The efficacy of combined treatment in active acromegaly with both long-acting somatostatin analogs (SRIF) and pegvisomant (PEG-V) has been well established. The aim was to describe the PEG-V dose reductions after the conversion from daily PEG-V to combination treatment. To clarify the individual beneficial and adverse effects, in two acromegaly patients, who only normalized their insulin like growth factor (IGF-I) levels with high-dose pegvisomant therapy. We present two cases of a 31 and 44 years old male with gigantism and acromegaly that were controlled subsequently by surgery, radiotherapy, SRIF analogs and daily PEG-V treatment. They were converted to combined treatment of monthly SSA and (twice) weekly PEG-V. High dose SSA treatment was added while the PEG-V dose was decreased during carful monitoring of the IGF-I. After switching from PEG-V monotherapy to SRIF analogs plus pegvisomant combination therapy IGF-I remained normal. However, the necessary PEG-V dose, to normalize IGF-I differed significantly between these two patients. One patient needed twice weekly 100 mg, the second needed 60 mg once weekly on top of their monthly lanreotide Autosolution injections of 120 mg. The weekly dose reduction was 80 and 150 mg. After the introducing of lanreotide, fasting glucose and glycosylated haemoglobin concentrations increased. Diabetic medication had to be introduced or increased. No changes in liver tests or in pituitary adenoma size were observed. In these two patients, PEG-V in combination with long-acting SRIF analogs was as effective as PEG-V monotherapy in normalizing IGF-I levels, although significant dose-reductions in PEG-V could be achieved. However, there seems to be a wide variation in the reduction of PEG-V dose, which can be obtained after conversion to combined treatment.
Pituitary tumor; Acromegaly; Acromegaly treatment; Pegvisomant; Combined treatment; Somatostatin analogs
This article examines the role of pegvisomant in the treatment of acromegaly. This syndrome, caused by excessive growth hormone (GH) secretion by a pituitary adenoma, is associated with a doubled mortality rate and poor quality of life. Pituitary microsurgery has long been the first choice of treatment since it cures many patients, especially those with localized tumors. Adjuvant irradiation was given if insulin-like growth factor-I (IGF-I) or GH did not normalize. The introduction of long-acting slow- release somatostatin analogs was a breakthrough for adjuvant treatment, although not always effective. Rather, targeting excessive GH production, muting the GH signal at its receptor, was a totally different approach. The development of GH antagonists (by mutation of glycine at position 120) and other modifications to enhance receptor binding, and subsequent pegylation of the molecule led to the development of B2036. After pegylation of B2036 at 5 positions the distribution volume is restricted and its serum half-life considerably increased. In short-term clinical studies performed in selected, mostly pretreated, acromegalic patients, IGF-I normalized in the majority of cases. Combination therapy with long-acting somatostatin analogs and weekly rather than daily pegvisomant injections appears to be successful in one clinical study and might limit the high cost of pegvisomant. Long-term efficacy and safety has to be demonstrated. The drug does not cross the blood–brain barrier, and whether it distributes freely into the extracellular space of other organs than the liver has not been investigated, which might have implications for persistent local IGF-I production under unrestrained GH concentrations.
pegvisomant; Somavert; receptor antagonist; growth hormone; insulin-like growth factor-I; treatment
The Endocrine Tumor Summit convened in December 2008 to address 6 statements prepared by panel members that reflect important questions in the treatment of acromegaly and carcinoid syndrome. Data pertinent to each of the statements were identified through review of pertinent literature by one of the 9-member panel, enabling a critical evaluation of the statements and the evidence supporting or refuting them. Three statements addressed the validity of serum growth hormone (GH) and insulin-like growth factor-I (IGF-I) concentrations as indicators or predictors of disease in acromegaly. Statements regarding the effects of preoperative somatostatin analog use on pituitary surgical outcomes, their effects on hormone and symptom control in carcinoid syndrome, and the efficacy of extended dosing intervals were reviewed. Panel opinions, based on the level of available scientific evidence, were polled. Finally, their views were compared with those of surveyed community-based endocrinologists and neurosurgeons.
Acromegaly; Carcinoid syndrome; Neuroendocrine tumor; NET; Somatostatin analogs; Somatostatin analogues; Lanreotide; Octreotide; Insulin-like growth factor-I; IGF-I; Growth hormone; GH
Traditionally, acromegaly evaded diagnosis until in its clinically obvious later stages when treatment is more difficult. Over the last 25 years diagnostic tests have improved, but whether clinical disease detection also improved was unknown so we tested if disease severity at diagnosis had changed from 1981 to 2006.
Data on 324 consecutive acromegaly patients presenting from 1981–2006 at two New York City hospitals were collected by retrospective review (n=324) and by interview (n=200). The main complaint, acromegaly-associated co-morbidities, signs, symptoms, healthcare providers visited, pre-operative growth hormone (GH) and insulin-like growth factor I (IGF-I) levels and pituitary tumor size at diagnosis were compared in patients presenting in the earlier vs. later halves of the time period.
Times from symptom onset to diagnosis were 5.9 yr. (early) vs. 5.2 yr. (late)(p=ns). At diagnosis, 96% of early and late groups had facial feature changes and/or hand/foot enlargement. Co-morbidities included hypertension (HTN) 37 % (early) vs. 36% (late), carpal tunnel syndrome (24 vs. 24%), sleep apnea (13 vs. 29%)(p <0.01), osteoarthritis (25 vs. 23%), and diabetes mellitus (DM) (18 vs.15%); each patient had 1.2 (early) vs. 1.3 (late) (p=0.53) co-morbidities. Groups were similar in signs, symptoms, tumor size, GH and IGF-I.
Clinical, biochemical and tumor size characteristics at diagnosis of acromegaly patients were unchanged from 1981–2006. Most patients still have marked manifestations of acromegaly at diagnosis suggesting that acromegaly remains clinically under-recognized. Healthcare professionals should more commonly consider acromegaly, which can lead to earlier diagnosis and better treatment outcome.
Acromegaly; pituitary tumor; growth hormone; insulin-like growth factor 1
Acromegaly is a rare disease with a multifaceted clinical presentation. In 90–95% of patients with acromegaly, the disease is caused by a growth hormone (GH)-secreting pituitary adenoma with elevated GH levels that ultimately induce excessive hepatic secretion of insulin-like growth factor-1 (IGF-1). Somatostatin receptor ligands (SRLs) are considered the standard medical choice for the treatment of acromegaly, and normalization of GH and IGF-1 is attainable with effective therapy. This review aims to summarize the literature relative to SRL dose escalation therapy in patients with acromegaly. A United States National Library of Medicine PubMed search of SRL’s was conducted using the following search terms: ((((LAR) OR ATG) OR octreotide) OR lanreotide Autogel) AND acromegaly. Related articles in non peer-reviewed journals were excluded. The rationale and benefits of SRL dose optimization therapy were investigated with emphasis on describing the clinical recognition, treatment, and management of patients with acromegaly. We found that dose escalation could provide additional biochemical control of acromegaly in patients who are inadequately controlled with conventional starting doses of octreotide LAR and lanreotide Autogel®. Furthermore, patients should routinely have their GH and IGF-1 levels closely monitored and their SRL dose increased or decreased thereafter according to individual response.
Octreotide LAR; Lanreotide Autogel®; Dose optimization; Acromegaly
Although there are international guidelines orienting physicians on how to manage patients with acromegaly, such guidelines should be adapted for use in distinct regions of the world. A panel of neuroendocrinologists convened in Mexico City in August of 2007 to discuss specific considerations in Latin America. Of major discussion was the laboratory evaluation of acromegaly, which requires the use of appropriate tests and the adoption of local institutional standards. As a general rule to ensure diagnosis, the patient’s GH level during an oral glucose tolerance test and IGF-1 level should be evaluated. Furthermore, to guide treatment decisions, both GH and IGF-1 assessments are required. The treatment of patients with acromegaly in Latin America is influenced by local issues of cost, availability and expertise of pituitary neurosurgeons, which should dictate therapeutic choices. Such treatment has undergone profound changes because of the introduction of effective medical interventions that may be used after surgical debulking or as first-line medical therapy in selected cases. Surgical resection remains the mainstay of therapy for small pituitary adenomas (microadenomas), potentially resectable macroadenomas and invasive adenomas causing visual defects. Radiotherapy may be indicated in selected cases when no disease control is achieved despite optimal surgical debulking and medical therapy, when there is no access to somatostatin analogues, or when local issues of cost preclude other therapies. Since not all the diagnostic tools and treatment options are available in all Latin American countries, physicians need to adapt their clinical management decisions to the available local resources and therapeutic options.
Acromegaly; Growth hormone; Insulin-like growth factor 1; Latin America; Octreotide; Radiotherapy; Somatostatin receptors; Surgery
Dysregulated growth hormone (GH) hypersecretion is usually caused by a GH-secreting pituitary adenoma and leads to acromegaly — a disorder of disproportionate skeletal, tissue, and organ growth. High GH and IGF1 levels lead to comorbidities including arthritis, facial changes, prognathism, and glucose intolerance. If the condition is untreated, enhanced mortality due to cardiovascular, cerebrovascular, and pulmonary dysfunction is associated with a 30% decrease in life span. This Review discusses acromegaly pathogenesis and management options. The latter include surgery, radiation, and use of novel medications. Somatostatin receptor (SSTR) ligands inhibit GH release, control tumor growth, and attenuate peripheral GH action, while GH receptor antagonists block GH action and effectively lower IGF1 levels. Novel peptides, including SSTR ligands, exhibiting polyreceptor subtype affinities and chimeric dopaminergic-somatostatinergic properties are currently in clinical trials. Effective control of GH and IGF1 hypersecretion and ablation or stabilization of the pituitary tumor mass lead to improved comorbidities and lowering of mortality rates for this hormonal disorder.
Acromegaly is a rare disease most often caused by the prolonged secretion of excess growth hormone from a pituitary adenoma. The disease is associated with multiple significant comorbidities and increased mortality. The delay to diagnosis is often long. This may be because of low disease awareness among health care professionals, the insidious onset of differentiating features, and because patients are likely to present with complaints typical of other conditions more frequently seen in primary care. Early identification of acromegaly facilitates prompt treatment initiation and may minimize the permanent effects of excess growth hormone. The primary treatment for many patients will be pituitary surgery, although not all patients will be eligible for surgery or achieve a surgical cure. If biochemical control is not achieved following surgery, other treatment options include medical therapy and radiation therapy. Improved biochemical control may only alleviate rather than reverse the associated comorbidities. Thus, lifelong monitoring of patient health is needed, with particular attention to the management of cardiovascular risk factors. It is additionally important to consider the impact of both disease and treatment on patients’ quality of life and minimize that impact where possible, but particularly for chronic therapies. For the majority of patients, chronic therapy is likely to include somatostatin analog injections. In some circumstances, it may be possible to extend the dosing interval of the analog once good biochemical control is achieved. Additional convenience may be gained from the possibility of self-/partner administration of treatment or administration of treatment by a health care professional at home. Overall, it is clear that the care of patients with acromegaly requires a highly coordinated approach involving numerous specialties (eg, endocrinology, surgery, cardiology). Further, patients’ needs must be at the core of management and every effort must be made to improve health care experiences and minimize treatment burdens.
acromegaly; diagnosis; treatment; quality of life; convenience
Radiotherapy (RT) remains an effective treatment in patients with acromegaly refractory to medical and/or surgical interventions, with durable tumor control and biochemical remission; however, there are still concerns about delayed biochemical effect and potential late toxicity of radiation treatment, especially high rates of hypopituitarism. Stereotactic radiotherapy has been developed as a more accurate technique of irradiation with more precise tumour localization and consequently a reduction in the volume of normal tissue, particularly the brain, irradiated to high radiation doses. Radiation can be delivered in a single fraction by stereotactic radiosurgery (SRS) or as fractionated stereotactic radiotherapy (FSRT) in which smaller doses are delivered over 5-6 weeks in 25-30 treatments. A review of the recent literature suggests that pituitary irradiation is an effective treatment for acromegaly. Stereotactic techniques for GH-secreting pituitary tumors are discussed with the aim to define the efficacy and potential adverse effects of each of these techniques.
acromegaly; fractionated stereotactic radiotherapy; radiosurgery; toxicity; GH-secreting pituitary tumors
The aim of this study was to assess the effects of replacement with recombinant human growth hormone (rhGH) in patients with GH deficiency (GHD) after treatment of acromegaly. Intervention study. Sixteen patients (8 men, age 56 years), treated for acromegaly by surgery and radiotherapy, with an insufficient GH response to insulin-induced hypoglycaemia, were treated with 1 year of rhGH replacement. Study parameters were assessed at baseline and after 1 year of rhGH replacement. Study parameters were cardiac function, body composition, bone mineral density (BMD), fasting lipids, glucose, bone turnover markers, and Quality of Life (QoL). During rhGH replacement IGF-I concentrations increased from −0.4 ± 0.7 to 1.0 ± 1.5 SD (P = 0.001), with a mean daily dose of 0.2 ± 0.1 mg in men and 0.3 ± 0.2 mg in women. Nonetheless, rhGH replacement did not alter cardiac function, lipid and glucose concentrations, body composition or QoL. Bone turnover markers (PINP and β crosslaps) levels increased (P = 0.005 and P = 0.021, respectively), paralleled by a small, but significant decrease in BMD of the hip. The beneficial effects of rhGH replacement in patients with GHD during cure from acromegaly are limited in this study.
Growth hormone deficiency; Growth hormone replacement; Acromegaly
Acromegaly is an endocrine disorder characterised by increased morbidity and mortality. It is usually caused by a growth hormone secreting pituitary adenoma and is manifested by a variety of clinical features. Surgery is usually the treatment of choice, however over the last few years, several new methods of treatment have been developed. A recent consensus on the targets for treatment has led to multiple studies being conducted to assess the efficacy of the currently available options. This review examines the evidence for and against these treatments.
Although acromegaly is a rare disease, the clinical, economic and health-related quality of life (HRQoL) burden is considerable due to the broad spectrum of comorbidities as well as the need for lifelong management. We performed a comprehensive literature review of the past 12 years (1998–2010) to determine the benefit of disease control (defined as a growth hormone [GH] concentration <2.5 μg/l and insulin-like growth factor [IGF]-1 normal for age) on clinical, HRQoL, and economic outcomes. Increased GH and IGF-1 levels and low frequency of somatostatin analogue use directly predicted increased mortality risk. Clinical outcome measures that may improve with disease control include joint articular cartilage thickness, vertebral fractures, left ventricular function, exercise capacity and endurance, lipid profile, and obstructive apnea events. Some evidence suggests an association between controlled disease and improved HRQoL. Total direct treatment costs were higher for patients with uncontrolled compared to controlled disease. Costs incurred for management of comorbidities, and indirect cost could further add to treatment costs. Optimizing disease control in patients with acromegaly appears to improve outcomes. Future studies need to evaluate clinical outcomes, as well as HRQoL and comprehensive economic outcomes achieved with controlled disease.
Acromegaly; Somatostatin analogues; Octreotide; Lanreotide; Quality of life; Morbidity; Mortality
Pegvisomant-related lipohypertrophy may revert when changing the site of injection, but the lipohypertrophy may recur at the new site of injection. The strength of evidence, however, is weak and comes from information obtained from physical examination only.
We studied two Caucasian women with acromegaly, aged 51 and 71 years, with pegvisomant-related lipohypertrophy. Our two patients were evaluated at baseline, when the site of pegvisomant injection was the periumbilical abdominal region, and then four months after switching the injection site from the abdomen to both thighs. Both physical examination and radiological studies (magnetic resonance imaging and dual energy X-ray absorptiometry) demonstrated that the abdominal lipohypertrophy progressively reverted in both patients after switching the site of injection to the thighs. However, lipohypertrophy reappeared at the new site of injection. The radiological outcome confirmed the reversibility of pegvisomant-related lipohypertrophy and strengthened the body of evidence on this issue.
In clinical practice, physical examination of the injection site or sites leads to an early detection of lipohypertrophy during pegvisomant treatment. Radiological procedures may be of help to confirm subcutaneous fat changes and for a precise monitoring of fat redistribution. Patients should get appropriate information about lipohypertrophy before starting pegvisomant treatment since the rotation of the site of injection may prevent lipohypertrophy.
Acromegaly is caused by hypersecretion of growth hormone (GH) and consequently of insulin-like growth factor-I (IGF-1) due to pituitary tumor. Other causes, such as increased growth-hormone releasing hormone (GHRH) production, ectopic GHRH production, and ectopic GH secretion, are rare. Growth hormone and IGF-1 play a role in the regulation of bone metabolism, but accurate effect of growth hormone excess on bone is not fully explained. The issue of osteoarticular manifestations is still very actual, due to development of complications in the majority of patients with acromegaly. Traditionally, acromegaly is considered as a cause of secondary osteoporosis. Nowadays, it is discussed if BMD as predictor of osteoporotic fractures in acromegalic patient is decreased or even normal. Thus, bone quality remains to be more important in assessment of fracture risk. GH excess leads to increased bone turnover, defined by changes of bone markers. The articular manifestations are frequent clinical complications and may be present as the earliest symptom in a significant proportion of acromegalic patients. Articular manifestations are the main causes of morbidity and immobility of these patients, and they are persistent even after successful treatment. Quick recognition of osteoarticular changes and aiming the therapy lead to decrease in complication number.
We report a patient presenting with ALS in whom acromegaly was later confirmed. Insulin-like growth factor-1 (IGF-1) has been tried in the treatment of ALS and despite equivocal results from clinical trials, efforts have continued to try to harness the significant positive effects on motor neuron growth observed in vitro and in survival of mouse models of the disease. One subsequent study has reported an association between higher circulating serum IGF-1 levels and longer disease duration in ALS patients. Concern therefore arose in our case that treatment of the acromegaly with a somatostatin analogue might adversely affect the natural course of his ALS through lowering of potentially beneficial IGF-1 levels. Through clinical observation and prognostic modelling we suggest that this concern was unfounded. The potential interaction of these two rarely coincident disorders in our patient is discussed.
Survival; prognostic; epidemiology
The concomitant presence of three histopathologically different entities in the pituitary gland is a rare occurrence. Most publications identify at least two distinct pathologies, mainly, a pituitary adenoma coexisting with a second intrasellar lesion. We present a case of a 71-year-old female referred for evaluation and treatment of acromegaly. Questioning revealed she was experiencing facial palsy, visual disturbances, and syncopal spells for several weeks. When laboratory evaluation showed elevated somatomedin (IGF-I) levels and an oral glucose tolerance test failed to demonstrate any suppression of her growth hormone (GH) values, an MRI of the pituitary revealed a sellar mass. A presumptive diagnosis of pituitary adenoma was established. The patient underwent transsphenoidal resection of the sellar mass, which proved to be a large B-cell lymphoma (Stage I-E) associated with areas of adenoma and lymphocytic hypophysitis.
In acromegaly, expert surgery is curative in only about 60% of patients. Postoperative radiation therapy is associated with a high incidence of hypopituitarism and its effect on growth hormone (GH) production is slow, so that adjuvant medical treatment becomes of importance in the management of many patients.
To delineate the role of lanreotide in the treatment of acromegaly.
Search of Medline, Embase, and Web of Science databases for clinical studies of lanreotide in acromegaly.
Treatment with lanreotide slow release and lanreotide Autogel® normalized GH and insulin-like growth factor-I (IGF-I) concentrations in about 50% of patients. The efficacy of 120 mg lanreotide Autogel® on GH and IGF-I levels was comparable with that of 20 mg octreotide LAR. There were no differences in improvement of cardiac function, decrease in pancreatic β-cell function, or occurrence of side effects, including cholelithiasis, between octreotide LAR and lanreotide Autogel®. When postoperative treatment with somatostatin analogs does not result in normalization of serum IGF-I and GH levels after noncurative surgery, pegvisomant alone or in combination with somatostatin analogs can control these levels in a substantial number of patients.
acromegaly; lanreotide; somatostatin analog; growth hormone; pegvisomant
Long-acting somatostatin analogs are frequently used as adjuvant treatment of acromegaly patients after noncurative surgery. This sudy aims to compare the efficacy of octreotide long-acting release (OCT) and lanreotide Autogel (LAN) in acromegaly patients. Sixty-eight patients not cured by transsphenoidal endoscopic or microscopic pituitary surgery between 2003 and 2009 were retrospectively analyzed (25 men; 43 women; mean age 41.1 ± 10.9 years [range 18–65 years]). The patients were assigned randomly to OCT (n = 36) and LAN (n = 32) groups. Evaluations included insulin-like growth factor I (IGF-I) and growth hormone (GH) after oral glucose tolerance test (OGTT) 3, 6, 12 and 18 months after starting medical treatment; pituitary magnetic resonance imaging was performed before treatment and after 3 and 12 months. Patients achieving IGF-I levels within the age and gender normal range and GH level <1 μg/l following OGTT were considered a ‘biochemical cure’. Mean IGF-I and GH values and tumor volumes (cm3) in the LAN and OCT groups were similar in the post-operative period before initiation of medical treatment. A statistically significant decrease in GH and IGF-I levels was obtained for both treatment groups at each follow-up visit compared to the previous value. Tumor shrinkage after 12 months of treatment was statistically significant in both groups but the percentage tumor shrinkage (28.5% vs. 34.9%, P = 0.166) and rate of patients achieving biochemical cure (63.9 and 78.1%, P = 0.454) were similar between OCT and LAN groups, respectively. OCT and LAN treatment options have similar efficacy for ensuring biochemical cure and tumor shrinkage in acromegaly patients who had noncurative surgery.
Acromegaly; Somatostatin analogs; Octreotide; Lanreotide
Pituitary adenomas are associated with a variety of clinical manifestations resulting from excessive hormone secretion and tumor mass effects, and require a multidisciplinary management approach. This article discusses the treatment modalities for the management of patients with a prolactinoma, Cushing's disease and acromegaly, and summarizes the options for medical therapy in these patients.
First-line treatment of prolactinomas is pharmacotherapy with dopamine agonists; recent reports of cardiac valve abnormalities associated with this class of medication in Parkinson's disease has prompted study in hyperprolactinemic populations. Patients with resistance to dopamine agonists may require other treatment.
First-line treatment of Cushing's disease is pituitary surgery by a surgeon with experience in this condition. Current medical options for Cushing's disease block adrenal cortisol production, but do not treat the underlying disease. Pituitary-directed medical therapies are now being explored. In several small studies, the dopamine agonist cabergoline normalized urinary free cortisol in some patients. The multi-receptor targeted somatostatin analogue pasireotide (SOM230) shows promise as a pituitary-directed medical therapy in Cushing's disease; further studies will determine its efficacy and safety. Radiation therapy, with medical adrenal blockade while awaiting the effects of radiation, and bilateral adrenalectomy remain standard treatment options for patients not cured with pituitary surgery.
In patients with acromegaly, surgery remains the first-line treatment option when the tumor is likely to be completely resected, or for debulking, especially when the tumor is compressing neurovisual structures. Primary therapy with somatostatin analogues has been used in some patients with large extrasellar tumors not amenable to surgical cure, patients at high surgical risk and patients who decline surgery. Pegvisomant is indicated in patients who have not responded to surgery and other medical therapy, although there are regional differences in when it is prescribed.
In conclusion, the treatment of patients with pituitary adenomas requires a multidisciplinary approach. Dopamine agonists are an effective first-line medical therapy in most patients with a prolactinoma, and somatostatin analogues can be used as first-line therapy in selected patients with acromegaly. Current medical therapies for Cushing's disease primarily focus on adrenal blockade of cortisol production, although pasireotide and cabergoline show promise as pituitary-directed medical therapy for Cushing's disease; further long-term evaluation of efficacy and safety is important.
A 29 year old woman with difficult to control acromegaly and a pituitary macroadenoma responded to pegvisomant therapy and subsequently conceived with her first cycle of in-vitro fertilization and intra-cytoplasmic sperm injection. Pregnancy was complicated by gestational diabetes, pituitary gland enlargement and deteriorating visual fields. Conservative management with elective cesarean section was performed at 32 weeks gestation. A healthy boy was delivered who remains developmentally normal at 1 year. This complex case required intricate care by a multi-disciplinary team and is likely to represent the first in many cases of assisted conception on pegvisomant therapy for active acromegaly.
Acromegaly; ICSI; IVF; Pegvisomant; Pregnancy
Asymptomatic pituitary abnormalities occur in about 10% of cranial magnetic resonance imaging scans, but metastatic carcinoma of the pituitary gland is rare: 133 cases have been reported. Two thirds secreted either prolactin or adrenocorticotropic hormone, and another 24% were non-secreting.
A 42-year-old Caucasian man lived for 30 years after the diagnosis of a pituitary tumor whose clinical and biochemical features were those of acromegaly and hypogonadism. Radiotherapy, totaling 7300 rad, was administered to the sella over two courses. Growth hormone levels normalized, but he developed both thyroid and adrenal insufficiency, and replacement therapy was commenced. Fourteen years later, growth hormone levels again became elevated, and bromocriptine was commenced but led to side effects that could not be tolerated. An attempted surgical intervention failed, and octreotide and pergolide were used in succession. Twenty-seven years after the diagnosis, a mass from an excisional biopsy of below the angle of the mandible proved to be metastatic pituitary carcinoma. Immunohistochemical staining was positive for synaptophysin, growth hormone, and prolactin. One year later, an octreotide scan showed uptake at the sella, neck, and spleen. Our patient declined further active oncology treatment.
Metastatic pituitary carcinoma associated with acromegaly is particularly rare. To the best of our knowledge, this is the eighth such case and is the first report of growth hormone and prolactin present in the metastatic mass.
Metastatic pituitary carcinoma; Acromegaly
Acromegaly is a disease with unique clinical manifestations. Its confirmatory diagnosis, however, requires basal and dynamic tests of growth hormone secretion. The measurement of circulating levels of somatomedin C has been a valuable addition to the diagnostic armamentarium. We review the etiology of acromegaly, with particular reference to the different histochemical and ultrastructural forms of somatotropic adenomas and their respective clinical behaviors. Ectopic sources of growth hormone-releasing hormone and of growth hormone itself are now well-recognized, though unusual, causes of acromegaly. The treatment of acromegaly is often problematic and far from uniformly successful. Initial enthusiasm for the results of surgical treatment has now been tempered by reports of increasing rates of recurrence on long-term follow-up. The roles of irradiation and pharmacotherapy are reviewed with particular emphasis on the use of bromocriptine, which has added a new dimension to the control of the somatic and metabolic manifestations of hypersomatotropism. Studies have been done recently using a long-acting somatostatin analog with encouraging results.
A highly specific and sensitive radioimmunoassay was developed for measuring circulating growth hormone releasing factor (GRF) in human plasma. Before measuring immunoreactive GRF plasma samples were extracted on to Vycor glass. Immunoreactive GRF concentrations in plasma samples from 37 fasting normal subjects ranged from less than 10 to 60 ng/l (mean 21 ng/l). Fasting concentrations in 76 out of 80 acromegalic subjects were within the normal range, but the remaining four patients had values of 92 to 25 000 ng/l. Of these, only the patient with the highest concentration had evidence of ectopic GRF secretion from a disseminated carcinoid tumour. Two of the others had longstanding pituitary tumours, and the fourth patient had a pituitary growth hormone (GH) secreting tumour proved by its removal and subsequent remission of acromegaly. There was no correlation between serum GH and plasma immunoreactive GRF concentrations, irrespective of whether the patients were untreated or had been given radiotherapy or dopamine agonists. The assay should help elucidate the physiological role(s) of GRF and may also prove useful in differentiating between pituitary and hypothalamic defects in patients with acromegaly.
The sebum excretion rate (S.E.R.) was measured in 20 patients with acromegaly. Eleven were untreated at the time of the measurement and nine had previously undergone surgical hypophysectomy or had received pituitary irradiation by yttrium-90 or radiotherapy. In five patients the S.E.R. was measured before and after such treatment. The mean S.E.R. in the untreated acromegalics was much greater than in a normal population and decreased significantly after successful pituitary ablation. No significant decrease in mean S.E.R. occurred in the group of patients with a poor clinical response to ablation. The correlations between S.E.R. and log serum growth hormone, plasma 11-hydroxycorticosteroid levels, and heel-pad thickness were significant, but there was no significant correlation between S.E.R. and serum protein-bound iodine levels. This suggests that the changes in S.E.R. were due to pituitary ablation but could not necessarily be attributed solely to changes in growth hormone, thyroid-stimulating hormone, or adrenocorticotrophic hormone. The association between the clinical state of the acromegaly and the S.E.R. was better than the association between acromegaly and serum growth hormone. We conclude that the S.E.R. is a useful addition to the clinical and endocrinological data used in assessing acromegaly.
The discovery of somatotropin-release inhibitory factor (SRIF) in hypothalamic extract in 1970 led to the synthesis of the first somatostatin analog octreotide, discovery of five somatostatin receptor subtypes, and development of additional somatostatin receptor ligands (SRL) as pharmacotherapy for acromegaly and other neuroendocrine tumors. Long-acting formulations of SRL (octreotide LAR Depot, lanreotide SR and lanreotide autogel) assure improved patient compliance with weekly up to monthly injections, and are commonly used as primary or adjuvant treatment of acromegaly. We review SRL currently available, emphasizing long-acting compounds and their efficacy in controlling acromegaly. Disease control is evaluated by biochemical markers, tumor shrinkage, and disease-symptom improvement balanced against drug-related side effects.
Acromegaly; Somatostatin analogs; Efficacy; Side effects