The surgical treatment of acromegaly

Clinical and therapeutic implications of cavernous sinus invasion in pituitary adenomas

Invasion of the cavernous sinus by pituitary adenomas impedes complete surgical resection, compromises biochemical remission, and increases the risk of further tumor recurrence. Accurate preoperative MRI-based diagnosis or intraoperative direct inspection of cavernous sinus invasion are essential for optimal surgical planning and for tailoring postoperative therapeutic strategies, depending on whether a total resection has been achieved, or tumoral tissue has been left in surgically inaccessible locations. The molecular mechanisms underlying the invasive behavior of pituitary adenomas remain poorly understood, hindering the development of targeted therapies. Some studies have identified genes overexpressed in pituitary adenomas invading the cavernous sinus, offering insights into the acquisition of invasive behavior. Their main limitation however lies in comparing purely intrasellar specimens obtained from invasive and non-invasive adenomas. Further, precise anatomical knowledge of the medial wall of the cavernous sinus is crucial for grasping the mechanisms of invasion. Recently, alongside the standard intrasellar surgery, extended endoscopic intracavernous surgical procedures with systematic selective resection of the medial wall of the cavernous sinus have shown promising results for invasive secreting pituitary adenomas. The first- and second-generation somatostatin agonist ligands and cabergoline are used with variable efficacy to control secretory activity and/or growth of intracavernous remnants. Tumor regrowth usually requires surgical reintervention, sometimes combined with radiotherapy or radiosurgery which is applied despite their benign nature. Unraveling the molecular pathways driving invasive behavior of pituitary adenomas and their tropism to the cavernous sinuses is the key for developing efficient innovative treatment modalities that could reduce the need for repeated surgery or radiotherapy.

Assessment of multimodal treatment options in recurrent and persistent acromegaly: a systematic review and meta-analysis

PURPOSE

In patients with acromegaly, secondary treatment options in cases of hormonal non-remission or tumor progression include repeat transsphenoidal surgery (TSS), radiation-based treatment (RT), or medical therapy (MT). In this study, we aim to evaluate the clinical effectiveness of various second-line treatment options for acromegaly.

METHODS

Using the PRISMA guideline, a systematic review was performed by searching MEDLINE (PubMed), Web of Science, Scopus, and Cochrane electronic bibliographic databases from conception to the end of 2022. Outcomes of interest included hormonal remission rate, complications, and mortality associated with each treatment modality for refractory acromegaly.

RESULTS

A total of 79 studies including 3,208 refractory acromegaly patients (44.90% males) were analyzed, with a mean patient age of 43.89 years. There was a statistically significant difference between various therapeutic modalities in terms of remission rate, with MT offering the highest remission rate (62.55%), followed by RT (50.15%) and TSS (37.39%). Subgroup analysis of radiotherapeutic and medical modalities did not show a significant difference in remission rate between different kinds of sub-modalities in each treatment approach. Recurrence following secondary treatment was not different in patients treated with reoperation TSS compared to other modalities.

CONCLUSIONS

The management of persistent and recurrent acromegaly optimally requires a multimodal approach. In different scenarios of refractory acromegaly based on previous treatment, secondary treatments may vary in terms of remission rate and complications. Medical agents provide considerable effectiveness as a second-line therapy for recurrent or persistent disease. In selected cases, however, reoperation still provides an opportunity for cure or freedom from medications. The findings of this study may help clinicians to prioritize varying options involved in this multifaceted decision-making process.

Unravelling pituitary tumours in medically treated patients with acromegaly: the impact of systematic MRI reassessment

BACKGROUND

In acromegaly, the primary tumor is usually found during magnetic resonance imaging (MRI) of the pituitary gland. A remnant tumor after surgery is, however, harder to depict. When a tumor is missed, the remaining option is usually lifelong pharmacological treatment.

PURPOSE

To identify tumors by reassessment of all available MRI scans in pharmacologically treated patients, operated or not, and to compare our results with the routine MRI reports.

MATERIAL AND METHODS

Adult patients diagnosed with acromegaly and managed at a tertiary care center between 2005 and 2021 and currently on pharmacological treatment were included. MRI scans were evaluated in a standardized manner and classified independently by a radiologist and an endocrinologist into "certain," "suspected," or "no tumor." In case of disagreement, consensus was achieved with a senior neuroradiologist. The results were compared using the clinical radiologists' routine MRI reports.

RESULTS

We identified certain and suspected tumors in 29/74 and 36/74 patients, respectively. No tumor was identified in nine patients. In five of these, no MRI contrast agent was given. Discrepancy between our results and the routine MRI reports was found in 31/74 patients (P = 0.01). In 22 patients, the routine reports described no tumor while we identified certain tumors in 2/22 patients and suspected tumors in 13/22 patients.

CONCLUSION

In most patients with pharmacologically treated acromegaly, we identified a certain or suspected pituitary tumor. These findings were more frequent compared to the routine MRI reports. Based on our results, patients will be considered for a change in long-term treatment modality.

Pilot study to define criteria for Pituitary Tumors Centers of Excellence (PTCOE): results of an audit of leading international centers

PURPOSE

The Pituitary Society established the concept and mostly qualitative parameters for defining uniform criteria for Pituitary Tumor Centers of Excellence (PTCOEs) based on expert consensus. Aim of the study was to validate those previously proposed criteria through collection and evaluation of self-reported activity of several internationally-recognized tertiary pituitary centers, thereby transforming the qualitative 2017 definition into a validated quantitative one, which could serve as the basis for future objective PTCOE accreditation.

METHODS

An ad hoc prepared database was distributed to nine Pituitary Centers chosen by the Project Scientific Committee and comprising Centers of worldwide repute, which agreed to provide activity information derived from registries related to the years 2018-2020 and completing the database within 60 days. The database, provided by each center and composed of Excel® spreadsheets with requested specific information on leading and supporting teams, was reviewed by two blinded referees and all 9 candidate centers satisfied the overall PTCOE definition, according to referees' evaluations. To obtain objective numerical criteria, median values for each activity/parameter were considered as the preferred PTCOE definition target, whereas the low limit of the range was selected as the acceptable target for each respective parameter.

RESULTS

Three dedicated pituitary neurosurgeons are preferred, whereas one dedicated surgeon is acceptable. Moreover, 100 surgical procedures per center per year are preferred, while the results indicated that 50 surgeries per year are acceptable. Acute post-surgery complications, including mortality and readmission rates, should preferably be negligible or nonexistent, but acceptable criterion is a rate lower than 10% of patients with complications requiring readmission within 30 days after surgery. Four endocrinologists devoted to pituitary diseases are requested in a PTCOE and the total population of patients followed in a PTCOE should not be less than 850. It appears acceptable that at least one dedicated/expert in pituitary diseases is present in neuroradiology, pathology, and ophthalmology groups, whereas at least two expert radiation oncologists are needed.

CONCLUSION

This is, to our knowledge, the first study to survey and evaluate the activity of a relevant number of high-volume centers in the pituitary field. This effort, internally validated by ad hoc reviewers, allowed for transformation of previously formulated theoretical criteria for the definition of a PTCOE to precise numerical definitions based on real-life evidence. The application of a derived synopsis of criteria could be used by independent bodies for accreditation of pituitary centers as PTCOEs.

Pituitary adenomas registry in Thailand

PURPOSE

Pituitary adenomas are the most common sellar tumors, and may cause adverse outcomes in terms of morbidity and mortality if left untreated or if diagnosis is delayed. No data exists on the prevalence, characteristics, and prognosis of pituitary adenomas in Thailand. The systematic registration of clinical characteristics may improve patient care and prognosis for this disease in Thailand.

METHODS

This was a retrospective study conducted in 11 academic referral centers. All patients diagnosed with pituitary adenomas during the 2011---2014 period were enrolled in the study. The information was correlated with two national databases.

RESULTS

A total of 1,283 pituitary adenoma patients were identified. The adenomas were: non-functioning 50.1%, prolactinoma 29.4%, acromegaly 14.7%, Cushing disease 3.8%, gonadotropin-producing tumor 1.0%, TSH-secreting tumor 0.6%. The mean age was 49.2±15.2 years. Sixty-three percent of patients were female. Most common complaint was visual impairment (27.7%). The average size of the tumor was 22.2±16.1 mm. Fifty-nine percent of patients underwent surgery. Median follow-up was 27.4 months (0-24 years). After treatment, 72.4% improved, and 10.4% were cured. Overall results of treatment in non-functioning adenoma, prolactinoma (medically treated), acromegaly, Cushing, TSH, gonadotropin producing adenoma were: improved/cured in 81/5.5, 86/5.7, 55.9/30, 54.2/31.2, 85.7/14.3, 69.2/15.4% respectively.

CONCLUSION

Pituitary adenomas in academic centers in Thailand were found predominantly in female in the 4th decade of life. After treatment 72.4% of patients improved and 10% had full recovery. A health promotion system aimed to improve patient and physician recognition and physician expertise may improve the prognosis of these diseases.

The socioeconomic burden of acromegaly

Acromegaly is a rare and insidious disease characterized by chronic excess growth hormone, leading to various morphological changes and systemic complications. Despite its low prevalence, acromegaly poses a significant socioeconomic burden on patients and healthcare systems. This review synthesizes the current state of knowledge on the psychosocial burden, disability, impact on daily life, and cost of acromegaly disease, focusing on the quality of life, partnership, medical care and treatment afflictions, participation in daily activities, professional and leisure impairment, and cost of treatment for acromegaly and its comorbidities. It also examines management strategies, coping mechanisms, and interventions aimed at alleviating this burden. A comprehensive understanding of the extent of the socioeconomic burden in acromegaly is crucial to develop effective strategies to improve treatment and care. Further research is warranted to explore the myriad factors contributing to this burden, as well as the efficacy of interventions to alleviate it, ultimately enhancing the quality of life for patients with acromegaly.

Surgical Treatment of Prolactinomas: Potential Role as a First-Line Treatment Modality

PURPOSE

Treatment with dopamine agonists (DAs) has been the first-line standard treatment for prolactinoma, and surgery has been reserved for drug intolerance and resistance for several decades. We evaluated whether surgery plays a primary role in prolactinoma management.

MATERIALS AND METHODS

We conducted a retrospective study of 210 prolactinoma patients who had received surgical treatment at our institution. We analyzed the treatment outcomes according to tumor extent, sex, and preoperative DA medication.

RESULTS

Overall hormonal remission was achieved in 164 patients (78.1%), and complete removal was achieved in 194 patients (92.4%). When the tumors were completely removed, the remission rate increased to 84.5%. Anterior pituitary function was normalized or improved in 94.6% of patients, whereas only 4.1% of patients showed worsening of hormone control. Hormonal remission was higher in patients who had not received DA preoperatively than in those who had received preoperative DA treatment. Smaller tumor size (<1 cm), no invasion into the cavernous sinus, and female sex were predictors of good surgical outcomes.

CONCLUSION

Although DAs remain the first-line standard treatment for prolactinomas, surgery can be an excellent option and should be considered as an alternative primary treatment modality when patients are predicted to achieve a good surgical outcome.

Endoscopic endonasal approach for acromegaly: surgical outcomes using 2018 consensus criteria for remission

Objective

The primary aim is to analyze the endoscopic endonasal surgical results in short-term and two-year follow-ups according to the 11th Acromegaly Consensus statement (2018). Indeed, prognostic factors and complications were analyzed.

Subjects and methods

40 patients who underwent endoscopic endonasal surgery by acromegaly between 2013 to 2020 was analyzed. Patients were considered in remission if an upper limit of normal (ULN) IGF-1 was less than 1.0 at the six-month and two-year follow-ups. Moreover, we assessed the Knosp grade, tumor volumetry, ULN, T2 signal in MRI, reoperation, and complications.

Results

The mean age of admission was 46.7 years. Thirty-two patients were in remission after six months of surgery (80%), decreasing to 76.32% at the two-year follow-up. All microadenomas presented remission (n = 6). Regarding the complications, three patients had permanent panhypopituitarism (7.5%); postoperative cerebrospinal fluid (CSF) leaks did not occur in this series. The hyperintense signal on the T2 MRI and a higher tumor volumetry were the single predictor's factors of non-emission in a multivariate regression logistic analysis (p < 0.05). Preoperative hormone levels (GH and IGF-1) were not a prognostic factor for remission. The re-operated patients who presented hypersignal already had a high predictor of clinical-operative failure.

Conclusion

The endoscopic endonasal surgery promotes high short-term and two-year remission rates in acromegaly; the tumor's volumetry and the T2 hypersignal were statistically significant prognostic factors in non-remission - the complications presented at similar rates in comparison to the literature. In invasive GH-secreting tumors, we should offer these patients a multi-disciplinary approach to improve acromegalic patients' remission rates.

Gigantism: microsurgical treatment by transsphenoidal approach and prognostic factors

PURPOSE

We present the results of transsphenoidal microsurgical treatment in 14 patients with gigantism. The influence on the prognosis of factors such as the tumor size and preoperative levels of GH and IGF-1 is also quantified.

MATERIALS AND METHODS

The patients, operated between 1982 and 2004, were reviewed retrospectively in June 2022. All patients had complete endocrinological studies in the preoperative period and a postoperative control between 6 days and 3 weeks. Follow-up has been supported with annual check-ups between 3 and 31 years. We have compared the preoperative levels of GH and IGF-1 of these patients with the levels of a series of acromegalic patients operated on in the same Center.

RESULTS

In this series there were 4 women and 10 men. The age ranged between 14 and 21 years. In 6 patients, postoperative hormone levels achieved the disease control criteria (42.8%). The CT/MRI studies revealed the existence of invasive tumors in 10 of the patients (71.4%). Postoperative CT/MRI showed no tumor tissue in 3 patients but in 7 patients there were tumor remains. The remaining 4 patients had abnormal images although not considered as tumor. A statistical comparison of preoperative serum GH and IGF-1 levels in patients with gigantism and patients with acromegaly showed a significant elevation in the former.

CONCLUSION

Pituitary adenomas that cause gigantism are generally large and invasive, which makes them difficult to cure. High preoperative levels of GH and IGF-1 are also factors that decrease remission.

[Predictors of postoperative remission of acromegaly. (Experience of the Burdenko Neurosurgical Center)]

BACKGROUND

Treatment of acromegaly is still an unresolved problem. Overall postoperative remission rate ranges from 34 to 85%. These values are better for microadenomas (75-90%) and worse for macroadenomas (45-70%). Identification of predictors of acromegaly remission after surgical treatment is an urgent objective to improve the quality of medical care for these patients.

OBJECTIVE

To analyze postoperative freedom from acromegaly and predictors of remission.

MATERIAL AND METHODS

A retrospective single-center study included 227 patients with acromegaly who underwent resection of pituitary adenoma between August 2018 and August 2021.

RESULTS

Remission (normalization of serum IGF-1) was achieved in 65 (55%) patients. Growth hormone and IGF-1 index decreased after surgery in all patients. Mean preoperative serum growth hormone was 12.45 [6.88, 29.85] ng/ml, early postoperative concentration - 1.54 [0.80, 3.38] ng/ml, in delayed period - 1.15 [0.57, 3.80] ng/ml. Mean IGF-1 index was 2.18 [1.69, 2.71], 1.47 [0.99, 1.90] and 0.99 [0.74, 1.43], respectively.

CONCLUSION

Significant predictors of acromegaly remission after neurosurgical treatment were age, preoperative level of growth hormone, tumor size and location, growth hormone and IGF-1 index in early postoperative period and residual tumor after surgery. Multivariate analysis revealed a significant association of acromegaly remission with small tumor size, low postoperative level of growth hormone and no residual tumor within 3-6 month after surgery.

The value of intraoperative MRI for resection of functional pituitary adenomas-a critical assessment of a consecutive single-center series of 114 cases

This series sought to evaluate the role of intraoperative MRI (iMRI) for resection of functional pituitary adenomas (FPAs). We retrospectively reviewed clinical data of 114 consecutive FPAs with excessive hormone secretion treated with transsphenoidal surgery and iMRI during 01/2010–12/2017. We focused on iMRI findings, extend of resection and postoperative hormonal remission. Variables of incomplete resections and persistent hormone excess were evaluated by binary regression. Patients with FPAs presented with hypercortisolism (n = 23, 20%), acromegaly (n = 56, 49%), and as prolactinomas (n = 35, 31%) resistant to medical treatment. Preoperative MRI showed 81 macroadenomas (71%) and optic system involvement in 41 cases (36%). IMRI was suggestive for residual tumor in 51 cases (45%). Re-inspection of the cavity cleared equivocal findings in 16 cases (14%). Additional tumor was removed in 22 cases (19%). Complete resection was achieved in 95 cases (83%). Postoperative morbidity was low (1.7% revision surgeries, 0.8% permanent diabetes insipidus). Overall hormonal remission-rate was 59% (hypercortisolism 78%, acromegaly 52%, prolactinoma 57%). Supra- and parasellar invasion and preoperative visual impairment were significant predictors for incomplete resections despite use of iMRI. Risk for persistent hormone excess was increased sevenfold after incomplete resections. IMRI enabled reliable identification of tumor remnants during surgery and triggered further resection in a considerable proportion of cases. Nevertheless, tumor size and invasiveness set persistent boundaries to the completeness of resections. The low rate of surgical complications could point at a less invasive iMRI-guided surgical approach while achieving a complete tumor resection was a crucial determinant for hormonal outcome.

Implications of Heterogeneity of Epithelial-Mesenchymal States in Acromegaly Therapeutic Pharmacologic Response

Acromegaly is caused by excess growth hormone (GH) produced by a pituitary tumor. First-generation somatostatin receptor ligands (SRLs) are the first-line treatment. Several studies have linked E-cadherin loss and epithelial-mesenchymal transition (EMT) with resistance to SRLs. Our aim was to study EMT and its relationship with SRLs resistance in GH-producing tumors. We analyzed the expression of EMT-related genes by RT-qPCR in 57 tumors. The postsurgical response to SRLs was categorized as complete response, partial response, or nonresponse if IGF-1 was normal, had decreased more than 30% without normalization, or neither of those, respectively. Most tumors showed a hybrid and variable EMT expression profile not specifically associated with SRL response instead of a defined epithelial or mesenchymal phenotype. However, high SNAI1 expression was related to invasive and SRL-nonresponsive tumors. RORC was overexpressed in tumors treated with SRLs before surgery, and this increased expression was more prominent in those cases that normalized postsurgical IGF-1 levels under SRL treatment. In conclusion, GH-producing tumors showed a heterogeneous expression pattern of EMT-related genes that would partly explain the heterogeneous response to SRLs. SNAI1 and RORC may be useful to predict response to SRLs and help medical treatment decision making.

Diagnosis and Treatment of Acromegaly: An Update

Acromegaly is typically caused by a growth hormone-secreting pituitary adenoma, driving excess secretion of insulin-like growth factor 1. Acromegaly may result in a variety of cardiovascular, respiratory, endocrine, metabolic, musculoskeletal, and neoplastic comorbidities. Early diagnosis and adequate treatment are essential to mitigate excess mortality associated with acromegaly. PubMed searches were conducted using the keywords growth hormone, acromegaly, pituitary adenoma, diagnosis, treatment, pituitary surgery, medical therapy, and radiation therapy (between 1981 and 2021). The diagnosis of acromegaly is confirmed on biochemical grounds, including elevated serum insulin-like growth factor 1 and lack of growth hormone suppression after glucose administration. Pituitary magnetic resonance imaging is advised in patients with acromegaly to identify an underlying pituitary adenoma. Transsphenoidal pituitary surgery is generally first-line therapy for patients with acromegaly. However, patients with larger and invasive tumors (macroadenomas) are often not in remission postoperatively. Medical therapies, including somatostatin receptor ligands, cabergoline, and pegvisomant, can be recommended to patients with persistent disease after surgery. Select patients may also be candidates for preoperative medical therapy. In addition, primary medical therapy has a role for patients without mass effect on the optic chiasm who are unlikely to be cured by surgery. Clinical, endocrine, imaging, histologic, and molecular markers may help predict the response to medical therapy; however, confirmation in prospective studies is needed. Radiation therapy is usually a third-line option and is increasingly administered by a variety of stereotactic techniques. An improved understanding of the pathogenesis of acromegaly may ultimately lead to the design of novel, efficacious therapies for this serious condition.

Machine learning-based clinical outcome prediction in surgery for acromegaly

PURPOSE

Biochemical remission (BR), gross total resection (GTR), and intraoperative cerebrospinal fluid (CSF) leaks are important metrics in transsphenoidal surgery for acromegaly, and prediction of their likelihood using machine learning would be clinically advantageous. We aim to develop and externally validate clinical prediction models for outcomes after transsphenoidal surgery for acromegaly.

METHODS

Using data from two registries, we develop and externally validate machine learning models for GTR, BR, and CSF leaks after endoscopic transsphenoidal surgery in acromegalic patients. For the model development a registry from Bologna, Italy was used. External validation was then performed using data from Zurich, Switzerland. Gender, age, prior surgery, as well as Hardy and Knosp classification were used as input features. Discrimination and calibration metrics were assessed.

RESULTS

The derivation cohort consisted of 307 patients (43.3% male; mean [SD] age, 47.2 [12.7] years). GTR was achieved in 226 (73.6%) and BR in 245 (79.8%) patients. In the external validation cohort with 46 patients, 31 (75.6%) achieved GTR and 31 (77.5%) achieved BR. Area under the curve (AUC) at external validation was 0.75 (95% confidence interval: 0.59-0.88) for GTR, 0.63 (0.40-0.82) for BR, as well as 0.77 (0.62-0.91) for intraoperative CSF leaks. While prior surgery was the most important variable for prediction of GTR, age, and Hardy grading contributed most to the predictions of BR and CSF leaks, respectively.

CONCLUSIONS

Gross total resection, biochemical remission, and CSF leaks remain hard to predict, but machine learning offers potential in helping to tailor surgical therapy. We demonstrate the feasibility of developing and externally validating clinical prediction models for these outcomes after surgery for acromegaly and lay the groundwork for development of a multicenter model with more robust generalization.

Surgery for acromegaly: Indications and goals

Acromegaly is a disease that occurs secondary to high levels of GH, most often from a hormone-secreting pituitary adenoma, with multisystem adverse effects. Diagnosis includes serum GH and IGF-1 levels, and obtaining an MRI pituitary protocol to assess for a functional pituitary adenoma. Attempted gross total resection of the GH-secreting adenoma is the gold standard in treatment for patients with acromegaly for a goal of biochemical remission. Medical and radiation therapies are available when patients do not achieve biochemical cure after surgical therapy.

Predicting Subtype of Growth Hormone Pituitary Adenoma based on Magnetic Resonance Imaging Characteristics

Supplemental digital content is available in the text.

This study aimed to investigate the value of magnetic resonance (MR) characteristics in differentiating the subtypes of growth hormone pituitary adenomas.

Pharmacological and safety profile of a prolonged-release lanreotide formulation in acromegaly

BACKGROUND

Patients with acromegaly require lifelong medication; a longer dosing interval would reduce treatment burden. This study investigated the pharmacokinetics, pharmacodynamics and safety profile of a new prolonged-release formulation (PRF) of lanreotide every 12 weeks.

RESEARCH DESIGN AND METHODS

In this multicenter, open-label, dose-ascending study, cohorts of nine patients with acromegaly received single doses of lanreotide PRF according to a 3 + 3 + 3 scheme in order to determine the maximum tolerated dose (MTD). Following a 12-week treatment period, patients were followed up for a further 12 weeks. Serum lanreotide, insulin-like growth factor-1 and growth hormone concentrations were analyzed. Adverse events were monitored throughout the study.

RESULTS

The MTD was not reached. Peak lanreotide serum concentration values were similar in all cohorts, whereas area under the curve values from time zero to 85 days increased but were not dose-proportional. The apparent elimination half-life of lanreotide PRF was approximately 54-63 days, in line with the expected prolonged-release characteristics. Growth hormone and insulin-like growth factor-1 levels were generally stable.

CONCLUSIONS

The safety and tolerability profile was in-line with the known safety profile of lanreotide autogel. Lanreotide PRF was well tolerated and the pharmacokinetic profile suggests that a dosing interval of 12 weeks could be achievable.

CLINICAL TRIAL REGISTRATION

www.clinicaltrials.gov identifier is NCT02396953; EudraCT 2014-002389-62.

Usefulness of the Texture Signatures Based on Multiparametric MRI in Predicting Growth Hormone Pituitary Adenoma Subtypes

Objective

To explore the usefulness of texture signatures based on multiparametric magnetic resonance imaging (MRI) in predicting the subtypes of growth hormone (GH) pituitary adenoma (PA).

Methods

Forty-nine patients with GH-secreting PA confirmed by the pathological analysis were included in this retrospective study. Texture parameters based on T1-, T2-, and contrast-enhanced T1-weighted images (T1C) were extracted and compared for differences between densely granulated (DG) and sparsely granulated (SG) somatotroph adenoma by using two segmentation methods [region of interest 1 (ROI₁), excluding the cystic/necrotic portion, and ROI₂, containing the whole tumor]. Receiver operating characteristic (ROC) curve analysis was performed to determine the differentiating efficacy.

Results

Among 49 included patients, 24 were DG and 25 were SG adenomas. Nine optimal texture features with significant differences between two groups were obtained from ROI₁. Based on the ROC analyses, T1WI signatures from ROI₁ achieved the highest diagnostic efficacy with an AUC of 0.918, the accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 85.7, 72.0, 100.0, 100.0, and 77.4%, respectively, for differentiating DG from SG. Comparing with the T1WI signature, the T1C signature obtained relatively high efficacy with an AUC of 0.893. When combining the texture features of T1WI and T1C, the radiomics signature also had a good performance in differentiating the two groups with an AUC of 0.908. In addition, the performance got in all the signatures from ROI₂ was lower than those in the corresponding signature from ROI_1.

Conclusion

Texture signatures based on MR images may be useful biomarkers to differentiate subtypes of GH-secreting PA patients.

Molecular determinants of enhanced response to somatostatin receptor ligands after debulking in large GH-producing adenomas

OBJECTIVE

Large somatotrophic adenomas depict poor response to somatostatin receptor ligands (SRLs). Debulking has shown to enhance SRLs effect in some but not all cases and tumour volume reduction has been proposed as the main predictor of response. No biological studies have been performed so far in this matter. We aimed to identify molecular markers of response to SRLs after surgical debulking in GH-secreting adenomas.

DESIGN

We performed a multicenter retrospective study.

PATIENTS

24 patients bearing large GH-producing tumours.

MEASUREMENTS

Clinical data and SRLs response both before and after surgical debulking were collected, and 21 molecular biomarkers of SRLs response were studied in tumour samples by gene expression.

RESULTS

From the 21 molecular markers studied, only two of them predicted enhanced SRLs response after surgery. Tumours with improved response to SRLs after surgical debulking showed lower levels of Ki-67 (MKI67, FC = 0.17 and P = .008) and higher levels of RAR-related orphan receptor C (RORC) (FC = 3.1 and P ˂ .001). When a cut-off of no detectable expression was used for Ki-67, the model provided a sensitivity of 100% and a specificity of 52.6% with an area under the curve of 65.8%. Using a cut-off of 2 units of relative expression of RORC, the prediction model showed 100% of sensitivity and specificity.

CONCLUSIONS

High levels of RORC and low levels of Ki-67 identify improved SRLs response after surgical debulking in large somatotropic adenomas. To determine their expression would facilitate medical treatment decision-making after surgery.

Pharmacological Acromegaly Treatment: Cost-Utility and Value of Information Analysis

OBJECTIVES

To conduct a cost-utility analysis comparing drug strategies involving octreotide, lanreotide, pasireotide, and pegvisomant for the treatment of patients with acromegaly who have failed surgery, from a Brazilian public payer perspective.

METHODS

A probabilistic cohort Markov model was developed. One-year cycles were employed. The patients started at 45 years of age and were followed lifelong. Costs, efficacy, and quality of life parameters were retrieved from the literature. A discount rate (5%) was applied to both costs and efficacy. The results were reported as costs per quality-adjusted life year (QALY), and incremental cost-effectiveness ratios (ICERs) were calculated when applicable. Scenario analyses considered alternative dosages, discount rate, tax exemption, and continued use of treatment despite lack of response. Value of information (VOI) analysis was conducted to explore uncertainty and to estimate the costs to be spent in future research.

RESULTS

Only lanreotide showed an ICER reasonable for having its use considered in clinical practice (R$ 112,138/US$ 28,389 per QALY compared to no treatment). Scenario analyses corroborated the base-case result. VOI analysis showed that much uncertainty surrounds the parameters, and future clinical research should cost less than R$ 43,230,000/US$ 10,944,304 per year. VOI also showed that almost all uncertainty that precludes an optimal strategy choice involves quality of life.

CONCLUSIONS

With current information, the only strategy that can be considered cost-effective in Brazil is lanreotide treatment. No second-line treatment is recommended. Significant uncertainty of parameters impairs optimal decision-making, and this conclusion can be generalized to other countries. Future research should focus on acquiring utility data.

A single-center observational study assessing the predictive factors associated with the prognosis of acromegaly

AIM

The aim of this study was to clarify the prognostic values of various preoperative factors, including the surgeon's ability as well as the patient's age, gender, tumor size, cavernous sinus invasion, compression of the optic chiasm, hypopituitarism, immunohistochemical (IHC) staining pattern of the adenoma, and insulin-like growth factor-1 (IGF-1) level, in acromegalic patients who had undergone pituitary surgery.

STUDY DESIGN

This single-center, retrospective study assessed the medical records of 108 patients who had undergone pituitary surgery with the same neurosurgical team.

RESULTS

The mean total follow-up period after surgery was 44.8 (min: 24, max: 59) months. Remission was reported in 67 (62.0%) patients, and 57 (52.8%) patients did not experience recurrence. Initial tumor volume, IGF-1 level, and optic chiasm compression, but not patients' age, gender, cavernous sinus invasion, and IHC staining patterns of the adenoma, were prognostic of either remission or recurrence. An IGF-1 level of 860 ng/mLwas found to be a convenient cut-off point for determining remission.

CONCLUSIONS

The experience of the surgical team suggests that the initial tumor volume, IGF-1 level, and optic chiasm compression have high prognostic values in relation to pituitary surgery for patients with acromegaly.

miR-34a is upregulated in AIP-mutated somatotropinomas and promotes octreotide resistance

Pituitary adenomas (PAs) are intracranial tumors associated with significant morbidity due to hormonal dysregulation, mass effects and have a heavy treatment burden. Growth hormone (GH)-secreting PAs (somatotropinomas) cause acromegaly-gigantism. Genetic forms of somatotropinomas due to germline AIP mutations (AIPmut+) have an early onset and are aggressive and resistant to treatment with somatostatin analogs (SSAs), including octreotide. The molecular underpinnings of these clinical features remain unclear. We investigated the role of miRNA dysregulation in AIPmut+ vs AIPmut- PA samples by array analysis. miR-34a and miR-145 were highly expressed in AIPmut+ vs AIPmut- somatotropinomas. Ectopic expression of AIPmut (p.R271W) in Aip^-/- mouse embryonic fibroblasts (MEFs) upregulated miR-34a and miR-145, establishing a causal link between AIPmut and miRNA expression. In PA cells (GH3), miR-34a overexpression promoted proliferation, clonogenicity, migration and suppressed apoptosis, whereas miR-145 moderately affected proliferation and apoptosis. Moreover, high miR-34a expression increased intracellular cAMP, a critical mitogenic factor in PAs. Crucially, high miR-34a expression significantly blunted octreotide-mediated GH inhibition and antiproliferative effects. miR-34a directly targets Gnai2 encoding Gαi2, a G protein subunit inhibiting cAMP production. Accordingly, Gαi2 levels were significantly lower in AIPmut+ vs AIPmut- PA. Taken together, somatotropinomas with AIP mutations overexpress miR-34a, which in turn downregulates Gαi2 expression, increases cAMP concentration and ultimately promotes cell growth. Upregulation of miR-34a also impairs the hormonal and antiproliferative response of PA cells to octreotide. Thus, miR-34a is a novel downstream target of mutant AIP that promotes a cellular phenotype mirroring the aggressive clinical features of AIPmut+ acromegaly.

Normal Insulin-like Growth Factor 1 During Somatostatin Receptor Ligand Treatment Predicts Surgical Cure in Acromegaly

CONTEXT

Treatment with somatostatin receptor ligands (SRLs) is often given before pituitary surgery to patients with acromegaly.

OBJECTIVE

To study whether the response to treatment with SRLs is predictive of surgical outcome.

DESIGN

Retrospective, observational study.

SETTING

Tertiary care center.

PATIENTS

We investigated 272 patients with acromegaly who had been treated with an SRL between 1990 and 2018.

INTERVENTION

All patients underwent pituitary surgery performed by a skilled neurosurgeon.

MAIN OUTCOME MEASURE

Outcome of pituitary surgery in patients who had normalization of insulin-like growth factor 1 (IGF-1) levels during SRL therapy in comparison with patients who did not normalize IGF-1 levels.

RESULTS

Normalization of IGF-1 levels during SRL treatment occurred in 62 patients (22.8%) and was similar for the 3 different types of SRL (P = .88). Surgical remission occurred in 59.6% of the patients. Patients who normalized IGF-1 levels during SRL treatment had a higher probability of surgical cure than patients without IGF-1 normalization (83.9% vs 52.4%, respectively; P < .001). Multivariate analysis confirmed that lack of cavernous sinus invasion, small maximum tumor diameter, and IGF-1 normalization during SRL therapy were the only factors independently associated with a favorable surgical outcome.

CONCLUSIONS

Our study demonstrates that the normalization of IGF-1 levels during treatment with SRLs is an independent predictive factor of a favorable surgical outcome. The underlying mechanisms remain unclear, but an optimal response to medical therapy may be a characteristic of less aggressive tumors that are more likely to be entirely removed at surgery.

Endoscopic Surgery for Pituitary Tumors

Endoscopic transsphenoidal surgery for pituitary adenoma is a safe and highly effective first-line treatment that is well tolerated by patients. Potential complications are plenty, and there is a large variation in complexity of surgery. This article presents the philosophy, surgical techniques, and outcomes of a high-volume pituitary adenoma center. Three surgical videos illustrate some procedures. The experience has reinforced the authors' belief that experience and surgical volume are key to high quality of care.

Long-term real-life outcomes in a georrefered cohort of acromegalic patients in Brazil

PURPOSE

Epidemiological data on acromegaly therapeutic outcomes in real-life conditions are scarce in Brazil. Information on the geographical accessibility to the dispensation of medicines and its impact on biochemical control is also poorly known. We aimed to describe the clinical outcomes of long-term therapy in patients with acromegaly at a referral medical centre in Brazil and to perform a spatial analysis of patients according to the distance from home to the drug-dispensing pharmacies aiming to evaluate its impact on biochemical control.

METHODS

Global retrospective data analysis of 111 patients followed at the University Hospital of Brasília from January 1980 to March 2015 was performed, as well as a separate review of 17 new cases operated on from April 2015 to June 2019 according to surgery results. Spatial analysis of patients under pharmacological treatment applying Geographic Information System (GIS) software (ArcGIS, ESRI, Redlands, CA) was performed.

RESULTS

Considering surgery alone, the cure rate was 23% from 1980 to 2015 and 29.4% from 2015 to 2019. In the long-term follow-up of the 111 patients from 1980 to 2015, 25.2% (n = 29) were cured, 40.6% (n = 44) presented controlled disease and 34.2% (n = 38) were biochemically uncontrolled after a period of follow-up of 8.9 ± 6.4 years. Biochemical control obtained in patients on pharmacological treatment (n = 76) was 58% (n = 44) after 5.8 ± 3.8 years. The distance from home to the drug-dispensing pharmacy did not influence biochemical control (p = 0.7616).

CONCLUSIONS

Most patients presented with disease under control. No evidence on the effect of the distance between home and drug-dispensing pharmacies on biochemical control was obtained.

Patient Characteristics, Diagnostic Delays, Treatment Patterns, Treatment Outcomes, Comorbidities, and Treatment Costs of Acromegaly in China: A Nationwide Study

PURPOSE

Acromegaly is a rare, intractable endocrine disease. We aimed to describe the patient characteristics, diagnostic delays, treatment patterns, treatment outcomes, comorbidities and treatment costs of acromegaly in China.

METHODS

This is a nationwide cross-sectional study. Patients diagnosed with and treated for acromegaly between 1996 and 2019 across China were surveyed via the Chinese Association of Patients with Acromegaly platform.

RESULTS

In total, 473 patients (58.8% females, mean age at diagnosis: 39.4±9.5 years) were included. The median disease duration was 3 years. The most common symptoms were extremity enlargement (91.8%) and facial changes (90.1%). Overall, 63.0% of patients experienced diagnostic delays within healthcare systems; 63.8% of the delays were <1 year. The most common first-line therapy was surgery with a transsphenoidal (76.1%) or transcranial approach (3.2%). Somatostatin analogues or dopamine agonists were administered in 20.5% of the patients as first-line therapies and in 41.7% as adjuvant therapies. Radiotherapy was performed in 32.1% of patients, 99.3% of whom received radiotherapy as an adjuvant therapy. After a median 5-year follow-up, 46.2% achieved biochemical control. Comorbidities were reported in 88.2% of the patients at follow-up; memory deterioration and thyroid nodules were the most common. Controlled patients had greater improvements in symptoms and comorbidities during follow-up than uncontrolled patients. The annual per-capita cost-of-treatment was $11013 in 2018, with medical treatments being the largest contributor (67%). Medical insurance covered 47.2% of all treatment costs.

CONCLUSION

This study provides the first comprehensive description of real-world acromegaly data in China, serving as a basis for future population-based studies.

Reversibility of Cardiac Involvement in Acromegaly Patients After Surgery: 12-Month Follow-up Using Cardiovascular Magnetic Resonance

PURPOSE

Cardiac comorbidity is one of the leading causes of death among acromegaly patients. We aimed to investigate the reversibility of acromegalic cardiac involvement after surgical treatment using the gold standard method, cardiovascular magnetic resonance, and to explore the effects of endocrine remission and gender on reversibility.

METHODS

In this single-center, prospective cohort study, fifty untreated acromegaly patients were enrolled. Comprehensive cardiac assessments were performed using a 3.0 T magnetic resonance scanner before and 3 and 12 months after transsphenoidal adenomectomy.

RESULTS

Preoperatively, left ventricular (LV) enlargement (13.0%), LV systolic dysfunction (6.5%), right ventricular (RV) enlargement (4.3%), RV systolic dysfunction (2.2%) and myocardial fibrosis (12.0%) were identified. On average, the LV and RV ejection fractions of acromegaly patients were higher than the healthy reference values. Male patients had thicker LV myocardia, wider ventricular diameters and more dilated pulmonary artery roots than female patients. After surgery, LV myocardial hypertrophy was reversed, the left atrium was remodeled, and ventricular systolic dysfunction recovered to normal. Cardiac alterations were detected early in the 3^rd postoperative month and persisted until the 12^th month. The interventricular septum was initially thickened in the 3^rd postoperative month and then recovered at the 12th month. Notable postoperative cardiac reversibility was observed in male patients but did not occur in all female patients. Patients achieving endocrine remission with normalized hormone levels had thinner LV myocardia than patients without normalized hormone levels.

CONCLUSION

Our findings demonstrated that some of the cardiac involvement in acromegaly patients is reversible after surgical treatment which lowers hormone levels. Endocrine remission and gender significantly impacted postoperative cardiac reversibility.

Economics of Acromegaly Treatment in Brazil: A Budget Impact Analysis of Pituitary Surgery Compared with Long-Term Octreotide LAR

BACKGROUND

Acromegaly is a rare, chronic and debilitating disease whose treatment places a high burden on health systems. In the reality of the Brazilian public health network, many patients are kept on drug treatment because of barriers to access to surgery.

OBJECTIVE

The aim of this study was to estimate the costs and budget impact of routine transsphenoidal endoscopic surgery in relation to those of long-term drug treatment with octreotide long-acting release (LAR) from a cohort of patients followed at the referral medical centre for acromegaly treatment in the Federal District, Brazil.

METHODS

Based on micro-costing data collected using mixed methods from a local perspective of the public health system, we performed a budget impact analysis (BIA) on a 3-year time horizon. Uncertainty was handled with deterministic (tornado and scenario) and probabilistic (Monte Carlo simulations) sensitivity analyses.

RESULTS

Compared with the continued use of octreotide LAR at a dose of 30 mg every 28 days, the incremental budget impact of conducting two surgeries per month, considering a cure rate of 55%, could bring savings of approximately US$879,362.18 (95% CI 860,176.29-898,548.08) over 3 years. Depending on the key variable values, the savings amplitude ranged from US$431,836.39 to US$1,519,132.04.

CONCLUSIONS

Improving access to surgery could result in significant cost reductions in acromegaly treatment. The present study stands out for being the first to estimate the costs of transsphenoidal surgery in the context of the public health system in Brazil.

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.

Predictors of surgical outcome and early criteria of remission in acromegaly

BACKGROUND

Transsphenoidal surgery (TSS) is the cornerstone of acromegaly treatment, however there are no robust predictors of surgical outcome and remission can only be defined three months after surgery.

PURPOSE

To analyze if biochemical, demographical, radiological, and immunohistochemical characteristics are predictors of surgical remission and investigate if immediate postoperative GH and IGF-I levels can help defining remission earlier.

METHODS

Consecutive acromegaly patients submitted to TSS between 2013-2016 were evaluated. Remission criteria was defined as normal IGF-I and GH <1 mcg/L three months after surgery. Data of age, sex, GH and IGF-I levels, tumor volume, cavernous sinus invasion, T2-weighted signal, Ki-67, and granulation pattern were correlated with remission status. GH and IGF-I levels at 24, 48 h, and one week postoperative were evaluated as early criteria of remission.

RESULTS

Sixty-nine patients were included (84% macroadenomas) and surgical remission was achieved in 45%. No difference between cured and not cured patients concerning age, gender, preoperative GH or IGF-I levels, tumor volume, T2-weighted signal, Ki-67 and tumor granularity was observed. Remission was obtained in 20 of 36 (56%) of the non-invasive tumors, and in 3 of 16 (19%) of the invasive tumors (p = 0.017). A GH <1.57 mcg/L 48 h after surgery was able to predict remission with 93% sensitivity and 86% specificity and an IGF-I < 231% ULNR one week after surgery predicted remission with 86% sensitivity and 93% specificity.

CONCLUSION

Cavernous sinus invasion is the only preoperative predictor of surgical remission. GH at 48 h and IGF-I one week after surgery can define earlier not cured patients.

Quantification of specific growth patterns and frequency of the empty sella phenomenon in growth hormone-secreting pituitary adenomas

PURPOSE

To assess and quantify the prevalence and co-occurence of a sellar floor lowering and empty sella phenomenon in patients with GH (growth hormone)-secreting pituitary adenoma.

METHODS

A total number of 159 acromegalic patients were included in this study, as well as two control groups (150 patients with non-GH-secreting adenomas and 50 patients without pituitary adenomas). Magnetic resonance images of all patients were evaluated for presence of an empty sella, downward and lateral tumor extension, and maximum superoinferior diameter of the mass. Additionally, these values were correlated with growth hormone and IGF-1 levels.

RESULTS

The empty sella phenomenon was detected significantly more often in patients with a GH-secreting adenoma with a prevalence of 22% vs. 5.3% in non-GH-secreting adenomas (p < 0.001) or 8% in the healthy control group (p = .036). Moreover, GH-secreting adenomas presented with a significant rate of downward tumor extension (74.8% vs. 35.5%; p < 0.001), whose extent correlated inversely but weakly with the GH hormone level (r = - 0.17; p = .036). It was also found that a decreased superoinferior diameter and higher ratio of intrasellar to suprasellar extension are predictive quantitative values for the presence of a GH-secreting adenoma (area under curve, 0.712).

CONCLUSIONS

GH-secreting pituitary adenomas are frequently associated with an empty sella phenomenon. Moreover, GH-secreting adenomas are frequently accompanied by an enhanced, quantitatively measurable impression of the sellar floor. Hypothetically, this is caused by tumor-induced local bone remodeling processes.

Trends in surgery, hospital admissions and imaging for pituitary adenomas in Australia

PURPOSE

There is a paucity of epidemiological information on treatment and imaging of pituitary adenomas in Australia.

METHODS

Australian data on pituitary surgery, hospital admissions for pituitary adenomas, and pituitary imaging on patients 15 years and over were obtained from administrative databases between 2000/2001 and 2014/2015. Changes over time and by age and sex were assessed.

RESULTS

In 2014/15 there were 37.7 pituitary procedures/million population, corresponding to a 35.4% (p < 0.05) increase over the 2000/2001 rate. Overall, most (87.2%) procedures were partial excisions of pituitary gland via transsphenoidal surgery (TSS). Admissions for acromegaly increased from 7.1/million in 2000/2001 to 17.2/million in 2003/2004 and then decreased to 6.5/million in 2014/2015. The average age-adjusted rate of pituitary imaging over the study period was 689.6/million/year, which increased significantly (p < 0.05). There was a significant increase in pituitary MRIs (p < 0.05) and a significant decline in pituitary CTs (p < 0.05). Surgical procedure rates were correlated with the pituitary imaging rates (r = 0.62, p < 0.05).

CONCLUSION

Pituitary surgery rates increased between 2000/2001 and 2014/2015. The most common procedure was partial excision of the pituitary gland via TSS. Admissions for pituitary neoplasms increased over the study while admissions for acromegaly rose to their highest rate in 2003/2004 and then decreased. There was a substantial increase in the rate of pituitary imaging, which may have resulted in increased detection of pituitary incidentalomas. The underlying reasons for the increased rate of pituitary surgery, and the non-sustained increased rate of admissions for acromegaly are unclear and warrant further investigation.

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.

Biochemical investigations in diagnosis and follow up of acromegaly

Measurements of human growth hormone (GH) and insulin-like growth-factor I (IGF-I) are cornerstones in the diagnosis of acromegaly. Both hormones are also used as biochemical markers in the evaluation of disease activity during treatment. Management of acromegaly is particularly challenging in cases where discordant information is obtained from measurement of GH concentrations following oral glucose load and from measurement of IGF-I. While in some patients biological factors can explain the discrepancy, in many cases issues with the analytical methods seem to be responsible. Assays used by endocrine laboratories to determine concentrations of GH and IGF-I underwent significant changes during the last decades. While generally leading to more sensitive and reproducible methods, these changes also had considerable impact on absolute concentrations measured. This must be reflected by updated decision limits, cut-offs and reference intervals. Since different commercially available assays do not agree very well, method specific interpretation of GH and IGF-I concentrations is required. This complexity in the interpretation of hormone concentrations is not always appropriately reflected in laboratory reports, but also not in clinical guidelines reporting decision limits not related to a specific analytical method. The present review provides an overview about methodological and biological variables affecting the biochemical assessment of acromegaly in diagnosis and follow up.