly in the era of endoscopic endonasal skull base approaches. One possible factor for better results may be the increasing surgical experience in EETSA, which follows a trend toward gradual improvement of long-term late remissions via a multidisciplinary approach.

Gender differences and temporal trends over two decades in acromegaly: a single center study in 112 patients

PURPOSE

To evaluate the impact of gender and year at surgery on clinical presentation and postoperative outcomes in acromegaly.

METHODS

Retrospective review of patients operated between 1994 and 2016 to compare presentation and outcomes in groups defined by gender and year of surgery. Kaplan-Meier survival analyses with a composite endpoint (recurrence, reoperation, and radiation) were used for gender comparison and Youden indices for biochemical remission rates changes during study period.

RESULTS

Primary indications for evaluation were phenotype, neurological symptoms, incidentaloma, hypogonadism, and galactorrhea. At surgery, men (N = 54) were younger (43.6 ± 12.7 years) than women (N = 58, 48.7 ± 12.3, P = 0.04). Male:female ratios before and after age 50 were 1.4 and 0.6 respectively. Men had higher mean IGF-1 levels (874 ± 328 vs 716 ± 296, P < 0.01) and smaller tumors (1.8 ± 1.3 cm vs 2.3 ± 1.5, P = 0.04). Postoperative remission rates were comparable (51% men, 56% women) and inversely associated with cavernous sinus invasion and GH levels. Women had longer mean follow-up (5.2 ± 3.4 years vs 3.6 ± 3.6 men, P = 0.02) and longer endpoint-free survival (P < 0.01). At last follow-up, 89.6% women and 70% men had normal IGF-1 levels (P = 0.03). Postoperative remission rates were higher in patients operated after February 15, 2011 (67.35 vs 43.5% previously, P = 0.01). In late vs early surgery group, physical changes as main indication for screening decreased (54 vs 30%, P < 0.01), while incidentaloma and hypogonadism increased. Median GH levels were lower in late vs early surgery group (P = 0.03).

CONCLUSION

We demonstrate gender-specific characteristics and an evolving spectrum of clinical presentation with implications for earlier diagnosis and personalized management of acromegaly.

Pre-operative MRI predictors of hormonal remission status post pituitary adenoma resection

INTRODUCTION

Contrast-enhanced (CE) Constructive Interference in Steady State (CISS) and Volumetric Interpolated Breath-hold Examination (VIBE) are MRI sequences used to improve the detection of pituitary adenomas and adjacent cranial nerves. The purpose of this study was to assess image quality and identify imaging predictors of postoperative hormonal remission of functioning pituitary adenomas using CE-T1 weighted image (WI), T2WI, CE-CISS, and CE-VIBE MRI sequences.

MATERIALS AND METHODS

Patients with pre-operative CE-T1WI, T2WI, CE-CISS, and CE-VIBE pituitary MRI sequences were included in this institutional retrospective review. Three raters independently reviewed randomized sequences in a blinded fashion for adenoma characteristics and parasellar invasion. Subgroup analysis of hormonal remission was performed.

RESULTS

A total of 34 functioning pituitary adenoma patients were included (average age 39.3 ± 12.2; female n = 27), 30 of which had post-operative hormonal remission (n = 34; 88.2%). Compared to CE-T1WI, CE-CISS has significantly higher number of sequences rated "good" image quality (p = 0.02). Hormone remission was associated with decreased degrees of pre-operative internal carotid artery (ICA) contact and Knosp score (p ≤ 0.02) on all sequences except for Knosp score on T2WI. On receiver operating characteristic analysis, the area under curve for differentiating endocrine remission ranged from 0.88 to 0.92 for Knosp score and 0.85-0.93 for ICA contact, depending on sequence.

CONCLUSION

Extent of pituitary adenoma cavernous sinus invasion as measured by degrees of ICA contact and Knosp score is associated with postoperative endocrine outcomes. Given improved image quality, inclusion of CE-CISS may be helpful for pre-surgical planning.

Surgical-pharmacological interactions in the treatment of acromegaly

INTRODUCTION

Acromegaly requires a multimodal treatment approach that includes surgery by an expert pituitary neurosurgeon, pharmacological treatment with one or more of the available drugs and radiation therapy. These treatment alternatives are not mutually exclusive but rather complement each other when properly indicated in the individual patient. In this review, we summarize and analyze the available data concerning the choice of the surgical approach (microscopy vs. endoscopy) and the interactions between medical treatment with somatostatin analogs and pituitary surgery.

AREAS COVERED

Technical aspects, complications and outcome of transsphenoidal surgery (TSS); Advantages and disadvantages of the microscopic and endoscopic approaches; Safety and efficacy of somatostatin analogs (SSA); Primary pharmacological therapy versus primary TSS; Benefits of the preoperative treatment with SSA; and the effect of surgical tumor debulking in the therapeutic response to SSA.

EXPERT COMMENTARY

Continuing efforts at improving surgical techniques and at generating more efficacious pharmacological therapies for acromegaly are likely to improve the outcome of these patients. However, an integral approach of the patient aimed not only at achieving biochemical criteria of cure but also at treating the individual comorbidities is mandatory to improve the quality of life of these patients and to reduce their mortality rate.

Microsurgical versus endoscopic transsphenoidal resection for acromegaly: a systematic review of outcomes and complications

PURPOSE

The aim of this systematic review is to evaluate the long-term endocrine outcomes and postoperative complications following endoscopic vs. microscopic transsphenoidal resection (TSR) for the treatment of acromegaly.

METHODS

A literature review was performed, and studies with at least five patients who underwent TSR for acromegaly, reporting biochemical remission criteria and long-term remission outcomes were included. Data extracted from each study included surgical technique, perioperative complications, biochemical remission criteria, and long-term remission outcomes.

RESULTS

Fifty-two case series from 1976 to 2016 met the inclusion criteria, comprising 4375 patients. Thirty-six reports were microsurgical (n = 3144) and 13 were endoscopic (n = 940). Three studies compared microsurgical (n = 111) to endoscopic TSR outcomes (n = 180). The overall initial and long-term remission rates were 58.2 vs. 57.4% and 69.2 vs. 70.2% for the microsurgical and endoscopic groups, respectively. For microadenomas, the initial and long-term remission rates were 77.6 vs. 82.2% and 76.9 vs. 73.5% for microsurgical and endoscopic approaches, respectively. For macroadenomas, the initial and long-term remission rates were 46.9 vs. 60.0% and 40.2 vs. 61.5% for microsurgical and endoscopic approaches, respectively. The rates of postoperative CSF leak were 3.0 vs. 2.3% for the microscopic and endoscopic groups, respectively. The rates of hypopituitarism and transient diabetes insipidus were 6.7 vs. 6.4% and 9.0 vs. 7.8% for the microscopic and endoscopic groups, respectively.

CONCLUSIONS

Both endoscopic and microsurgical approaches for TSR of growth hormone-secreting adenomas are viable treatment options for patients with acromegaly, and yield similarly high rates of remission under the most current consensus criteria.

Surgical management of acromegaly: Long term functional outcome analysis and assessment of recurrent/residual disease

Context:

Functional growth hormone producing adenomas have long-term deleterious effects on the visual apparatus, the cardiovascular and musculoskeletal systems, and often predispose to malignancies. Since persistence of acromegaly affects outcome and quality of life, therapeutic interventions become mandatory.

Aim:

This study represents an analysis of long-term clinical and endocrinal outcome of 115 patients of acromegaly after surgical management.

Setting and Design:

Tertiary care retrospective study.

Materials and Methods:

One hundred and fifteen patients (male:female ratio: 1:1.09) with acromegalic features were studied. Apart from acromegalic features, their main clinical presentation also included headache, diminution of vision, field defects, ptosis, irregular menstruation, diabetes insipidus, diabetes mellitus and hypertension. Six of them presented with apoplexy. Their preoperative endocrinal evaluation included basal and suppressed growth hormone (GH), prolactin and thyroid levels. On the basis of axial and coronal CT scan or multiplanar MR imaging or both, the tumors were classified according to their suprasellar and parasellar extension (Hardy's grade). Transnasal trans-sphenoidal surgery (TSS) (n = 37) and sublabial, rhinoseptal TSS (n = 72) were the preferred approaches. Six patients with significant parasellar extensions underwent trans-cranial explorations. The patients were followed up at 6 and 12 weeks and then at 6 monthly intervals. Hormonal and CT/MR evaluation were also done. Attainment of random GH value less than 2.5 µg/L, and the nadir GH value after oral glucose tolerance test (OGTT) less than 1 µg/L were used as the criteria of cure.

Findings:

The patients were preoperatively in Hardy's tumor grade 0 (29), A (21), A+E (3), B (21), B+E (5), C (9), C+E (10), D (1) D+E (11), E (5), respectively. One hundred and one patients were available for follow-up (FU; median FU duration: 84 months; range: 6 to 132 months). Surgical cure was achieved in 73 patients following the first surgery; and, in 10 additional patients following a second intervention. No patient with a preoperative grade 0, A, B, C had a recurrence after attaining the initial remission. Recurrence after an initial cure occurred in 7 patients (overall remission rate following surgery: 75.24%). The preoperative grade of the latter patients was A+E:1, B+E:1, C+E:1, D:1, D+E:2, E:1, respectively. All these patients underwent subsequent radiotherapy (RT). The twelve patients with persistent symptoms and high GH levels following surgery underwent RT; six others with improved symptoms despite high GH levels were kept under strict observation. There was no surgical mortality.

Conclusions:

A high remission rate without significant morbidity could be achieved following surgical intervention in acromegalic patients. Following surgery, tumors with greater than or equal to 3 cm suprasellar height and without parasellar extension had no clinical recurrence at FU. A continuous monitoring is mandatory to pick up relapsed cases as well as those who develop delayed signs of hypopituitarism. A subset of patients who show clinical improvement following surgery but still have higher GH levels may be followed up without additional therapy unless clinical signs reappear or the serum GH levels progressively increase.

Neurosurgical Treatment of Acromegaly

Surgical removal of as much tumor mass as possible is usually considered the first step of treatment in acromegaly, unless the patients are unfit for surgery or refuse an operation. To date, in almost all cases, minimally invasive, transsphenoidal microscopic or endoscopic approaches are used. Whether a curative approach is feasible or a debulking procedure is planned, can be anticipated on the basis of preoperative magnetic resonance imaging. It mostly depends on localization, size, and the invasive character of the lesion. The surgical results depend on tumor-related factors such as size, extension, the presence or absence of invasion, and the magnitude of IGF-1 and growth hormone oversecretion, respectively. However, even surgeon-related factors such as experience and case load of the centers have been shown to strongly affect surgical results and complication rates. A reoperation can be considered at various stages in the treatment algorithm. There are several new technical gadgets which might aid in the surgical procedure: navigation, the Doppler probe, and variants of intraoperative imaging.

Diagnostic features and outcome of surgical therapy of acromegalic patients: experience of the last three decades

OBJECTIVE

Transsphenoidal (TNS) surgery remains the primary therapeutic option for GH-secreting pituitary adenomas. The aims of this study were to verify the impact of TNS surgery on treatment of acromegaly before and after identification by a dedicated neurosurgical team and to enumerate diagnostic features of the disease described over three decades.

DESIGN

41 patients (group A) who underwent TNS surgery by a dedicated neurosurgical team (2000-2008) and 126 patients (group B) operated on by surgeons not specialized in pituitary surgery (1979-1999) were retrospectively analyzed.

RESULTS

No significant differences were observed between the two groups in terms of delay of diagnosis, mean basal GH levels and GH nadir values, prevalence of hypopituitarism and hypertension. IGF-I SDS were significantly higher, while prevalence of IGT/diabetes was significantly lower in group B than in group A. Overall remission rate after surgery was 58.5% for group A (75% in microadenomas and 48% in macroadenomas, P=NS) and 37% for group B (P<0.05 vs group A; for microadenomas, 34% vs 75% of group A, P<0.05, for macroadenomas, 36% vs 48% of group A, P=NS). The mean delay of diagnosis was 4.9 and 5.9 years in group A and B, respectively.

CONCLUSIONS

Our data confirm that a dedicated neurosurgical team is needed in order to improve remission rates in acromegalic patients. No changes in biochemical, clinical and neuroradiological presentation of disease were observed over the last three decades. As the high prevalence of macroadenomas negatively influences surgical cure, earlier diagnosis should be considered as mandatory to achieve a better outcome.

Emerging drugs for acromegaly

INTRODUCTION

Acromegaly is a rare disease that severely impacts patients' health all the while, being a slowly progressing illness. In the past decades, advancements in treatment modalities, especially development of new drugs, as well as focused guidelines has improved management of acromegaly. Still, many patients are considered not sufficiently treated and there remains an ongoing need for further development.

AREAS COVERED

This article reviews new medical treatments currently under clinical investigation (such as pasireotide, oral octreotide and somatoprim) and under experimental development (such as octreotide implants, CAM2029 and ATL-1103).

EXPERT OPINION

As it seems unlikely that one single agent may achieve cure in 100% of cases, there is an urgent need for new agents that help patients where current medication fails. Imperatively, this means we have to improve our understanding of the underlying pathogenetic and molecular mechanisms.

Endoscopic endonasal approach for growth hormone secreting pituitary adenomas: outcomes in 53 patients using 2010 consensus criteria for remission

We report the outcomes of the endoscopic endonasal approach (EEA) for resection of growth hormone secreting pituitary adenomas using 2010 consensus criteria. We also assess outcomes with additional medical therapy and radiosurgery (RS) for patients not achieving remission with EEA alone. A retrospective review of 53 patients who had follow up endocrinologic data at least 3 months post-surgery was performed among patients who were treated by EEA between 1998 and 2012. Data were analyzed for remission using GH and IGF-I levels based on 2010 consensus criteria. We also analyzed the outcomes using 2000 consensus criteria for ease in comparison to prior studies of outcomes of surgery for acromegaly. In this series of mostly large (88.2% macroadenomas), invasive (46.9% Hardy-Wilson C, D, E) adenomas, there were 27 patients (50.9%) who achieved remission after EEA only. For patients who had no remission with EEA alone, RS and/or medical therapy were used and 37 patients (69.8 %) achieved remission overall. Statistical analysis showed larger tumor size, Hardy Stages C, D, E and Knosp Scores 3, 4 to be predictive against remission for EEA only and EEA with other modalities. The volume of residual tumor after EEA was not found to be predictive of remission with additional therapies. We used stringent consensus criteria from 2010 in a series which included a high proportion of invasive GH secreting adenomas to show that EEA alone or combined with other modalities results in comparable remission rates to earlier studies which used less strict criteria, while retaining low complication rates.

Acromegaly: role of surgery in the therapeutic armamentarium

Acromegaly is a complex disease that requires the intervention of a multidisciplinary team. The most frequent clinical manifestations are growing of distal parts of the body and some areas of the face. Patients may also present arterial hypertension, diabetes mellitus, colonic polyps, cardiomegaly, neurological and endocrine changes secondary to the presence of a GH-secreting tumor in pituitary or extrapituitary origin, or eutopic hypothalamic GHRH hypersecretion and peripheral GHRH hypersecretion. Surgery is the first treatment used for most patients, regardless of the cause. In the great majority of cases, pituitary tumor can be removed through a transsphenoidal approach. Craniotomy is reserved for those cases with giant tumors, particularly when they grow toward the middle or posterior cranial fossa. Best surgical results are obtained when the tumor is confined into the sella turcica or if it has a regular suprasellar extension. When the disease cannot be controlled with surgery, medical treatment is indicated. Somatostatin analogues are included as the first line of medication, followed by dopamine agonist and growth hormone receptors antagonists. Radiation therapy can be also indicated in two main forms for residual tumor with medically refractory patients: radiosurgery for small tumors or fractionated stereotactic radiotherapy for larger ones.

Medical therapy of acromegaly

This paper outlines the present status of medical therapy of acromegaly. Indications for permanent postoperative treatment, postirradiation treamtent to bridge the interval until remission as well as primary medical therapy are elaborated. Therapeutic efficacy of the different available drugs-somatostatin receptor ligands (SRLs), dopamine agonists, and the GH antagonist Pegvisomant-is discussed, as are the indications for and efficacy of their respective combinations. Information on their mechanism of action, and some pharmakokinetic data are included. Special emphasis is given to the difficulties to define remission criteria of acromegaly due to technical assay problems. An algorithm for medical therapy in acromegaly is provided.

Endoscopic endonasal transsphenoidal approach: an additional reason in support of surgery in the management of pituitary lesions

The outcome of endoscopic endonasal transsphenoidal surgery in 10 patients with pituitary adenomas was compared with that of traditional transnasal transsphenoidal approach (TTA) in 20 subjects. Among the 10 individuals subjected to "pure endoscopy," 2 had a microadenoma, 1 an intrasellar macroadenoma, 4 had a macroadenoma with suprasellar expansion, 2 had a macroadenoma with supra-parasellar expansion, and 1 a residual tumor; 5 had acromegaly and 5 had a nonfunctioning adenoma (NFA). Among the patients subjected to TTA, 4 had a microadenoma, 2 had an intrasellar macroadenoma, 6 had a macroadenoma with suprasellar expansion, 4 had a macroadenoma with supra-parasellar expansion, and 4 had a residual tumor; 9 patients had acromegaly, 1 hyperprolactinemia, 1 Cushing's disease, and 9 a NFA. At the macroscopic evaluation, tumor removal was total (100%) after endoscopy in 9 patients and after TTA in 14 patients. Six months after surgery, magnetic resonance imaging (MRI) confirmed the total tumor removal in 21 of 23 patients (91.3%). Circulating growth hormone (GH) and insulin-like growth factor-I (IGF-I) significantly decreased 6 months after surgery in all 14 acromegalic patients: normalization of plasma IGF-I levels was obtained in 4 of 5 patients after the endoscopic procedure and in 4 of 9 patients after TTA. Before surgery, pituitary hormone deficiency was present in 14 out of 30 patients: pituitary function improved in 4 patients, remaining unchanged in the other 10 patients. Visual field defects were present before surgery in 4 patients, and improved in all. Early surgical results in the group of 10 patients who underwent endoscopic pituitary tumor removal were at least equivalent to those of standard TTA, with excellent postoperative course. Postsurgical hospital stay was significantly shorter (3.1 +/- 0.4 vs. 6.2 +/- 0.3 days, p < 0.001) after endoscopy as compared to TTA.

Intraoperative magnetic resonance imaging–assisted transsphenoidal pituitary surgery in patients with acromegaly

Object

Acromegaly is a rare disease, usually caused by a growth hormone (GH)–producing pituitary adenoma. If untreated, severe cardiovascular, metabolic, cosmetic, and orthopedic disturbances will result. Surgery is generally recommended as the first-line treatment. Transsphenoidal surgical techniques were recently extended by the introduction of intraoperative MR (iMR) imaging. In the present study, the contribution of ultra-low-field (0.15-T) iMR imaging to tumor resection, complication avoidance, and endocrinological and neurological outcome was analyzed.

Methods

A series of 39 consecutive transsphenoidal iMR imaging–guided (using the PoleStar N20 device) surgical procedures performed between September 2005 and August 2009 for GH-producing pituitary adenomas was retrospectively analyzed. In addition to the patients' clinical data, the following criteria were evaluated independently: duration of surgery; length of hospital stay; endocrinological parameters; results of neurological examinations; and pre-, post-, and intraoperative MR imaging results.

Results

Thirty-seven patients with acromegaly underwent 39 transsphenoidal surgeries for pituitary adenomas. During a median follow-up period of 30 months (range 9–56 months), the remission rate was 73.5% in 34 patients with primary surgery and 20% in 5 cases with previous surgery; overall the remission rate was 66.7%. There were no serious postoperative complications. Detection of tumor remnant on iMR imaging led to a 5.1% increase in remission rate.

Conclusions

In this largest study to date of GH-producing pituitary adenomas in which iMR imaging–guided transsphenoidal surgery was analyzed, the results suggest that this method is a highly effective and safe treatment modality, even compared with previously published surgical series in which high-field iMR imaging was used. Limitations of iMR imaging are the detection of small residual tumor in the cavernous sinus and persisting disease that could not be observed, even on diagnostic high-field follow-up MR images. This points to a general limitation regarding remission rates that can be achieved using iMR imaging. Nevertheless, iMR imaging led to an increase of the remission rate in this study.

[Casuistry review of patients undergoing surgery for pituitary adenomas in Getafe University Hospital (Spain)]

OBJECTIVE

To perform a casuistry review of patients diagnosed with pituitary adenomas (PA) who underwent surgery performed by the same neurosurgeon after 1995.

MATERIAL AND METHODS

A descriptive and retrospective study was performed in 98 patients with PA undergoing surgery from 1995-2008. Tumor size and data on functionality, pathology and postprocedural complications were analyzed. The study was divided into two periods: 1995-2002 (first period) and 2003-2008 (second period).

RESULTS

A total of 110 surgical interventions (59 in the first period and 51 in the second) were performed for 49 non-hormone-producing PA and 61 hormone-producing PA. There were 85 macroadenomas and 25 microadenomas. Cure was achieved in 31 patients (36%) with macroadenomas and in 21 patients (84%) with microadenomas (P=0.05).The number of complications was significantly higher in the first period [32 patients (54 %)] than in the second period [16 patients (31.3%)] (P<0.05). Cure was achieved in 28 patients (47.4%) in the first period compared with 31 (52.1%) in the second (P=0.1). The mortality rate was 0.9%.

CONCLUSIONS

As described in previous studies, the cure rate was significantly higher for microadenomas than for macroadenomas. There was a significant reduction in the incidence of surgical complications and a trend toward an increase in the percentage of overall healing in the second period of the study. These results are probably related to the neurosurgeon's greater experience and surgical skill.

Variations in referral patterns for hypophysectomies among pediatric patients with sellar and parasellar tumors

PURPOSE

It has been shown that patients admitted to high-volume hospitals for resection of sellar and parasellar lesions experience reduced mortality and morbidity. It remains unknown what preoperative factors influence admission to high-volume centers. We report a nationwide analysis of patients <18 years of age undergoing neurosurgical intervention for these lesions.

METHODS

A retrospective analysis of the Nationwide Inpatient Sample was performed with additional factors from the Area Resource File. International Classification of Diseases, 9th Revision diagnosis/procedural codes were used to identify patients undergoing resection of tumors from the pituitary gland or related structures. Patients >or=18 years old were excluded. Covariates included age, gender, race, and insurance status. Multivariate analysis was performed using multiple logistic regression models. A p value <0.05 was considered statistically significant.

RESULTS

In total, 1,063 patients were identified. Most (69.8%) were seen at low-volume centers. Mean (median) patient age was 13.7 (15) years. The majority of patients were female (54.8%), white (61.9%), and insured (90.3%). Hispanics were 44% less likely (odds ratio (OR) 0.56, 95% confidence interval (CI) 0.34-0.92, p < 0.05) to be seen at high-volume centers than their Caucasian counterparts. Each increase in 2-year patient age category was associated with greater access to high-volume centers (OR 1.12, 95% CI 1.03-1.23, p < 0.05), relative to 0-2 years old. Female gender, insurance status, county poverty, neurosurgeon density, and calendar year were not significantly associated with admission to high-volume centers.

CONCLUSIONS

Age and racial disparities play a significant role in access neurosurgical care, affecting admission of pediatric patients to high-volume neurosurgical centers across the USA.

Endoscopic pituitary surgery: a systematic review and meta-analysis

Object

Surgery on the pituitary gland is increasingly being performed through an endoscopic approach. However, there is little published data on its safety and relative advantages over traditional microscope-based approaches. Published reports are limited by small sample size and nonrandomized study design. A meta-analysis allows for a description of the impact of endoscopic surgery on short-term outcomes.

Methods

The authors performed retrospective review of data from their institution as well as a systematic review of the literature. The pooled data were analyzed for descriptive statistics on short-term outcomes.

Results

Nine studies (821 patients) met inclusion criteria. Overall, the pooled rate of gross tumor removal was 78% (95% CI 67–89%). Hormone resolution was achieved in 81% (95% CI 71–91%) of adrenocorticotropic hormone secreting tumors, 84% (95% CI 76–92%) of growth hormone secreting tumors, and 82% (95% CI 70–94%) of prolactin secreting tumors. The pooled complication rates were 2% (95% CI 0–4%) for CSF leak and 1% (95% CI 0–2%) for permanent diabetes insipidus. There were 2 deaths reported in the literature that were both related to vascular injury, giving an overall mortality rate of 0.24%.

Conclusions

The results of this meta-analysis support the safety and short-term efficacy of endoscopic pituitary surgery. Future studies with long-term follow-up are required to determine tumor control.

Treatment of elderly acromegalics

We assessed the incidence of elderly patients in Japanese acromegalics and the characteristics of their clinical presentation. We also evaluated the safety and efficacy of transsphenoidal surgery (TSS) in this patient group. During the 28-year period from 1980 to 2007 we treated 290 patients with acromegaly at our hospitals. Of these, 9 (3.1%) were elderly, i.e. 70 years old or older. They comprised 0.7% of acromegalics treated during the first- and 4.5% of patients with acromegaly treated during the 2nd 14-year period. Before treatment, all manifested abnormal glucose tolerance; 6 had diabetes mellitus (DM), 6 presented with hypertension, and 2 had cardiovascular disease, malignant neoplasms, or hyperlipidemia. Of the 7 elderly acromegalics who underwent TSS none manifested surgical morbidity or new pituitary hormone deficiencies. Postoperatively, the nadir growth hormone (GH) level at the oral glucose tolerance test (OGTT) was under 1.0 ng/mL in 5 patients, insulin-like growth factor (IGF-1) levels normalized in 4. Glucose tolerance improved in all operated patients. Only 1 of 6 patients with preoperatively diagnosed DM continued to manifest DM post-treatment, anti-hypertensive drugs could be tapered in 3 of patients with preoperative hypertension. In conclusion, we found that there was a high incidence of abnormal glucose tolerance and hypertension in elderly acromegalics, that surgical treatment was effective and safe in this population, and that it was useful for the control of co-morbidities.

Inhibition of NFkappaB reduces cellular viability in GH3 pituitary adenoma cells

OBJECTIVE

Adenomas of the pituitary gland are among the most common types of tumors of the adult brain. Although adenomas are histologically benign, they may be associated with significant morbidity and mortality, mostly because of their invasive growth pattern and hormone hypersecretion. Current medical therapies are suppressive, acting at a receptor level. Thus, there is a need to identify novel cellular and molecular targets for pituitary tumors. We investigated the possible role of the NFkappaB transcription factor in pituitary tumor cell growth.

METHODS

The effect of NFkappaB pathway inhibition on cellular viability was studied in the GH3 pituitary adenoma cell line, a well-characterized rat cell line that secretes growth hormone and prolactin. Cells were treated with mechanistically diverse pharmacological NFkappaB pathway inhibitors or with molecular inhibitors that were overexpressed in tumor cells before the assessment of cellular viability. NFkappaB activity was also assessed in GH3 cells using deoxyribonucleic acid binding assays.

RESULTS

GH3 cells exhibited constitutive NFkappaB activity, which contributed to increased cellular proliferation. Treatment with wedelolactone, an IkappaB kinase inhibitor, or overexpression of an IkappaB super-repressor reduced cell viability, further implicating NFkappaB in pituitary tumor cell growth. Pharmacological or molecular inhibition of Akt similarly reduced GH3 viability and NFkappaB binding, suggesting that constitutive activation of NFkappaB may be, at least in part, mediated by Akt.

CONCLUSION

Directed targeting of the Akt and NFkappaB signaling pathways may be a useful adjunct in the clinical management of pituitary tumors. Further elucidation of this pathway may yield novel information regarding the behavior of pituitary tumors in humans.

Current diagnosis of acromegaly

Acromegaly is a rare and chronic condition that is characterized by sustained unregulated hypersecretion of growth hormone (GH). More than 99% of the cases of acromegaly are due to a pathologic proliferation of pituitary somatotrophs presenting in the form of a pituitary adenoma. The excessive amounts of GH and its target hormone, insulin like growth factor-1 (IGF-1) cause metabolic changes and tissue enlargement that, collectively, lead to significant morbidity and a two to threefold increase in mortality. Thus, early diagnosis has proved to be crucial to improve survival and quality of life in this condition. The development of radioimmunoassay (RIA) in the 1960s provided clinicians with a biochemical tool to diagnose acromegaly. Many limitations were inherent to this methodology which necessitated the development of more sensitive tools, such as immunoradiometric (IRMA) or immunoluminometric (ILMA) assays for GH and IGF-1 measurements. These newer assays have not come without imperfections. The reference ranges to describe normalcy of the somatotropic axis and the biochemical criteria of "cure" of acromegaly are areas of great debate. Nevertheless, the current international consensus agrees that the diagnosis of acromegaly should be based on both clinical presentation and biochemical data.

Biochemical remission and recurrence rate of secreting pituitary adenomas after transsphenoidal adenomectomy: long-term endocrinologic follow-up results

BACKGROUND

Transsphenoidal surgery is safe and effective in patients with secreting pituitary adenomas; however, variable outcomes have been reported according to the different criteria used to define the biochemical remission of hormone hypersecretion. We report the long-term endocrinologic follow-up results of a large cohort of patients who underwent TSS for secreting pituitary adenomas according to the most recent stringent criteria of cure.

METHODS

Two hundred ten consecutive patients were operated on by TSS between 1995 and 2004 for a secreting pituitary adenoma (65 PRL-, 109 GH-, and 36 ACTH-secreting adenomas) and were considered for the study.

RESULTS

The overall remission rate was 65% for the whole series, being 64%, 61%, and 75% for PRL-, GH-, and ACTH-secreting adenomas, respectively. Eighty-six percent of microadenomas and 53% of macroadenomas were cured by surgery. Remission rates were significantly higher in GH- and ACTH-secreting pituitary macroadenomas than in macroprolactinomas. At a median follow-up of 56 months, tumor recurrence was 0%, 11%, and 14% for GH-, ACTH-, and PRL-secreting tumors. Tumor size, cavernous sinus invasion, and high hormone levels were negatively correlated to the outcome.

CONCLUSION

Transsphenoidal surgery remains an effective treatment for secreting pituitary tumors according to the most recent criteria of cure. Patients with PRL- or ACTH-secreting adenomas may recur after apparently successful surgery, thereby justifying long-term careful endocrinologic follow-up.

Defining normalcy of the somatotropic axis: an attainable goal?

The diagnoses of acromegaly and dwarfism require biochemical confirmation of abnormal GH and IGF-1 concentrations. The same parameters are used for therapeutic decisions, i.e. initiation or termination of particular treatments. Therefore, reliable and epidemiologically and statistically proven criteria of normalcy for GH and IGF-1 are required for these tasks to be accomplished. Despite major progress in all these areas, the definition of what constitutes "normalcy" of the somatotropic axis is still lacking. Using an example of acromegaly, we discuss the contradictions and the uncertainties of the biochemical diagnosis of this disease.

The outcome of surgery in 668 patients with acromegaly using current criteria of biochemical 'cure'

BACKGROUND AND AIM

The aim of this study was to illustrate the present role of transsphenoidal surgery as primary therapy in GH-secreting adenomas, and to compare the results concerning control of disease with previous series using older criteria of cure.

METHOD

We report on a consecutive series of 688 acromegalic patients treated over a time period of 19 years. Biochemical cure was defined as normalisation of basal GH level, suppression of GH levels to below 1 ng/ml during an oral glucose load and normalisation of IGF-I levels. Of the 506 patients undergoing primary transsphenoidal surgery, a total of 57.3% postoperatively fulfilled the criteria used.

RESULTS

The rate of biochemical 'cure' correlated with the magnitude of the initial GH levels, the tumour size and invasion. The overall complication rate was below 2%. Mortality in this series was 0.1% (1 of 688). During a follow-up period of 10.7 years only two recurrences (0.4%) occurred. However, in the patients treated by transcranial surgery and by repeat surgery the cure rate was found to be relatively low (5.2 and 21.3% respectively).

CONCLUSIONS

These data suggest that surgery remains with very few exceptions the primary treatment of acromegaly for (i) a high cure rate, (ii) low morbidity, (iii) low recurrence rate and (iv) immediate decline of GH. Based on current criteria of cure, recurrences are uncommon. However, cure by surgery alone is improbable in patients harbouring extended, invasive tumours with high secretory activity, in whom further adjuvant treatment is mandatory.

Early postoperative indicators of late outcome in acromegalic patients

OBJECTIVE

According to current criteria, normalised serum IGF-1 and glucose-suppressed GH < 1 ng/ml are indicators of biochemical cure in acromegalic patients. We performed a retrospective study to assess whether the attainment of these values in the early postoperative period was predictive of future IGF-1 normalisation and disease inactivity.

PATIENTS, MEASUREMENTS AND RESULTS

Between 1978 and 1999, 78 acromegalic patients underwent resection for pituitary adenomas. At the end of the mean follow-up period of 7 years, 43 (55.1%) showed normalised IGF-1 levels and no disease activity. In 51 cases, both IGF-1 and glucose-suppressed GH were examined within the first postoperative month. Of this group, all 19 patients who had early glucose-suppressed GH < 1 ng/ml and were treated by surgery alone maintained normal IGF-1 levels throughout the follow-up; four of them demonstrated delayed (i.e. more than 30 days after the operation) IGF-1 normalisation. In 19 patients with early glucose-suppressed GH levels of 1-4 ng/ml, seven of 11 patients with early normalised IGF-1 and two of eight patients with early IGF-1 elevation manifested eventual IGF-1 normalisation. However, none of the 13 patients with early glucose-suppressed GH > 4 ng/ml attained IGF-1 normalisation. Both univariate and multivariate analyses indicated that early glucose-suppressed GH was a significant factor for predicting late normalised IGF-1; the cut-off value was 1.5 ng/ml (sensitivity: 0.97; specificity: 0.75; odds ratio: 90).

CONCLUSION

The attainment of both normalised IGF-1 and glucose-suppressed GH < 1 ng/ml, even during the early postoperative period, suggests absolute cure in acromegalic patients. However, even in patients who do not meet both criteria within the first postoperative month, glucose-suppressed GH < 1.5 ng/ml, or glucose-suppressed GH < 4 ng/ml coupled with early IGF-1 normalisation indicate the possibility of eventual normalisation of IGF-1 and disease inactivity without adjuvant therapy. These postoperative parameters may be useful for assessing the desirability of further treatment.

Effectiveness of secondary transnasal surgery in GH-secreting pituitary macroadenomas

Transsphenoidal surgery is the first therapeutic option in acromegaly, but the management of persistent or recurrent cases of the disease after surgery has been controversial. This study presented the results of secondary transnasal surgery for residual or recurring growth hormone (GH)-secreting macroadenoma with reference to intraoperative GH measurement. It focused on 22 patients who underwent secondary transsphenoidal surgery for 18 residual and 4 recurring GH-secreting pituitary macroadenomas from 1990 to 1999. To assess complete tumor removal, plasma GH concentration was measured intraoperatively. Before secondary surgery, plasma GH levels without medical treatment ranged from 2.0 to 239.0 microg/l (mean 31.5 +/- 50.4). Magnetic resonance imaging demonstrated 16 transnasally resectable tumors and 6 nonresectable grossly invasive tumors. Intraoperative plasma GH concentrations declined sufficiently in 9 of 16 with transnasally resectable tumors, but in the remaining 7 cases the tumors were further explored and normalization of GH levels was ultimately obtained in 4 out of these cases. It was impossible to completely remove the tumors in all the 6 patients with transnasally nonresectable tumors. Thirteen of 22 patients achieved endocrinological remission by rigorous criteria. In transnasally resectable tumors, the endocrinological remission rate was 81.3% (13 of 16 patients) with no recurrence during the follow-up period of at least 4 years. Secondary transnasal surgery for residual or recurring GH-secreting pituitary macroadenomas is a safe and effective treatment, if done along with intraoperative GH measurement. Endocrinological remission can be obtained with high probability in patients who suffer from macroadenomas with suprasellar extension, with the exception of transnasally nonresectable grossly invasive tumors.

Mortality in 154 surgically treated patients with acromegaly--a 10-year follow-up survey

To determine the effects of surgery and adjuvant therapy on the mortality rate of Japanese patients with acromegaly, 154 surgically treated patients were followed until death or December 2000. Mean follow-up period was 10.0 +/- 6.5 (SD) years. Postoperative GH levels, mean values of GH levels measured in the first postoperative month, were <2.5 ng/mL in 73 (47.4%), 2.5-5.0 ng/mL in 50 (32.5%), and >5.0 ng/mL in 31 patients (20.1%). Three of 123 patients with postoperative GH levels <5.0 ng/mL underwent a second transsphenoidal surgery (TSS), the other 120 received no further treatment. Additional treatments, including second TSS, medical treatment, and gamma-knife irradiation for residual tumor, were administered to 25 of 31 patients whose postoperative GH was >5.0 ng/mL. Among the total 154 patients surveyed, 11 (7.1%) died during the follow-up period. The standard mortality ratio (SMR) was 1.17, not different from age- and sex-matched controls. The SMR of the 72 patients with postoperative GH <2.5 ng/mL was better than that of the 51 patients whose postoperative GH was 2.5-5.0 ng/mL (1.09 vs. 1.64); however, the difference was not statistically significant. In conclusion, TSS and adequate adjuvant treatment decreased the excess mortality rate of acromegalics to nearly the same level as that of the general Japanese population.

Assessment of long-term remission of acromegaly following surgery

OBJECT

The criteria for remission of acromegaly following transsphenoidal adenoma resection are in evolution. In the present study the authors evaluate the utility of predicting long-term remission by reference to a single fasting growth hormone (GH) level on the 1st postoperative day.

METHODS

A retrospective analysis was conducted on 181 patients with acromegaly who underwent transsphenoidal resection between 1973 and 1990 and completed a 5-year follow-up period. Fasting serum GH levels were obtained in all patients on the 1st postoperative day in the absence of exogenous glucocorticoids. All patients participated in a follow-up evaluation lasting at least 5 years, which included measurements of serum insulin-like growth factor-I (IGF-I) levels as an index of acromegalic activity. Among the 181 patients, GH levels ranged from 0 to 8 ng/ml in 131 (72%) on the 1st postoperative day, suggesting biochemical remission. This group included 107 (84%) of the 127 patients with microadenomas, but only 24 (44%) of the 54 with macroadenomas. Nevertheless, 15 (11%) of the 131 patients who initially had attenuated GH levels displayed recurrent acromegaly within the first 2 years (with elevated levels of IGF-I in all cases, and abnormalities appearing on magnetic resonance images in nine cases). Only one of 116 patients in whom the initial postoperative GH level was lower than 2 ng/ml experienced a recurrence, whereas 14 (93%) of the 15 patients with postoperative GH levels between 2.2 and 8 ng/ml subsequently displayed biochemical evidence of acromegaly.

CONCLUSIONS

The findings indicate that a fasting morning serum GH level lower than 2 ng/ml on the 1st postoperative day portends long-term biochemical remission of acromegaly, whereas higher levels are a significant marker for recurrent disease.

Radiation tolerance of functioning pituitary tissue in gamma knife surgery for pituitary adenomas

OBJECTIVE

This study is intended to contribute to a determination of the sensitivity of preserved hypophyseal function to focal radiation in pituitary adenomas.

METHODS

We compared two subgroups of patients followed up for a median of 5 years after gamma knife surgery (GKS). Subgroup 1 (n = 30) showed postirradiation hypopituitarism. Subgroup 2 (n = 33) was continually eupituitary. These subgroups were taken from a previously published study relating to a larger group of 163 patients with pituitary adenomas treated by GKS and evaluated after a median follow-up period of 2 years. A relatively high treatment dose was used in this larger group (median, 20 Gy to the tumor margin for growth control in nonfunctioning adenomas; median, 35 Gy for hypersecreting adenomas). Early results approached those of microsurgery, and there were only a few side effects. In the present study, we compared 16 different variables in the same two subgroups to discover the relationships that caused a delayed appearance of postirradiation hypopituitarism. The main pretreatment and treatment parameters were measured on reconstructed treatment plans. This database was used for statistical evaluation.

RESULTS

The relationship between the mean dose and the volume of functioning hypophysis was stronger in terms of worsening of pituitary function than that of the spot dose to different intrasellar structures. We found that for our group of patients, the safe mean dose of radiation to the hypophysis was 15 Gy for gonadotropic and thyrotropic functions and 18 Gy for adrenocorticotropic function. The worsening of pituitary function was also significantly dependent on the dose to different anatomic levels of the infundibulum, but we did not succeed in fully characterizing this relationship. In addition, we discovered significant levels of dependency of postirradiation pituitary damage to different pretreatment and treatment variables.

CONCLUSION

Knowledge of the radiation tolerance of functioning pituitary structures subjected to GKS can ensure better preservation of pituitary function after irradiation. This is valid for the group of patients we studied. Our study's findings can be used as a guideline for GKS treatment of new patients with pituitary adenomas, and it can serve for comparison with the experience of other gamma knife centers.

Growth pattern and rate in residual nonfunctioning pituitary adenomas: correlations among tumor volume doubling time, patient age, and MIB-1 index

OBJECT

Surgical cure can be achieved in pituitary adenomas when they are completely removed. It is controversial whether postoperative radiation therapy should be given to prevent recurrence, and whether an early reoperation should be performed for residual adenomas, because we have little information about the natural history of postoperative residual adenomas.

METHODS

The residual tumor volume was serially measured in 40 nonfunctioning pituitary adenomas (NFPAs) and the tumor volume doubling time (TVDT) was calculated. Correlations between the patients' age, tumor volume, log TVDT, and MIB-1 index were examined. Other factors including the patient's sex, cavernous sinus (CS) invasion by the tumor, or presence of an intratumoral cyst were analyzed to assess their influence on the TVDT. Values are expressed as the means +/- standard deviations. Thirty-eight adenomas increased in volume and two decreased during a follow-up period ranging from 4 to 141 months (mean 52.5 months). Exponentially linear tumor growth was observed in the 38 growing adenomas regardless of the residual tumor volume, with the TVDT ranging from 506 to 5378 days (mean 1836 days). The patients' age was 57.1 +/- 15.7 years (range 15-79 years), the tumor volume at the beginning of the magnetic resonance imaging observation period was 2.5 +/- 2.2 cm3 (range 0.07-14.5 cm3), and the MIB-1 index was 0.73 +/- 0.68% (range 0.1-2.9%). There was a correlation between the log TVDT and patient age (R = 0.73), an inverse correlation between the log TVDT and MIB-1 index (r = -0.49), and an inverse correlation between the MIB-1 index and patient age (r = -0.61). A significant difference (p = 0.0001) was noted between the TVDT (1,106 days) in the 19 patients younger than 61 years of age and the TVDT (2566 days) in the 19 patients who were 61 years of age or older. There was also a significant difference (p = 0.0002) between the age (50.8 +/- 15.3 years) of the patients with rapidly growing tumors (TVDT < 1,836 days, 24 patients) and the age (69.1 +/- 7.6 years) of the patients with slowly growing tumors (TVDT> 1836 days, 14 patients). Other factors including the patients' sex, CS invasion, and intratumoral cyst formation did not affect the TVDT of residual NFPAs.

CONCLUSIONS

The tumor growth rate of residual NFPAs is strongly influenced by the patient's age. The TVDT in elderly patients is much longer than that previously reported. Treatment strategies that take into consideration the natural history of residual adenomas should be established especially in the elderly population.

Long-term management and outcome for pituitary tumors

As we enter the twenty-first century, neurosurgeons and endocrinologists are armed with a greater variety of treatment options for pituitary adenomas, both secreting and nonsecreting. These include an ever-increased availability of different drugs that can be used for suppression of hypersecretion of pituitary adenomas in conjunction with their shrinkage (at least for the duration of the treatment), surgical techniques that have greatly improved, and newer techniques, such as endoscopic microsurgery, that have been added to the surgeon's armamentarium. Radiation therapy techniques have also improved in terms of structuring the radiation field as well as in terms of dosimetry and delivery.

Gender-related differences in growth hormone-releasing pituitary adenomas. A clinicopathological study

BACKGROUND/AIMS

Pituitary adenomas are the third most common primary intracranial neoplasm, after astrocytomas and meningiomas, and about 30% of them secrete growth hormone (GH). Other subtypes of pituitary tumors are characterized by well-known gender-related differences, not only in clinical presentation and other biological characteristics but also in surgical outcome. For GH-releasing pituitary adenomas, however, detailed data on gender differences of postsurgical treatment are not available.

PATIENTS AND METHODS

The patient charts of a series of 18 patients with acromegaly who met strict immunohistochemical and electron microscopic criteria and who underwent surgical resection of their tumors between January 1990 and June 1999 were retrospectively reviewed.

RESULTS

There were eight women and ten men; the male-to-female-ratio was 1.3:1. The men and women were equal in age at surgery. Men demonstrated higher IGF-1 and smaller GH levels pre- and postoperatively, whereas the reduction in IGF-1 was more pronounced compared to women (58% vs. 27%). The overall outcome was better in women than in men. Mixed GH- and prolactin-secreting adenomas showed a worse outcome among all other histological subtypes. Mitose- and MIB-1 labeling index was increased in men compared to women.

CONCLUSION

The clinical course and tumor biology of GH-releasing pituitary adenomas appear to differ in women and men. Men demonstrated a shorter preoperative duration of symptoms, larger and more invasive tumors, and a worse clinical outcome. These findings suggest that therapy for GH-releasing adenomas should be more aggressive in men than in women. The gender-related differences in GH-releasing pituitary adenomas appear to have a basis in different biologic behavior, which warrants further investigation.

Marked improvement in cardiovascular function after successful transsphenoidal surgery in acromegalic patients

OBJECTIVE

Transsphenoidal surgery results in biochemical remission of acromegaly in 45-80% of patients; however, few studies have addressed the impact of transsphenoidal surgery on cardiovascular function in acromegalic patients. The aim of this prospective study was to investigate the effects of postoperative GH/IGF-I normalization on echocardiographic parameters and blood pressure (BP) in a series of patients with active acromegaly.

DESIGN

An open prospective study.

PATIENTS

Thirty newly diagnosed acromegalic patients undergoing transsphenoidal surgery.

MEASUREMENTS

Doppler echocardiography and 24-h ambulatory blood pressure monitoring were performed before and 6 months after transsphenoidal surgery.

RESULTS

Fifteen patients were considered to be well controlled postoperatively (group A), as defined by normal age-corrected IGF-I levels and glucose-suppressed GH levels less than 2 mU/l, the remaining 15 patients being considered as poorly controlled (group B). In group A, a postoperative decrease of left ventricular mass index was observed (104.4 +/- 6.6 vs. 127.1 +/- 7.7 g/m2; P < 0.001), associated with an improvement of some indices of diastolic function, such as an increase of the early/late transmitral peak flow velocity (P < 0.05) and a decrease of isovolumic relaxation time (P < 0.01). No significant change was observed in group B. A significant decrease of 24-h systolic BP was also observed in group A (P < 0.05) and five of six patients normalized their BP circadian rythm. In contrast, a nonsignificant increase in BP values, with a persistent blunted BP profile where present, was observed in group B.

CONCLUSIONS

We conclude that successful transsphenoidal surgery is able to induce a significant improvement in some cardiac parameters and a slight reduction in systolic blood pressure in acromegalic patients.

Transsphenoidal surgery and adjuvant gamma knife treatment for growth hormone-secreting pituitary adenoma

OBJECT

The results of combined transsphenoidal surgery and adjuvant gamma knife surgery (GKS) for growth hormone (GH)-secreting adenoma were investigated using biochemical cure criteria for surgery and biological cure criteria for adjuvant GKS.

METHODS

Ninety patients (42 male and 48 female patients), ranging from 11 to 75 years of age, underwent transsphenoidal surgery for GH-secreting pituitary adenoma. Preoperative and postoperative GH and insulin-like growth factor-I levels were measured, as was the postoperative GH level after the oral glucose tolerance test. Tumor size, cavernous sinus (CS) invasion, and residual tumor were evaluated using magnetic resonance (MR) imaging. Transsphenoidal microsurgery was performed, followed by adjuvant GKS when there was persistent biochemical evidence of GH hypersecretion with residual tumor detectable in the CS on MR imaging. Patients in whom GKS was contraindicated were treated with conventional radiotherapy or by medical means.

CONCLUSIONS

The overall surgical cure rate was 57% based on recently accepted biochemical cure criteria. Patients with no CS invasion achieved a 100% cure rate, whereas patients with CS invasion achieved an 82% cure rate (14 of 17 patients) after adjuvant GKS. The combination of transsphenoidal microsurgery and adjuvant GKS is the optimal therapy for patients with GH-secreting adenoma.

Postoperative radiotherapy in acromegaly is effective in reducing GH concentration to safe levels

OBJECTIVE

Several studies have established that in treated acromegaly mortality is only normalized in patients achieving a serum GH concentration below 5 mU/l. Few studies however, have addressed results of radiotherapy using this strict criterion. The aim of our study was to assess the efficacy of postoperative radiotherapy in reducing serum GH concentration below 5 mU/l.

PATIENTS AND METHODS

Forty acromegalic patients who underwent radiotherapy for postoperative persistent disease after transsphenoidal surgery were studied. Mean time of follow-up after radiotherapy was 123+/-11.1 months. A serum GH concentration of <5 mU/l was used to define remission.

RESULTS

Following surgery mean GH concentration decreased from 120.8+/-21 mU/l to 24.4+/-5.2 mU/l and mean GH concentration prior to radiotherapy, administered after a mean of 8.2+/-2.7 (0.5-96) months postoperatively was 26.0+/-5.1 mU/l. Using individual regression plots, GH was reduced to 50% by radiotherapy after a mean of 27+/-5 months (range 3-105 months). The observed mean GH concentration as measured at follow-up visits was reduced by 55% (-36-95%) after the first year, by 65% (-29-97.3%) after 2 years and by 78% (-29-99%) after 5 years. We could not demonstrate a significant correlation between a normalized GH concentration on the one hand and tumour size, preradiotherapy GH concentration or duration of follow-up on the other hand. During follow-up, GH-suppressive medical therapy was used in 11 patients, five of whom were still using medication at the end of follow-up. Eight patients had a follow-up of less than 5 years and three of them had a serum GH concentration of <5 mU/l at their latest follow-up visit (38%). At 5 years of follow-up after radiotherapy, 24 out of 32 patients had a GH level of <5 mU/l without medication (75%). At 10 years following irradiation, 16 of 21 patients (76%) had a GH level of <5 mU/l without medical treatment. At 15 years follow-up, a serum GH concentration of <5 mU/l was observed in 13 out of 15 patients (87%) without GH suppressive medication. At the latest follow-up visit, serum GH concentration below 5 mU/l was present in 75% of patients (30 out of 40) without medical therapy after a mean of 10.4+/-0.9 years, but five patients required octreotide up to the end of follow-up. Twenty-seven out of 37 patients with available IGF-I data had normal IGF-I at the end of follow-up (73%). Fifty percent of patients needed substitution therapy for (partial) hypopituitarism after 10 years and 75% after 15 years of radiotherapy.

CONCLUSION

In our group of patients who were incompletely cured by surgery, but had a significant postoperative decrease of serum GH concentrations, radiotherapy was able to achieve 'safe' serum GH concentrations in the majority in the long term.

Long-term follow-up results of postoperative radiotherapy in 36 patients with acromegaly

In acromegaly, pituitary irradiation is a slow, but effective, intervention in decreasing GH concentration. Few studies addressing the outcome of radiotherapy have used the currently accepted strict criteria for remission in the analysis of data. These studies report a low percentage of remission after radiotherapy. Doubt has especially been raised as to whether radiotherapy is effective in normalizing serum insulin-like growth factor (IGF)-I concentration. We analyzed the long-term follow-up data of postoperatively administered radiotherapy in 36 patients with postoperative persistent acromegaly, using both the normalization of GH suppression during oral glucose loading (GTT) and the normalization of IGF-I concentration as criteria for remission. Before radiotherapy, mean suppressed GH was 9.8 +/- 1.9 mU/L (n = 31), and mean IGF-I concentration was 44.3 +/- 3.9 nmol/L, equivalent to + 4.76 +/- 0.78 age-related IGF-I SD score (n = 13). The median radiation dose was 40 Gray (range, 25-50 Gray). At 5, 10, and 15 yr follow-up, 18 out of 30 patients (60%), 23 out of 31 patients (74%), and 16 out of 19 patients (84%), respectively, achieved normal serum IGF-I concentration. At the last assessment of all patients, after a mean follow-up period of 139 +/- 12 months, 27 out of 36 (75%) patients had a normal IGF-I concentration without additional medication, whereas 5 patients still required treatment with octreotide. Remission, as judged by normalization of GH suppression during GTT, was documented in 65% of patients from 2-5 yr after radiotherapy (n = 34); in 69% of patients, up to 10 yr after radiotherapy (n = 29); and in 71% of patients, up to 15 yr post irradiation (n = 17). At the latest assessment, a mean of 125 +/- 11 months after radiotherapy, 71% of patients (n = 35) were in remission, as defined by normal suppression of serum GH during GTT. Remission, as judged by normalization of both GTT and IGF-I, was found in 40% of patients 3-5 yr after radiotherapy (n = 30); in 61% of patients, 6-10 yr after radiotherapy (n = 28); in 65%, after 11-15 yr after radiotherapy (n = 17); and in 63% of patients, at the end of the follow-up period (n = 35). Substitution of one or more pituitary hormone deficiencies was required in 11% of patients postoperatively; in 29%, 5 yr after radiotherapy; in 54%, 10 yr after radiotherapy; and in 58%, more than 15 yr after radiotherapy. Our findings support the use of radiotherapy as an effective intervention in the treatment of residual clinical activity of disease after surgery for acromegaly.

Early postoperative growth hormone levels: high predictive value for long-term outcome after surgery for acromegaly

OBJECTIVES

To explore the prognostic value of early - within 1 week - postoperative growth hormone (GH) measurements with regard to outcome after surgery for acromegaly in a short- and a long-term perspective.

DESIGN

Retrospective study of patients operated on between 1987 and 1998, including follow-up for up to 60 months.

SETTING

University hospital.

SUBJECTS

Sixty-eight patients with acromegaly.

INTERVENTION

Pituitary surgery aiming at adenomectomy with preservation of pituitary function.

MAIN OUTCOME MEASURES

The effect of the operation was evaluated after 3 months, mostly by means of an oral glucose load or by insulin-like growth factor 1 (IGF-1). The specificity, sensitivity and the predictive values of an early postoperative mean GH concentration </= 4.8 mU L-1, as well as of the GH response to thyrotropin-releasing hormone (TRH) 3 months after surgery, were calculated with regard to outcome of the operation in both 3-month and long-term perspectives.

RESULTS

Fifty patients (73.5%) showed a satisfactory effect at the evaluation 3 months postoperatively; 45 of these were followed between 12 and 60 months. Relapse was registered in five cases: 12, 12, 24, 24 and 48 months after surgery. In the long-term perspective, the predictive value of an early mean GH </= 4.8 mU L-1 was 93.6% with regard to a satisfactory effect of surgery, compared with 90.2% for a normalized somatomedin C (SmC)/IGF-1 and 90.0% for an absent GH response after TRH. An early mean GH > 4.8 mU L-1 had a 77.8% predictive value for persistent or recurrent disease, compared with 85.7% for persistently increased SmC/IGF-1 and 68.8% for an abnormal GH release after TRH 3 months after surgery. In the short-term perspective, the specificity and the predictive value of an early GH </= 4.8 mU L-1 were 77.3 and 97.1%, respectively. Early GH > 4.8 mU L-1 had a 94.4% sensitivity but a predicative value of only 63.0% for an unsatisfactory effect.

CONCLUSION

Measurement of GH within 1 week after surgery is highly predictive for outcome of surgery for acromegaly. Specifically, an early mean GH </= 4.8 mU L-1 is as predictive for a satisfactory effect of treatment as a normalized IGF-1 3 months after surgery. Early postoperative GH values > 4.8 mU L-1 have a high sensitivity for persistent or recurrent disease in both the short- and long-term perspectives, but lower predictive value. The usefulness of the TRH test can be questioned.

Transsphenoidal surgery for pituitary gigantism and galactorrhea in a 3.5 year old child

The management of pituitary macroadenomas which lead to gigantism may require multiple therapeutical approaches, including medical treatment, surgery, and radiation therapy. Transsphenoidal surgery (TSS) during early childhood that achieves total removal of a growth hormone (GH) secreting tumor is rarely reported. The surgeon is confronted with special problems regarding the infantile anatomy. In this case, a 3.5 year old child, the youngest successfully treated by TSS so far, suffered from a GH- and prolactin (PRL) secreting macroadenoma of the pituitary gland. The girl initially presented with an increasing growth rate, later with breast development, and finally, at the age of 2.8 years, with galactorrhea and secretion of blood from the nipples. Increased levels of GH [122 micrograms/l], insulin-like growth factor (IGF-1) [830 micrograms/l], insulin-like growth factor binding protein 3 (IGFBP-3) [8.6 mg/l] and PRL [590 micrograms/l] were found. MRI scans revealed a macroadenoma of 2.7 cm diameter. An eight-week trial of relatively low dose dopamine agonists led to a reduction of PRL, while the GH- and IGF-1 levels remained unchanged; the tumor showed only little shrinkage. Since there was chiasma compression, we opted for early TSS. A complete tumor removal was achieved despite the difficulties of a narrow approach. After TSS, low levels of GH, IGF-1, and PRL documented a complete tumor removal, but persistent diabetes insipidus and anterior lobe deficits resulted from surgery. In summary, if primary medical therapy alone is unable to adequately reduce hormone hypersecretion and tumor size in early childhood, TSS is recommended. Thus, radiation therapy may be reserved for surgical failure.

Current therapy for acromegaly

Acromegaly is a disabling disease that is associated with reduced life expectancy. Lowering growth hormone (GH) concentrations rapidly improves patient wellbeing. Recent data also indicate that GH concentrations < 2.5 micrograms l-1 are associated with improved mortality, providing a therapeutic goal in the majority of patients. In most cases, initial therapy should be surgical via the transsphenoidal route and conducted by an experienced operator. In such centres of excellence, approximately 60 out of every 100 acromegalic patients should be 'cured' (GH < 2.5 micrograms l-1) by surgery alone. Effective medical therapies have been introduced in the form of long-acting somatostatin analogues--octreotide and lanreotide--and depot preparations of these drugs result in lowering of GH to < 2.5 micrograms l-1 and normalization of IGF-I concentrations in 55-65% of cases. Preliminary results are also emerging on Pegvisomant, a genetically engineered GH receptor antagonist, which is clinically and biochemically very effective. It is likely that this drug will be licensed for use in patients with acromegaly in the near future. These effective medical therapies will undoubtedly raise the issue of their use as primary therapy for acromegaly but at present they should be used as an adjunct to surgery and/or radiotherapy.

Growth hormone secreting adenoma with unusual extension: coexisting pituitary cyst and its clinical significance

A 58 year old man showed acromegalic features. The serum growth hormone (GH) level was 7.3 ng/ml and SMC (somatomedin-C) 637 U/ml. Triple stimulation test showed abnormal response compatible with a GH secreting tumour. The conventional enhanced MRI revealed a less enhanced hemisphere-shaped lesion at the right corner of the sella turcica. In addition, dynamic MRI demonstrated an elongated lesion extending to the left beyond the midline. The patient underwent transsphenoidal surgery. Besides the soft and suckable tumour at the right corner, we entered into a small cavity loosely filled with the tumour, which was subsequently also removed. The operative finding corresponded to the lesion shown in dynamic MRI. Postoperative GH and SMC levels became 2.3 ng/ml and 326 U/ml respectively. Incidental pituitary cystic lesions in autopsied cases have been reported to be 6-33%. This case had a GH secreting adenoma with coexisting pituitary cyst. The coexisting pituitary cyst supposedly influenced the unusual shape and extension of the pituitary adenoma. Coexistence of such lesion should be kept in mind for microadenoma on neuroradiological evaluation and on intraoperative inspection surrounding the tumour.

Epidemiology of acromegaly

Acromegaly is a consequence of chronic growth hormone (GH) excess, due in the majority of cases to a GH-secreting pituitary adenoma, and occurring with a population prevalence of 60 per million and an incidence of 3-4 per million per year. Males and females appear to be equally affected with an average age of presentation of 44 years. Younger patients may have more aggressive tumours and higher GH concentrations. There is co-existent hyperprolactinaemia in about one third of cases, and a variable proportion of [figure: see text] tumours appear to have activating mutations of the gsp gene or other genetic abnormalities. Acute complications such as carpal tunnel syndrome, sweating and obstructive sleep apnoea are usually readily reversible with treatment of the condition, but chronic complications such as hypertension, diabetes and heart disease are less readily corrected and post-treatment GH levels of < 2.5 ug/L (5 mU/L) are needed to achieve the prevalence found in the general community. Such 'curative' levels of GH are achieved in only about 50% of patients with current therapies, and as a result there is an ongoing excess of patients with chronic complications of acromegaly leading to increased morbidity and mortality from the disorder, with observed-to-expected mortality ratios ranging from 1.6-3.3 and only approaching unity in those with growth hormone levels < 2.5 ug/L following treatment. Prognostic factors include in some studies the presence of diabetes and [table: see text] hypertension prior to diagnosis as well as measures of exposure to excessive growth hormone derived from the product of preoperative serum GH and the time from first symptoms to treatment. Overall, however, the most important prognostic variable appears to be the serum GH concentration achieved by treatment, with an increasing consensus that this needs to be < 2.5 ug/L (5 mU/L) to achieve cure of the condition.

Medical therapy for acromegaly

Both somatostatin analogues, which bind to the somatostatin receptor subtypes 2 and 5, and dopamine agonists, which are specific for the D2 receptor, have been used to treat acromegaly. Each of these classes of drugs contains several compounds that vary in duration of action, efficacy, and side effect profile. Although somatostatin analogues reduce GH levels and alleviate symptoms in most patients and restore IGF-1 levels to normal in 60% to 65% of patients, tumor shrinkage is limited to 40% of patients. evidence in the literature supports the use of these medications as secondary therapy in patients with acromegaly who have had surgery and who continue to have elevated GH levels (above 2 ng/mL during an oral glucose tolerance test) with or without IGF-1 concentrations that are above the upper limit of normal for age. In addition, medical therapy indicated in patients who refuse surgery and in patients who are poor surgical candidates. The controversial question is whether medical therapy should be an option for primary treatment of the acromegalic patient. Currently, ther are no data from prospective randomized trials comparing the effects of surgery versus somatostatin analogues as first-line therapy for for newly diagnosed acromegalic patients. Limited data from nonrandomized studies demonstrate that somatostatin analogues are effective long-term in suppressing GH and reducing IGF-1 into the normal range in approximately two-thirds of patients who have never undergone previous treatment. It is still the consensus that patients with GH-secreting microadenomas should undergo surgical resection, because the likelihood of complete cure by an experience neurosurgeon is high, at least 70% or greater. Successful surgical treatment has the advantage of completely removing the tumor in contrast to medical therapy, which rarely produces shrinkage greater than 50% despite the fact that IGF-1 and GH levels may be normal. In patients with macroadenomas of a size and location that suggest that the chance of complete resection is 40% or less, primary treatment with a somatostatin analogue should be considered as one option in the initial management of the patient. Another option in such an individual would be surgical debulking followed by medical therapy, because it is theoretically possible that biochemical cure with medical therapy after surgical debulking might be achieved with lower doses. The cost-effectiveness of these approaches has not yet been determined. Once the decision has been made to begin medical therapy, a choice must be made between dopamine agonists and somatostatin analogues. Most evidence suggests that somatostatin analogues are more effective than dopamine agonists and therefore would be the therapy of choice. In select patients, dopamine agonists, particularly the long-acting agonist cabergoline, may be preferred initially if the patient is unwilling to take injections or if the GH elevations are relatively modest (< 10 ng/mL). Biochemical cure should be assessed by measurement of GH (which can be performed 2 hours after an octreotide injection) and IGF-1 concentrations. The goal of treatment include reduction of of GH below 2 ng/mL and reduction of IGF-1 into the normal range. In patients who do not reach these goals, the dose or frequency of injection of the somatostatin analogue or both should be increased. If such measures are unsuccessful, a dopamine agonist may be added to the medical regimen because some studies suggest that combination therapy may be more effective in select cases than octreotide therapy alone. If such measures are still unsuccessful, other options should be considered, including surgery, pituitary radiation, and medical treatment with investigational drugs.