Place of preoperative treatment of acromegaly with somatostatin analog on surgical outcome: a systematic review and meta-analysis

Acromegaly management in the Nordic countries: A Delphi consensus survey

OBJECTIVE

Acromegaly is associated with increased morbidity and mortality if left untreated. The therapeutic options include surgery, medical treatment, and radiotherapy. Several guidelines and recommendations on treatment algorithms and follow-up exist. However, not all recommendations are strictly evidence-based. To evaluate consensus on the treatment and follow-up of patients with acromegaly in the Nordic countries.

METHODS

A Delphi process was used to map the landscape of acromegaly management in Denmark, Sweden, Norway, Finland, and Iceland. An expert panel developed 37 statements on the treatment and follow-up of patients with acromegaly. Dedicated endocrinologists (n = 47) from the Nordic countries were invited to rate their extent of agreement with the statements, using a Likert-type scale (1-7). Consensus was defined as ≥80% of panelists rating their agreement as ≥5 or ≤3 on the Likert-type scale.

RESULTS

Consensus was reached in 41% (15/37) of the statements. Panelists agreed that pituitary surgery remains first line treatment. There was general agreement to recommend first-generation somatostatin analog (SSA) treatment after failed surgery and to consider repeat surgery. In addition, there was agreement to recommend combination therapy with first-generation SSA and pegvisomant as second- or third-line treatment. In more than 50% of the statements, consensus was not achieved. Considerable disagreement existed regarding pegvisomant monotherapy, and treatment with pasireotide and dopamine agonists.

CONCLUSION

This consensus exploration study on the management of patients with acromegaly in the Nordic countries revealed a relatively large degree of disagreement among experts, which mirrors the complexity of the disease and the shortage of evidence-based data.

Position statement on the diagnosis and management of acromegaly: The French National Diagnosis and Treatment Protocol (NDTP)

Acromegaly is a rare disease with prevalence of approximately 60 cases per million, slight female predominance and peak onset in adults in the fourth decade. Clinical diagnosis is often delayed by several years due to the slowly progressive onset of symptoms. There are multiple clinical criteria that define acromegaly: dysmorphic syndrome of insidious onset, symptoms related to the pituitary tumor (headaches, visual disorders), general signs (sweating, carpal tunnel syndrome, joint pain, etc.), complications of the disease (musculoskeletal, cardiovascular, pneumological, dental, metabolic comorbidities, thyroid nodules, colonic polyps, etc.) or sometimes clinical signs of associated prolactin hypersecretion (erectile dysfunction in men or cycle disorder in women) or concomitant mass-induced hypopituitarism (fatigue and other symptoms related to pituitary hormone deficiencies). Biological confirmation is based initially on elevated IGF-I and lack of GH suppression on oral glucose tolerance test or an elevated mean GH on repeated measurements. In confirmed cases, imaging by pituitary MRI identifies the causal tumor, to best determine management. In a minority of cases, acromegaly can be linked to a genetic predisposition, especially when it occurs at a young age or in a familial context. The first-line treatment is most often surgical removal of the somatotroph pituitary tumor, either immediately or after transient medical treatment. Medical treatments are most often proposed in patients not controlled by surgical removal. Conformal or stereotactic radiotherapy may be discussed on a case-by-case basis, especially in case of drug inefficacy or poor tolerance. Acromegaly should be managed by a multidisciplinary team, preferably within an expert center such as a reference or skill center for rare pituitary diseases.

A retrospective study of the role of hypercapnia in patients with acromegaly

BACKGROUND

Acromegaly is a multisystemic disease characterized by an excessive release of growth hormone (GH) and insulin-like growth factor-1. Obstructive sleep apnea (OSA) is a common consequence of acromegaly, and hypercapnia is frequently observed in patients with acromegaly, OSA, and obesity. However, the effects of hypercapnia on acromegaly remain unknown. This study was designed to investigate whether there are differences in clinical symptoms, sleep variables, and biochemical remission after surgery for acromegaly in patients with OSA with or without hypercapnia.

METHODS

A retrospective analysis was conducted involving patients with acromegaly and OSA. The pharmacotherapy history for acromegaly before surgery, anthropometric measures, blood gas, sleep monitoring data, and biochemical assays of hypercapnic and eucapnic individuals were collected 1-2 weeks before surgery. Univariate and multivariate logistic regression analyses were performed to determine the risk factors for failed postoperative biochemical remission.

RESULTS

In this study, 94 patients with OSA and acromegaly were included. Among them, 25 (26.6%) had hypercapnia. The hypercapnic group had higher body mass index (92% vs. 62.3%; p = 0.005) and poorer nocturnal hypoxemia index. No serological differences were found between the two groups. According to the post-surgery GH level, 52 patients (55.3%) reached biochemical remission. Univariate logistic regression analysis revealed that diabetes mellitus (odds ratio [OR], 2.59; 95% confidence interval [CI], 1.02-6.55), instead of hypercapnia (OR, 0.61; 95% CI, 0.24-1.58), was associated with lower remission rates. Patients who received pharmacotherapy for acromegaly before surgery (OR, 0.21; 95% CI, 0.06-0.79) and had higher thyroid-stimulating hormone levels (OR, 0.53; 95% CI, 0.32-0.88) were more likely to have biochemical remission after surgery. Multivariate analysis further showed that only diabetes mellitus (OR, 3.29; 95% CI, 1.15-9.46) and preoperative pharmacotherapy (OR, 0.21; 95% CI, 0.06-0.83) remained significant. Hypercapnia, hormone levels, and sleep indicators had no effect on biochemical remission after surgery.

CONCLUSIONS

Single-center evidence shows that hypercapnia alone may not be a risk factor for lower biochemical remission rates. Correcting hypercapnia does not appear to be required before surgery. More evidence is needed to further support this conclusion.

Preoperative Medical Treatment for Patient with Acromegaly: yes or no?

Transsphenoidal surgery is the first-line treatment for acromegaly. However, several factors can modify surgical remission rates, such as the initial hormone levels, the size and invasiveness of the tumor, and the degree of experience of the surgeon. Physicians treating patients with acromegaly should thus consider how to improve surgical remission rates. As stated in recent guidelines, the major point is to consider that any patient with acromegaly should be referred to an expert neurosurgeon to maximize the chances of surgical sure. The benefits of presurgical medical treatment, mainly using somatostatin receptor ligands (SRLs), given 3 to 6 months before surgery, remain controversial. By normalizing growth hormone and insulin-like growth factor 1 levels, SRLs may improve the overall condition of the patient, thus decreasing anesthetic and surgical complications. By decreasing the tumor size and modifying the consistency of the tumor, SRLs might also make surgical excision easier. This is however theoretical as published data are contradictory on both points, and only limited data support the use of a systematical presurgical medical treatment. The aim of this review is to analyze the potential benefits and pitfalls of using presurgical medical treatment in acromegaly in view of the contradictory literature data. We also attempt to determine the profile of patients who might most benefit from this presurgical medical treatment approach as an individualized therapeutic management of acromegaly.

The Dose of Somatostatin Analogues during Pre-Surgical Treatment Is a Key Factor to Achieve Surgical Remission in Acromegaly

Purpose: to determine whether pre-surgical treatment using long-acting somatostatin analogues (SSAs) may improve surgical outcomes in acromegaly. Methods: retrospective study of 48 patients with acromegaly operated by endoscopic transsphenoidal approach and for first time. Surgical remission was evaluated based on the 2010 criteria. Results: most patients, 83.3% (n = 40), harbored macroadenomas and 31.3% (n = 15) invasive pituitary adenomas. In this case, 14 patients were treated with lanreotide LAR and 6 with octreotide LAR, median monthly doses of 97.5 [range 60–120] and 20 [range 20–30] mg, respectively, for at least 3 months preoperatively. Presurgical variables were comparable between pre-treated and untreated patients (p > 0.05). Surgical remission was more frequent in those pre-treated with monthly doses ≥90 mg of lanreotide or ≥30 mg of octreotide than in untreated or pre-treated with lower doses (OR = 4.64, p = 0.025). However, no differences were found between pre-treated and untreated patients when lower doses were included or between those treated for longer than 6 months compared to those untreated or pre-treated for shorter than 6 months. Similarly, no differences were found either in terms of surgical or endocrine complications (OR = 0.65, p = 0.570), independently of the doses and the duration of SSA treatment (p > 0.05). Conclusions: the dose of SSAs is a key factor during pre-surgical treatment, since the beneficial effects in surgical remission were observed with monthly doses equal or higher than 90 mg of lanreotide and 30 mg of octreotide, but not with lower doses.

Presurgical somatostatin receptor ligand treatment does not affect tumor consistency in GH-secreting pituitary macroadenomas

PURPOSE

To evaluate whether presurgical treatment using long-acting somatostatin receptor ligands (SRL) may change pituitary tumor consistency and improve surgical outcome in GH-secreting pituitary macroadenomas.

METHODS

Retrospective study of 40 patients with GH-secreting pituitary macroadenomas operated for the first time by endoscopic transsphenoidal approach. Tumor consistency was evaluated intraoperatively and then correlated with histopathological fibrosis parameters and surgical outcomes. Surgical remission was reported based on the 2010 criteria.

RESULTS

The mean tumor size of GH-secreting macroadenomas was of 16.9 ± 8.2 mm and 25 were invasive pituitary adenomas (PAs). Presurgical treatment with long-acting SRL was performed in 17 patients (11 lanreotide, 6 octreotide). The cure rate was higher in those patients pre-treated with monthly doses ≥30 mg of octreotide or ≥90 mg of lanreotide than in those treated with lower doses or untreated (8/11 (72.7%) vs 11/29 (37.9%), P = 0.049). However, although the proportion of soft tumors increased as higher doses of SRL were considered in the pre-treated group, no statistical significance was reached, even when the highest approved monthly doses were used (6/6 (100%) vs 23/34 (67.7%), P = 0.102). Moreover, we found that the remission rate was similar between fibrous and soft tumors (P = 0.873) and also of surgical complications (P = 0.859), despite of the higher prevalence of Knosp >2 (P = 0.035) and very large PA (P = 0.025) in fibrous tumors than in soft tumors.

CONCLUSIONS

Although presurgical treatment with high doses of SRL was associated with a 2.2-fold greater chance of surgical remission, this benefit was not related with changes in tumor consistency induced by the presurgical treatment.

Octreotide-Resistant Acromegaly: Challenges and Solutions

Acromegaly is a rare and severe disease caused by an increased and autonomous secretion of growth hormone (GH), thus resulting in high circulating levels of insulin-like growth factor 1 (IGF-1). Comorbidities and mortality rate are closely related to the disease duration. However, in most cases achieving biochemical control means reducing or even normalizing mortality and restoring normal life expectancy. Current treatment for acromegaly includes neurosurgery, radiotherapy and medical therapy. Transsphenoidal surgery often represents the recommended first-line treatment. First-generation somatostatin receptor ligands (SRLs) are the drug of choice in patients with persistent disease after surgery and are suggested as first-line treatment for those ineligible for surgery. However, only about half of patients treated with octreotide (or lanreotide) achieve biochemical control. Other available drugs approved for clinical use are the second-generation SRL pasireotide, the dopamine agonist cabergoline, and the GH-receptor antagonist pegvisomant. In the present paper, we revised the current literature about the management of acromegaly, aiming to highlight the most relevant and recent therapeutic strategies proposed for patients resistant to first-line medical therapy. Furthermore, we discussed the potential molecular mechanisms involved in the variable response to first-generation SRLs. Due to the availability of different medical therapies, the choice for the most appropriate drug can be currently based also on the peculiar clinical characteristics of each patient.

Preoperative Somatostatin Analogues in Patients with Newly-diagnosed Acromegaly: A Systematic Review and Meta-analysis of Comparative Studies

Biochemical remission after transsphenoidal surgery is still unsatisfied in acromegaly patients with macroadenomas, especially with invasive macroadenomas. Concerning the impact of preoperative somatostatin analogues (SSAs) on surgical outcomes, previous studies with limited cases reported conflicting results. To assess current evidence of preoperative medical treatment, we performed a systematic review and meta-analysis of comparative studies. A literature search was conducted in Pubmed, Embase, and the Cochrane Library. Five randomized controlled trials (RCT) and seven non-RCT comparative studies were included. These studies mainly focused on pituitary macroadenomas though a small number of microadenoma cases were included. For safety, preoperative SSAs were not associated with elevated risks of postoperative complications. With respect to efficacy, the short-term cure rate was improved by preoperative SSAs, but the long-term cure rate showed no significant improvement. For invasive macroadenomas, the short-term cure rate was also improved, but the long-term results were not evaluable in clinical practice because adjuvant therapy was generally required. In conclusion, preoperative SSAs are safe in patients with acromegaly, and the favorable impact on surgical results is restricted to the short-term cure rate in macroadenomas and invasive macroadenomas. Further well-designed RCTs to examine long-term results are awaited to update the finding of this meta-analysis.

Current perspectives on the impact of clinical disease and biochemical control on comorbidities and quality of life in acromegaly

Acromegaly is a rare chronic, systemic disorder caused by excessive growth hormone (GH) secretion from a somatotroph pituitary adenoma. GH hypersecretion leads to overproduction of insulin-like growth factor-1 (IGF-1), which contributes to the somatic overgrowth, physical disfigurement, onset of multiple systemic comorbidities, reduced quality of life (QoL) and premature mortality of uncontrolled patients. Somatostatin receptor ligands, dopamine agonists and a GH receptor antagonist are currently available for medical therapy of acromegaly. The main aim of treatment is biochemical normalisation, defined as age-normalised serum IGF-1 values and random GH levels <1.0 μg/L. However, there is an increasing evidence suggesting that achieving biochemical control does not always decrease the burden of disease-related comorbidities and/or improve patients' QoL. This lack of correlation between biochemical and clinical control can be due to both disease duration (late diagnosis) or to the peculiarity of a given comorbidity. Herein we conducted ad hoc literature searches in order to find the most recent and relevant reports on biochemical and clinical disease control during medical treatment of acromegaly. Particularly, we analyse and describe the relationship between biochemical, as well as clinical disease control in patients with acromegaly receiving medical therapy, with a focus on comorbidities and QoL. In conclusion, we found that current literature data seem to indicate that clinical disease control (besides biochemical control), encompassing clinical signs and symptoms, comorbidities and QoL, emerge as a primary focus of acromegaly patient management.

The effect of somatostatin analogues on Ki-67 levels in GH-secreting adenomas

PURPOSE

Somatostatin analogues (SSAs) can slow down the growth of neuroendocrine tumors. However, the mechanism remains unclear. Recent studies on patients with acromegaly suggest that SSAs may induce apoptosis, increase autophagy, and decrease cell proliferation of pituitary adenoma. Ki-67-labeling index is a marker of cellular proliferation; therefore, decreased levels are associated with inhibition of proliferation. The aim of this study was to evaluate and compare the Ki-67-labeling index of GH-secreting pituitary adenoma tissues in patients who had undergone pituitary surgery twice due to residual or recurrent tumors and had received SSA treatment between the two surgeries.

METHOD

Thirty acromegaly patients who met the above criteria were identified and evaluated for the demographic, clinical and radiological features retrospectively. Surgical pathology samples of each operation were stained for Ki-67 and evaluated blindly by a staff pathologist specialized in pituitary diseases.

RESULTS

Among patients who received SSA treatment between the first and second operations, the Ki-67 index of the adenoma at the second operation was significantly lower than the Ki-67 index at the first operation. There were no differences in clinical and radiological prognostic markers between the groups with decreased and unchanged Ki-67 index.

CONCLUSION

We concluded that SSA treatment appears to decrease Ki-67 proliferation index independent of tumor features, SSA type, dose and treatment duration. This result suggests that SSA treatment may decrease cellular proliferation, supporting the previous studies.

Acromegaly

Acromegaly is characterized by increased release of growth hormone and, consequently, insulin-like growth factor I (IGF1), most often by a pituitary adenoma. Prolonged exposure to excess hormone leads to progressive somatic disfigurement and a wide range of systemic manifestations that are associated with increased mortality. Although considered a rare disease, recent studies have reported an increased incidence of acromegaly owing to better disease awareness, improved diagnostic tools and perhaps a real increase in prevalence. Acromegaly treatment approaches, which include surgery, radiotherapy and medical therapy, have changed considerably over time owing to improved surgical procedures, development of new radiotherapy techniques and availability of new medical therapies. The optimal use of these treatments will reduce mortality in patients with acromegaly to levels in the general population. Medical therapy is currently an important treatment option and can even be the first-line treatment in patients with acromegaly who will not benefit from or are not suitable for first-line neurosurgical treatment. Pharmacological treatments include somatostatin receptor ligands (such as octreotide, lanreotide and pasireotide), dopamine agonists and the growth hormone receptor antagonist pegvisomant. In this Primer, we review the main aspects of acromegaly, including scientific advances that underlie expanding knowledge of disease pathogenesis, improvements in disease management and new medical therapies that are available and in development to improve disease control.

E-cadherin expression is associated with somatostatin analogue response in acromegaly

Acromegaly is a rare disease resulting from hypersecretion of growth hormone (GH) and insulin‐like growth factor 1 (IGF1) typically caused by pituitary adenomas, which is associated with increased mortality and morbidity. Somatostatin analogues (SSAs) represent the primary medical therapy for acromegaly and are currently used as first‐line treatment or as second‐line therapy after unsuccessful pituitary surgery. However, a considerable proportion of patients do not adequately respond to SSAs treatment, and therefore, there is an urgent need to identify biomarkers predictors of response to SSAs. The aim of this study was to examine E‐cadherin expression by immunohistochemistry in fifty‐five GH‐producing pituitary tumours and determine the potential association with response to SSAs as well as other clinical and histopathological features. Acromegaly patients with tumours expressing low E‐cadherin levels exhibit a worse response to SSAs. E‐cadherin levels are associated with GH‐producing tumour histological subtypes. Our results indicate that the immunohistochemical detection of E‐cadherin might be useful in categorizing acromegaly patients based on the response to SSAs.

International Union of Basic and Clinical Pharmacology. CV. Somatostatin Receptors: Structure, Function, Ligands, and New Nomenclature

Somatostatin, also known as somatotropin-release inhibitory factor, is a cyclopeptide that exerts potent inhibitory actions on hormone secretion and neuronal excitability. Its physiologic functions are mediated by five G protein-coupled receptors (GPCRs) called somatostatin receptor (SST)1-5. These five receptors share common structural features and signaling mechanisms but differ in their cellular and subcellular localization and mode of regulation. SST₂ and SST₅ receptors have evolved as primary targets for pharmacological treatment of pituitary adenomas and neuroendocrine tumors. In addition, SST₂ is a prototypical GPCR for the development of peptide-based radiopharmaceuticals for diagnostic and therapeutic interventions. This review article summarizes findings published in the last 25 years on the physiology, pharmacology, and clinical applications related to SSTs. We also discuss potential future developments and propose a new nomenclature.

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.

Cost-effectiveness of acromegaly treatments: a systematic review

PURPOSE

Acromegaly is a rare disease that results in the enlargement of body extremities and in organomegaly. Treatments include surgery, drugs, and radiotherapy, which are all onerous. Therefore, well-conducted cost-analyses are crucial in the decision-making process.

METHODS

A systematic review of cost-effectiveness studies on acromegaly therapies was performed following PRISMA and Cochrane recommendations. The search for records was conducted in PubMed, Scopus, and Web of Science (May 2018). The quality of the included studies was assessed using the Joana Briggs Institute Tool.

RESULTS

From initial 547 records, 16 studies were included in the review. The studies could present more than one economic evaluation, and encompassed cost-effectiveness (n = 13), cost-utility (n = 5), and cost-consequence (n = 1) analyses. All studies were model-based and evaluated only direct medical costs. Eleven records did not mention discounting and only 10 performed sensitivity analyses. The characteristic of the studies, the cost-effectiveness results and the studies' conclusions are described and commented upon. The main limitation of the studies was discussed and aspects to improve in future studies were pointed out.

CONCLUSIONS

Cost-effectiveness studies on acromegaly have been performed in several scenarios, evaluating different phases of treatment. However, the studies present limitations and, overall, were considered of moderate quality. Further economic models should be developed following health economics guidelines recommendations, and must improve transparency.

Pre-surgical medical treatment, a major prognostic factor for long-term remission in acromegaly

PURPOSE

To determine whether pre-surgical medical treatment (PSMT) using long-acting Somatostatin analogues in acromegaly may improve long-term surgical outcome and to determine decision making criteria.

METHODS

This retrospective study included 110 consecutive patients newly diagnosed with acromegaly, who underwent surgery in a reference center (Marseille, France). The mean long-term follow-up period was 51.4 ± 36.5 (median 39.4) months. Sixty-four patients received PSMT during 3-18 (median 5) months before pituitary surgery. Remission was defined at early (3 months) evaluation and at last follow-up by GH nadir after oral glucose tolerance test < 0.4 µg/L and normal IGF-1.

RESULTS

Pretreated and non-pretreated groups were comparable for the main confounding factors except for higher IGF-1 at diagnosis in PSMT patients. Remission rates were significantly different in pretreated or not pretreated groups (61.1% vs. 36.6%, respectively at long-term evaluation). In multivariate analysis, PSMT was significantly linked to 3 months (p < 0.01) and long-term remission (p < 0.01). Duration of PSMT was not significantly different in cured or non-cured patients, at both evaluation times. PSMT appeared to be more beneficial for patients with an invasive tumor. No patient with a tumor greater than 18 mm or mean GH level exceeding 35 ng/mL at diagnosis was cured by surgery alone (vs. 8 and 9 patients in the pretreated group, respectively). Patients with PSMT showed more transient mild hyponatremia after surgery.

CONCLUSIONS

PSMT significantly improved short and long-term remission in patients with acromegaly, independent of its duration, especially in invasive adenomas.

Cost-effectiveness of somatostatin analogues in the treatment of acromegaly

INTRODUCTION

Somatostatin analogues (SSAs) are the largest contributor to the direct medical cost of acromegaly management worldwide. The aim of this review was to identify and report available evidence on the cost-effectiveness of SSAs in the treatment of acromegaly.

AREAS COVERED

A literature search on relevant papers published up to April 2018 was performed. A total of 22 eligible studies (10 full-text articles and 12 conference abstracts) conducted in 14 countries were included in the analysis. In majority of studies, modelling technique was the principal research method.

EXPERT COMMENTARY

The results of cost-effectiveness analyses: 1) support published recommendations where SSAs are indicated as first-line medical treatment for patients with persistent disease after surgery or who are not eligible for surgery; 2) suggest that preoperative medical therapy with SSAs may be highly cost-effective in acromegalic patients with macroadenoma, in centres without optimal surgical results 3) indicate that in some countries pasireotide and pegvisomant appeared to be cost-effective or even dominant strategies in comparison to first-generation SSAs. The main limitation of economic evaluations was the lack of high-quality studies designed to directly compare various treatment strategies in acromegaly.

Medical Treatments for Acromegaly: A Systematic Review and Network Meta-Analysis

BACKGROUND

Acromegaly results from the hypersecretion of growth hormone. Because of the low incidence rates of this disease worldwide, few clinical trials evaluating drug treatments have been conducted.

OBJECTIVES

To conduct the first network meta-analysis simultaneously comparing all available drugs used in acromegaly treatment so as to provide more robust evidence in this field.

METHODS

A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Cochrane Collaboration recommendations (PROSPERO database under the registration number CRD42017059880). The electronic searches were conducted in PubMed (MEDLINE), Scopus, and Web of Science databases. Randomized controlled trials comparing any drug for the treatment of acromegaly head-to-head or versus placebo were included. Outcomes concerning the efficacy and safety of treatments were evaluated. The statistical analyses were performed using Aggregate Data Drug Information System version 1.16.8 (drugis.org, Groningen, The Netherlands).

RESULTS

The initial search retrieved 2059 articles. Of these, 10 randomized controlled trials were included in a qualitative analysis and 7 in a quantitative analysis. The network meta-analysis for the efficacy outcome (number of patients achieving insulinlike growth factor 1 control) showed that pegvisomant and lanreotide autogel were statistically superior to placebo (odds ratio [95% credible interval] 0.06 [0.00-0.55] and 0.09 [0.01-0.88]). No further differences were found. The probability rank indicated that pegvisomant and pasireotide have the highest probabilities (33% and 34%, respectively) of being the best therapeutic options. No major side effects were noted.

CONCLUSIONS

Pegvisomant is still a good option for acromegaly treatment, but pasireotide seems to be a promising alternative. Nevertheless, other important key factors such as drug costs and effectiveness (real-world results) should be taken into account when selecting acromegaly treatment.

Association between dopamine and somatostatin receptor expression and pharmacological response to somatostatin analogues in acromegaly

Acromegaly is a hormonal disorder resulting from excessive growth hormone (GH) secretion frequently produced by pituitary adenomas and consequent increase in insulin‐like growth factor 1 (IGF‐I). Elevated GH and IGF‐I levels result in a wide range of somatic, cardiovascular, endocrine, metabolic and gastrointestinal morbidities. Somatostatin analogues (SSAs) form the basis of medical therapy for acromegaly and are currently used as first‐line treatment or as second‐line therapy in patients undergoing unsuccessful surgery. However, a considerable percentage of patients do not respond to SSAs treatment. Somatostatin receptors (SSTR1‐5) and dopamine receptors (DRD1‐5) subtypes play critical roles in the regulation of hormone secretion. These receptors are considered important pharmacological targets to inhibit hormone oversecretion. It has been proposed that decreased expression of SSTRs may be associated with poor response to SSAs. Here, we systematically examine SSTRs and DRDs expression in human somatotroph adenomas by quantitative PCR. We observed an association between the response to SSAs treatment and DRD4, DRD5, SSTR1 and SSTR2 expression. We also examined SSTR expression by immunohistochemistry and found that the immunohistochemical detection of SSTR2 in particular might be a good predictor of response to SSAs.

Pitfalls in early biochemical evaluation after transsphenoidal surgery in patients with acromegaly

Although the current remission criteria for acromegaly are clear and concise, some pitfalls have been reported in early endocrinological evaluation after surgery. To evaluate the long-term (>4 year) outcome and to detect the pitfalls in early evaluation, we retrospectively reviewed 128 patients with acromegaly who underwent primary transsphenoidal surgery during 2011 and 2012. These included 66 men and 62 women, aged from 7 to 76 (mean 46) years old. 49 patients (38.3%) were preoperatively treated with somatostatin analog (SSA). Follow-up period ranged from 52 to 75 (63) months. Long-term remission using the current consensus criteria was achieved in 107 patients (83.6%), 105 of which patient had achieved remission in early evaluation. In 5 patients with preoperative SSA treatment, IGF-1 levels re-elevated more than one year after surgery. Five female patients without pretreatment with SSA showed delayed normalization of IGF-1 between 13 to 27 months postoperatively, two of which patients satisfied the remission criteria. In conclusion, the long-term results can be reliably predicted by the remission criteria early after surgery in most patients with acromegaly. For the accurate evaluation within a year after surgery, however, influence of preoperative treatment with SSA, delayed normalization of IGF-1, and poor GH suppression due to low insulin resistance must be considered, particularly in women.

Prolonged preoperative treatment of acromegaly with Somatostatin analogs may improve surgical outcome in patients with invasive pituitary macroadenoma (Knosp grades 1-3): a retrospective cohort study conducted at a single center

BACKGROUND

This study aimed to investigate preoperative somatostatin analogs (SSAs) treatment on the surgical outcome in patients with acromegaly.

METHODS

An analysis of 358 patients with acromegaly was conducted. The preoperative medical therapy group (81 patients) received SSA treatment for at least 3 months prior to surgery, while the primary surgery group (277 patients) underwent transsphenoidal surgery directly. Follow-up duration was ≥3 months. Tumor invasion was evaluated by magnetic resonance imaging (MRI) and classified according to the Knosp grading system.

RESULTS

Most patients were diagnosed with macroadenoma. Among all patients (Knosp grades 0-4), preoperative SSA therapy did not significantly improve the curative effect of surgery, according to the levels of growth hormone (GH) and/or insulin-like growth factor 1 (IGF-1) markers. In patients with macroadenoma (Knosp grades 1-3), the remission rates were significantly higher in the SSA group compared to the surgery group when considering GH (56.4% vs. 37.3%, P = 0.048) and IGF-1 (43.2% vs. 17.6%, P = 0.004). In the preoperative medical therapy group, long-term use of SSAs (>6 months) led to higher remission rates (GH, 72.2% vs. 51.0%; and IGF-1, 61.1% vs. 29.8%; P = 0.12 and 0.02, respectively].

CONCLUSIONS

The long-term preoperative SSAs treatment may improve the surgical curative rate in acromegalic patients with invasive macroadenomas (Knosp grades 1-3).

Theoretical analysis of somatostatin receptor 5 with antagonists and agonists for the treatment of neuroendocrine tumors

We report on SSTR5 receptor modeling and its interaction with reported antagonist and agonist molecules. Modeling of the SSTR5 receptor was carried out using multiple templates with the aim of improving the precision of the generated models. The selective SSTR5 antagonists, agonists and native somatostatin SRIF-14 were employed to propose the binding site of SSTR5 and to identify the critical residues involved in the interaction of the receptor with other molecules. Residues Q2.63, D3.32, Q3.36, C186, Y7.34 and Y7.42 were found to be highly significant for their strong interaction with the receptor. SSTR5 antagonists were utilized to perform a 3D quantitative structure-activity relationship study. A comparative molecular field analysis (CoMFA) was conducted using two different alignment schemes, namely the ligand-based and receptor-based alignment methods. The best statistical results were obtained for ligand-based ([Formula: see text], [Formula: see text] = 0.988, noc = 4) and receptor-guided methods (docked mode 1:[Formula: see text], [Formula: see text], noc = 5), (docked mode 2:[Formula: see text] = 0.555, [Formula: see text], noc = 5). Based on CoMFA contour maps, an electropositive substitution at [Formula: see text], [Formula: see text] and [Formula: see text] position and bulky group at [Formula: see text] position are important in enhancing molecular activity.

Theoretical analysis of somatostatin receptor 5 with antagonists and agonists for the treatment of neuroendocrine tumors

We report on SSTR5 receptor modeling and its interaction with reported antagonist and agonist molecules. Modeling of the SSTR5 receptor was carried out using multiple templates with the aim of improving the precision of the generated models. The selective SSTR5 antagonists, agonists and native somatostatin SRIF-14 were employed to propose the binding site of SSTR5 and to identify the critical residues involved in the interaction of the receptor with other molecules. Residues Q2.63, D3.32, Q3.36, C186, Y7.34 and Y7.42 were found to be highly significant for their strong interaction with the receptor. SSTR5 antagonists were utilized to perform a 3D quantitative structure-activity relationship study. A comparative molecular field analysis (CoMFA) was conducted using two different alignment schemes, namely the ligand-based and receptor-based alignment methods. The best statistical results were obtained for ligand-based ([Formula: see text], [Formula: see text] = 0.988, noc = 4) and receptor-guided methods (docked mode 1:[Formula: see text], [Formula: see text], noc = 5), (docked mode 2:[Formula: see text] = 0.555, [Formula: see text], noc = 5). Based on CoMFA contour maps, an electropositive substitution at [Formula: see text], [Formula: see text] and [Formula: see text] position and bulky group at [Formula: see text] position are important in enhancing molecular activity.

Somatostatin analogues in acromegaly and gastroenteropancreatic neuroendocrine tumours: past, present and future

Acromegaly is a hormonal disorder that arises when the pituitary gland secretes excess growth hormone (GH), which in turn stimulates a concomitant increase in serum insulin-like growth factor 1 (IGF-1) levels. Gastroenteropancreatic neuroendocrine tumours (GEP-NET) constitute a heterogeneous group of tumours that can secrete serotonin and a variety of peptide hormones that may cause characteristic symptoms known as carcinoid syndrome or other symptoms and hormonal hypersecretion syndromes depending on the tumour's site of origin. Current medical therapy for the treatment of acromegaly and GEP-NET involves the administration of somatostatin analogues that effectively suppress excess hormone secretion. After its discovery in 1979, octreotide became the first synthetic biologically stable somatostatin analogue with a short-acting formulation of octreotide introduced into clinical practice in the late 1980s. Lanreotide, another somatostatin analogue, became available in the mid-1990s initially as a prolonged-release formulation administered every 10 or 14 days. Long-acting release formulations of both octreotide (Sandostatin LAR and Novartis) and lanreotide (Somatuline Autogel, Ipsen), based on microparticle and nanoparticle drug-delivery technologies, respectively, were later developed, which allowed for once-monthly administration and improved convenience. First-generation somatostatin analogues remain one of the cornerstones of medical therapy in the management of pituitary and GEP-NET hormone hypersecretion, with octreotide having the longest established efficacy and safety profile of the somatostatin analogue class. More recently, pasireotide (Signifor), a next-generation multireceptor-targeted somatostatin analogue, has emerged as an alternative therapeutic option for the treatment of acromegaly. This review summarizes the development and clinical success of somatostatin analogues.

AMERICAN ASSOCIATION OF CLINICAL ENDOCRINOLOGISTS AND AMERICAN COLLEGE OF ENDOCRINOLOGY DISEASE STATE CLINICAL REVIEW: MANAGEMENT OF ACROMEGALY PATIENTS: WHAT IS THE ROLE OF PRE-OPERATIVE MEDICAL THERAPY?

OBJECTIVE

Acromegaly is a complex disease characterized by growth hormone (GH) excess originating in most cases from a pituitary tumor. The goals of treatment include removing the tumor or reducing tumor burden, normalizing GH secretion and insulin-like growth factor 1 levels, and preserving normal pituitary function if possible. Surgery by an experienced neurosurgeon is still considered first-line therapy, especially in cases with small tumors. In the last few decades, significant progress in the development of selective pharmacologic agents has greatly facilitated the management of active acromegaly, with agents such as somatostatin-receptor ligands (SRLs), GH-receptor antagonists, and dopamine agonists. In addition to adjuvant treatment, pre-operative medical therapy and primary therapy in de novo patients are increasingly employed.

METHODS

A United States National Library of Medicine PubMed search (through July 2014) was conducted for the following terms: acromegaly, pre-operative medical therapy, somatostatin-receptor ligands, and somatostatin analogs. Articles not in English and those not in peer-reviewed journals were excluded. In reviewing pertinent articles, focus was placed on biochemical and other postoperative outcomes of medical therapy.

RESULTS

An analysis of the full effect of pre-operative use of SRLs on surgical outcomes (remission rates and peri-operative complications) is limited by heterogeneity of methodology, low overall surgical cure rates, and different study designs. The assumption that SRL use prior to surgery reduces peri-operative surgical risk has yet to be proven. A variable degree of tumor shrinkage with preoperative SRLs is observed. Likewise, SRL treatment 3 months before surgery may improve surgical remission rates in the short term; however, positive results do not persist in the long term.

CONCLUSION

We consider that medical therapy before surgery could play a role in carefully selected patients, but treatment should be individualized. Primary medical therapy with a SRL may be considered in patients with macroadenomas without local mass effects on the optic chiasm, as SRLs have been shown to reduce tumor size and control GH hypersecretion. However, the data are insufficient to support general use of a SRL prior to surgery in order to improve post-surgery biochemical outcomes. Theoretically, patients with severe cardiac and respiratory complications due to acromegaly could potentially benefit from pre-operative SRLs in order to reduce peri-operative morbidity. Further investigation and investment in large randomized long-term clinical trials are needed to define the precise role and duration of pre-surgical medical treatment in acromegaly patients.

Growth hormone–secreting macroadenoma of the pituitary gland successfully treated with the radiolabeled somatostatin analog 90Y-DOTATATE: case report

Pituitary tumors causing acromegaly are usually macroadenomas at the time of diagnosis, and they can grow aggressively, infiltrating surrounding tissues. Difficulty in achieving complete tumor removal at surgery can lead toward a strong tendency for recurrence, making it necessary to consider a means of treatment other than those currently used such as somatostatin analogs (SSAs), growth hormone (GH) receptor antagonist, surgical removal, and radiotherapy. The purpose of this paper is to describe a patient diagnosed with an aggressive, giant GH-secreting tumor refractory to medical therapy but ultimately treated with the radiolabeled somatostatin analog 90Y-DOTATATE.

A 26-year-old male with an invasive macroadenoma of the pituitary gland (5.6 × 2.5 × 3.6 cm) and biochemically confirmed acromegaly underwent 2 partial tumor resections: the first used the transsphenoidal approach and the second used the transcranial method. The patient received SSAs pre- and postoperatively. Because of the progression in pituitary tumor size, he underwent classic irradiation of the tumor (50 Gy). One and a half years later, the patient presented with clinically and biochemically active disease, and the tumor size was still 52 mm in diameter (height). Two neurosurgeons disqualified him from further surgical procedures. After confirming the presence of somatostatin receptors in the pituitary tumor by using 68Ga-DOTATATE PET/CT, we treated the patient 4 times with an SSA bound with 90Y-DOTATATE. After this treatment, the patient attained partial biochemical remission and a reduction in the tumor mass for the first time.

Treatment with an SSA bound with 90Y-DOTATATE may be a promising option for some aggressive GH-secreting pituitary adenomas when other methods have failed.

Pros and cons in endocrine practice: pre-surgical treatment with somatostatin analogues in acromegaly

The aim of this commentary is to balance the pros and cons for pre-surgical SSA treatment in a modern perspective ending up with a pragmatic recommendation for treatment based on the current evidence and expertise of the authors. Even though prospective and randomized studies in this particular area are hampered by obvious limitations, the interpretation of the four published trials has in general been in favor of pre-treatment with SSA, showing a better outcome following surgery. However, major drawbacks of these studies, such as non-optimal diagnostic criteria for cure, potential selection bias, and timing of the postoperative evaluation in SSA pre-treated patients, limit their overall interpretation. Three matched-controlled studies showed remarkably similar results with no apparent beneficial effect of SSA pre-treatment on surgical outcome. Both prospective, randomized studies and retrospective studies did not find any significant difference in the rate of endocrine and non-endocrine complications related to surgery, despite the beneficial clinical effects of SSA treatment in most acromegalic patients. The newly diagnosed patient with acromegaly should be carefully evaluated in the trans-disciplinary neuroendocrine team and treatment individualized accordingly. The issue of SSA pre-treatment to improve surgical outcome is yet to be settled and further methodologically sound studies are probably necessary to clarify this point.

The effects of somatostatin analogue therapy on pituitary tumor volume in patients with acromegaly

INTRODUCTION

In nearly all cases, acromegaly is caused by excess GH from a pituitary adenoma, resulting in elevated circulating levels of GH and, subsequently, IGF-1. Treatment goals are to eliminate morbidity and restore the increased mortality to normal rates. Therapeutic strategies aim to minimize tumor mass and normalize GH and IGF-1 levels. Somatostatin analogues are the medical treatment of choice in acromegaly, as first-line or post-surgical therapy, and have proven efficacy in pituitary tumor volume reduction (TVR).

METHODS

Here we review the effects of somatostatin analogue therapy on pituitary tumor volume in patients with acromegaly.

RESULTS

TVR with somatostatin analogues may be mediated by direct anti-proliferative effects via activation of somatostatin receptors, or by indirect effects, such as angiogenesis inhibition, and is more pronounced when they are administered as first-line therapy. Various studies of first-line treatment with octreotide LAR have shown significant TVR in ≥73% of patients. First-line treatment with lanreotide Autogel has shown evidence of TVR, although more studies are needed. In a recent randomized, double-blind, 12-month trial in 358 medical-treatment-naïve acromegaly patients, significant TVR was achieved by 81% of patients administered pasireotide LAR and 77% administered octreotide LAR. Pre-operative somatostatin analogue therapy may also induce TVR and improve post-operative disease control compared with surgery alone. TVR is progressive with prolonged treatment, and decreased IGF-1 levels may be its best predictor, followed by age and degree of GH decrease. However, TVR does not always correlate with degree of biochemical control.

CONCLUSION

Somatostatin analogues (first- or second-line treatment) are the mainstay of medical therapy and, as first-line medical therapy, are associated with significant pituitary TVR in most patients.

Evidence-based guidelines in acromegaly: implications on the clinic

Acromegaly is a rare disease with many challenges in its management. In order to address these challenges, many clinical practice guidelines were recently published. They were based on the literature evidence, aiming at guiding primary care physicians, general endocrinologists and neuroendocrinologists. The majority of these guidelines were developed following the GRADE system that classifies the recommendations according to strength (weak or strong) and quality of the evidence that supports them. In this review, we discuss how the evidence-based guidelines are developed, how to interpret the different strengths of recommendations and discuss the clinical implications of the evidence-based guidelines in acromegaly, pointing its utility and limitations on the diagnosis, management of comorbidities and in the disease treatment.

Impact of pre-treatment with somatostatin analogs on surgical management of acromegalic patients referred to a single center

First-line treatment of patients with growth hormone secreting adenomas is surgical resection. Disease control can be obtained by surgery (one or multiple steps), in case followed by medical treatment or adjuvant radiation therapy (radiosurgery or radiotherapy). The impact of pre-surgical treatment with somatostatin analogs (SSAs) on surgical outcome is still controversial. The aim of this study is to retrospectively evaluate the impact of SSA pre-treatment on biochemical outcome and post-surgical hypopituitarism in a consecutive surgical series from a single referral centre, with data covering 17 years' experience and to investigate the possible predictive value of early postoperative insulin-like factor 1 (IGF-I) on long-term biochemical control. Data from 68 acromegalic patients were revised. Endocrinological long-term follow-up (minimum 6 months) was available for 57 patients. Eighty-eight percent of patients received a single-step surgical treatment (single surgery, with or without adjuvant medical therapy). The remaining 12% underwent a multi-step strategy: redo-surgery (three macroadenomas) and/or radiation (four macro- and two microadenomas). Pre-surgical SSA treatment was performed in 77.9% and resulted in a significant lowering of basal IGF-I values (p = 0.0001). Early post-surgical IGF-I was significantly lower in patients biochemically controlled with single surgery alone (p = 0.016) and after overall treatment strategies (p = 0.005). Normalization of GH and IGF-I was obtained in 56.1%, and normalization of either one of them in 27.8% of patients. No major surgery-related complications occurred. Post-treatment hypopituitarism occurred in 11.9% and was lower in SSA pre-treated patients. Our results well compare with other recently published series. Very early post-surgical IGF-I improvement might be a useful predictor for biochemical disease control. Moreover, our results suggest that pre-surgical treatment with somatostatin analogs seems to prevent hypopituitarism.

Preoperative octreotide therapy and surgery in acromegaly: associations between glucose homeostasis and treatment response

In acromegaly, high GH/IGF-1 levels associate with abnormal glucose metabolism. Somatostatin analogs (SSAs) reduce GH and IGF-1 but inhibit insulin secretion. We studied glucose homeostasis in de novo patients with acromegaly and changes in glucose metabolism after treatment with SSA and surgery. In this post hoc analysis from a randomized controlled trial, 55 de novo patients with acromegaly, not using antidiabetic medication, were included. Before surgery, 26 patients received SSAs for 6 months. HbA1c, fasting glucose, and oral glucose tolerance test were performed at baseline, after SSA pretreatment and at 3 months postoperative. Area under curve of glucose (AUC-G) was calculated. Glucose homeostasis was compared to baseline levels of GH and IGF-1, change after SSA pretreatment, and remission both after SSA pretreatment and 3 months postoperative. In de novo patients, IGF-1/GH levels did not associate with baseline glucose parameters. After SSA pretreatment, changes in GH/IGF-1 correlated positively to change in HbA1c levels (both p < 0.03). HbA1c, fasting glucose, and AUC-G increased significantly during SSA pretreatment in patients not achieving hormonal control (all p < 0.05) but did not change significantly in patients with normalized hormone levels. At 3 months postoperative, HbA1c, fasting glucose, and AUC-G were significantly reduced in both cured and not cured patients (all p < 0.05). To conclude, in de novo patients with acromegaly, disease activity did not correlate with glucose homeostasis. Surgical treatment of acromegaly improved glucose metabolism in both cured and not cured patients, while SSA pretreatment led to deterioration in glucose homeostasis in patients not achieving biochemical control.

Medical Treatment of Acromegaly with Dopamine Agonists or Somatostatin Analogs

Treatment of acromegaly aims to correct (or prevent) tumor compression of surrounding tissues by excising the disease-causing lesion and reduce growth hormone (GH) and IGF-1 levels to normal values. When surgery (the usual first-line treatment) fails to correct GH/IGF-1 hypersecretion, medical treatment with dopamine agonists (DAs; particularly cabergoline) or somatostatin analogs (SAs) can be used. The GH receptor antagonist pegvisomant is helpful in patients who are totally or partially resistant to SAs and can be given in association with both SAs and/or DAs. Thanks to this multistep therapeutic strategy, adequate hormonal disease control is achieved in most patients, giving them normal life expectancy. Comorbidities associated with acromegaly generally improve after treatment, but persistent sequelae may nonetheless impair quality of life.

Recent advances in the management of acromegaly

Acromegaly is a rare condition of GH excess associated with significant morbidities (e.g. hypertension, glucose intolerance or diabetes mellitus, cardiac, cerebrovascular, respiratory disease and arthritis) and, when uncontrolled, high mortality. Surgery, medical treatment and radiotherapy remain our therapeutic tools. Advances in these options during the last years have offered further perspectives in the management of patients and particularly those with challenging tumours; the impact of these on the long-term morbidity and mortality remains to be assessed.

Cost-effectiveness analysis of preoperative treatment of acromegaly with somatostatin analogue on surgical outcome

CONTEXT

There is no uniform standard of care for acromegaly. Due to the high costs involved, steps must be taken to ensure the cost-effective delivery of treatment.

OBJECTIVE

Taking the results of an earlier meta-analysis as a starting point, this study aims to determine whether treatment with long-acting somatostatin analogue (SSA) prior to surgery improves the cost-effectiveness of the treatment of acromegaly.

METHODS

The results are presented as an Incremental Cost Effectiveness Ratio (ICER) immediately after surgery, for the following year and over the next four decades. The cure rates percentage (95% CI) for the three randomized prospective controlled trials were 44.4% (34.2-54.7) and 18.2% (10.1-26.3) for preoperative treated and untreated patients respectively. The cost of pharmacological treatments was based on the number of units prescribed, dose and length of treatment.

RESULTS

The mean (95% CI) ICER immediately after surgery was €17,548 (12,007-33,250). In terms of the postoperative SSA treatment, the ICER changes from positive to negative before two years after surgery. One decade after surgery the ICER per patient/year was €-9973 (-18,798; -6752) for postoperative SSA treatment and €-31,733 (-59,812; -21,483) in the case of postoperative pegvisomant treatment.

CONCLUSIONS

In centres without optimal surgical results, preoperative treatment of GH-secreting pituitary macroadenomas with SSA not only shows a significant improvement in the surgical results, but is also highly cost-effective, with an ICER per patient/year one decade after surgery, of between €-9973 (-18,798; -6752) and €-31,733 (-59,812; -21,483) for SSA and pegvisomant respectively.

Diagnosis, treatment and clinical perspectives of acromegaly

Acromegaly is an insidious disease of the pituitary caused by a growth hormone-secreting adenoma. Generally, the diagnosis is made rather late in the course of the disease. Currently, acromegaly can be cured in about half of the patients with the disease by expert surgery. The remainder of non-surgically cured patients often can be effectively treated with somatostatin analogs; either with the new generation of dopaminergic drugs or with Pegvisomant, a GH-receptor blocking agent. However, at the time of diagnosis many patients suffer from serious comorbidities, including hypertension, heart disease, arthrosis, sleep apnea and diabetes mellitus. Recent reports have shown that mortality risk can be normalized. Nevertheless, all efforts should be undertaken to treat comorbidities. New strategies for surgery and medical treatment are discussed.

Cost-effectiveness analysis of two therapeutic schemes in the treatment of acromegaly: a retrospective study of 168 cases

PURPOSE

This study aimed to estimate the cost effectiveness of two therapeutic schemes, including preoperative medical therapy and surgery as primary therapy.

METHODS

A total of 168 acromegaly cases were retrospectively investigated for a comparative evaluation of surgery and preoperative medical therapy. A Markov model was developed to simulate treatment cost-effectiveness and progression of acromegaly.

RESULTS

Overall effectiveness of preoperative medical therapy was significantly higher than surgery in acromegalic patients with macroadenoma. In addition, life expectancy, and cost per life-year gained were slightly higher in the preoperative medical therapy group than in the initial surgery group when patients received surgery as a secondary treatment. Interestingly, preoperative medical therapy achieved a significant increase in life expectancy and reduced cost for patients who received long-term medical therapy as secondary treatment.

CONCLUSIONS

In acromegalic patients with macroadenoma, the cost-effectiveness analysis revealed more satisfactory outcomes in preoperative therapy, compared with primary surgery.

Pharmacotherapy for acromegaly: future role for pasireotide?

Somatostatin receptor ligands (octreotide and lanreotide) are currently first-line pharmacotherapy for patients with acromegaly in whom surgery fails to control the disease or cannot be considered. The efficacy of a new pan somatostatin receptor ligand, pasireotide, has been investigated as a potential treatment of acromegaly. Several clinical trials showed disease-remission with pasireotide in one-third of patients and some octreotide-resistant patients were responsive to pasireotide. Pasireotide can likely be used for patients with suboptimal response or resistance to treatment with the approved maximal doses of octreotide long-acting release (LAR) or lanreotide Autogel; however, the development or exacerbation of diabetes mellitus is of concern.

Should all patients with acromegaly receive somatostatin analogue therapy before surgery and, if so, for how long?

Current guidelines do not recommend the routine use of somatostatin analogue pretreatment prior to surgery in patients with growth hormone-secreting pituitary tumours. In theory, presurgical use of somatostatin analogues should improve metabolic control and reduce soft tissue swelling, leading to improved anaesthetic outcomes. Shrinkage of tumours prior to surgery might also improve surgical remission rates. Hence, this article addresses the question: Should all patients with acromegaly receive a somatostatin analogue prior to surgery? Clinical trials published before December 2013 were reviewed, although literature in this area remains relatively deficient. We conclude: (i) On the basis of limited data available, somatostatin analogue pretreatment does not improve anaesthetic or immediate postoperative outcomes (i.e. hospital stay, rates of surgical complications and postoperative pituitary dysfunction). (ii) Somatostatin analogues should be considered in all patients with growth hormone-secreting macroadenomas, including invasive macroadenomas, when the overall surgical remission rate for macroadenomas at the treating centre is below 50%. Four recent RCTs have demonstrated increased rates of surgical remission using such an approach. (iii) When deemed appropriate, patients should be treated with somatostatin analogues for at least 3 months before surgery; there is currently no evidence that treatment beyond 6 months provides any additional benefit. Patients with minimally invasive macroadenomas are those most likely to benefit in terms of improved surgical remission.

Outcome of endoscopic transsphenoidal surgery in combination with somatostatin analogues in patients with growth hormone producing pituitary adenoma

Objective

To determine the efficacy of endoscopic surgery in combination with long-acting somatostatin analogues (SSAs) in treating patients with growth hormone (GH)-secreting pituitary tumor.

Methods

We performed retrospective analysis of 133 patients with GH producing pituitary adenoma who underwent pure endoscopic transsphenoidal surgery in our center from January 2007 to July 2012. Patients were followed up for a range of 3-48 months. The radiological remission, biochemical remission and complication were evaluated.

Results

A total of 110 (82.7%) patients achieved radiological complete resection, 11 (8.2%) subtotal resection, and 12 (9.0%) partial resection. Eighty-eight (66.2%) patients showed nadir GH level less than 1 ng/mL after oral glucose administration. No mortality or severe disability was observed during follow up. Preoperative long-acting SSA successfully improved left ventricle ejection fraction (LVEF) and blood glucose in three patients who subsequently underwent success operation. Long-acting SSA (20 mg every 30 days) achieved biochemical remission in 19 out 23 (82.6%) patients who showed persistent high GH level after surgery.

Conclusion

Endoscopic transsphenoidal surgery can biochemically cure the majority of GH producing pituitary adenoma. Post-operative use of SSA can improve biochemical remission.

Preoperative octreotide treatment of acromegaly: long-term results of a randomised controlled trial

OBJECTIVE

Randomised studies have demonstrated a beneficial effect of pre-surgical treatment with somatostatin analogues (SSA) in acromegaly when evaluated early postoperatively. The objective of this study was to evaluate the long-term surgical cure rates.

METHODS

Newly diagnosed patients were randomised to direct surgery (n=30) or 6-month pretreatment with octreotide LAR (n=32). The patients were evaluated 1 and 5 years postoperatively. Cure was defined as normal IGF1 levels and by normal IGF1 level combined with nadir GH <2 mU/l in an oral glucose tolerance test, all without additional post-operative treatment. A meta-analysis using the other published randomised study with long-term analyses on preoperative SSA treatment was performed.

RESULTS

The proportion of patients receiving post-operative acromegaly treatment was equal in the two groups. When using the combined criteria for cure, 10/26 (38%) macroadenomas were cured in the pretreatment group compared with 6/25 (24%) in the direct surgery group 1 year postoperatively (P=0.27), and 9/22 (41%) vs 6/22 (27%) macroadenomas, respectively, 5 years postoperatively (P=0.34). In the meta-analysis, 16/45 (36%) macroadenomas were cured using combined criteria in the pretreatment group vs 8/45 (18%) in the direct surgery group after 6-12 months (P=0.06), and 15/41 (37%) vs 8/42 (19%), respectively, in the long-term (P=0.08).

CONCLUSION

This study does not prove a beneficial effect of SSA pre-surgical treatment, but in the meta-analysis a trend towards significance can be claimed. A potential favourable, clinically relevant response cannot be excluded.

Expert consensus document: A consensus on the medical treatment of acromegaly

In March 2013, the Acromegaly Consensus Group met to revise and update guidelines for the medical treatment of acromegaly. The meeting comprised experts skilled in the medical management of acromegaly. The group considered treatment goals covering biochemical, clinical and tumour volume outcomes, and the place in guidelines of somatostatin receptor ligands, growth hormone receptor antagonists and dopamine agonists, and alternative modalities for treatment including combination therapy and novel treatments. This document represents the conclusions of the workshop consensus.

Clinical applications of somatostatin analogs for growth hormone-secreting pituitary adenomas

Excessive growth hormone (GH) is usually secreted by GH-secreting pituitary adenomas and causes gigantism in juveniles or acromegaly in adults. The clinical complications involving cardiovascular, respiratory, and metabolic systems lead to elevated morbidity in acromegaly. Control of serum GH and insulin-like growth factor (IGF) 1 hypersecretion by surgery or pharmacotherapy can decrease morbidity. Current pharmacotherapy includes somatostatin analogs (SAs) and GH receptor antagonist; the former consists of lanreotide Autogel (ATG) and octreotide long-acting release (LAR), and the latter refers to pegvisomant. As primary medical therapy, lanreotide ATG and octreotide LAR can be supplied in a long-lasting formulation to achieve biochemical control of GH and IGF-1 by subcutaneous injection every 4-6 weeks. Lanreotide ATG and octreotide LAR provide an effective medical treatment, whether as a primary or secondary therapy, for the treatment of GH-secreting pituitary adenoma; however, to maximize benefits with the least cost, several points should be emphasized before the application of SAs. A comprehensive assessment, especially of the observation of clinical predictors and preselection of SA treatment, should be completed in advance. A treatment process lasting at least 3 months should be implemented to achieve a long-term stable blood concentration. More satisfactory surgical outcomes for noninvasive macroadenomas treated with presurgical SA may be achieved, although controversy of such adjuvant therapy exists. Combination of SA and pegvisomant or cabergoline shows advantages in some specific cases. Thus, an individual treatment program should be established for each patient under a full evaluation of the risks and benefits.