Discordant growth hormone and IGF-1 levels post pituitary surgery in patients with acromegaly naïve to medical therapy and radiation: what to follow, GH or IGF-1 values?

Effect of Cabergoline on weight and glucose metabolism in patients with acromegaly

PURPOSE

Cabergoline (CAB) has shown to have benefic effects on the metabolism in different clinical settings but its metabolic role in acromegaly disease has not been studied yet. Aim of our study was to evaluate the impact of CAB on glucose metabolism and weight in patients with acromegaly.

METHODS

All patients with acromegaly undergoing continuous treatment with CAB for at least 6 months were retrospectively screened. Exclusion criteria were discontinuation of CAB for more than one month, change of antidiabetic or other therapy for acromegaly, concomitant untreated hormonal deficiency, initiation of pregnancy and/or breastfeeding. All patients were evaluated in terms of biochemical disease control, glucose metabolism and weight at baseline (T0) and after the introduction of CAB therapy at 6 (T6) and 12 months (T12).

RESULTS

Twenty-six patients (15 females and 11 males) were evaluated at T0 and T6 and 19 patients (12 females and 7 males) were also evaluated at T12. Insulin-like growth factor I (IGF-I) and prolactin (PRL) levels were significantly lower at T6 and T12 compared to baseline (p < 0.001 for IGF-I, p < 0.05 for PRL) even if no further differences were observed between T12 and T6. Considering the entire cohort, no differences were appreciated regarding the metabolic parameters but a significant reduction in weight and body mass index (BMI) was observed at both T6 (p = 0.009 for weight, p = 0.021 for BMI) and T12 (p = 0.014 for weight, p = 0.017 for BMI) compared to baseline.

CONCLUSION

Our results confirm the efficacy of CAB in providing a significant improvement in the biochemical disease control but do not demonstrate a marked benefit on glucose metabolism of acromegaly patients. In such patients, CAB appears to have a rapid effect on weight and BMI, with significant changes noticeable as early as 6 months and persisting for at least 12 months.

Discordant biochemical parameters of acromegaly remission do not influence the prevalence or aggressiveness of metabolic comorbidities: a single-center study

Purpose

The discrepancy between the biomarkers of disease's activity in acromegalic patients (GH and IGF-1) is almost frequent representing a challenge for the development of comorbidities in the long term. The aim of this study was to evaluate the prevalence and severity of metabolic comorbidities (diabetes, hypertension, and dyslipidemia) in surgically treated acromegalic patients with disease control and discordant GH and/or IGF-1 levels compared with those with concordant values.

Patients and methods

Retrospective monocentric observational study on acromegalic surgically treated patients with biochemical remission (group A) or mild discordant GH or IGF-1 levels (group B). Metabolic complications and medical therapy were assessed at diagnosis and at the last follow-up visit. Severity of the disease was set for drug titration or shift to another molecule or more than before.

Results

There were 18 patients that met the inclusion criteria [group A: nine patients; group B: nine patients, follow-up 7 years (IQR 5.0;11.25)]. The prevalence of female patients was significantly higher in the remission group compared with the discordant group (p < 0.02). Considering metabolic complications, at the last follow-up, 61.1% was affected by hypertension, 33.3% by diabetes, and 61.1% by dyslipidemia, without differences between groups. Drug characteristics (dose, shift, number) during the follow-up did not differ significantly between groups.

Conclusion

Metabolic complications, mainly dyslipidemia, are frequent in cured acromegalic patients, but GH/IGF-1 discrepancy does not seem to represent a risk factor for their presence or persistence. More extended studies are needed to confirm our results in a long-term period.

Survivin: A Potential Marker of Resistance to Somatostatin Receptor Ligands

CONTEXT

Invasive and somatostatin receptor ligand (SRL)-resistant pituitary tumors represent a challenge in the clinical practice of endocrinologists. Efforts have been made to elucidate reliable makers for both. Survivin and eukaryotic translation initiation factor-binding protein 1 (4EBP1) are upregulated in several cancers and involved in apoptosis and cell proliferation.

OBJECTIVE

We explored the role of these markers in somatotropinomas.

METHODS

Immunostains for survivin and 4EBP1, and also for somatostatin receptor type 2 (SSTR2), Ki-67, and cytokeratin 18, were analyzed in tissue microarrays containing 52 somatotropinoma samples. Tumor invasiveness was evaluated in all samples while drug resistance was evaluated in 34 patients who received SRL treatment. All these parameters were correlated with first-generation SRL (fg-SRL) responsiveness and tumor invasiveness.

RESULTS

Low survivin expression (P = 0.04), hyperintense signal on T2 weighted image (T2WI) (P = 0.01), younger age (P = 0.01), sparsely granular adenomas (SGA) (P = 0.04), high postoperative growth hormone (GH) and insulin-like growth factor-1 (IGF-1) levels (P = 0.049 and P < 0.001, respectively), and large postoperative tumor size (P = 0.02) were associated with resistance to fg-SRL. Low survivin and SSTR2 expression and high 4EBP1 expression were associated with SGA (P = 0.04, P = 0.01, and P = 0.001, respectively). Younger age (P = 0.03), large tumor pre- and postoperative (P = 0.04 and P = 0.006, respectively), low SSTR2 expression (P = 0.03), and high baseline GH and IGF-1 (P = 0.01 and P = 0.02, respectively) were associated with tumor invasiveness. However, survivin, 4EBP1, Ki-67, and granulation patterns were not associated with tumor invasion.

CONCLUSION

This study suggests that low survivin expression is predictive of resistance to fg-SRL in somatotropinomas, but not of tumor invasiveness.

Insulin-Like Growth Factor 1 in the Early Postoperative Assessment of Acromegaly

OBJECTIVES

Assessment of surgical outcome in acromegaly is typically recommended at 3 to 6 months following surgery. The purpose of this study was to determine if insulin-like growth factor 1 (IGF-1) concentrations at 6 weeks were equally predictive of surgical outcomes compared with IGF-1 concentrations at 3 to 6 months postoperatively applying newer IGF-1 assays.

METHODS

Retrospective review of patients with newly diagnosed acromegaly who had surgery between 2013 and 2020 and had postoperative IGF-1 measured by 6 weeks and 3 to 6 months.

RESULTS

At 6 weeks, 20 (35%) of the total 57 had normal IGF-1 and became abnormal in 1 at 3 to 6 months, whereas 37 (65%) of 57 had abnormal IGF-1 concentrations at 6 weeks, which normalized in 1 patient by 3 to 6 months. In patients who changed clinical status, IGF-1 at 6 weeks was within ±0.1-fold of normal. Although a difference was seen between median IGF-1 concentrations (286 vs 267 ng/mL, P = .009) at 6 weeks and 3 to 6 months, the mean reduction was small (-19.9 ng/mL).

CONCLUSIONS

Compared with 3 to 6 months, use of IGF-1 at 6 weeks was associated with a change in clinical status in 3.5% of patients. Therefore, in most patients, IGF-1 at 6 weeks can be used to assess clinical outcome via newer assays.

[Discordant parameters of insulin-like growth factor 1 and growth hormone in the diagnosis and monitoring of acromegaly]

Acromegaly is a rare endocrine disorder associated with multiple complications and increased mortality. Timely diagnosis and adequate treatment can bring the life expectancy of patients with acromegaly closer to the general population level. The tests for the diagnosis of acromegaly are measurement of both serum GH, and GH after oral glucose administration; serum insulin-like growth factor-1 (IGF-1). However, in clinical practice, up to 39% of patients with discordant results are found. The patients with discordant GH and IGF-1levels, are the most difficult to manage. This review discusses the prevalence of discordant GH and IGF-1 outcomes in patients with acromegaly; factors causing this discrepancy; the impact of hormone levels on treatment outcomes. Although endocrinologists are used to dealing with this discrepancy in clinical practice for many years, discordant patients'outcome remains uncertain and undefined The optimal treatment should be individually tailored for each patient, taking into account all clinical parameters.

Revisiting the Role of Insulin-like Growth Factor-1 Measurement After Surgical Treatment of Acromegaly

CONTEXT

In the management of growth hormone (GH)-secreting pituitary adenomas, the oral glucose tolerance test (OGTT) has been the gold standard not only for diagnoses but also for the determination of biochemical remission. Insulin-like growth factor-1 (IGF-1) is an essential biomarker, although it should be adjusted for both age and sex.

OBJECTIVE

We evaluated whether IGF-1 levels could serve as a reliable alternative to an OGTT for disease monitoring after the surgical treatment of acromegaly. We retrospectively reviewed the medical records of 320 patients who underwent surgical resection of their GH-secreting pituitary tumors at the Severance hospital. Receiver operator characteristic (ROC) analyses were performed to validate the accuracy of IGF-1 levels for the assessment of remission. In addition, regression analyses were performed to identify factors associated with discrepancy between OGTT and IGF-1 levels.

RESULTS

Except for 1 week after surgery, ROC analyses showed an area under the curve of greater than 0.8 for IGF-1 at all time points. Of 320 patients, 270 achieved endocrine remission after surgery alone. Among these patients, IGF-1 levels were normalized in 250 patients. The mean duration from surgery to IGF-1 normalization was 4.7 months. Regression analyses demonstrated that risk of failed IGF-1 normalization was increased by 3.1-fold when the tumor invaded the cavernous sinus and increased by 9.0-fold in patients with incomplete tumor removal.

CONCLUSION

IGF-1 level is a reliable alternative to OGTT and plays a valuable role in monitoring acromegaly status.

Discordant biological parameters of remission in acromegaly do not increase the risk of hypertension or diabetes: a study with the Liege Acromegaly Survey database

PURPOSE

Acromegaly is a rare disease due to growth hormone (GH)-secreting pituitary adenoma. GH and IGF-1 levels are usually congruent, indicating either remission or active disease; however, a discrepancy between GH and IGF-1 may occur. We aimed to evaluate the outcome of diabetes mellitus (DM) and hypertension (HT) in acromegalic patients with congruent GH and/or IGF-1 levels vs. discordant biochemical parameters.

METHODS

Retrospective analysis of the data of 3173 patients from the Liege Acromegaly Survey (LAS) allowed us to include 190 patients from 8 tertiary referral centers across Europe, treated by surgery, with available data concerning DM and HT both at diagnosis and at the last follow-up (LFU). We recorded the number of anti-HT and anti-DM drugs used at the first evaluation and at LFU for every patient.

RESULTS

Ninety-nine patients belonged to the REM group (concordant parameters), 65 patients were considered as GH_dis (high random GH/controlled IGF-1), and 26 patients were considered as IGF-1_dis (high IGF-1/controlled random GH). At diagnosis, 72 patients (37.8%) had HT and 54 patients had DM (28.4%). There was no statistically significant difference in terms of the number of anti-HT and anti-DM drugs at diagnosis versus LFU (mean duration: 7.3 ± 4.5 years) between all three groups.

CONCLUSION

The long-term outcome of DM and HT in acromegaly does not tend to be more severe in patients with biochemical discordance in comparison with patients considered as in remission on the basis of concordant biological parameters, suggesting that patients with biochemical discordance do not require a closer follow-up.

ACROMEGALY AND A GIANT RETROPERITONEAL LIPOSARCOMA PRODUCING IGF-1

Objective

Liposarcoma is the most common histotype of retroperitoneal sarcomas, representing up to 45% of all cases. We report a rare combination of acromegaly and liposarcoma in the same individual.

Methods

Laboratory and imaging studies including an oral glucose tolerance test, measurements of growth hormone (GH) and insulin-like growth factor-1 (IGF-1), and a computed tomography scan were performed.

Results

The patient was a 60-year-old male with a history of acromegaly diagnosed on the basis of elevated IGF-1 at 1,373 ng/mL (age-appropriate reference range is 87 to 225 ng/mL) and macroadenoma treated with transsphenoidal surgery. He presented 8 years later with a history of abdominal distension and weight loss. Physical examination was notable for a right-sided abdominal mass that was tense and non-fluctuant. Two years earlier, he had a post oral glucose tolerance test GH level <0.25 ng/mL and IGF-1 level of 256 ng/mL (age-appropriate reference range is 55 to 206 ng/mL). Pituitary magnetic resonance imaging reported a 3.7 × 2.0-mm left-sided parasagittal lesion. Computed tomography scan showed a 25.0 × 22.0 × 32.3-cm heterogeneous giant mass in the right abdomen corresponding to a liposarcoma causing displacement of kidney, liver, and bowel loops. The patient was treated with a complete en bloc resection of the liposarcoma with the right kidney (45 × 33 × 17 cm) and tumor (9,400 g). Immunohistochemical examination revealed positive IGF-1 and GH staining. The patient suffered postoperative gastrointestinal bleeding that resulted in hemorrhagic shock and died on the 29th postoperative day after a cardiorespiratory arrest.

Conclusion

Acromegalic patients are at increased risk of developing various types of neoplasms. This is the first documented coexistence of liposarcoma and history of acromegaly.

Serum phosphate: Does it more closely reflect the true state of acromegaly?

An increased serum phosphate (P) level is common in acromegaly patients, however, the relationships among P, growth hormone (GH), insulin-like growth factor 1 (IGF-1) and disease status remain unknown. To reveal these relationships, we examined the association of P with comprehensive clinical data. We measured the serum P, calcium, GH, oral glucose tolerance test-GH (OGTT-GH), IGF-1, and insulin-like growth factor binding protein-3 (IGBP-3) levels in 103 acromegaly patients. SAGIT® was used to assess the disease status comprehensively. Spearman's rank correlation coefficient was obtained to evaluate the associations among the above parameters. Stepwise multiple linear regression analysis was performed to investigate factors independently associated factors with the SAGIT scores. The area under the receiver operating characteristic curve (AUCROC) was used to evaluate the efficacy of the percentage change in the serum phosphate level in predicting remission in patients with postoperatively discordant GH and IGF-1 levels. Hyperphosphatemia was found in 68.9% of patients at baseline. The serum P level was higher in the non-remission group, but no correlation was found between hyperphosphatemia and remission. We revealed a significant correlation between the P level and SAGIT® score in patients both preoperatively (r = 0.659, p = 0.000) and 1-year postoperatively without remission patients (r = 0.534, p = 0.027). All biochemical levels decreased significantly postoperatively, and the GH and OGTT-GH levels achieved early stability (1 month); however, the P, IGF-1 and IGBP-3 levels showed a gradual decline. A percentage change in P of -8.12% is recommended as a cut-off value for predicting remission in patients with postoperatively discordant GH and IGF-1 levels. As a metabolic product which affected by the GH/IGF-1 axis, serum P appears to more closely reflect the comprehensive disease status in acromegaly. When the GH and IGF-1 levels are discordant during follow-up, perioperative change in the P level may be a potential predictor of remission.

[Not Available]

Acromegaly is characterized by increased release of growth hormone (GH) and, consequently, Insulin-Like Growth Factor I (IGF-I), most often by a pituitary adenoma. Prolonged exposure to excess hormone leads to progressive somatic disfigurement and a wide range of systemic manifestations that are associated with increased mortality. Transsphenoidal adenomectomy is the treatment of choice of GH-secreting pituitary tumors but surgical cure is not achieved in around 50% of patients, then adjuvant treatment is necessary. Mortality in acromegaly is normalized with biochemical control and has decreased in the last decade with the increased use of adjuvant therapy. Both GH and IGF-I are currently biomarkers for assessing disease activity in patients with acromegaly. However, discordance between GH and IGF-I results is encountered in a quarter of treated patients. The impacts of such a discrepancy over mortality and morbidity and the risk of biochemical and/or clinical recurrence are unclear. Moreover, despite a good biochemical control, some symptoms persist, leading to a decreased quality of life. Back pain due to vertebral fractures seem to be frequent in these patients and underdiagnosed. In patients with acromegaly, bone mineral density is not a reliable predictor of fracture risk. A more accurate evaluation of bone microstructural alterations associated with GH hypersecretion and vertebral fractures may be provided by new radiological devices analyzing alteration of trabecular microarchitecture, leading to a better prevention. © 2019 Published by Elsevier Masson SAS. All rights reserved. Cet article fait partie du numéro supplément Les Must de l'Endocrinologie 2019 réalisé avec le soutien institutionnel de Ipsen-Pharma.

Delayed Remission of Growth Hormone-Secreting Pituitary Adenoma After Transsphenoidal Adenectomy

OBJECTIVE

To investigate the clinical characteristics of delayed remission (DR) of growth hormone (GH)-secreting pituitary adenoma after transsphenoidal adenectomy and inform follow-up treatments.

METHODS

We retrospectively reviewed 87 patients who had undergone transsphenoidal surgery for acromegaly. Demographic, radiological, and endocrinological data were reviewed before, immediately after, 3 months after, and in the long term (2.4 ± 1.1 years) after surgery. The definition of DR was that patients did not achieve GH remission immediately, 3 months, or later after surgery, but did so in the long term without any additional postoperative treatment.

RESULTS

Fifty-one patients (58.6%) achieved long-term GH remission. There were 24 (27.6%) DR patients immediately postoperatively and 9 (10.3%) DR patients 3 months postoperatively. On average, the 24 DR patients achieved remission at 10.2 (range, 3-32) months. Immediate postoperative random and nadir GH after an oral glucose load were significantly lower in the DR group than in the nonremission group (2.73 ± 3.17 and 2.03 ± 2.59 vs. 8.05 ± 10.35 and 5.55 ± 5.91 μg/L, respectively). Three-month postoperative nadir GH was significantly lower in the DR group than in the nonremission group (1.63 ± 2.82 vs. 3.48 ± 4.25 μg/L, P = 0.007). Immediate postoperative random GH effectively predicted long-term remission (Spearman's ρ = 0.513, area under the curve = 0.905 > 0.90). However, the best predictor of long-term remission was 3-month postoperative nadir GH (Spearman's ρ = 0.728, area under the curve = 0.944 > 0.90), with 76.5% sensitivity and 97.2% specificity.

CONCLUSIONS

For certain groups of patients likely to achieve DR, additional treatments should not be performed early after surgery. Prolonged follow-up and close observation could help determine the therapeutic effect of surgery and guide postoperative treatments.

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.

Silent somatotroph pituitary adenomas: an update

Silent growth hormone adenomas (SGHA) are a rare entity of non-functioning pituitary neuroendocrine tumors. Diagnosis is invariably made post-operatively of a tumor immunopositive for GH (and Pit-1 in selected cases) but without clinical acromegaly. Mainly young females are affected, and tumors are often uncovered by investigation for headaches or oligoamenorrhea. Integration of clinical, pathological and biochemical data is required for proper diagnosis. Beside normal IGF-1 levels, a third of SGHAs displays elevated GH levels and some will eventually progress to acromegaly. Almost two-thirds will be mixed GH-prolactin tumors and sparsely-granulated monohormonal GH tumors seems the more aggressive subtype. Recurrence and need for radiation is higher than other non-functioning tumors so close follow-up is warranted.

Twenty-four-hour growth hormone profiling in the assessment of acromegaly

OBJECTIVES AND BACKGROUND

Recent guidelines recommend insulin-like growth factor (IGF-1), random growth hormone (GH) and nadir GH on an oral glucose tolerance test (OGTT) for assessment of acromegaly. At this Regional Centre, the 24-hour GH profile has also been used.

DESIGN PATIENTS AND MEASUREMENTS

We evaluated 57 GH profiles from 34 patients from 2008 to 2012. Samples were drawn every 2 hour and matched with 0800 GH, nadir GH after OGTT and IGF-1.

RESULTS

Correlations between the mean 13-point profiles and mean 5-point profile, OGTT nadir and 0800 GH were as follows: r = .99, .99 and .90, respectively (P < .01 for all). The correlation between the mean 13-point profiles and IGF-1 was r = .32 P = .02.Of 5 patients with very high 0800 GH preoperatively (≥20 μg/L), mean 13-point GH reduced by 88%-99% postoperatively. IGF-1 did not normalize in these patients, and all required extra treatment. Preoperatively, all patients had concordant 0800 GH and IGF-1. Postoperatively, 6 patients had 0800 GH <1 μg/L and high IGF-1; only 2 of these had a 13-point mean >1 μg/L, but 5 required further treatment.

CONCLUSIONS

Growth hormone profiling is not necessary for assessing the majority of patients with acromegaly if there is confidence in the local IGF-1 assay. When undertaken, a 5-point profile is adequate. In patients with very high 0800 GH, 24-hour profiling was useful in demonstrating partial therapeutic success but did not alter management. Further work is needed to explore the possible role of GH profiling in stratifying patients with discordant IGF-1 and GH results.

SOCS2 polymorphisms are not associated with clinical and biochemical phenotypes in acromegalic patients

PURPOSE

Suppressor of cytokine signaling 2 (SOCS2) is a STAT5b-regulated gene and one of its functions is to influence growth and development through negative regulatory effects on GH/IGF-1 pathway. So, we evaluate the potential influence of SOCS2 single nucleotide polymorphisms (SNPs) on clinical and laboratorial characteristics of a large cohort of Brazilian patients with acromegaly.

METHODS

Four SOCS2 SNPs (rs3782415, rs3816997, rs3825199 and rs11107116) were selected and genotyped by real-time PCR using specific Taqman probe assays. A total of 186 patients (116 women, age range 26-88 years) were evaluated.

RESULTS

No association of SOCS2 genotypes was observed with none of the following clinical and laboratorial characteristics: age, sex, body mass index, comorbidities, basal GH, oral glucose tolerance test GH nadir, IGF-I, ULNR-IGF-I.

CONCLUSION

Despite of the key role of SOCS2 in the regulation of GH receptor signaling, we did not find any significant association between SOCS2 polymorphisms and acromegaly.

Surgical treatment of acromegaly according to the 2010 remission criteria: systematic review and meta-analysis

BACKGROUND

In 2010, the Acromegaly Consensus Group revised the criteria for cure of acromegaly and thus rates of surgical remission need to be revised in light of these new thresholds. Two subgroups consisted of patients with discordant GH and IGF-1 levels and patients in remission according to the 2000 criteria, but not to the 2010 criteria, have been reported after adenomectomy and for these subgroups the precise incidence and management has not been established. The objective of the study was to update rates of surgical remission and complications and to evaluate the incidence, management, and long-term outcome of the two previously described subgroups of patients.

METHODS

Systematic review and meta-analysis of surgical series that defined remission according to the 2010 biochemical criteria.

RESULTS

We included 13 studies (1105 patients). The pooled rate of overall surgical remission was 54.8 % (95 % CI 44.4-65.2 %), and 72.2 % with previous criteria. Remission was achieved in 77.9 % (95 % CI 68.1-87.6 %) of microadenomas; 52.7 % (95 % CI 41-64.4 %) of macroadenomas; 29 % (95 % CI 20.1-37.8 %) of invasive and 68.8 % (95 % CI 60-77.6 %) of non-invasive adenomas. Complication rates were 1.2 % (95 % CI 0.6-1.9 %) for CSF leak, 1.3 % (95 % CI 0.6-2.1 %) for permanent diabetes insipidus, 8.7 % (95 % CI 4.8-12.5 %) for new anterior pituitary dysfunction and 0.6 % (95 % CI 0.1-1.1 %) for severe intraoperative hemorrhage. We identified an intermediate group of patients, defined as: (1) Remission according to one, but not the other biochemical criteria (GH or IGF-1) or 2010 criteria (14.3 % and 47.1 % cases), (2) Remission according to 2000, but not 2010 criteria (13.2-58.8 % cases). Two studies reported a remission rate of 56.5 % and 100 %, in the two subgroups respectively, in a long-term outcome without adjuvant therapy.

CONCLUSIONS

Overall remission with transsphenoidal surgery is achieved in ∼55 % of patients. For the intermediate group of patients, future prospective studies with long-term follow-up are required to determine the long-term biochemical remission rates and clinical implications.

The ongoing challenge of discrepant growth hormone and insulin-like growth factor I results in the evaluation of treated acromegalic patients: a systematic review and meta-analysis

OBJECTIVE

Growth hormone (GH) and insulin-like growth factor I (IGF-I) are the principal biomarkers used to assess disease activity in acromegaly, and any discrepancy between them renders interpretation of results inconclusive. Purpose of this study was to assess the frequency of this discrepancy and identify parameters that might affect its occurrence.

DESIGN

A systematic review of MEDLINE and Scopus was performed (1987-2013) followed by a meta-analysis to address the frequency of discrepant results between GH and IGF-I levels. Meta-regression and subgroup analyses were performed assessing the effects of the year of publication, the different types of GH testing and GH assays used, as well as the impact of treatment with somatostatin analogues (SSAs) on the occurrence of this discrepancy.

RESULTS

The analysis retrieved 39 eligible studies totalling 7071 patients. The pooled discordance rate between GH and IGF-I was 25·7% (95% CI: 22·3-29·4), and the predominant format was that of elevated IGF-I with normal GH levels (15·3%, 95% CI: 12·5-18·7). No significant correlation between the discordance rate and the year of publication was shown; whereas, the use of ultrasensitive GH assays resulted in higher discordance rates (30·7%, 95% CI: 25·9-35·9 vs 19·8%, 95% CI: 14·1-27·2, P = 0·04) as did treatment with SSAs (32·5%, 95% CI: 27·8-37·4) vs (21·6%, 95% CI: 17·8-25·6, P = 0·001).

CONCLUSIONS

Discrepancy between GH and IGF-I results is encountered in a quarter of treated patients with acromegaly, especially when using ultrasensitive GH assays or in patients receiving SSAs, a fact that the clinician should take into consideration when making clinical decisions.

DISCORDANCE BETWEEN GH AND IGF-1 LEVELS IN TURKISH ACROMEGALIC PATIENTS

OBJECTIVE

Discordance between insulin-like growth factor-1 (IGF-1) and growth hormone (GH) levels is an important problem in the follow-up of patients diagnosed with acromegaly. Our aims were to evaluate the discordance between IGF-1 and GH levels and compare the performance of different cut-off levels for the nadir in GH (GHn) in acromegalic patients.

METHODS

The study included 63 acromegalic patients in a follow-up at a tertiary care university hospital facility. Levels of IGF-1, IGF binding protein-3 (IGFBP-3), and GH were investigated. The baseline GH and GHn levels were evaluated after an oral glucose tolerance test (cut-offs of 0.4 and 1 ng/mL, respectively). The discordance rates between GHn and IGF-1 levels, and IGF-1/IGFBP-3 ratios were determined.

RESULTS

We first adopted a GHn cut-off value of 1 ng/mL and found that 27 patients (42.9%) exhibited biochemical remission (BR) (IGF-1 <95^th percentile, GH <1), and 25 patients (39.7%) had no BR (NBR) (IGF-1 ≥95^th percentile, GH >1). Discordance in the presence of normal IGF-1 and nonsuppressed GH (DC1) occurred in 2 of 63 (3.2%) patients; discordance in the presence of high IGF-1 and suppressed GH (DC2) occurred in 9 of 63 (14.3%) patients. If the GHn cut-off value adopted was 0.4 ng/mL, the distributions were 17 of 63 (27.0%) patients in BR, 29 of 63 (46.0%) patients in NBR, 12 of 63 (19.0%) in DC1, and 5 of 63 (7.9%) patients in DC2. If only the baseline GH values were considered, the distributions were very similar to those with a GHn cut-off value of 0.4 ng/mL. The IGF-1/IGFBP-3 ratio was lowest in the BR group.

CONCLUSION

Adopting a GHn cut-off value of 0.4 ng/mL did not increase the test performance compared with baseline GH only. In contrast, in the follow-up of acromegalic patients, the IGF-1/IGFBP-3 ratio might be a useful measurement when discordance between IGF-1 and GH levels occurs. We propose that these values be considered in clinical practice.

ABBREVIATIONS

BR = biochemical remission DC1 = discordance group 1 DC2 = discordance group 2 DM = diabetes mellitus GH = growth hormone GHn = nadir in GH IGF-1 = insulin-like growth factor-1 IGFBP-3 = IGF binding protein-3 LAR = long-acting release NBR = not in biochemical remission OGTT = oral glucose tolerance test.

The clinical and cardiometabolic effects of d3-growth hormone receptor polymorphism in acromegaly

PURPOSE

Exon 3-deleted GH receptor variant (d3-GHR) is associated with increased responsiveness to exogenous GH. The aim of this study was to determine the effect of d3-GHR polymorphism on the GH/IGF-1 relationship, clinical parameters, and comorbidity in acromegalic patients.

METHODS

The study included 118 acromegalic patients (61 female and 57 male; mean age: 50.3 ± 12.2 years) and 108 healthy controls (94 female and 14 male: mean age: 41.1 ± 11.1 years). The prevalence of GHR genotypes was evaluated via PCR.

RESULTS

In all, 71 (60.2%) patients had the fl/fl-GHR genotype, 40 (33.9%) were heterozygous for the fl/d3-GHR genotype, and 7 (5.9%) were homozygous for the d3/d3-GHR genotype. The prevalence of fl/fl-GHR, fl/d3-GHR, and d3/d3-GHR genotypes in the control group was 57.4, 29.6, and 13.0%, respectively-similar prevalences as in the patient group. Patients that were heterozygous and homozygous for the d3 allele were subgrouped (d3-GHR subgroup), and were compared to those with the fl/fl-GHR genotype (fl/fl-GHR subgroup). Anthropometric measures, features of pituitary adenoma, and baseline GH and IGF-1 levels were similar in both subgroups. The prevalence of coronary artery disease, hypertension, hyperlipidemia, type 2 diabetes mellitus, and multinodular goiter did not differ between patient subgroups. In total, 24 (20.3%) of the patients had cancer and the prevalence of cancer was similar in the d3-GHR (14.9%) and fl/fl-GHR (23.9%) subgroups (P = 0.23). More of the acromegalic patients that were d3 carriers had discordant GH and IGF-1 levels at baseline and post surgery, but the difference was not significant. A significant correlation between basal GH and IGF-1 levels was observed only in the patients with the fl/fl-GHR genotype (R(2) = 0.227, P < 0.001).

CONCLUSION

The d3-GHR variant genotype did not have an effect on clinical features or comorbidity in acromegalic patients, but it might play a role in GH/IGF-1 level discordance in acromegaly.

Discordance between growth hormone and insulin-like growth factor-1 after pituitary surgery for acromegaly: a stepwise approach and management

INTRODUCTION

Follow-up management of patients with acromegaly after pituitary surgery is performed by conducting biochemical assays of growth hormone (GH) and insulin-like growth factor-1 (IGF1). Despite concordant results of these two tests in the majority of cases, there is increasing recognition of patients who show persistent or intermittent discordance between GH and IGF1 (normal GH and elevated IGF1 or vice versa).

METHOD

In this narrative review, the last three decades materials on the issue of discrepancy between GH and IGF1 were thoroughly assessed.

RESULTS

Various studies have obtained different discordance rates, ranging from 5.4 to 39.5%. At present, despite the use of current sensitive assays and more stringent criteria to define remission, the rate of discordance still remains high. A number of mechanisms have been proposed to explain the postoperative discordance of GH and IGF1 including; altered dynamics of the GH secretion after surgery, early postoperative hormone assay, inaccurate or less sensitive tests and laboratory errors, too high cut-off point for GH suppression in the GH assays, GH nadir values not adjusted to age, sex, and body mass index, the influence of concomitant medication, co-existing physiologic and pathologic conditions, and many other proposed reasons. Nevertheless, the underlying mechanisms are still far from clear, and the solution continues to evade complete elucidation. Similarly, the impacts of such a discrepancy over mortality and morbidity and the risk of biochemical and/or clinical recurrence are unclear.

CONCLUSION

As a challenging clinical problem, a stepwise evaluation and management of these patients appears to be more rational.

Role of IGF1-(CA)19 promoter microsatellite in the clinical presentation of acromegaly

BACKGROUND

A highly polymorphic Cytosine-Adenosine (CA) repeat sequence microsatellite has been identified in the promoter region of IGF1 gene. Several studies investigated the relationship between IGF1-(CA)n polymorphism and IGF1 levels, with conflicting results. Aim of this study was to investigate the influence of this polymorphism on clinical and biochemical characteristics of acromegalic patients.

METHODS

Eighty-eight acromegalic patients and 104 normal subjects were included in the study. Blood DNA was extracted and analysed by microsatellite technique using capillary electrophoresis. Patients and controls were subdivided in 19/19 [homozygous for the (CA)19 allele], 19/X [heterozygous for the (CA)19 allele] and X/X (any other genotype).

RESULTS

The genotype frequency was significantly different between patients and controls, the proportion of 19/19 being lower (28·4% vs. 50·0%) and 19/X and X/X higher in acromegalic patients than in controls (P = 0·004). There were no significant differences in age, gender, basal and nadir GH, IGF1-SDS, tumour size, metabolic parameters, outcome and treatment among the three groups. The different frequency of genotypes in acromegalic patients vs. controls, as well as the lack of relationship between IGF1-(CA)n polymorphism and clinical and biochemical data in acromegalic patients, was confirmed using an additional alternative genotyping considering (CA)19 and (CA)20 homozygotes and heterozygotes vs. alleles with more than 19 of 20 repeats or less.

CONCLUSIONS

Our results do not support the hypothesis that IGF-(CA)n alleles may have a significant role in determining clinical, biochemical and outcome of patients with acromegaly. The possible role of IGF1 polymorphism on susceptibility to acromegaly remains to be investigated.

Multicenter study on adult growth hormone level in postoperative pituitary tumor patients

The objective of this study is to observe the adult growth hormone level in postoperative pituitary tumor patients of multi-centers, and explore the change of hypophyseal hormones in postoperative pituitary tumor patients. Sixty patients with pituitary tumor admitted during March, 2011-March, 2012 were selected. Postoperative hypophyseal hormone deficiency and the change of preoperative, intraoperative, and postoperative growth hormone levels were recorded. Growth hormone hypofunction was the most common hormonal hypofunction, which took up to 85.0 %. Adrenocortical hormone hypofunction was next to it and accounted for 58.33 %. GH + ACTH + TSH + Gn deficiency was the most common in postoperative hormone deficiency, which took up to 40.00 %, and GH + ACTH + TSH + Gn + AVP and GH deficiencies were next to it and accounted for 23.33 and 16.67 %, respectively. The hormone levels in patients after total pituitary tumor resection were significantly lower than those after partial pituitary tumor resection, and the difference was statistically significant; growth hormone and serum prolactin levels after surgery in two groups were decreased, and the difference was statistically significant. The incidence rate of growth hormone deficiency in postoperative pituitary tumor patients is high, which is usually complicated with deficiency of various hypophyseal hormones. In clinical, we should pay attention to the levels of the hypopnyseal hormones, and take timely measures to avoid postoperative complications.

Determination of nadir growth hormone concentration cutoff in patients with acromegaly

OBJECTIVE

The purpose of this study was to define an appropriate nadir growth hormone (nGH) cutoff for patients with acromegaly in remission using the Access Ultrasensitive human growth hormone (hGH) assay (Beckman Coulter, Brea, CA).

METHODS

This cross-sectional study included 55 acromegalic subjects and 41 healthy adult volunteers. All subjects underwent oral glucose tolerance testing (OGTT) for growth hormones (GHs). An optimal cutoff for nGH for patients with active disease versus those in remission was determined using receiver-operating curve analysis.

RESULTS

The nGH of 0.53 ng/mL revealed a sensitivity of 97% (95% confidence interval [CI], 83-100%) and a specificity of 100% (95% CI, 82-100%). All 22 patients with acromegaly in remission suppressed GH to <1 ng/mL, 20/22 (91%) suppressed to <0.4 ng/mL, and 19/22 (86%) of subjects suppressed to <0.3 ng/mL (the maximum nGH measured in our healthy volunteer group).

CONCLUSION

When using the Access Ultrasensitive hGH assay for OGTT, a cutoff of 0.53 ng/mL was found to most accurately differentiate patients with acromegaly in remission from those with active disease.

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

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

Diagnosis of acromegaly: state of the art

INTRODUCTION

Biochemical diagnosis of acromegaly relies on measurement of insulin-like growth factor-1 (IGF-1) and growth hormone (GH). An elevated IGF-1 level above the age- and gender-specific normal range and nonsuppression of GH to oral glucose load to a nadir < 0.4 ng/ml in sensitive assays are currently considered diagnostic of acromegaly. Lack of normative data for both IGF-1 and GH across a wide range of populations and ethnicities, interassay and intraassay laboratory variability, pulsatility of GH secretion, and effects of medications and hormones may confound interpretation of these biochemical tests.

AREAS COVERED

Clinical situations in which acromegaly should be suspected and/or investigated. Strengths and limitations of current IGF-1/GH assays are discussed. Clinical scenarios with discordant GH suppression test and IGF-1 levels and, briefly, acromegaly in pregnancy, prolactin-cosecreting tumors, familial acromegaly, and nonpituitary acromegaly are also discussed.

EXPERT OPINION

Serum IGF-1 is the cornerstone and in most cases the stand-alone test in the diagnosis and follow-up in patients with acromegaly. Diagnosis depends on the accurate and reliable measurement of serum IGF-1. GH suppression testing is currently used in limited clinical setting. Standardization of IGF-1 assay and development of normative data across a wide population base are needed. Newer bioassays for IGF-1 hold promise for future.

Management options for persistent postoperative acromegaly

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