Preoperative octreotide treatment in newly diagnosed acromegalic patients with macroadenomas increases cure short-term postoperative rates: a prospective, randomized trial

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.

Oral Octreotide Capsules and Paltusotine in Management of Acromegaly

Injectable somatostatin receptor ligands (iSRL) are the most frequently utilized medical therapy in patients with acromegaly; however, satisfaction rates are suboptimal. Injections can result in local erythema, discomfort and subcutaneous nodule formation, encompassed with the inconvenience of attending either primary or secondary care medical facilities for injections every 4 weeks. Some patients also note breakthrough of acromegaly-related symptoms towards the end of the injection cycle. To improve acceptance and ultimately improve wellbeing of these individuals, two oral SRLs, oral octreotide capsules (OOC) and paltusotine, have been developed. The OOC combines an enteric coating to allow delivery to the small intestines and a transient permeability enhancer to enable oral bioavailability. Comparable octreotide levels are obtained with twice-daily OOC and subcutaneous octreotide 100 µg. Phase III studies show OOC to maintain equivalent biochemical control in at least 60% of patients previously receiving a stable dose of iSRL. In longer-term studies, the response to OOC was durable up to 3 years. Paltusotine is a novel potent orally available non-peptidyl somatostatin receptor subtype-2 ligand. Studies in healthy volunteers show dose-dependent suppression of growth hormone-releasing hormone-induced growth hormone secretion and suppression of insulin-like growth factor-I (IGF-I) with repeat doses. In the recent phase II study, patients with acromegaly who were partial responders (IGF-I 1.0 - 2.5 x upper limit of normal) to monotherapy with iSRL when switched to once-daily paltusotine maintained control of IGF-I within 20% of baseline or lower in 87% after 13 weeks. Adverse events with both OOC and paltusotine were reflective of those recognized with iSRL and occurred at a similar frequency. OOC and paltusotine are well-received additions to the therapeutic armamentarium in medical therapy for the management of acromegaly; however, further data on efficacy, tumour control and shrinkage are required to allow positioning of this medication within the management algorithm for acromegaly.

Long-term pasireotide therapy in acromegaly: extensive real-life experience of a referral center

PURPOSE

Pasireotide is a novel therapeutic option for patients with acromegaly resistant to first-generation somatostatin receptor ligands. To date, real-life data are still scant, therefore, the aim of the current study is to evaluate the impact of long-term pasireotide therapy on disease control, pituitary tumor size, gluco-insulinemic and lipid profile in a real-life setting.

METHODS

Retrospective study of data prospectively collected, evaluating hormonal, tumoral, and metabolic data of 28 patients with acromegaly administered with pasireotide in a pituitary tertiary referral center.

RESULTS

Within the first 12 months of treatment, 70.4% of patients achieved normal IGF-I levels, which was maintained at 36-month evaluation in these responders patients. Patients who started with pasireotide 60 mg monthly exhibited significantly lower IGF-I levels after 36 months (p = 0.05) as compared to patients administered first with pasireotide 20 or 40 mg monthly. The maximal tumoral diameter was significantly decreased after 12 months of pasireotide (p < 0.001) and a further reduction was registered throughout the following months, with 41.2% of patients achieving a significant reduction (> 25% of baseline measurement) after 36 months of treatment. Fasting glucose significantly increased during the first 6 months (p < 0.001) with a gradual rise in diabetes prevalence during the following months, resulting diabetes prevalence after 36 months of pasireotide significantly increased compared to baseline (p = 0.003), although with glycated hemoglobin levels within the normal range. Diabetes was managed using oral glucose-lowering drugs or glucagon-like peptide 1 agonists, with no patient requiring insulin therapy. Pasireotide improved lipid profile, mainly during the first 12 months of treatment, by increasing HDL and decreasing triglycerides levels.

CONCLUSION

Pasireotide is effective and safe in the long-term. Hyperglycemia is a common event and is manageable even without insulin treatment.

The changing landscape of acromegaly - an epidemiological perspective

Acromegaly is a rare disease and thus challenging to accurately quantify epidemiologically. In this comprehensive literature review, we compare different approaches to studying acromegaly from an epidemiological perspective and describe the temporal evolution of the disease pertaining to epidemiological variables, clinical presentation and mortality. We present updated epidemiological data from the population-based Danish cohort of patients with acromegaly (AcroDEN), along with meta-analyses of existing estimates from around the world.Based on this, we conclude that the incidence, prevalence and age at acromegaly diagnosis are all steadily increasing, but with considerable variation between studies. An increased number of incidental cases may contribute to the increase in incidence and age at diagnosis, respectively. The clinical features at presentation are trending toward a milder disease phenotype at diagnosis, and advances in therapeutic options have reduced the mortality of patients with acromegaly to a level similar to that of the general population. Moreover, the underlying cause of death has shifted from cardiovascular to malignant neoplastic diseases.

Surgical and non-surgical interventions for primary and salvage treatment of growth hormone-secreting pituitary adenomas in adults

BACKGROUND

Growth hormone (GH)-secreting pituitary adenoma is a severe endocrine disease. Surgery is the currently recommended primary therapy for patients with GH-secreting tumours. However, non-surgical therapy (pharmacological therapy and radiation therapy) may be performed as primary therapy or may improve surgical outcomes.

OBJECTIVES

To assess the effects of surgical and non-surgical interventions for primary and salvage treatment of GH-secreting pituitary adenomas in adults.

SEARCH METHODS

We searched CENTRAL, MEDLINE, WHO ICTRP, and ClinicalTrials.gov. The date of the last search of all databases was 1 August 2022. We did not apply any language restrictions.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs of more than 12 weeks' duration, reporting on surgical, pharmacological, radiation, and combination interventions for GH-secreting pituitary adenomas in any healthcare setting.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened titles and abstracts for relevance, screened for inclusion, completed data extraction, and performed a risk of bias assessment. We assessed studies for overall certainty of the evidence using GRADE. We estimated treatment effects using random-effects meta-analysis. We expressed results as risk ratios (RR) for dichotomous outcomes together with 95% confidence intervals (CI) or mean differences (MD) for continuous outcomes, or in descriptive format when meta-analysis was not possible.

MAIN RESULTS

We included eight RCTs that evaluated 445 adults with GH-secreting pituitary adenomas. Four studies reported that they included participants with macroadenomas, one study included a small number of participants with microadenomas. The remaining studies did not specify tumour subtypes. Studies evaluated surgical therapy alone, pharmacological therapy alone, or combination surgical and pharmacological therapy. Methodological quality varied, with many studies providing insufficient information to compare treatment strategies or accurately judge the risk of bias. We identified two main comparisons, surgery alone versus pharmacological therapy alone, and surgery alone versus pharmacological therapy and surgery combined. Surgical therapy alone versus pharmacological therapy alone Three studies with a total of 164 randomised participants investigated this comparison. Only one study narratively described hyperglycaemia as a disease-related complication. All three studies reported adverse events, yet only one study reported numbers separately for the intervention arms; none of the 11 participants were observed to develop gallbladder stones or sludge on ultrasonography following surgery, while five of 11 participants experienced any biliary problems following pharmacological therapy (RR 0.09, 95% CI 0.01 to 1.47; 1 study, 22 participants; very low-certainty evidence). Health-related quality of life was reported to improve similarly in both intervention arms during follow-up. Surgery alone compared to pharmacological therapy alone may slightly increase the biochemical remission rate from 12 weeks to one year after intervention, but the evidence is very uncertain; 36/78 participants in the surgery-alone group versus 15/66 in the pharmacological therapy group showed biochemical remission. The need for additional surgery or non-surgical therapy for recurrent or persistent disease was described for single study arms only. Surgical therapy alone versus preoperative pharmacological therapy and surgery Five studies with a total of 281 randomised participants provided data for this comparison. Preoperative pharmacological therapy and surgery may have little to no effect on the disease-related complication of a difficult intubation (requiring postponement of surgery) compared to surgery alone, but the evidence is very uncertain (RR 2.00, 95% CI 0.19 to 21.34; 1 study, 98 participants; very low-certainty evidence). Surgery alone may have little to no effect on (transient and persistent) adverse events when compared to preoperative pharmacological therapy and surgery, but again, the evidence is very uncertain (RR 1.23, 95% CI 0.75 to 2.03; 5 studies, 267 participants; very low-certainty evidence). Concerning biochemical remission, surgery alone compared to preoperative pharmacological therapy and surgery may not increase remission rates up until 16 weeks after surgery; 23 of 134 participants in the surgery-alone group versus 51 of 133 in the preoperative pharmacological therapy and surgery group showed biochemical remission. Furthermore, the very low-certainty evidence did not suggest benefit or detriment of preoperative pharmacological therapy and surgery compared to surgery alone for the outcomes 'requiring additional surgery' (RR 0.48, 95% CI 0.05 to 5.06; 1 study, 61 participants; very low-certainty evidence) or 'non-surgical therapy for recurrent or persistent disease' (RR 1.22, 95% CI 0.65 to 2.28; 2 studies, 100 participants; very low-certainty evidence). None of the included studies measured health-related quality of life. None of the eight included studies measured disease recurrence or socioeconomic effects. While three of the eight studies reported no deaths to have occurred, one study mentioned that overall, two participants had died within five years of the start of the study.

AUTHORS' CONCLUSIONS

Within the context of GH-secreting pituitary adenomas, patient-relevant outcomes, such as disease-related complications, adverse events and disease recurrence were not, or only sparsely, reported. When reported, we found that surgery may have little or no effect on the outcomes compared to the comparator treatment. The current evidence is limited by the small number of included studies, as well as the unclear risk of bias in most studies. The high uncertainty of evidence significantly limits the applicability of our findings to clinical practice. Detailed reporting on the burden of recurrent disease is an important knowledge gap to be evaluated in future research studies. It is also crucial that future studies in this area are designed to report on outcomes by tumour subtype (that is, macroadenomas versus microadenomas) so that future subgroup analyses can be conducted. More rigorous and larger studies, powered to address these research questions, are required to assess the merits of neoadjuvant pharmacological therapy or first-line pharmacotherapy.

A Novel Preoperative Score to Predict Long-Term Biochemical Remission in Patients with Growth-Hormone Secreting Pituitary Adenomas

OBJECTIVE

Transsphenoidal surgery (TSS) is considered the treatment of choice in most patients with growth hormone (GH)-secreting pituitary adenomas. Several preoperative factors have been studied to predict postsurgical remission. Our objective was to design a score that could be used in the preoperative setting to identify patients that will achieve long-term biochemical remission after TSS.

METHODS

A retrospective analysis of consecutive patients with GH-secreting pituitary adenomas that underwent TSS in our institution from 2000 to 2015 who fulfilled prespecified criteria were included. Logistic regression methods were used to evaluate independent preoperative variables predicting long-term remission. Beta coefficients were used to create a scoring system for clinical practice.

RESULTS

Sixty-eight patients were included, with a mean follow-up time of 87 months. Twenty (29%) patients had tumors with a Knosp grade ≥ 3A. Gross-total resection was achieved in 43 (63%) patients. Thirty-three (48%) patients had long-term biochemical remission after TSS. In a multivariate analysis, the following variables were statistically significantly associated with long-term biochemical remission: age, adenoma size (diameter), Knosp grade, GH level, and insulin growth-factor 1index 1 at diagnosis. A score of <3 out of 8 total points was identified as a cutoff associated with long-term remission, with a sensitivity of 91.4% and specificity of 72.7% (AUC 0.867, OR 28.44, 95% CI 6.94-116.47, P = < 0.001).

CONCLUSIONS

A novel, simple, easy-to-use scoring system was created to identify patients with the highest chances of long-term biochemical remission following TSS. This scale should be prospectively validated in a multicenter study before widespread adoption.

Newer parameters of the octreotide test in patients with acromegaly

PURPOSE

Predicting the therapeutic effects of first-generation somatostatin receptor ligands (fg-SRLs) is important when assessing or planning effective treatment strategies in patients with acromegaly. The oft-used maximum growth hormone (GH) suppression rate parameter of the octreotide test has a suboptimal predictive value. Therefore, this study explored newer parameters of the octreotide test for predicting the therapeutic effect of long-acting fg-SRLs.

METHODS

In this single-center retrospective study, the octreotide test parameters and the therapeutic effects of fg-SRL at 3 months were investigated in 45 consecutive treatment-naïve patients with acromegaly between April 2008 and March 2023. Additionally, the relationship between the octreotide test parameters and the therapeutic effects of fg-SRLs was investigated. Tumor shrinkage was evaluated based on changes in the longitudinal diameter of the macroadenomas. The area GH suppression rate-time under the curve (AUC) and the time to nadir GH level were calculated and compared with the maximum GH suppression rate.

RESULTS

The AUC estimated reductions in serum insulin-like growth factor I, and tumor shrinkage. The time to nadir GH level predicted tumor shrinkage more robustly than the maximum GH suppression rate in patients with macroadenoma.

CONCLUSION

The AUC and time to nadir GH level may potentially be newer parameters of the octreotide test for estimating the therapeutic effect of fg-SRLs.

Current role of pasireotide in the treatment of acromegaly

"First-generation" somatostatin receptor agonists (SSTRAs) octreotide and lanreotide are the most commonly used first-line pharmacological therapy for patients with acromegaly. A subset of patients respond only partially or not at all to the first-generation SSTRA, necessitating the use of additional pharmacological agents or other modes of therapy. Pasireotide is a "second-generation" SSTRA that has multi-receptor activity. Prospective studies have shown promise in the use of pasireotide in patients with poor response to first-generation SSTRA. Here we elucidate the molecular pathways of resistance to first-generation SSTRA, the mechanism of action, pre-clinical and clinical evidence of the use of pasireotide in patients having incomplete / lack of response to first-generation SSTRA. We also discuss the clinical, pathological, and radiological markers predicting response to pasireotide, and the difference in side-effect profiles of pasireotide, compared to first-generation SSTRA.

Long-term control of acromegaly after pituitary surgery in South-Eastern Norway

PURPOSE

Sustained cure of acromegaly can only be achieved by surgery. Most growth hormone (GH) secreting pituitary adenomas are macroadenomas (≥ 10 mm) at diagnosis, with reported surgical cure rates of approximately 50%. Long-term data on disease control rates after surgery are limited. Our aim was to estimate short- and long-term rates of biochemical control after pituitary surgery in acromegaly and identify predictive factors.

METHODS

Patients operated for GH-secreting pituitary adenomas between 2005-2020 were included from the local pituitary registry (n = 178). Disease activity and treatment data were recorded at one-year (short-term) and five-year (long-term) postoperative follow-up. Biochemical control was defined as insulin-like growth factor 1 (IGF-1) ≤ 1.2 × upper limit of normal value. Multivariate regression models were used to identify factors potentially predicting biochemical control.

RESULTS

A total of 178 patients with acromegaly (median age at diagnosis 49 (IQR: 38-59) years, 46% women) were operated for a pituitary adenoma. Biochemical control was achieved by surgery in 53% at short-term and 41% at long-term follow-up, without additional treatment for acromegaly. Biochemical control rates by surgery were of same magnitude in paired samples (45% vs. 41%, p = 0.213) for short- and long-term follow-up, respectively. At short-term, 62% of patients with microadenomas and 51% with macroadenomas, achieved biochemical control. At long-term, the biochemical control rate was 58% for microadenomas and 37% for macroadenomas (p = 0.058). With adjunctive treatment, 82% achieved biochemical control at long-term. Baseline IGF-1 levels significantly predicted biochemical control by surgery at short-term (OR: 0.98 (95% CI: 0.96-0.99), p = 0.011), but not at long-term (OR: 0.76 (95% CI: 0.57-1.00), p = 0.053).

CONCLUSION

In unselected patients with acromegaly, the long-term biochemical control rate remains modest. Our findings indicate a need to identify patients at an earlier stage and improve therapeutic methods and surgical outcomes.

MRI features of pituitary adenoma apoplexy and their relationship with hypoxia, proliferation, and pathology

OBJECTIVE

We aim to study the MRI features of pituitary adenoma (PA) apoplexy and their relationship with hypoxia, proliferation, and pathology.

METHODS

Sixty-seven patients with MRI signs of PA apoplexy were selected. According to the MRI signs, they were divided into the parenchymal group and the cystic group. The parenchymal group had a low signal area on T2WI without cyst >2 mm and this area was not significantly enhanced on the corresponding TW1 enhancement. The cystic group had a cyst >2 mm on T2WI, and the cyst showed liquid stratification on T2WI or high signal on T1WI. The relative T1WI (rT1WI) enhancement value and relative T2WI (rT2WI) value of non-apoplexy areas were measured. Protein levels of hypoxia-inducible factor-1 (HIF-1α), pyruvate dehydrogenase kinase 1 (PDK1), and Ki67 were detected with immunohistochemistry and Western blot. Nuclear morphology was observed with HE staining.

RESULTS

The rT1WI enhancement average value, rT2WI average value, Ki67 protein expression level, and the number of abnormal nuclear morphology of non-apoplexy lesions in the parenchymal group were significantly lower than those in the cystic group. The protein expression levels of HIF-1α and PDK1 in the parenchymal group were significantly higher than those in the cystic group. HIF-1α protein was positively correlated with PDK1 but negatively correlated with Ki67.

CONCLUSION

When there is PA apoplexy, the ischemia and hypoxia of the cystic group are lesser than those of the parenchymal group, but the proliferation is stronger.

Trends in incidence and mortality risk for acromegaly in Norway: a cohort study

PURPOSE

Recent data have shown a decreasing overall mortality in acromegaly over the last decades. However, cancer incidence and cancer-related mortality still appear to be increased. Our aim was to obtain updated epidemiological data from Norway in a clinically well-defined cohort with complete register-based follow-up.

METHODS

Patients diagnosed with acromegaly from South-Eastern Norway between 1999-2019 (n = 262) and age and sex matched population controls (1:100) were included (n = 26,200). Mortality and cancer data were obtained from the Norwegian Cause of Death and Cancer Registry. Mortality and cancer incidence were compared by Kaplan-Meier analyses and Cox regression; we report hazard ratios (HRs) with 95% confidence intervals (95% CI).

RESULTS

Median age at diagnosis was 48.0 years (interquartile range (IQR): 37.6-58.0). Mean annual acromegaly incidence rate was 4.7 (95% CI 4.2-5.3) cases/10⁶ person-years, and the point prevalence (2019) was 83 (95% CI 72.6-93.5) cases/10⁶ persons. Overall mortality was not increased in acromegaly, HR 0.8 (95% CI 0.5-1.4), cancer-specific and cardiovascular-specific mortality was also not increased (HR: 0.7 (95% CI 0.3-1.8) and 0.8 (95% CI: 0.3-2.5) respectively). The HR for all cancers was 1.45 (1.0-2.1; p = 0.052).

CONCLUSION

In this large cohort study, covering the period 1999-2019, patients were treated with individualized multimodal management. Mortality was not increased compared to the general population and comparable with recent registry studies from the Nordic countries and Europe. Overall cancer risk was slightly, but not significantly increased in the patients.

Transcriptome of GH-producing pituitary neuroendocrine tumours and models are significantly affected by somatostatin analogues

Pituitary neuroendocrine tumours (PitNETs) are neoplasms of the pituitary that overproduce hormones or cause unspecific symptoms due to mass effect. Growth hormone overproducing GH-producing PitNETs cause acromegaly leading to connective tissue, metabolic or oncologic disorders. The medical treatment of acromegaly is somatostatin analogues (SSA) in specific cases combined with dopamine agonists (DA), but almost half of patients display partial or full SSA resistance and potential causes of this are unknown. In this study we investigated transcriptomic landscape of GH-producing PitNETs on several levels and functional models-tumour tissue of patients with and without SSA preoperative treatment, tumour derived pituispheres and GH3 cell line incubated with SSA to study effect of medication on gene expression. MGI sequencing platform was used to sequence total RNA from PitNET tissue, pituispheres, mesenchymal stromal stem-like cells (MSC), and GH3 cell cultures, and data were analysed with Salmon-DeSeq2 pipeline. We observed that the GH-producing PitNETs have distinct changes in growth hormone related pathways related to its functional status alongside inner cell signalling, ion transport, cell adhesion and extracellular matrix characteristic patterns. In pituispheres model, treatment regimens (octreotide and cabergoline) affect specific cell proliferation (MKI67) and core functionality pathways (RYR2, COL8A2, HLA-G, ARFGAP1, TGFBR2). In GH3 cells we observed that medication did not have transcriptomic effects similar to preoperative treatment in PitNET tissue or pituisphere model. This study highlights the importance of correct model system selection for cell transcriptomic profiling and data interpretation that could be achieved in future by incorporating NGS methods and detailed cell omics profiling in PitNET model research.

Preoperative medical treatments and surgical approaches for acromegaly: A systematic review

OBJECTIVE

Acromegaly is a condition characterized by an overproduction of growth hormone which infers high morbidity and mortality if left untreated. The objective of this review is to analyse and appraise the current evidence for the generalized use of preoperative medications and the various surgical approaches as described in the literature.

DESIGN

A thorough search from MEDLINE via PubMed, EMBASE, and Cochrane Library has been performed which identified a total of 37 papers.

CONCLUSION

The preoperative use of somatostatin receptor agonists (SAs) in acromegaly is a controversial topic with current guidelines suggesting against their generalized routine use. Most authors noticed an insignificant long-term remission of acromegaly when given SAs compared with nil preoperative therapy, except for invasive macroadenomas as SAs have been found to reduce the tumour volume and aid towards the total resection of the adenoma. Furthermore, according to the evidence available, endoscopic transsphenoidal surgery is the optimum method for hypophysectomy in terms of its remission and safety profile.

Cost-effectiveness of direct surgery versus preoperative octreotide therapy for growth-hormone secreting pituitary adenomas

PURPOSE

The objective of this study was to compare the cost-effectiveness of preoperative octreotide therapy followed by surgery versus the standard treatment modality for growth-hormone secreting pituitary adenomas, direct surgery (that is, surgery without preoperative treatment) from a public third-party payer perspective.

METHODS

We developed an individual-level state-transition microsimulation model to simulate costs and outcomes associated with preoperative octreotide therapy followed by surgery and direct surgery for patients with growth-hormone secreting pituitary adenomas. Transition probabilities, utilities, and costs were estimated from recent published data and discounted by 3% annually over a lifetime time horizon. Model outcomes included lifetime costs [2020 United States (US) Dollars], quality-adjusted life-years (QALYs) and incremental cost-effectiveness ratios (ICERs).

RESULTS

Under base case assumptions, direct surgery was found to be the dominant strategy as it yielded lower costs and greater health effects (QALYs) compared to preoperative octreotide strategy in the second-order Monte Carlo microsimulation. The ICER was most sensitive to probability of remission following primary therapy and duration of preoperative octreotide therapy. Accounting for joint parameter uncertainty, direct surgery had a higher probability of demonstrating a cost-effective profile compared to preoperative octreotide treatment at 77% compared to 23%, respectively.

CONCLUSIONS

Using standard benchmarks for cost-effectiveness in the US ($100,000/QALY), preoperative octreotide therapy followed by surgery may not be cost-effective compared to direct surgery for patients with growth-hormone secreting pituitary adenomas but the result is highly sensitive to initial treatment failure and duration of preoperative treatment.

The prevalence of acromegaly is higher than previously reported: Changes over a three-decade period

OBJECTIVE

To study time-related changes in the prevalence and patient characteristics of acromegaly, as well as to assess the impact of changes in treatment on disease control.

METHODS

A total of 107 patients with acromegaly were identified by healthcare registries and subsequently validated by patient chart review over a three-decade period (1992-2021). A systematic literature review focusing on the incidence and prevalence of acromegaly was performed identifying 31 studies.

RESULTS

The prevalence of acromegaly significantly increased throughout the study period (R²  = 0.94, p < .001) and was 122 cases/10⁶ persons in 2021 whereas the annual incidence remained constant at 4.6 cases/10⁶ persons. The age at the first sign of acromegaly and the age at diagnosis significantly increased during the study period, whereas growth hormone and insulin-like growth factor I decreased. Incidentalomas constituted 32% of all cases diagnosed with acromegaly in the last decade. Primary surgery was used in 93% of all cases, and repeated surgery decreased from 24% to 10% during the three decades. The use of first-generation somatostatin analogues (21%-48%) and second-line medical treatment (4%-20%) increased with a concomitant improvement of biochemical disease control (58%-91%).

CONCLUSION

The prevalence of acromegaly is higher than previously reported and the clinical presentation has shifted towards a milder phenotype. Modern treatment of acromegaly enables individualized treatment and disease control in the majority of patients.

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.

Efficacy of lanreotide 120 mg primary therapy on tumour shrinkage and ophthalmologic symptoms in acromegaly after 1 month

INTRODUCTION

Few studies have attempted to evaluate the early efficacy of first-generation somatostatin analogues in somatotroph macroadenomas.

OBJECTIVE

To investigate the short-term efficacy of primary therapy with lanreotide 120 mg at 1 and 3 months on tumour shrinkage and ophthalmologic symptoms in newly diagnosed patients with acromegaly.

DESIGN AND PATIENTS

This single-centre retrospective study included 21 patients with de novo acromegaly resulting from pituitary macroadenoma, with optic chiasm compression (Grade ≤ 2) and/or cavernous sinus invasion, treated with a monthly injection of lanreotide 120 mg. Clinical, hormonal, ophthalmologic and magnetic resonance imaging scan evaluations were conducted after the first and the third months of treatment.

RESULTS

Tumour volume reduction was more pronounced at 1 month; mean volume change: -31.4 ± 19.5%, p < .0001 than between the first and third month of treatment; mean volume reduction: -20.6 ± 13.4%, p = .0009. The mean volume change between baseline and the third month was - 46.4 ± 21.6, (p < .0001). A significant volume reduction (≥25%) was observed in 61.9% of individuals (13/21) at the first month. Among 14 individuals with optic chiasm compression and visual field defects, visual field normalization or improvement were observed in seven cases (50%), stabilization in four cases (28.5%), and mild worsening in three cases (21.4%) at 1 month. The decrease in growth hormone and IGF-1 serum values was significant at 1 month.

CONCLUSIONS

Primary treatment with lanreotide 120 mg in patients with somatotroph macroadenomas provides early significant tumour shrinkage with rapid improvement of visual symptoms at the end of the first month in 50% of patients.

Personalized Medical Treatment in Patients with Acromegaly: A Review

Acromegaly is associated with significant morbidity and mortality if not appropriately treated. In addition to insulin-like growth factor 1 (IGF-1) and growth hormone (GH) normalization, and tumor shrinkage, treatment goals include symptom relief, managing complications and improving quality of life. Surgical resection is a first-line treatment in most patients, with few being pretreated pre-operatively with medications. Somatostatin receptor ligands (SRLs), injectable and more recently oral capsules, have been the cornerstone of first-line medical therapy for persistent disease. However, several factors, including sparsely granulated adenomas, absent/low somatostatin receptor (SSTR2) status, imaging T2-hyperintensity, young age and aryl hydrocarbon receptor interacting protein mutations could predict first-generation SRL resistance. Patients with these characteristics may be better candidates for the GH receptor antagonist, pegvisomant, or in cases of large tumors the second-generation SRL, pasireotide. Combination therapy should be further pursued in patients who remain biochemically uncontrolled or have high remnant tumor after monotherapy. An efficacious and cost-effective pegvisomant dose-sparing effect of SRLs when used in combination has been demonstrated. With such a wide array of medical treatment options, it is increasingly important to tailor treatment to patients' unique characteristics as well as preferences, with a goal of personalizing management to achieve high quality outcomes.

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.

Clinical relevance of tumor consistency in pituitary adenoma

PURPOSE

To review the clinical relevance of pituitary adenoma (PA) consistency and its relationship to clinical presentation, radiologic and histopathological characteristics, and surgical outcomes.

BACKGROUND

PA consistency is a critical factor influencing operative planning, surgical outcomes, and patient counseling. There is no validated classification of PA consistency in the literature, and there are no current preoperative variables capable of predicting it.

REVIEW

We conducted a thorough literature review of the Medline, Embase, Web of Science, and Cochrane Library databases. The inclusion criteria were all articles that described PA consistency and correlated it with preoperative aspects, radiological, pathological, and operative findings, or clinical outcomes.

DISCUSSION

Although most authors differentiate easily aspirated (soft) tumors from those that are not (fibrous, might require prior fragmentation), there is no universally accepted PA consistency classification. Fibrous PA tends to be hypointense on T2WI and has lower apparent diffusion coefficient (ADC) values. Fibrous tumors seemed to present higher invasion into neighboring structures, including the cavernous sinus. Several articles suggest that dopamine agonists could increase PA consistency and that prior surgery and radiotherapy also make PA more fibrous. The anatomopathological studies identify collagen as being mainly responsible for fibrous consistency of adenomas.

CONCLUSIONS

Preoperative knowledge of PA consistency affords the neurosurgeon substantial benefit, which clearly appears to be relevant to surgical planning, risks, and surgery outcomes. It could also encourage the centralization of these high complexity tumors in reference centers. Further studies may be enhanced by applying standard consistency classification of the PA and analyzing a more extensive and prospective series of fibrous PA.

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.

Medication for Acromegaly Reduces Expression of MUC16, MACC1 and GRHL2 in Pituitary Neuroendocrine Tumour Tissue

Acromegaly is a disease mainly caused by pituitary neuroendocrine tumor (PitNET) overproducing growth hormone. First-line medication for this condition is the use of somatostatin analogs (SSAs), that decrease tumor mass and induce antiproliferative effects on PitNET cells. Dopamine agonists (DAs) can also be used if SSA treatment is not effective. This study aimed to determine differences in transcriptome signatures induced by SSA/DA therapy in PitNET tissue. We selected tumor tissue from twelve patients with somatotropinomas, with half of the patients receiving SSA/DA treatment before surgery and the other half treatment naive. Transcriptome sequencing was then carried out to identify differentially expressed genes (DEGs) and their protein–protein interactions, using pathway analyses. We found 34 upregulated and six downregulated DEGs in patients with SSA/DA treatment. Three tumor development promoting factors MUC16, MACC1, and GRHL2, were significantly downregulated in therapy administered PitNET tissue; this finding was supported by functional studies in GH3 cells. Protein–protein interactions and pathway analyses revealed extracellular matrix involvement in the antiproliferative effects of this type of the drug treatment, with pronounced alterations in collagen regulation. Here, we have demonstrated that somatotropinomas can be distinguished based on their transcriptional profiles following SSA/DA therapy, and SSA/DA treatment does indeed cause changes in gene expression. Treatment with SSA/DA significantly downregulated several factors involved in tumorigenesis, including MUC16, MACC1, and GRHL2. Genes that were upregulated, however, did not have a direct influence on antiproliferative function in the PitNET cells. These findings suggested that SSA/DA treatment acted in a tumor suppressive manner and furthermore, collagen related interactions and pathways were enriched, implicating extracellular matrix involvement in this anti-tumor effect of drug treatment.

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.

Common Pitfalls in the Interpretation of Endocrine Tests

Endocrine tests are the cornerstone of diagnosing multiple diseases that primary care physicians are frequently faced with. Some of these tests can be affected by situations that affect the proper interpretation, leading to incorrect diagnoses and unnecessary treatment, such as the interference of biotin with thyroid function test, falsely elevated prolactin values in presence of macroprolactinemia or falsely normal due to the "hook effect" in macroprolactinomas. Recognizing these situations is essential for the clinician to make an adequate interpretation of these tests as well as an accurate diagnosis that guarantees the best outcomes for the patient.

Efficacy and predictors of short-term first-generation somatostatin analog presurgical treatment in acromegaly: A hospital-based study of 237 cases

OBJECTIVE

To investigate the effectiveness and predictors of short-term somatostatin analog (SSA) presurgical therapy in a large cohort and to assess the correlation between clinical and pathological variables.

DESIGN

237 newly diagnosed patients with acromegaly received presurgical SSA treatment for three months were recruited. Clinical characteristics were collected, and response to SSA in hormone and tumor size was evaluated. The correlation between clinical information and pathological variables were analyzed.

RESULTS

After 3 months presurgical SSA therapy, 51 (21.5%) patients were biochemically responsive with ≥50% decrease in IGF-1 while 126 (53.2%) patients showed at least 20% tumor size decrease. Biochemical responders were associated with a smaller maximum tumor diameter (MTD) and an older age (OR, 0.448; P = 0.003; OR, 1.050; P = 0.001). Tumor size responders were associated with a smaller MTD (OR, 0.435; P < 0.001). A combination of MTD < 2 cm and age ≥49 years predicted biochemical responders (PPV, 54.5%; NPV, 86.0%; P < 0.001), while MTD ≤2.2 cm (PPV, 67.1%; NPV, 67.0%; P < 0.001) predicted tumor size responders. Compared to patients with MTD < 2 cm, patients with MTD ≥ 2 cm showed higher percentage of sparsely granulated (SG) adenoma (62.1% vs. 31.3%, P = 0.005). In addition, the percentage of SG adenoma tended to be higher in patients < 49 years than ≥49 years (48.1% and 31.0% P = 0.089).

CONCLUSIONS

The baseline MTD and age correlate with granulation patterns and may be used as easily acquired predictors of presurgical SSA treatment in acromegaly. Patients over their 50s with a tumor less than 2 cm in diameter are more likely to have a response to the short-term presurgical SSA therapy.

Radiomics model predicts granulation pattern in growth hormone-secreting pituitary adenomas

PURPOSE

To investigate whether radiomic features from magnetic resonance image (MRI) can predict the granulation pattern of growth hormone (GH)-secreting pituitary adenoma patients.

METHODS

Sixty-nine pathologically proven acromegaly patients (densely granulated [DG] = 50, sparsely granulated [SG] = 19) were included. Radiomic features (n = 214) were extracted from contrast-enhancing and total tumor portions from T2-weighted (T2) MRIs. Imaging features were selected using a least absolute shrinkage and selection operator (LASSO) logistic regression model with fivefold cross-validation. Diagnostic performance for predicting granulation pattern was compared with that for qualitative T2 signal intensity assessment and T2 relative signal intensity (rSI) using the area under the receiver operating characteristics curve (AUC).

RESULTS

Four significant radiomic features from the contrast-enhancing tumor (1 from shape, 1 from first order feature, and 2 from second order features) were selected by LASSO for model construction. The radiomics model showed an AUC, accuracy, sensitivity, and specificity of 0.834 (95% confidence interval [CI] 0.738-0.930), 73.7%, 74.0%, and 73.9%, respectively. The radiomics model showed significantly better performance than the model using qualitative T2 signal intensity assessment (AUC 0.597 [95% CI 0.447-0.747], P = 0.009) and T2 rSI (AUC 0.647 [95% CI 0.523-0.759], P = 0.037).

CONCLUSION

Radiomic features may be useful biomarkers to differentiate granulation pattern of GH-secreting pituitary adenoma patients, and showed better performance than qualitative assessment or rSI evaluation.

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.

Diagnosis, treatment and follow-up of patients with acromegaly in a clinical practice setting in Spain: the ACROPRAXIS program Delphi survey

AIM

The ACROPRAXIS program aims to describe the management of acromegaly in Spain and provide guidance.

METHODS

Ninety-three endocrinologists were organized into 13 panels to discuss the practical issues in managing acromegaly. Based on the key learnings, an online Delphi survey with 62 statements was performed, so those statements achieving consensus could be used as guidance. Statements were rated on a 9-point scale (9, full agreement; consensus > 66.6% of response in the same tertile).

RESULTS

Ninety-two endocrinologists (98.8%) answered two rounds of the survey (mean age 47.6 years; 59.8% women; median 18.5 years of experience). Consensus was achieved for 49 (79%) statements.

DIAGNOSIS

The levels of insulin-like growth factor I (IGFI) is the preferred screening test. If IGFI levels 1-1.3 ULN, the test is repeated and growth hormone (GH) after oral glucose tolerance test (OGTT) is assessed. A pituitary magnetic resonance is performed after biochemical diagnosis.

TREATMENT

Surgery is the first treatment choice for patients with microadenoma or macroadenoma with/without optical pathway compression. Pre-surgical somatostatin analogues (SSA) are indicated when surgery is delayed and/or to reduce anaesthesia-associated risks. After unsuccessful surgery, reintervention is performed if the residual tumor is resectable, while if non-resectable, SSA are administered. Follow-up First biochemical and clinical controls are performed 1-3 months after surgery. Disease remission is considered if random GH levels are < 1 µg/L or OGTT is < 1 or ≤ 0.4 µg/L, depending on the assay's sensitivity.

CONCLUSION

Current clinical management for acromegaly is homogeneous across Spain and generally follows clinical guidelines.

Development and assessment of machine learning algorithms for predicting remission after transsphenoidal surgery among patients with acromegaly

PURPOSE

Preoperative prediction of transsphenoidal surgical (TSS) response is important for determining individual treatment strategies for acromegaly. There is currently no accurate predictive model for TSS response for acromegaly. The current study sought to develop and validate machine learning (ML)-based models for preoperative prediction of TSS response for acromegaly.

METHODS

Six hundred sixty-eight patients with acromegaly were enrolled and divided into training (n = 534) and text datasets (n = 134) in this retrospective, data mining and ML study. The forward search algorithm was used to select features, and six ML algorithms were applied to construct TSS response prediction models. The performance of these ML models was validated using receiver operating characteristics analysis. Model calibration, discrimination ability, and clinical usefulness were also assessed.

RESULTS

Three hundred forty-nine (52.2%) patients achieved postoperative remission criteria and exhibited good TSS response. A univariate analysis was conducted and eight features, including age, hypertension, ophthalmic disorders, GH, IGF-1, nadir GH, maximal tumor diameter, and Knosp grade, were significantly associated with the TSS response in patients with acromegaly. After feature selection, the gradient boosting decision tree (GBDT), which was constructed with the eight significant features showed the best favorable discriminatory ability both the training (AUC = 0.8555) and validation (AUC = 0.8178) cohorts. The GBDT model showed good discrimination ability and calibration, with the highest levels of accuracy and specificity, and provided better estimates of TTS responses of patients with acromegaly compared with using only the Knosp grade. Decision curve analysis confirmed that the model was clinically useful.

CONCLUSIONS

ML-based models could aid neurosurgeons in the preoperative prediction of TTS response for patients with acromegaly, and could contribute to determining individual treatment strategies.

Italian Association of Clinical Endocrinologists (AME) and Italian AACE Chapter Position Statement for Clinical Practice: Acromegaly - Part 2: Therapeutic Issues

Any newly diagnosed patient should be referred to a multidisciplinary team experienced in the treatment of pituitary adenomas. The therapeutic management of acromegaly always requires a personalized strategy. Normal age-matched IGF-I values are the treatment goal. Transsphenoidal surgery by an expert neurosurgeon is the primary treatment modality for most patients, especially if there are neurological complications. In patients with poor clinical conditions or who refuse surgery, primary medical treatment should be offered, firstly with somatostatin analogs (SSAs). In patients who do not reach hormonal targets with first-generation depot SSAs, a second pharmacological option with pasireotide LAR or pegvisomant (alone or combined with SSA) should be offered. Irradiation could be proposed to patients with surgical remnants who would like to be free from long-term medical therapies or those with persistent disease activity or tumor growth despite surgery or medical therapy. Since the therapeutic tools available enable therapeutic targets to be achieved in most cases, the challenge is to focus more on the quality of life.

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.

Pituitary magnetic resonance imaging predictive role in the therapeutic response of growth hormone-secreting pituitary adenomas

Background

Growth hormone (GH)-secreting pituitary adenomas, responsible for the development of acromegaly, are the second most frequent type of secreting pituitary adenomas and are characterized by very variable T2-weighted signal intensity on pituitary magnetic resonance imaging (MRI). Previous data have demonstrated a correlation between T2-weighted tumor signal intensity and response to therapy with conventional somatostatin analogs (SSA) in patients with acromegaly. The aim of the current retrospective study was to investigate the correlation between the T2-weighted tumor signal on pituitary MRI and both biochemical and radiological response to first-line SSA therapy.

Methods

Twenty-two naive patients with acromegaly were eligible for the study (14 females and 8 males, mean age ± SD: 58.8±15.74). A biochemical evaluation (GH and IGF-I levels) and an MRI assessment (volume and signal intensity analysis of adenoma) were conducted in each patient at diagnosis and after 12 months of SSA therapy.

Results

On diagnostic pituitary MRI, 16 (72.7%) adenomas were T2- hypointense and 6 (27.2%) T2-hyperintense. After 12 months of SSA therapy, IGF-I levels decreased by more than 50% from baseline in 62.5% of patients with T2-hypointense and 33.3% of patients with T2- hyperintense tumor signal, respectively (P=0.03). Moreover, GH levels decreased by more than 80% from baseline in 81.3% and 33.3% of patients with T2-hypointense and T2-hyperintense tumor signal (P=0.02). A significant tumor volume reduction (≥20%) was observed in 75% of the T2-hypointense and 33.3% of the T2-hyperintense adenomas (P=0.001).

Conclusions

In naive patients with acromegaly, first-line SSA therapy is associated with a better biochemical response and greater tumor shrinkage in T2-hypointense compared to T2-hyperintense adenomas. Therefore, T2-weighted sequences of pituitary MRI can help to classify GH-secreting pituitary adenomas into a T2-hypointense and T2-hyperintense type and, therefore, to identify patients who can better respond to first-line SSA therapy.

The effects of pre-operative somatostatin analogue therapy on treatment cost and remission in acromegaly

PURPOSE

To investigate the effects of preoperative somatostatin analogue (SSA) treatment on the annual cost of all acromegaly treatment modalities and on remission rates.

METHODS

The medical records of 135 patients with acromegaly who were followed at endocrinology clinic of Cerrahpasa Medical Faculty for at least 2 years after surgery between 2009 and 2016 were reviewed.

RESULTS

The mean follow-up time was 50.9 ± 25.7 months. Early remission was defined according to 3rd month values in patients who didn't achieve remission, and 6th month values in patients who achieved remission at the 3rd month after surgery. The early and late remission rates of the entire study population were 40% and 80.7%, respectively. The early remission of the preoperative SSA-treated group (61.5%) was significantly higher than SSA-untreated group (31.2%) (p = 0.002). The early remission of the preoperative SSA-treated patients with macroadenomas (52.2%) was also significantly higher than the SSA-untreated group (23.5%) (p = 0.02). In the subgroup analysis; this difference was much more pronounced in invasive macroadenomas (p = 0.002). There were no differences between the groups in terms of late remission.The median annual cost of all acromegaly treatment modalities in study population was €3788.4; the cost for macroadenomas was significantly higher than for microadenomas (€4125.0 vs. €3226.5, respectively; p = 0.03). Preoperative SSA use in both microadenomas and macroadenomas didn't alter the cost of treatment. The increase in the duration of preoperative medical treatment had no effect on early or late remissions (p = 0.09; p = 0.8).

CONCLUSIONS

Preoperative medical treatment had no effect on the costs of acromegaly treatment. There was a benefical effect of pre-operative SSA use on early remission in patients with macroadenomas; however, this effect didn't persist long term.

Pretreatment with somatostatin analogs does not affect the anesthesiologic management of patients with acromegaly

PURPOSE

Acromegaly may be associated with an increased risk of complex intraoperative management and anesthetic complications. No study addressed whether pretreatment with somatostatin receptor ligands (SRLs) affects anesthesiologic management.

METHODS

We studied 211 consecutive acromegalic patients who had a recorded intraoperative computerized anesthetic record (ICAR) available for analysis. Ninety-six (45.5%) patients were SRL-pretreated while 115 patients were treatment naïve.

RESULTS

Treatment with SRLs reduced mean basal growth hormone level from 23.8 ± 4.2 to 5.9 ± 1.3 µg/L. Normalization of insulin-like growth factor-1 was achieved in 26 patients (27.1%). The frequency of comorbidities at surgery was similar in the two groups. Five patients with difficult intubation were naïve (4.3%) as compared with 5 SRL-pretreated patients (5.2%; P = 1.0). ICAR registration did not show any significant change of intraoperative vital parameters in the two groups of patients as well as in the intraoperative utilization of drugs. Total duration of anesthesia and surgery were similar in the two groups. Four patients with an intraoperative adverse event were naïve (3.5%) as compared with 4 SRL-pretreated patients (4.2%; P = 1.00). Remission of disease occurred in 83 of 114 naïve patients (72.8%) and in 57 of 93 SRL-pretreated patients (61.3%; P = 0.11).

CONCLUSIONS

SRL-pretreatment of patients with acromegaly had no significant impact on intraoperative anesthesiologic management. Despite a better Cormack-Lehane score in SRL-pretreated than in naïve patients, the rate of difficult intubation was similar in both groups. SRL-pretreatment did not affect the rate of surgical remission or complications as well.

Early surgical intervention for patients with possible clinically silent somatotroph adenoma: a case series

Introduction

Clinically silent somatotroph adenoma is characterized by elevated serum growth hormone but without the clinical symptoms of acromegaly, and it is considered rare. The natural history is not well understood, progress to symptomatic is uncertain, and treatment strategy has not been established.

Case presentation

The first patient was a 48-year-old-Asian woman who presented with serum growth hormone 6.99 ng/ml and insulin-like growth factor 1 of 476 ng/ml, but no characteristic features of acromegaly. Five years after initial diagnosis, she presented with acromegalic facial appearance. Transsphenoidal surgery achieved gross total removal and endocrinological remission. The second patient was a 40-year-old-Asian woman who presented with serum growth hormone 31.14 ng/ml and insulin-like growth factor 1 of 709.6 ng/ml, but no characteristic features of acromegaly. Three years after initial diagnosis, she presented with acromegalic facial appearance. Transsphenoidal surgery achieved gross total removal and endocrinological remission. The third patient was a 64-year-old-Asian woman who presented with serum growth hormone 6.0 ng/ml and insulin-like growth factor 1 of 341 ng/ml, but no characteristic features of acromegaly. Eight months after initial diagnosis, hand enlargement was detected. Transsphenoidal surgery achieved gross total removal and endocrinological remission.

Conclusion

Due to its potential for evolving to symptomatic disease, the risks of surgery and observation for patients with somatotroph adenoma should be carefully compared from the viewpoint of better health outcome.

Medical Treatment with Somatostatin Analogues in Acromegaly: Position Statement

The Korean Endocrine Society (KES) published clinical practice guidelines for the treatment of acromegaly in 2011. Since then, the number of acromegaly cases, publications on studies addressing medical treatment of acromegaly, and demands for improvements in insurance coverage have been dramatically increasing. In 2017, the KES Committee of Health Insurance decided to publish a position statement regarding the use of somatostatin analogues in acromegaly. Accordingly, consensus opinions for the position statement were collected after intensive review of the relevant literature and discussions among experts affiliated with the KES, and the Korean Neuroendocrine Study Group. This position statement includes the characteristics, indications, dose, interval (including extended dose interval in case of lanreotide autogel), switching and preoperative use of somatostatin analogues in medical treatment of acromegaly. The recommended approach is based on the expert opinions in case of insufficient clinical evidence, and where discrepancies among the expert opinions were found, the experts voted to determine the recommended approach.

Long-Term Effects of Intracapsular Debulking and Adjuvant Somatostatin Analogs for Growth Hormone-Secreting Pituitary Macroadenoma: 10 Years of Experience in a Single Institute

OBJECTIVE

Long-term effects of endoscopic endonasal transsphenoidal intracapsular debulking and adjuvant somatostatin analogs (SSAs) were evaluated in patients with growth hormone- (GH) secreting pituitary macroadenomas.

METHODS

We retrospectively reviewed the medical records of 45 patients with acromegalic macroadenoma who underwent endonasal endoscopic transsphenoidal intracapsular debulking and received adjuvant SSAs (octreotide) between 2006 and 2015 who had >1 year of follow-up. To evaluate the predictive factors for 1 year and long-term biochemical outcomes, univariate and multivariate analyses were performed.

RESULTS

Biochemical remission was achieved in 1 year in 20 of the 45 (44.4%) patients, and in 31 of the 45 patients after long-term adjuvant SSA treatment. Tumor control was achieved in 43 of the 45 (93.3%) patients. The univariate analysis showed age (≥55 years), tumor size (diameter ≤1.5 cm), premedication GH levels (≤2.8 ng/mL), premedication insulin-like growth factor 1 levels (≤2-fold of upper limit of normal range), cavernous sinus invasion (Knops grades 2, 3, and 4), and near-total tumor resection were associated with long-term outcomes. The multivariate analysis showed near-total resection was a significant predictor for long-term outcomes (P = 0.019). There were no new pituitary dysfunctions. The observed complications included one case of cerebrospinal fluid leakage and one case of epistaxis requiring intervention.

CONCLUSIONS

Intracapsular debulking and adjuvant SSAs are a safe and viable treatment for patients with GH secreting pituitary macroadenoma to achieve biochemical remission and tumor control. Although adjuvant SSA treatment enhances residual tumor control, cavernous sinus invasion impedes the remission of endocrine tumors.

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.

Diabetes mellitus induced by somatostatin analogue therapy is not permanent in acromegalic patients

CONTEXT

Therapy with somatostatin analogues (SSAs) may have deleterious effects on glucose metabolism in patients with acromegaly, often leading to the development of diabetes mellitus (DM).

AIM

The aim of the study was to evaluate whether DM, developed during therapy with SSAs, may revert after drug withdrawal and cure of acromegaly with pituitary adenomectomy.

DESIGN

Retrospective cohort study, in a tertiary referral centre.

PATIENTS

Eighteen acromegalic patients without DM at the diagnosis of acromegaly treated with SSAs as a primary therapy, and then cured by pituitary adenomectomy.

METHODS

Endocrine status and glucose homeostasis were evaluated at diagnosis of acromegaly and at least every 6 months during SSA therapy. At each visit, patients were classified into one of the following classes: normal glucose tolerance, prediabetes, overt diabetes.

RESULTS

Median follow-up after starting SSAs therapy was 69 months (IQR 54.75-132.25). During SSA therapy, all patients had controlled acromegaly defined by normal serum IGF1 concentrations for the age. Of the 13 euglycaemic patients at diagnosis, three developed prediabetes and three diabetes, whereas, of the five prediabetic patients at diagnosis, two worsened to overt diabetes and three remained in the prediabetic range (P = 0.04). After curing acromegaly with pituitary adenomectomy and subsequent SSA withdrawal, prediabetes reverted in five of six patients, and diabetes in all five patients (three reverted to euglycaemia, while two reverted to prediabetes) (P = 0.01).

CONCLUSIONS

In acromegalic patients with controlled disease, changes in glycaemic status induced by SSAs are not permanent.

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.

Predicting response to somatostatin analogues in acromegaly: machine learning-based high-dimensional quantitative texture analysis on T2-weighted MRI

OBJECTIVE

To investigate the value of machine learning (ML)-based high-dimensional quantitative texture analysis (qTA) on T2-weighted magnetic resonance imaging (MRI) in predicting response to somatostatin analogues (SA) in acromegaly patients with growth hormone (GH)-secreting pituitary macroadenoma, and to compare the qTA with quantitative and qualitative T2-weighted relative signal intensity (rSI) and immunohistochemical evaluation.

METHODS

Forty-seven patients (24 responsive; 23 resistant patients to SA) were eligible for this retrospective study. Coronal T2-weighted images were used for qTA and rSI evaluation. The immunohistochemical evaluation was based on the granulation pattern of the adenomas. Dimension reduction was carried out by reproducibility analysis and wrapper-based algorithm. ML classifiers were k-nearest neighbours (k-NN) and C4.5 algorithm. The reference standard was the biochemical response status. Predictive performance of qTA was compared with those of the quantitative and qualitative rSI and immunohistochemical evaluation.

RESULTS

Five hundred thirty-five out of 828 texture features had excellent reproducibility. For the qTA, k-NN correctly classified 85.1% of the macroadenomas regarding response to SAs with an area under the receiver operating characteristic curve (AUC-ROC) of 0.847. The accuracy and AUC-ROC ranges of the other methods were 57.4-70.2% and 0.575-0.704, respectively. Differences in predictive performance between qTA-based classification and the other methods were significant (p < 0.05).

CONCLUSIONS

The ML-based qTA of T2-weighted MRI is a potential non-invasive tool in predicting response to SAs in patients with acromegaly and GH-secreting pituitary macroadenoma. The method performed better than the qualitative and quantitative rSI and immunohistochemical evaluation.

KEY POINTS

• Machine learning-based texture analysis of T2-weighted MRI can correctly classify response to somatostatin analogues in more than four fifths of the patients. • Machine learning-based texture analysis performs better than qualitative and quantitative evaluation of relative T2 signal intensity and immunohistochemical evaluation. • About one third of the texture features may not be excellently reproducible, indicating that a reliability analysis is necessary before model development.

Impact of preoperative pasireotide therapy on invasive octreotide-resistant acromegaly

A 43-year-old woman with an 8-year history of diabetes, hypertension, and dyslipidemia presented with amenorrhea and convulsion. Her MRI scan revealed a 3.5-cm T2-hyperintense pituitary macroadenoma with suprasellar extension to the frontal lobe and bilateral cavernous sinus invasion. Her serum levels of GH and insulin-like growth factor-I (IGF-I) were elevated to 9.08 ng/mL (normal range: <2.1 ng/mL) and 1,000 ng/mL (normal range: 90-233 ng/mL, SD score +10.6), respectively. Bromocriptine insufficiently suppressed her GH levels, while octreotide paradoxically increased her GH levels. Together with her characteristic features, she was diagnosed with acromegaly caused by an invasive GH-producing pituitary macroadenoma. As performing a one-stage operation would have been extremely difficult, she was first treated with pasireotide long-acting release (40 mg monthly) for 5 months followed by a successful transsphenoidal surgery. One month after the first injection, biochemical control was achieved (IGF-I, 220 ng/mL; GH, 1.26 ng/mL), and tumor shrinkage of approximately 50% was observed. The resected tumor was histologically diagnosed as a sparsely granulated somatotroph adenoma, with higher expression of somatostatin receptor subtype 5 (SSTR5) than that of SSTR2A. The germline aryl hydrocarbon receptor interacting protein (AIP) mutation was negative, and several tumor cells were weakly immunoreactive for AIP. Despite the presence of a residual tumor postoperatively, biochemical control was achieved 6 months after the final injection of pasireotide. In conclusion, this case suggests that pasireotide may be an option for preoperative first-line therapy in invasive and octreotide-resistant sparsely granulated somatotroph adenomas.

A Consensus Statement on acromegaly therapeutic outcomes

The 11th Acromegaly Consensus Conference in April 2017 was convened to update recommendations on therapeutic outcomes for patients with acromegaly. Consensus guidelines on the medical management of acromegaly were last published in 2014; since then, new pharmacological agents have been developed and new approaches to treatment sequencing have been considered. Thirty-seven experts in the management of patients with acromegaly reviewed the current literature and assessed changes in drug approvals, clinical practice standards and clinical opinion. They considered current treatment outcome goals with a focus on the impact of current and emerging somatostatin receptor ligands, growth hormone receptor antagonists and dopamine agonists on biochemical, clinical, tumour mass and surgical outcomes. The participants discussed factors that would determine pharmacological choices as well as the proposed place of each agent in the guidelines. We present consensus recommendations highlighting how acromegaly management could be optimized in clinical practice.

Presurgical treatment with somatostatin analogues in growth hormone-secreting pituitary adenomas: A long-term single-center experience

OBJECTIVE

Acromegalic patients with macro- or giant adenomas often had poor prognosis after surgery. Somatostatin analogues (SSAs) show high effectiveness in both tumor shrinkage and serum GH reduction. But the role of SSAs in pre-surgical treatment and the management among macro- and giant adenomas remains controversial.

PATIENTS AND METHODS

A total of 100 acromegalic patients with macro- or giant adenomas that underwent surgery in our institution between January 2010 and December 2016 were enrolled in the current retrospective study. The relationships between several potential parameters and surgical outcomes were further analyzed.

RESULTS

The overall long-term remission rate was 45% accompanied by gross total resection (GTR) rate of 44%. GTR (adjusted OR = 16.346; p = .001) and nadir GH level on OGTT 7 days after surgery (GH-7, adjusted OR = 0.660, p = .039) showed predictive significance for remission after surgery. Tumor size and invasiveness as well as cavernous sinus invasion were risk factors for residual tumor. For invasive macro- or giant adenomas, 6 of 15 patients achieved long-term remission with SSA pre-treatment whereas none of the 18 patients without any preoperative treatment was endocrine controlled.

CONCLUSIONS

Acromegalic patients did not gain more benefits from SSAs pretreatment. But, pre-treatment with SSA could be recommended to patients with invasive macro- or giant adenomas for significant improvement in long-term remission. GTR and GH-7 could be significant predictors in postoperative management of macro- or giant adenomas.

Pediatric Pituitary Adenoma: Case Series, Review of the Literature, and a Skull Base Treatment Paradigm

Background  Pediatric pituitary adenoma is a rare skull base neoplasm, accounting for 3% of all intracranial neoplasms in children and 5% of pituitary adenomas. Compared with pituitary tumors in adults, secreting tumors predominate and longer disease trajectories are expected due to the patient age resulting in a natural history and treatment paradigm that is complex and controversial. Objectives  The aims of this study were to describe a large, single-institution series of pediatric pituitary adenomas with extensive long-term follow-up and to conduct a systematic review examining outcomes after pituitary adenoma surgery in the pediatric population. Methods  The study cohort was compiled by searching institutional pathology and operative reports using diagnosis and site codes for pituitary and sellar pathology, from 1956 to 2016. Systematic review of the English language literature since 1970 was conducted using PubMed, MEDLINE, Embase, and Google Scholar. Results  Thirty-nine surgically managed pediatric pituitary adenomas were identified, including 15 prolactinomas, 14 corticotrophs, 7 somatotrophs, and 4 non-secreting adenomas. All patients underwent transsphenoidal resection (TSR) as the initial surgical treatment. Surgical cure was achieved in 18 (46%); 21 experienced recurrent/persistent disease, with secondary treatments including repeat surgery in 10, radiation in 14, adjuvant pharmacotherapy in 11, and bilateral adrenalectomy in 3. At the last follow-up (median 87 months, range 3-581), nine remained with recurrent/persistent disease (23%). Thirty-seven publications reporting surgical series of pediatric pituitary adenomas were included, containing 1,284 patients. Adrenocorticotropic hormone (ACTH)-secreting tumors were most prevalent (43%), followed by prolactin (PRL)-secreting (37%), growth hormone (GH)-secreting (12%), and nonsecreting (7%). Surgical cure was reported in 65%. Complications included pituitary insufficiency (23%), permanent visual dysfunction (6%), chronic diabetes insipidus (DI) (3%), and postoperative cerebrospinal fluid (CSF) leak (4%). Mean follow-up was 63 months (range 0-240), with recurrent/persistent disease reported in 18% at the time of last follow-up. Conclusion  Pediatric pituitary adenomas are diverse and challenging tumors with complexities far beyond those encountered in the management of routine adult pituitary disease, including nuanced decision-making, a technically demanding operative environment, high propensity for recurrence, and the potentially serious consequences of hypopituitarism with respect to fertility and growth potential in a pediatric population. Optimal treatment requires a high degree of individualization, and patients are most likely to benefit from consolidated, multidisciplinary care in highly experienced centers.

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.

Daily life reflections of acromegaly guidelines

PURPOSE

To determine the differences in acromegaly diagnosis, treatment, and follow-up among Turkish endocrinologists, and to investigate how the published guidelines are applied in clinical practice.

METHODS

The questionnaire was formatted as an electronic survey, conducted between November and December 2015, and sent weekly for 6 weeks via e-mail to 528 endocrinologists in Turkey.

RESULTS

The questionnaire was answered by 37.4 % of endocrinologists. Insulin-like growth factor-1 and nadir growth hormone level after 75 g oral glucose tolerance test (nadir GH-OGTT) were the most commonly preferred methods for the initial diagnosis. A total of 49.5 % of the participants reported using preoperative medical therapy (MT) either routinely or on a case-to-case basis. Somatostatin analogs were the most commonly used drugs, both in pre- and postoperative MT. Disease activity following surgery was assessed in the 3rd postoperative month using IGF-1 levels. Similarly, IGF-1 monitoring was preferred in the follow-up period. Monitoring nadir GH-OGTT levels was the most commonly used method in the assessment of discordant test results. The dose titration was done at month 3 after the start of MT. Resistance to SRLs was considered after using the maximal dose for at least 6 months. Pegvisomant was generally used in second- and third-line therapy. Similarly, cabergoline was not preferred in monotherapy by the majority of participants. Radiotherapy was considered in patients with incomplete response to surgery and medical treatments.

CONCLUSIONS

Although there were subtle differences, clinical practice guidelines were usually followed among Turkish endocrinologists.