The immune cell infiltrate in the tumour microenvironment of phaeochromocytomas and paragangliomas

Emerging evidence suggests the composition of the tumour microenvironment (TME) correlates with clinical outcome and that each tumour type has a unique TME including a variable population of inflammatory cells. We performed immunohistochemistry on 65 phaeochromocytoma and paraganglioma (PPGL) tumour samples with 20 normal adrenal medulla samples for comparison. The immune cells assessed were macrophages, lymphocytes and neutrophils, and we compared the proportion of infiltration of these immune cells with clinical and histopathological factors. There was a higher proportion of immune cells in tumour tissue compared to non-neoplastic adrenal medulla tissue, with a predominance of macrophages. There was a higher proportion of M2:M1 macrophages and T-helper lymphocytes in aggressive tumours compared to indolent ones. For SDHB-associated tumours, there was a higher proportion of M2 macrophage infiltration, with higher M2:M1 in aggressive SDHB PPGLs compared to indolent tumours. These data demonstrate that immune cells do infiltrate the TME of PPGLs, confirming that PPGLs are immunologically active tumours. Differences in the TME of PPGLs were observed between aggressive and indolent tumours. These differences could potentially be exploited as an aid in predicting tumour behaviour.

Monitoring patients receiving dopamine agonist therapy for hyperprolactinaemia

The surveillance strategy for patients taking low dose cabergoline for hyperprolactinaemia is controversial. As more evidence has emerged that the risks of cardiac valvulopathy in this population of patients are low, fewer and fewer endocrinologists adhere strictly to the original medicines and healthcare products agency MHRA guidance of "at least" annual echocardiography. Strict adherence to this guidance would be costly in monetary terms (£5.76 million/year in the UK) and also in resource use (90,000 extra echocardiograms/year). This article reviews the proposed pathophysiological mechanism underlying the phenomenon of dopamine agonist valvulopathy, the characteristic echocardiographic changes seen, summarises the published literature on the incidence of valvulopathy with low dose cabergoline and examines the previous and current evidence-based screening guidelines.

A meta-analysis of the prevalence of cardiac valvulopathy in hyperprolactinemic patients treated with Cabergoline

CONTEXT

Cabergoline is first line treatment for most patients with lactotrope pituitary tumors and hyperprolactinemia. Its use at high-dose in Parkinson's disease has largely been abandoned, because of its association with the development of a characteristic restrictive cardiac valvulopathy. Whether similar valvular changes occur in patients receiving lower doses for treatment of hyperprolactinemia is unclear, although stringent regulatory recommendations for echocardiographic screening exist.

OBJECTIVE

To conduct a meta-analysis exploring any link between the use of cabergoline for the treatment of hyperprolactinemia and clinically-significant cardiac valvulopathy.

DATA SOURCES

Full-text papers published up to and including January 2017 were found via PubMed and selected according to strict inclusion criteria.

STUDY SELECTION

All case-control studies were included where patients had received ≥6 months cabergoline treatment for hyperprolactinemia. Single case reports, previous meta-analyses, review papers and papers pertaining solely to Parkinson's disease were excluded. 13/76 originally selected studies met inclusion criteria.

DATA EXTRACTION

A list of desired data were compiled and extracted from papers by independent observers. Each also independently graded for paper quality (bias) and met to reach consensus.

DATA SYNTHESIS

More tricuspid regurgitation was observed (OR 3.74; 95% CI 1.79-7.8 p<0.001) in the cabergoline treated patients compared to controls. In no patient was tricuspid valve dysfunction diagnosed as a result of clinical symptoms. There was no significant increase in any other valvulopathy.

CONCLUSIONS

Treatment with low dose cabergoline in hyperprolactinemia appears to be associated with an increased prevalence of tricuspid regurgitation. The clinical significance of this is unclear and requires further investigation. 51.

Four generations of SDHB-related disease: complexities in management

SDHB mutations are linked to the familial paraganglioma syndrome type 4 (PGL4), which is associated with predominantly extra-adrenal disease and has high metastatic rates. Despite the lower penetrance rates in carriers of SDHB mutations compared to mutations in other paraganglioma susceptibility genes, the aggressive behavior of SDHB-linked disease warrants intensive surveillance to identify and resect tumors early. Patients with similar SDHB genotypes in whom the PGL syndrome manifests often exhibit very heterogeneous phenotypes. Tumors can arise in various locations, and management can be considerably different, depending on tumor site and pathology. We present a case series of five SDHB mutation carriers over four generations from the same family to illustrate the complexities in management.

Phaeochromocytoma and Paraganglioma Excision Involving the Great Vessels

Objective/background

Phaeochromocytomas and paragangliomas are vascular neuroendocrine tumours distributed between the neck and the pelvis and may be associated with catecholamine secretion. The aim of the study was to describe the complex surgical management required to excise these tumours when in close proximity to the great vessels (aorta and vena cava).

Methods

This was a retrospective case series. Patients included those undergoing surgical excision of a phaeochromocytoma or paraganglioma involving the great vessels. Data on clinical presentation; genetic mutations; tumour location; catecholamine/metanephrine secretion; surgical strategy; pre-, intra-, and post-operative course were collated.

Results

Five patients (age range 16–60 years) were identified; three had thoracic paragangliomas located under the arch of the aorta, one had an abdominal paraganglioma invading the aorta, and one had a massive phaeochromocytoma invading the inferior vena cava via the adrenal vein. Three patients had predisposing germline mutations. All patients had adrenergic blockade prior to surgery. A diverse range of complex surgical techniques were employed to excise tumours, including cardiopulmonary bypass, aortic resection, grafting and venotomy of the vena cava. Early post-operative complications were limited.

Conclusions

Excision of phaeochromocytomas and paragangliomas involving the great vessels is high risk surgery optimally undertaken within a multidisciplinary setting in a tertiary referral centre. Comprehensive radiological and biochemical assessment, meticulous pre-operative preparation and close intra- and post-operative monitoring are essential. Radiological imaging may be unable to resolve the tumour extent and anatomy pre-operatively and direct visualisation of the tumour may be the only way to clarify the surgical strategy. Pre-operative knowledge of the genetic predisposition may influence surgical management.

•

Highly vascular tumours which may be associated with catecholamine secretion.

•

Comprehensive pre- and intra-operative preparation is essential.

•

Final surgical strategy often requires direct tumour visualisation.

•

The surgical strategy may alter for germline associated tumours.

•

Management should be delivered by experienced multidisciplinary teams.

Clinical outcomes following unilateral adrenalectomy in patients with primary aldosteronism

BACKGROUND

In approximately half of cases of primary aldosteronism (PA), the cause is a surgically-resectable unilateral aldosterone-producing adrenal adenoma. However, long-term data on surgical outcomes are sparse.

AIM

We report on clinical outcomes post-adrenalectomy in a cohort of patients with PA who underwent surgery.

DESIGN

Retrospective review of patients treated for PA in a single UK tertiary centre.

METHODS

Of 120 consecutive patients investigated for PA, 52 (30 male, median age 54, range 30-74) underwent unilateral complete adrenalectomy. Blood pressure, number of antihypertensive medications, and serum potassium were recorded before adrenalectomy, and after a median follow-up period of 50 months (range 7-115). Recumbent renin and aldosterone were measured, in the absence of interfering antihypertensive medication, ≥3months after surgery, to determine if PA had been biochemically cured.

RESULTS

Overall, blood pressure improved from a median (range) 160/95 mmHg (120/80-250/150) pre-operatively to 130/80 mmHg (110/70-160/93), P < 0.0001. 24/52 patients (46.2%) had cured hypertension, with a normal blood pressure post-operatively on no medication. 26/52 (50%) had improved hypertension. 2/52 patients (3.8%) showed no improvement in blood pressure post-operatively. Median (range) serum potassium level increased from 3.2 (2.3-4.7) mmol/l pre-operatively to 4.4 mmol/l (3.3-5.3) post-operatively, P < 0.0001). Median (range) number of antihypertensive medications used fell from 3 (0-6) pre- to 1 post-operatively (range 0-4), P < 0.0001.

CONCLUSIONS

Unilateral adrenalectomy provides excellent long-term improvements in blood pressure control, polypharmacy and hypokalaemia in patients with lateralizing PA. These data may help inform discussions with patients contemplating surgery.

Circadian variation in serum cortisol during hydrocortisone replacement is not attributable to changes in cortisol-binding globulin concentrations

BACKGROUND

Patients taking hydrocortisone (HC) replacement for primary or secondary adrenal failure require individual adjustment of their dose. In addition to modifying the administered doses of HC for each patient, physicians are increasingly interested in variations in the bioavailability of glucocorticoid replacement. One potential determinant of the bioavailability of replaced HC is a variation in serum cortisol-binding globulin (CBG) concentration, which may, in turn, affect interpretation of cortisol profiles and individual dose selection for patients on hydrocortisone replacement therapy.

AIM

To investigate the hypothesis that there is a circadian variation in CBG levels.

METHODS AND RESULTS

A total of 34 male patients divided into 3 groups (10 patients with non-somatotroph structural pituitary disease on HC replacement, 11 patients with treated acromegaly on HC replacement and 13 patients with treated acromegaly not on HC replacement) and 10 healthy volunteers were included. Cortisol and CBG levels were measured at 6 time points (0800, 1100, 1300, 1500, 1700 and 1900). No significant circadian variation in CBG concentration was found in any of the 4 groups.

CONCLUSION

Circadian variation in serum cortisol during hydrocortisone replacement is not attributable to changes in cortisol-binding globulin concentration. Changes in serum cortisol levels may thus be explained by other factors including 11 β-hydroxysteroid dehydrogenase type 1 activity or circadian changes in the binding properties of CBG.

Contemporary surgical treatment of primary hyperparathyroidism without intraoperative parathyroid hormone measurement

INTRODUCTION

Primary hyperparathyroidism (pHPT) is usually the result of a single adenoma that can often be accurately located preoperatively and excised by a focused operation. Intraoperative parathyroid hormone (IOPTH) measurement is used occasionally to detect additional abnormal glands. However, it remains controversial as to whether IOPTH monitoring is necessary. This study presents the results of a large series of focused parathyroidectomy without IOPTH measurement.

METHODS

Data from 2003 to 2014 were collected on 180 consecutive patients who underwent surgical treatment for pHPT by a single surgeon. Preoperative ultrasonography and sestamibi imaging was performed routinely, with computed tomography (CT) and/or selective venous sampling in selected cases. The preferred procedure for single gland disease was a focused lateral approach guided by on-table surgeon performed ultrasonography. Frozen section was used selectively and surgical cure was defined as normocalcaemia at the six-month follow-up appointment.

RESULTS

Focused surgery was undertaken in 146 patients (81%) and 97% of these cases had concordant results with two imaging modalities. In all cases, an abnormal gland was discovered at the predetermined site. Of the 146 patients, 132 underwent a focused lateral approach (11 of which were converted to a collar incision), 10 required a collar incision and 4 underwent a mini-sternotomy. At 6 months following surgery, 142 patients were normocalcaemic (97% primary cure rate). Three of the four treatment failures had subsequent surgery and are now biochemically cured. There were no complications or cases of persistent hypocalcaemia.

CONCLUSIONS

This study provides further evidence that in the presence of concordant preoperative imaging, IOPTH measurement can be safely omitted when performing focused parathyroidectomy for most cases of pHPT.

Pure aldosterone-secreting adrenocortical carcinoma in a patient with refractory primary hyperaldosteronism

We describe a young male patient with longstanding hypertension, who was diagnosed with primary hyperaldosteronism and treated by an attempted retroperitoneoscopic total unilateral adrenalectomy for a left-sided presumed aldosterone-secreting adenoma. Imaging had shown an unremarkable focal adrenal lesion with normal contralateral adrenal morphology, and histology of the resected specimen showed no adverse features. Post-operatively, his blood pressure and serum aldosterone levels fell to the normal range, but 9 months later, his hypertension recurred, primary aldosteronism was again confirmed and he was referred to our centre. Repeat imaging demonstrated an irregular left-sided adrenal lesion with normal contralateral gland appearances. Adrenal venous sampling was performed, which supported unilateral (left-sided) aldosterone hypersecretion. Redo surgery via a laparoscopically assisted transperitoneal approach was performed and multiple nodules were noted extending into the retroperitoneum. It was thought unlikely that complete resection had been achieved. His blood pressure returned to normal post-operatively, although hypokalaemia persisted. Histological examination, from this second operation, showed features of an adrenocortical carcinoma (ACC; including increased mitoses and invasion of fat) that was assessed as malignant using the scoring systems of Weiss and Aubert. Biochemical hyperaldosteronism persisted post-operatively, and detailed urine steroid profiling showed no evidence of adrenal steroid precursors or other mineralocorticoid production. He received flank radiotherapy to the left adrenal bed and continues to receive adjunctive mitotane therapy for a diagnosis of a pure aldosterone-secreting ACC.

A cross-sectional study of the prevalence of cardiac valvular abnormalities in hyperprolactinemic patients treated with ergot-derived dopamine agonists

CONTEXT

Concern exists in the literature that the long-term use of ergot-derived dopamine agonist drugs for the treatment of hyperprolactinemia may be associated with clinically significant valvular heart disease.

OBJECTIVE

The aim of the study was to determine the prevalence of valvular heart abnormalities in patients taking dopamine agonists as treatment for lactotrope pituitary tumors and to explore any associations with the cumulative dose of drug used.

DESIGN

A cross-sectional echocardiographic study was performed in a large group of patients who were receiving dopamine agonist therapy for hyperprolactinemia. Studies were performed in accordance with the British Society of Echocardiography minimum dataset for a standard adult transthoracic echocardiogram. Poisson regression was used to calculate relative risks according to quartiles of dopamine agonist cumulative dose using the lowest cumulative dose quartile as the reference group.

SETTING

Twenty-eight centers of secondary/tertiary endocrine care across the United Kingdom participated in the study.

RESULTS

Data from 747 patients (251 males; median age, 42 y; interquartile range [IQR], 34-52 y) were collected. A total of 601 patients had taken cabergoline alone; 36 had been treated with bromocriptine alone; and 110 had received both drugs at some stage. The median cumulative dose for cabergoline was 152 mg (IQR, 50-348 mg), and for bromocriptine it was 7815 mg (IQR, 1764-20 477 mg). A total of 28 cases of moderate valvular stenosis or regurgitation were observed in 24 (3.2%) patients. No associations were observed between cumulative doses of dopamine agonist used and the age-corrected prevalence of any valvular abnormality.

CONCLUSION

This large UK cross-sectional study does not support a clinically concerning association between the use of dopamine agonists for the treatment of hyperprolactinemia and cardiac valvulopathy.

Sequelae and survivorship in patients treated with (131)I-MIBG therapy

Background:

¹³¹I-meta-iodobenzylguanidine (¹³¹I-MIBG) has been in therapeutic use since 1980s. Newer treatment modalities are emerging for neuroendocrine tumours (NETs) and chromaffin cell tumours (CCTs), but many of these do not yet have adequate long-term follow-up to determine their longer term efficacy and sequelae.

Methods:

Fifty-eight patients with metastatic NETs and CCTs who had received ¹³¹I-MIBG therapy between 2000 and 2011 were analysed. Survival and any long-term haematological or renal sequelae were investigated.

Results:

In the NET group, the overall median survival and median survival following the diagnosis of metastatic disease was 124 months. The median survival following the commencement of ¹³¹I-MIBG was 66 months. For the CCT group, median survival had not been reached. The 5-year survival from diagnosis and following the diagnosis of metastatic disease was 67% and 67.5% for NETs and CCTs, respectively. The 5-year survival following the commencement of ¹³¹I-MIBG therapy was 68%. Thirty-two patients had long-term haematological sequelae: 5 of these 32 patients developed haematological malignancies. Two patients developed a mild deterioration in renal function.

Conclusion:

Long follow up of ¹³¹I-MIBG therapy reveals a noteable rate of bone marrow toxicities and malignancy and long term review of all patients receiving radionuclide therapies is recommended.

Effective combination treatment with cabergoline and low-dose pegvisomant in active acromegaly: a prospective clinical trial

CONTEXT

With adequate dose titration, pegvisomant normalizes IGF-I in up to 97% of patients with acromegaly. Pegvisomant is indicated for treatment-resistant disease but is expensive, particularly at a high dose. It has been used successfully in combination with somatostatin analogs. However, there are no therapeutic reports of pegvisomant in combination with dopamine agonists. Cabergoline is orally active, well-tolerated, and relatively inexpensive, and as monotherapy for acromegaly it is reported to normalize IGF-I in up to 30% of patients.

OBJECTIVE

The aim of the study was to investigate the efficacy of cabergoline monotherapy and pegvisomant in combination with cabergoline to control serum IGF-I in patients with active acromegaly. Twenty-four patients were recruited into a United Kingdom, multicenter, open-label, prospective clinical trial.

MAIN OUTCOME MEASURE

We measured the change in serum IGF-I.

RESULTS

After 18 wk of dose titration to a maximum dose of 0.5 mg once daily, cabergoline monotherapy did not significantly reduce IGF-I (454 ± 219 baseline vs. 389 ± 192 ng/ml cabergoline), although two patients did normalize IGF-I. The addition of 10 mg pegvisomant daily for 12 wk significantly reduced IGF-I (389 ± 192 ng/ml cabergoline vs. 229 ± 101 ng/ml combination), and 68% achieved a normal IGF-I. Twelve weeks after cabergoline withdrawal, while continuing to receive pegvisomant 10 mg, only 26% of patients maintained an IGF-I within the reference range (229 ± 101 ng/ml combination vs. 305 ± 177 ng/ml pegvisomant). There were no significant changes in liver transaminases or glucose metabolism throughout the study.

CONCLUSION

These data suggest that combination treatment with cabergoline and pegvisomant is more effective at reducing IGF-I levels than either cabergoline or pegvisomant monotherapy.

The effect of exogenous glucocorticoids on plasma catecholamines and metanephrines in patients without phaeochromocytomas

The aim of the study was to evaluate the effects of steroid administration under standardised conditions in a range of patients both normal and with adrenal pathologies and to review the impact on plasma catecholamines and metanephrines. Corticosteroid administration has been linked to the development of hypertensive crises in patients with phaeochromocytoma, however a mechanism for this is not fully understood. We aimed to add useful information about the effect of steroids on levels of these hormones under usual circumstances. A prospective, observational cohort study of 50 patients undergoing the low-dose dexamethasone suppression test (LDDST) was undertaken. Additional blood samples were taken at the start and end of the standard LDDST. Biochemical analysis was carried out for plasma catecholamines and plasma free metanephrines. Demographic and hormonal data were acquired from review of the notes or measured at baseline. No significant changes in plasma catecholamines or metanephrines were seen at the end of the LDDST compared to baseline. This was also true of subgroup analysis, divided by age, gender, or type of underlying pathology. Our results suggest that hypertensive reaction responses, rare as they are, are unlikely to be related to normal adrenal physiology. Thus LDDST is likely to be safe under most circumstances, however caution should be exercised in patients with adrenal masses with imaging characteristics compatible with phaeochromocytoma. It may be prudent to defer glucocorticoid administration until functioning phaeochromocytoma has been excluded biochemically.

SDHD-related chromaffin tumours: disease localisation to genetic dysfunction

BACKGROUND/AIMS

To describe the management of a subject with multiple chromaffin tumours found to have a novel succinate dehydrogenase D (SDHD) mutation.

CASE

A 15-year-old boy with marked hypertension was found to have elevated urinary catecholamines and initial imaging thought to represent bilateral adrenal phaeochromocytomas. An adrenal venous catheter was required to clarify a right adrenal phaeochromocytoma and a left abdominal paraganglioma, distinct from the left adrenal gland. Excision of these tumours, with preservation of the left adrenal gland, provided a cure for this subject without the need for lifelong steroid replacement. Genetic analysis revealed a novel SDHD mutation (c. 169 + 1 G>A) which was shown to result in loss of the 5' splice site and exclusion of exon 2 during splicing. This suggests the likely pathogenicity of this mutation. Disease surveillance in this subject and genetic screening of first degree relatives is ongoing.

CONCLUSIONS

Genetic testing should be considered in all subjects presenting with a chromaffin tumour. In certain circumstances an adrenal venous sampling catheter for catecholamines may clarify diagnostic uncertainty. The complex management issues raised in the care of these subjects requires the involvement of a multidisciplinary team with the relevant expertise.

Repeated colonoscopic screening of patients with acromegaly: 15-year experience identifies those at risk of new colonic neoplasia and allows for effective screening guidelines

OBJECTIVE

It is suggested that patients with acromegaly have an increased risk of colorectal cancer and pre-malignant adenomatous polyps. However, the optimum frequency with which colonoscopic screening should be offered remains unclear.

DESIGN

To determine the optimum frequency for repeated colonoscopic surveillance of acromegalic patients.

METHODS

We retrospectively reviewed the case records of all patients with acromegaly seen in our centre since 1992: 254 patients had at least one surveillance colonoscopy, 156 patients had a second surveillance colonoscopy, 60 patients had a third surveillance colonoscopy and 15 patients had a fourth surveillance colonoscopy.

RESULTS

The presence of hyperplastic or adenomatous polyps was assessed in all patients, while one cancer was detected at the second surveillance. At the third surveillance, mean (+/-s.d.) serum IGF1 levels (ng/ml) in patients with hyperplastic polyps were significantly higher than those with normal colons (P<0.05). The presence of an adenoma rather than a normal colon at the first colonoscopy was associated with a significantly increased risk of adenoma at the second (odds ratio (OR) 4.4, 95% confidence interval (CI) 1.9-10.4) and at the third (OR 8.8, 95% CI 2.9-26.5) screens. Conversely, a normal colon at the first surveillance gave a high chance of normal findings at the second (78%) or third surveillance (78%), and a normal colon at the second colonoscopy was associated with normality at the third colonoscopy (81%).

CONCLUSIONS

Repeated colonoscopic screening of patients with acromegaly demonstrated a high prevalence of new adenomatous and hyperplastic colonic polyps, dependent on both the occurrence of previous polyps and elevated IGF1 levels.

d3-GHR genotype does not explain heterogeneity in GH responsiveness in hypopituitary adults

OBJECTIVE

Heterogeneity in growth hormone (GH) responsiveness in adult hypopituitary patients receiving recombinant human GH (rhGH) is poorly understood; doses vary up to fourfold between individuals. Deletion of exon 3 in the GH receptor (d3-GHR) has been linked to enhanced rhGH responsiveness in children. We investigated the role of the d3-GHR polymorphism in determining adult rhGH responsiveness.

METHODS

One hundred and ninety-four patients treated with an identical rhGH dosing protocol in a single centre were genotyped for the d3-GHR, and the results correlated with changes in serum IGF-I and clinical parameters of GH responsiveness after 6 and 12 months of GH replacement therapy.

RESULTS

Allele frequencies for homozygous full length (fl/fl), heterozygous d3 (fl/d3) and homozygous d3 (d3/d3) were 52%, 38.7% and 9.3%, respectively, and were in Hardy-Weinberg equilibrium. Baseline IGF-I and DeltaIGF-I at 6 months were comparable between groups. DeltaIGF-I at 12 months was significantly greater in the d3/d3 group (P = 0.028). No difference was detected between fl/d3 and fl/fl groups. Regression analyses of DeltaIGF-I at 12 months and DeltaIGF-I/rhGH dose confirmed a significant relationship of d3/d3 genotype on rhGH response. There was no difference between groups in maintenance rhGH dose between genotypes.

CONCLUSION

Homozygosity for d3-GHR confers a marginal increase in GH responsiveness at 12 months but without a detectable change in maintenance rhGH dose required. Both d3 alleles are required to achieve this response; given that only 10% of the population are d3 homozygotes, the d3GHR does not explain the marked heterogeneity of GH responsiveness in hypopituitary adults.

Intra-abdominal fibrosis in a recent cohort of patients with neuroendocrine ('carcinoid') tumours of the small bowel

BACKGROUND

Fibrosis is a hallmark of neuroendocrine tumours (NETs) arising in the jejunum and ileum and may manifest in the mesentery and elsewhere. It is clinically important and once-established, there are few effective therapies.

AIM

To examine the frequency, radiological manifestations and clinical significance of intra-abdominal fibrosis in a patient cohort using modern cross-sectional imaging. Current prevalence is compared to historical series and correlation with cardiac fibrosis evaluated.

DESIGN

Cross-sectional, retrospective survey of a cohort of patients with mid-gut NETs from a single centre.

METHODS

Review of clinical features, biochemistry and imaging of patients with sporadic mid-gut NET and available imaging between 2002 and 2008.

RESULTS

Thirty-one patients were included: 26 (83.9%) had liver metastases and 11 (35.4%) had small-bowel wall thickening; 17 patients (55%) had mesenteric involvement, with a mass, which contained coarse calcification in seven patients and fine calcification in a further two. There was soft-tissue stranding in 13 patients (plus in a further patient with no mass) and 'indrawing' of tissues in 11 patients. Two patients had a 'misty' mesentery and two had early retroperitoneal fibrosis. Mesenteric involvement was unrelated to gender and urinary 5HIAA excretion.

CONCLUSION

Intra-abdominal fibrosis can be detected radiologically in around half of patients with mid-gut NET using contemporary cross-sectional imaging. Although not statistically significant, small-bowel obstruction was seen more frequently in the group with fibrosis. There was no relationship with cardiac fibrosis. Prospective studies are needed to evaluate predictors of fibrosis onset and clinical course and determine optimal methods of prevention and treatment.

Gamma knife radiosurgery: a safe and effective salvage treatment for pituitary tumours not controlled despite conventional radiotherapy

OBJECTIVE

We report the use of 'gamma knife' (GK) radiosurgery in 25 patients with pituitary adenomas not cured despite conventional therapy, including external beam radiotherapy.

PATIENTS AND METHODS

All patients had previously received conventional radiotherapy for a mean of 11.8 years prior to receiving GK; 23 out of 25 had also undergone pituitary surgery on at least one occasion. Seventeen had hyperfunctioning adenomas that still required medical therapy without an adequate biochemical control--ten somatotroph adenomas, six corticotroph adenomas and one prolactinoma, while eight patients had non-functioning pituitary adenomas (NFPAs).

RESULTS

Following GK, mean GH fell by 49% at 1 year in patients with somatotroph tumours. Serum IGF1 fell by 32% at 1 year and by 38% at 2 years. To date, 80% of the patients with acromegaly have achieved normalisation of IGF1, and 30% have also achieved a mean GH level of <1.8 ng/ml correlating with normalised mortality. A total of 75% NFPAs showed disease stabilisation or shrinkage post GK. The patient with a prolactinoma showed a dramatic response: 75% reduction in prolactin at 2 years, with a marked shrinkage on magnetic resonance imaging. The results in corticotroph adenomas were variable. Prior to GK, 72% of the patients were panhypopituitary, and 42% of the remainder have developed new anterior pituitary hormone deficiencies to date. No other adverse events have been detected at a mean follow-up of 36.4 months.

CONCLUSIONS

These data indicate that GK is a safe and effective adjunctive treatment for patients with NFPAs and acromegaly not satisfactorily controlled with surgery and radiotherapy.

Long-term experience of pegvisomant therapy as a treatment for acromegaly

AIMS

To evaluate the long-term efficacy and safety of pegvisomant as a treatment for acromegaly.

DESIGN

Retrospective analysis of clinical and trial data from all patients treated with pegvisomant since 1997 at two centres with common protocols.

RESULTS

Fifty-seven patients (age range 27-78 years) have been treated with pegvisomant since 1997 for up to 91 months (median 18 months). Before commencing pegvisomant, patients had an IGF-I above the upper limit of normal (ULN) of the age-related reference range (median 1.8 x ULN, range 1.2-4.1). Ninety-five per cent normalized IGF-I using a median dose of 15 mg daily (range 10 mg alternate day to 60 mg daily) with no influence of gender on dose requirement. Five patients had combination therapy with either somatostatin analogues (SSA) or cabergoline. Two patients initially controlled on 10 mg and 20 mg required dose increases (to 20 mg + 40 mg) over 24 months to reduce IGF-I. Twenty-seven patients stopped pegvisomant. Reasons included side-effects [abnormal liver function tests (LFTs)] and patient choice. Two patients developed elevated liver transaminases, which normalized on stopping pegvisomant. Patients had 6-12-monthly pituitary magnetic resonance imaging (MRI) scans. One patient had significant tumour size increase.

CONCLUSION

This long-term experience in 57 patients indicates pegvisomant to be effective, safe and well-tolerated. Raised transaminases occurred within the first month of therapy in two patients, and tumour growth was seen in one patient (tumour was growing prior to pegvisomant). In two patients increasing doses of pegvisomant were required to keep IGF-I within the target range.

Successful use of weekly pegvisomant administration in patients with acromegaly

CONTEXT

Clinical trials using 80 mg once weekly pegvisomant (pegV) in active acromegaly led to a 30% fall in serum IGF1. Subsequent studies demonstrated that daily administration of up to 40 mg/day achieved an IGF1 within reference range in 97% of patients. PegV has a half-life of >70 h suggesting weekly dosing may be possible but using higher doses than in the initial trials.

OBJECTIVE

To determine the efficacy of weekly dosing of pegV.

DESIGN

A two center, open-label prospective study in patients with acromegaly converted from a stable daily dose of pegV (median dose 15 mg daily (range 10-20 mg od), IGF1 normal for 3 months prior to inclusion) to twice-weekly (week 0-16) followed by once-weekly (week 16-32) administration.

RESULTS

Seven patients (4M, age 57+/-7 years, 6/7 prior transsphenoidal surgery, 7/7 prior radiotherapy) were recruited. Six patients completed the twice-weekly and five patients both the twice-weekly and once-weekly administration. Headaches led to two patient withdrawals at 0+24 weeks. Mean pre-dose serum IGF1 levels remained stable with the different administration regimens (IGF1 baseline 145+/-39 ng/ml, twice-weekly 124+/-39 ng/ml and once-weekly 127+/-22 ng/ml) and all values were within age adjusted IGF1 reference range. PegV dose was reduced in two patients and five opted to continue weekly administration at trial termination. Safety and quality of life parameters remained stable.

CONCLUSIONS

Twice and once-weekly administration of pegV is effective in controlling serum IGF1 levels in acromegaly and although not formally assessed, continuation of weekly dosing in five patients at study conclusion suggests patient preference for this regimen.

Contrasting clinical manifestations of SDHB and VHL associated chromaffin tumours

Mutations in succinate dehydrogense-B (SDHB) and the von Hippel-Lindau (VHL) genes result in an increased risk of developing chromaffin tumours via a common aetiological pathway. The aim of the present retrospective study was to compare the clinical phenotypes of disease in subjects developing chromaffin tumours as a result of SDHB mutations or VHL disease. Thirty-one subjects with chromaffin tumours were assessed; 16 subjects had SDHB gene mutations and 15 subjects had a diagnosis of VHL. VHL-related tumours were predominantly adrenal phaeochromocytomas (22/26; 84.6%), while SDHB-related tumours were predominantly extra-adrenal paragangliomas (19/25; 76%). Median age at onset of the first chromaffin tumour was similar in the two cohorts. Tumour size was significantly larger in the SDHB cohort in comparison with the VHL cohort (P=0.002). Multifocal disease was present in 9/15 (60%) of the VHL cohort (bilateral phaeochromocytomas) and only 3/16 (19%) of the SDHB cohort, while metastatic disease was found in 5/16 (31%) of the SDHB cohort but not in the VHL cohort to date. The frequency of symptoms, hypertension and the magnitude of catecholamine secretion appeared to be greater in the SDHB cohort. Renal cell carcinomas were a feature in 5/15 (33%) of the VHL cohort and 1/16 (6%) of the SDHB cohort. These data indicate that SDHB-related tumours are predominantly extra-adrenal in location and associated with higher catecholamine secretion and more malignant disease, in subjects who appear more symptomatic. VHL-related tumours tend to be adrenal phaeochromocytomas, frequently bilateral and associated with a milder phenotype.

Treatment of Nelson's syndrome with temozolomide

A 64-year-old woman was previously treated for Cushing's disease with trans-sphenoidal surgery, external beam radiotherapy and bilateral adrenalectomy. Progression of an aggressive corticotroph adenoma was evident 3 years post-adrenalectomy; involvement of the clivus was treated with surgery and gamma knife radiosurgery. Tumour spread through the skull base, occiput and left ear with persistent facial pain and left ear discharge; progression continued despite second gamma knife treatment. ACTH levels peaked at 2472 and 2265 pmol/l pre- and post-hydrocortisone respectively. Treatment with temozolomide resulted in a significant improvement in symptoms, a reduction of plasma ACTH to 389 pmol/l and regression of tumour on magnetic resonance imaging scan after four cycles of treatment. We propose that temozolomide is an effective and well-tolerated therapeutic tool for the treatment of Nelson's syndrome and a useful addition to the range of therapies available to treat this condition.

Clinical use of cabergoline as primary and adjunctive treatment for acromegaly

BACKGROUND

Cabergoline is a dopamine agonist that may be used as primary or adjunctive therapy for acromegaly. Although one study suggested biochemical control may be achieved in a substantial proportion of patients, it is still commonly perceived to be a relatively ineffective treatment.

DESIGN AND METHOD

A prospective audit was performed of 15 consecutive acromegalic patients (eight males, seven females, median age 55, range 31-92 at presentation) treated with cabergoline to determine the effective dose and tolerability. All had normal anterior pituitary function; two patients had hyperprolactinaemia. Magnetic resonance imaging revealed nine adenomata, two partially empty sellae and four structurally normal pituitary glands. Nine patients had undergone transsphenoidal surgery 1-12 months, and one patient had received pituitary radiotherapy 18 years, prior to commencement of cabergoline. All patients had biochemical GH excess; median serum IGF1 471 ng/ml, range 239-746 ng/ml. The calculated mean of a series of GH measurements ranged from 2.7-45.8 mIU/l, median 9.7 mIU/l.

RESULTS

On a median weekly dose of cabergoline of 1.75 mg (range 0.5-7 mg) normalisation of both IGF1 and GH occurred in 4 out of the 15 patients (27%). Out of the 15 patients (33%), 5 achieved a serum IGF1 within the reference range with notable reductions seen in a further five patients. Nine patients (60%) achieved a mean serum GH level of less than 5 mIU/l. Duration of treatment was 2-52 months and was well tolerated in 14 patients.

CONCLUSION

Cabergoline can be an effective and well tolerated primary or adjunctive therapy for acromegaly and useful clinical responses are noted even with modest doses.

Safety of GH replacement in hypopituitary patients with nonirradiated pituitary and peripituitary tumours

BACKGROUND

Published data suggest that growth hormone replacement (GHR) may be given safely to patients with hypopituitarism consequent upon a pituitary/peripituitary tumour. However, a preponderance of patients treated with external pituitary irradiation were included.

OBJECTIVE

To assess the safety of GHR in nonirradiated pituitary/peripituitary tumour.

DESIGN

Prospective audit.

SETTING

Tertiary university referral centre.

PATIENTS

We imaged prospectively the pituitary glands of 48 patients (18 males; mean age 51.6 years range 21-77) who had adult onset growth hormone deficiency (AO-GHD) after appropriate treatment for a pituitary/peripituitary tumour but who did not receive external pituitary irradiation.

INTERVENTION

All patients were treated with a dose titration regimen of GH to maintain serum IGF-1 between the median and upper end of the age-related reference range. Pituitary surveillance imaging was performed prior to the commencement of GHR, at 6-12 months and then yearly. For patients with secretory tumours, biochemical markers (cortisol and prolactin) were used as evidence of tumour recurrence.

RESULTS

48 patients with median follow up since commencement of GHR was 38 months (range 9-104). Three patients were judged to have an apparent increase in tumour volume and/or marker, although only one was thought to be possibly GH related--a patient with a cystic chromophobe adenoma who demonstrated a marginal increase in residual tumour volume 4 years after commencement of GHR.

CONCLUSION

These data add to the growing body of evidence for the safety of GHR in hypopituitary patients consequent upon pituitary/peripituitary mass lesions and represents the first reported series in a heterogeneous group of nonirradiated patients.

Role of fasting plasma glucose, glycated haemoglobin and homeostatic model assessment in the detection of glucose intolerance in adult hypopituitary patients during growth hormone replacement therapy

AIMS

This study was designed to determine the sensitivity and specificity of conventional criteria for diagnosis of impaired glucose tolerance (IGT) in a high-risk population of GH-treated GH deficient (GHD) adults.

METHODS

33 hypopituitary GHD patients with HbA(1c) >5.1% and 13 gender- and age-matched control GHD patients were selected. Oral glucose tolerance test (OGTT), fasting plasma glucose (FPG), HbA(1c), and homeostatic model assessment (HOMA) parameters were determined in all patients. Receiver operator characteristic curves were used to determined sensitivity and specificity for the detection of glucose intolerance as defined by plasma glucose >7.8 mmol/l at 120 min during OGTT.

RESULTS

Sensitivity and specificity for this purpose for HbA(1c) (>5.1%) were 89 and 17%; for FPG (>5.5 mmol/l): 78 and 67%; for FPG (>6.1 mmol/l): 56 and 89%; for HOMA-derived beta-cell function (betaCF) (<40%): 78 and 58%; for HOMA-derived insulin sensitivity (IS) (<70%): 11 and 89%, and for betaCF-IS hyperbolic product (betaCF-IS) (<54%): 89 and 75%, respectively.

CONCLUSIONS

This study shows that FPG (>5.5 mmol/l) and betaCF-IS have high sensitivity and relatively high specificity for the detection of IGT and confirms that measurement of FPG or calculation of betaCF-IS provides appropriate safety surveillance in hypopituitary patients on GH replacement.

The endocrine system and ageing

Complex changes occur within the endocrine system of ageing individuals. This article explores the changes that occur in the metabolism and production of various hormones and discusses the resulting clinical consequences. As individuals age there is a decline in the peripheral levels of oestrogen and testosterone, with an increase in luteinizing hormone, follicle-stimulating hormone and sex hormone-binding globulin. Additionally there is a decline in serum concentrations of growth hormone, insulin-like growth factor-I and dehydroepiandrosterone and its sulphate-bound form. Even though there are complex changes within the hypothalmo-pituitary-adrenal/thyroid axis, there is minimal change in adrenal and thyroid function with ageing. The clinical significance of these deficiencies with age are variable and include reduced protein synthesis, decrease in lean body mass and bone mass, increased fat mass, insulin resistance, higher cardiovascular disease risk, increase in vasomotor symptoms, fatigue, depression, anaemia, poor libido, erectile deficiency and a decline in immune function. For each endocrine system, studies have been carried out in an attempt to reverse the effects of ageing by altering the serum hormonal levels of older individuals. However, the real benefits of hormonal treatment in older individuals are still being evaluated.

Serum IGF-I levels in the diagnosis and monitoring of acromegaly

Insulin-Like Growth Factor-I (IGF-I) is a reliable marker of disease activity and growth hormone (GH) status in acromegaly, but its clinical utility has been hampered over the years by various issues including a lack of robust reference range data and variability in assay sensitivity and specificity. In acromegaly IGF-I correlates well with GH activity and nadir GH on oral glucose tolerance test (OGTT) and is the most sensitive and specific test in diagnosis, where serum IGF-I is persistently seen to be elevated to a range that is distinct from that in healthy individuals. However it should not be relied on exclusively for diagnosis or used as the sole indication of disease severity and GH burden. Successful medical or surgical treatment of acromegaly is usually associated with normalisation of serum IGF-I but there is discordance between GH and IGF-I in some patients. Patients with a normal IGF-I but an abnormal GH suppression to OGTT are at risk of relapse and therefore it should not be used alone to establish disease remission. In contrast to the diagnosis of acromegaly, there is also considerable overlap in serum IGF-I with normality after primary treatment of disease, even in the presence of persisting GH excess. Gender, age and prior radiotherapy alters the relationship between GH and IGF-I and reliance on one marker of disease activity such as IGF-I is particularly precarious in certain disease states. However an elevated serum IGF-I has been shown to be associated with excess mortality and normalising IGF-I normalises mortality making it a useful marker. The tightening up of the assays means that establishing absolute concentrations as well as standard deviation scores are essential to allow cross-study comparisons. This becomes especially important in the use of Pegvisomant, where IGF-I becomes the sole biochemical marker of disease activity.

Selective parathyroid venous sampling in patients with complicated hyperparathyroidism

OBJECTIVE

The role of preoperative localisation of abnormal parathyroid glands remains controversial but is particularly relevant to the management of patients with recurrent or persistent hyperparathyroidism and familial syndromes. We report our experience of the use of selective parathyroid venous sampling (PVS) in the localisation of parathyroid disease in such patients.

DESIGN

We report a retrospective 10-year experience (n = 27) of the use of PVS in complicated primary hyperparathyroidism and contrast the use of PVS with neck ultrasound, magnetic resonance imaging (MRI), computed tomography (CT) and sestamibi imaging modalities.

RESULTS

In 14 out of 25 patients who underwent surgery PVS results were completely concordant with surgical and histological findings and 88% of patients achieved post-operative cure. Out of 13 patients referred after previous failed surgery, 12 underwent further surgery which was curative in 9. In total PVS yielded useful positive (n = 13) and/or negative information (n = 6) in 19 out of 25 patients undergoing surgery. Using histology as the gold standard, 59% of PVS studies were entirely consistent with histology, as compared with 39% of ultrasound scans, 36% of sestamibi scans and 17% of MRI/CT scans.

CONCLUSIONS

PVS is a valuable adjunct to MRI/CT and sestamibi scanning in selected patients with complicated hyperparathyroidism when performed in an experienced unit.

Cosegregation of a novel homozygous CYP11B1 mutation with the phenotype of non-classical congenital adrenal hyperplasia in a consanguineous family

We report a novel missense mutation of CYP11B1 causing non-classical 11beta-hydroxylase deficiency in 3 members of a consanguineous Turkish family. Two siblings presented with clinical evidence of precocious pseudopubarche. Biochemistry suggested 11beta-hydroxylase deficiency and genetic analysis revealed that they were homozygous for the missense mutation L489S within exon 9 of the CYP11B1 gene. The unaffected parents were heterozygotes for the same mutation. In addition, a paternal aunt of the affected siblings presenting with primary infertility and mild hirsutism was found to have the same homozygous mutation. This is the first report of a homozygous mutation in non-classical congenital adrenal hyperplasia that cosegregates with clinical phenotype. The significance of the missense mutation L489S in CYP11B1 is further supported by the conservation of leucine at position 489 in CYP11 genes in eleven other species. Molecular modelling of the enzyme suggests that the mutation L489S in CYP11B1 may alter the enzyme's substrate-binding affinity. These findings suggest that this homozygous mutation affects 11beta-hydroxylase function, resulting in the clinical features of non-classical adrenal hyperplasia in this family.

Reductions of circulating matrix metalloproteinase 2 and vascular endothelial growth factor levels after treatment with pegvisomant in subjects with acromegaly

BACKGROUND

Vascular endothelial growth factor (VEGF) is involved in activation of the matrix metalloproteinase (MMP) system; the latter is implicated in atherosclerosis and cardiovascular disease. Patients with acromegaly have reduced life expectancy primarily due to cardiac disease.

AIM

This study assessed plasma MMPs and VEGF levels in patients with active acromegaly (IGF-I > 130% upper limit of normal), and on treatment with pegvisomant.

SUBJECTS AND METHODS

Twenty patients [nine female, mean age 56.1 +/- 13.8 yr (mean +/- sd)] were studied at baseline and on pegvisomant therapy and compared with data from 25 healthy volunteers (12 female; 56.6 +/- 14.2 yr). Plasma MMP-2, MMP-9, and VEGF levels were measured.

RESULTS

Serum IGF-I fell from a baseline (mean +/- sd) level of 620.1 +/- 209.3 ng/ml to 237.5 +/- 118.5 ng/ml on pegvisomant (doses 10-60 mg; P < 0.001). MMP-2 levels at baseline were significantly higher in patients compared with healthy controls (380.7 +/- 204.8 vs. 207.4 +/- 62.6 ng/ml; P < 0.001), but with treatment a significant reduction in MMP-2 [380.7 +/- 204.8 vs. 203.0 +/- 77.4 ng/ml; P < 0.001] and VEGF (283.4 +/- 233.6 vs. 229.1 +/- 157.4 pg/ml; P = 0.008) was noted. There was no significant difference in MMP-9 levels between patients and controls at baseline (797.5 +/- 142.1 vs. 788.3 +/- 218.0 ng/ml; P = 0.87) or between baseline and posttreatment levels (797.5 +/- 142.1 vs. 780.0 +/- 214 ng/ml; P = 0.76).

CONCLUSIONS

Our novel data demonstrate that treatment of acromegaly with pegvisomant leads to reductions in MMP-2 and VEGF concentrations. Further studies are required to determine the significance of these findings with relation to cardiac disease.

Growth hormone deficiency and replacement in patients with treated Cushing's Disease, prolactinomas and non-functioning pituitary adenomas: effects on body composition, glucose metabolism, lipid status and bone mineral density

BACKGROUND/AIMS

This study was designed to determine whether previous Cushing's disease (CD) or prolactinoma (PRL) could exert adverse effects additional to those of growth hormone (GH) deficiency as a consequence of variable degrees of prior hypogonadism or hypercatabolism. We report the effects of 5 years GH treatment in 124 GH deficiency adults; 42 patients with non-functioning pituitary adenomas (NFPA), 43 with treated PRL and 39 with treated CD.

METHODS

Fasting plasma glucose, HbA(1c), lipoprotein profile, anthropometry and bone mineral density (BMD) were measured at baseline, 6 months and annually up to 5 years.

RESULTS

Mean body mass index remained unchanged in the PRL group and tended to increase in the NFPA group. In contrast, body mass index decreased in the CD group. Decreases in waist and waist/hip ratio were seen in all groups at 6 months. Decreases in total cholesterol and low-density lipoprotein cholesterol were seen in all groups and remained sustained at 5 years. Plasma glucose and HbA(1c) increased at 6 months. Subsequently, plasma glucose returned to baseline values at 5 years; in contrast, HbA(1c )remained unchanged at the end of the study. Baseline lumbar spine and hip BMD were lower in the PRL and CD groups than in the NFPA group, decreased over 1 year in all groups and subsequently increased by 2 years in NFPA with a subsequent increase in lumbar spine BMD in PRL and CD groups delayed to 3-5 years.

CONCLUSIONS

Baseline characteristics and response to GH replacement are qualitatively similar in NFPA, PRL and CD patients. Because improvements in BMD occur later in PRL and CD patients, an extended trial of GH therapy may be indicated in those patients who were commenced on GH therapy as an additional treatment for reduced BMD.

Benefits of screening in von Hippel-Lindau disease--comparison of morbidity associated with initial tumours in affected parents and children

Von Hippel-Lindau (VHL) is a rare autosomal dominant syndrome characterised by the association of retinal and CNS haemangioblastomas, phaeochromocytoma and renal cell carcinoma. If a child of an affected parent has inherited a VHL mutation or the parent's mutation cannot be identified, then clinical screening is recommended. We report the clinical features in three parent-offspring pairs where the parents have presented clinically with renal cell carcinoma, phaeochromocytoma, cerebellar haemangioblastoma and retinal haemangioma, and the children have undergone pre-symptomatic screening. During the first screening a 13-year-old boy was diagnosed with bilateral phaeochromocytoma and later developed an endolymphatic sac tumour at 19 years. A right phaeochromocytoma was found in a 12-year-old girl who was screened from the age of 4 years and in a 13-year-old boy screened from 5 years of age. All children were asymptomatic at the time of diagnosis. These families demonstrate that clinical screening of children at risk of VHL can detect tumours before the first symptoms arise with a consequent reduction in morbidity. These observations strongly support the recommendation to undertake screening of the children of VHL patients.

Tumour surveillance imaging in patients with extrapituitary tumours receiving growth hormone replacement

OBJECTIVE

GH replacement is widely used in the management of patients with adult-onset (AO)-GH deficiency (GHD). In most cases, AO-GHD arises as a result of pituitary/peripituitary tumours and/or their treatment, but the effect of GH replacement on recurrence/regrowth of these tumours is unknown. The aim of this study was to examine the effect of GH replacement in a group of patients with primary tumours of the parasellar region, many of which (e.g. craniopharyngioma, glioma or germ cell tumours) might be anticipated to have a higher recurrence rate than secretory and nonsecretory anterior pituitary tumours.

PATIENTS AND DESIGN

We report here our experience of prospective imaging in 50 consecutive patients (21 males; mean age 45.9 years) with nonanterior pituitary parasellar tumours treated with GH. All had severe GHD (peak serum GH 9 mU/l or less on dynamic testing) and were treated with an identical dose-titration regimen to maintain serum IGF-I concentrations between the median and upper end of the age-adjusted normal range. The primary diagnoses were: craniopharyngioma (28), germ cell tumour (8), arachnoid cyst (4), meningioma (4), glioma (4) and mensenchymal tumour (2). External pituitary irradiation had been given to 37 (74%) of patients. Measurements Surveillance imaging (magnetic resonance imaging (MRI) 70%, computed tomography (CT) 16%, both 14%) was performed at baseline (prior to GH), at 6--12 months, and then again yearly or as clinically indicated. Median follow-up was 36 months (range 7--129 months). All images were reviewed by the same radiologist.

RESULTS

Four patients had an apparent increase in tumour volume but in only one patient was it considered necessary to abandon GH replacement. In two of the four cases marginal increases in cystic parasellar tumours were not progressive; and in the fourth case apparent recurrence of a suprasellar germ cell tumour was shown to be acellular fibrous tissue only on biopsy. In all other cases either the appearances were unchanged or the amount of tissue was reduced during long-term follow-up on GH.

CONCLUSIONS

Overall, GH appears safe with respect to tumour recurrence over this time period in this patient group. Comparison with similar prospective series in patients not receiving GH replacement is desirable.

Markers of cell proliferation in a GH-producing adenoma of a patient treated with pegvisomant

We report our findings on markers of cell proliferation (Ki-67 labelling index and topoisomerase-alpha expression) in a somatotroph pituitary tumour before and after exposure to pegvisomant, a GH receptor antagonist developed for the treatment of acromegaly. Specimens from two separate pituitary operations, separated by a period of 17 years that included 4 years of pegvisomant treatment, were stained for markers of cellular proliferation. Ki-67 labelling index and topoisomerase-alpha expression were both markedly greater (1-3% compared with 0-0.5% and 15-80% compared with 2-10% respectively) in the pegvisomant-exposed tumour compared with the earlier specimen. Clearly, caution must be exercised when interpreting findings from a single case, particularly one sufficiently refractory to conventional therapies to require treatment with pegvisomant. However, our data reinforce the requirement for careful radiological surveillance of the pituitary in the context of a drug that does not target the tumour responsible and where serum GH cannot serve as a marker of disease activity or tumour size.

Disease activity in acromegaly may be assessed 6 weeks after discontinuation of pegvisomant

OBJECTIVE

Pegvisomant, a modified growth hormone (GH) molecule, is a novel medical therapy for acromegaly that functions as a GH receptor antagonist. Serum GH cannot be used as a marker of disease activity in patients taking this form of therapy, partly because GH levels rise on pegvisomant and partly because the drug cross-reacts with many routine GH assays. The purpose of this study was to assess the time for which it is necessary to discontinue pegvisomant prior to biochemical reassessment of acromegaly.

DESIGN AND METHODS

This was a retrospective study of 13 patients (seven male, median age 61 years, range 43-77) enrolled in two separate, open-label studies of the efficacy and tolerability of pegvisomant in the treatment of acromegaly. All had been taking a stable dose of pegvisomant (median dose 15 mg daily, range 10-30) as monotherapy for at least 3 months before discontinuing the drug. After discontinuation of pegvisomant, serum IGF-I was measured at 0, 2, 4, 6 and 8 weeks in all patients. Serum GH (single sample) was measured in nine patients at 2, 4, 6 and 8 weeks, but not at baseline on account of the cross-reactivity of pegvisomant with the GH assay.

RESULTS

Mean serum IGF-I rose from 210+/-105 ng/ml (S.D.) at baseline to 392+/-175 ng/ml at 2 weeks after discontinuation of pegvisomant (P < 0.0001). Although there was no statistically significant change in mean serum IGF-I beyond 2 weeks (412+/-181, 392+/-152 and 399+/-150ng/ml at 4, 6 and 8 weeks respectively; P = 0.13 (2 vs 4 weeks), 0.31 (4 vs 6 weeks) and 0.46 (6 vs 8 weeks), serum IGF-I rose by more than twice the interassay coefficient of variation (CV) in two of the 13 patients between weeks 2 and 4. The standard deviation of the difference in serum IGF-I between time points was calculated. The values declined from 118% (weeks 0-2) 17%, 19.7% and 10% (weeks 2-4, 4-6 and 6-8 respectively). The expected measure if there was no systematic change in base would be 15% (1.4 x interassay CV). Mean serum GH was virtually unchanged at 2-8 weeks after cessation of pegvisomant therapy.

CONCLUSIONS

These results suggest that the activity of acromegaly may be assessed by serum IGF-I levels 6 weeks after the discontinuation of pegvisomant.

Comparison of continuation or cessation of growth hormone (GH) therapy on body composition and metabolic status in adolescents with severe GH deficiency at completion of linear growth

Although GH replacement improves the features of GH deficiency (GHD) in adults, it has yet to be established whether cessation of GH at completion of childhood growth results in adverse consequences for the adolescent with GHD. Effects of continuation or cessation of GH on body composition, insulin sensitivity, and lipid levels were studied in 24 adolescents (13 males, 11 females, aged 17.0 +/- 0.3, yr, mean +/- se, puberty stage 4 or 5) in whom height velocity was less than 2 cm/yr. Provocative testing confirmed severe GHD [peak GH < 9 mU/liter (3 microg/liter)] in all cases and was followed by a lead-in period of 3 months during which the pediatric dose of GH continued unchanged. Baseline investigations were then performed using dual-energy x-ray absorptiometry (body composition), lipid measurements, and assessment of insulin sensitivity by both homeostasis model assessment and a short insulin tolerance test. Twelve patients remained on GH (0.35 U/kg.wk), and 12 patients ceased GH treatment. The groups were followed up in parallel with repeat observations made after 6 and 12 months. No endocrine differences were evident between the groups at baseline. GH cessation resulted in a reduction of serum IGF-I Z score [-1.62 +/- 0.29, baseline vs. -2.52 +/- 0.12, 6 months (P < 0.05) vs. -2.52 +/- 0.10, 12 months (P < 0.01)] but values remained unchanged in those continuing GH replacement. Lean body mass increased by 2.5 +/- 0.5 kg ( approximately 6%) over 12 months in those receiving GH but was unchanged after GH discontinuation. Cessation of GH resulted in increased insulin sensitivity [short insulin tolerance test, 153 +/- 22 micromol/liter.min, baseline vs. 187 +/- 20, 6 months (P < 0.05) vs. 204 +/- 14, 12 months (P = 0.05)], but no significant change was seen during 12 months of GH continuation. Lipid levels remained unaltered in both groups. Continuation of GH at completion of linear growth resulted in ongoing accrual of lean body mass (LBM), whereas skeletal muscle mass remained static after GH cessation in these adolescents with GHD. This divergence of gain in LBM is of potential importance because increases in LBM occur as a feature of healthy late adolescent development. GH is a major mediator of insulin sensitivity, independent of body composition in adolescents. Further studies are required to determine whether discontinuation of GH in the adolescent with severe GHD once linear growth is complete results in long-term irreversible adverse physical and metabolic consequences and to determine conclusively the benefits of continuing GH therapy.

Transitional care of GH deficiency: when to stop GH therapy

While the benefits of growth hormone (GH) therapy in adult hypopituitary patients with GH deficiency (GHD) are established, the role of continued GH therapy after final height in adolescent GH-deficient patients remains unclear. Preliminary data suggest that cessation of GH on completion of linear growth may be associated with impairment of somatic development and adverse changes in body composition. For the present time, the decision whether to continue GH treatment in adolescent patients with GHD is best made on an individual basis. For such patients, continuity of care is crucial. Children and adults with GHD are usually managed by physicians in separate departments, who may focus on different aspects of treatment and care. Close collaboration between paediatric and adult physicians is essential to ensure smooth transition and to minimize the drop-out rate from follow-up. Given the previous period of treatment during childhood, paediatric physicians should be best placed to discuss the potential benefits of continuing GH therapy and instigate retesting of GH secretion. Many children with isolated idiopathic GHD will produce normal GH responses if retested at adult height. Patients with multiple pituitary hormone deficits are more likely to have ongoing GHD, as are patients who have received CNS irradiation. Quality of life does not appear to be decreased in adolescents with GHD who stop treatment, so achievement of satisfactory bone mass is a major determinant of the decision whether to continue therapy.

Insulin sensitivity and glucose tolerance improve in patients with acromegaly converted from depot octreotide to pegvisomant

AIM AND METHOD

Insulin resistance leading, in some cases, to glucose intolerance is an important contributory factor to the cardiovascular morbidity and mortality associated with acromegaly. The aim of this study was to document changes in insulin sensitivity (IS) in a group of seven patients with acromegaly (three male, four female, mean+/-s.d. age 59+/-13 Years) treated initially with a stable dose of depot octreotide (OT; median dose 30 mg four times weekly, range 10-30 mg) for a median of 18 Months (range 16-19 Months) and who were then transferred to treatment with pegvisomant (median dose 15 mg daily, range 10-20 mg) for a median of 8 Months (range 7-9 Months). IS was assessed by homeostatic model assessment (HOMA) using fasting glucose and insulin concentrations and by a short insulin tolerance test (sITT). Body composition was assessed by dual energy X-ray absorptiometry.

RESULTS

Mean+/-s.d. serum IGF-I concentrations during therapy with OT and with pegvisomant were not statistically different (283+/-119 ng/ml on OT vs 191+/-39 ng/ml on pegvisomant (P=0.4)). However, mean+/-s.d. fasting plasma glucose fell from 6.2+/-1.0 mmol/l on OT to 5.2+/-0.6 mmol/l on pegvisomant (P=0.017) and was lower on pegvisomant in all seven patients. In four patients, fasting plasma glucose fell from values diagnostic of diabetes mellitus or impaired fasting glucose on OT to within the normal range on pegvisomant. Mean+/-s.d. peripheral IS (by sITT) increased from 139+/-39 micromol/l per min on OT to 169+/-59 micromol/l per min on pegvisomant (P=0.037). Mean+/-s.d. IS (by HOMA %S) was unchanged over the course of the study (149.1+/-43.7% on OT vs 139.9+/-76.6% on pegvisomant, P=0.28). Mean+/-s.d. pancreatic beta-cell secretory function (HOMA %B) improved significantly on pegvisomant compared with OT (49.4+/-19.2% vs 82.4+/-43.5%, P=0.01). No statistically significant change in total fat (P=0.3), % fat (P=0.28) or circulating non-esterified fatty acids (P=0.35) was observed.

CONCLUSIONS

IS and glucose tolerance improved in patients converted from OT therapy to pegvisomant, without a change in body composition and even when serum IGF-I concentrations remained equally well controlled. This may be an important factor in the choice of medical therapy for patients with acromegaly.

An investigation of the predictors of bone mineral density and response to therapy with alendronate in osteoporotic men

Male osteoporosis is an important disease, with 25-30% of all hip fractures occurring in men. In a recent randomized, placebo-controlled study of osteoporotic males, alendronate 10 mg daily for 2 yr led to significant increments in bone mineral density (BMD), of a similar magnitude to those observed in postmenopausal women. In this study, specimens collected at intervals during the recent trial of alendronate in male osteoporosis, from 197 of the original 241 participants, were assayed for testosterone, estradiol, IGF-I, IGF binding protein 3 (IGFBP-3), bone-specific alkaline phosphatase [BSAP (serum)], and N-telopeptide of type I collagen corrected for creatinine [NTx (urine)]. Together with fracture and densitometry data from the original study, relationships were examined between BMD and serum IGF-I, IGFBP-3, testosterone, estradiol, BSAP, and urine NTx, both at baseline and during treatment with alendronate, to gain possible insights into the pathogenesis of male osteoporosis. Statistically significant (P <or= 0.05) associations were documented, at baseline, between the presence of vertebral fracture and each of serum IGF-I, serum IGFBP-3, serum free testosterone, total spine BMD, and total body BMD. No statistically significant correlations were observed between any of the baseline variables (IGF-I, IGFBP-3, estradiol, testosterone, and presence of vertebral fracture) and the BMD response to alendronate at any site. In a multivariate analysis, used to identify possible combinations of factors capable of predicting baseline BMD or response to alendronate, statistically significant (P <or= 0.01) relationships were seen, at baseline, between BMD and body mass index, age, and prior fracture. However, no statistically significant relationships were seen between any of the baseline variables (age, body mass index, testosterone, estradiol, IGF-I, IGFBP-3, and prior fracture) and change in BMD at any site. These data suggest that among men with osteoporosis it is not possible to identify patients who would be particularly good candidates for therapy with alendronate on the basis of biochemical or hormonal markers. Alendronate therapy appears to benefit osteoporotic males equally, irrespective of baseline serum testosterone, estradiol, IGF-I, or markers of bone turnover.

The effect of pegvisomant-induced serum IGF-I normalization on serum leptin levels in patients with acromegaly

BACKGROUND

In humans, serum leptin correlates positively with fat mass. GH is lipolytic and patients with active acromegaly have lowered serum leptin compared to age, sex and body mass index (BMI)-matched controls, but a direct influence of GH on serum leptin remains unclear. In patients with acromegaly, total leptin increases following successful pituitary surgery and during somatostatin (SMS) analogue therapy (despite no change in BMI) but whether this represents changes in soluble leptin receptor, bound or free leptin is unclear. Pegvisomant, a GH receptor antagonist capable of normalizing serum IGF-I in over 97% of patients, represents a novel treatment strategy in acromegaly and its effect on leptin has not previously been reported.

PATIENTS

Sixteen patients (nine male (M), seven female (F), median age 52 years, range 27-78 years) with active acromegaly (serum IGF-I at least 30% above the upper limit of an age-related reference range) were studied. Serum IGF-I was normalized in all subjects with pegvisomant [mean duration 7 months (range 3-11 months), median dose 20 mg/day (range 10-40 mg/day)]. A single batch measurement of leptin, bound leptin (BL), soluble leptin receptor (SLR), insulin and glucose were performed on samples from baseline and first occurrence of serum IGF-I normalization.

RESULTS

As in normal subjects, females with acromegaly had higher baseline serum leptin [median M = 6.1 (range 1.6-58.7), F = 25.9 (range 3.19-54.1) ng/ml; P = 0.04], which correlated positively with BMI (R = 0.78, P = 0.0004). Forward step-wise regression analysis demonstrated that BMI and gender accounted for 90% of the variance in mean serum log10 leptin. Pegvisomant-induced serum IGF-I normalization was associated with a rise in serum leptin [8.9 (range 1.6-58.3) to 12.7 (range 2.3-90.8) ng/ml, P < 0.0001]. Although the absolute increase was not significantly different, mean percentage increase was greater in men (M = 66.6 +/- 51%, F = 11.8 +/- 16%, P = 0.017) despite similar serum IGF-I and BMI in male and female subjects at baseline. No change in BL or SLR accompanied serum IGF-I normalization [0.27 (range 0.15-1.26) to 0.27 (range 0.14-1.2) nmol/l, P = 0.27 and 3.2 (range 1.2-6.8) to 2.7 (range 1-7.4) nmol/l, P = 0.5, respectively]. After normalization of serum IGF-I, a correlation between BMI and leptin remained (R = 0.86, P < 0.0001) and together BMI and gender accounted for 87% of the variance in mean log10 serum leptin (P = 0.0002).

CONCLUSION

Pegvisomant-induced serum IGF-I normalization in patients with active acromegaly is associated with a significant increase in total, and by implication, free leptin.