Radiotherapy and radiosurgery in acromegaly

Diagnostic, therapeutic, and prognostic characteristics of patients with acromegaly according to tumor size at diagnosis

PURPOSE

To evaluate clinical, laboratory, radiological, therapeutic, and prognostic characteristics of patients with acromegaly according to the size of the growth hormone (GH)-secreting pituitary adenoma at diagnosis.

METHODS

Observational, retrospective, single-center study of patients with acromegaly followed at a tertiary center. Data were collected regarding clinical presentation, characteristics of the adenoma in the magnetic resonance imaging, GH and IGF-1 levels, and disease control after surgery or adjuvant treatment (normal IGF-1 levels). Patients were divided according to the adenoma size at diagnosis in: group I < 10 mm; II 10-19 mm; III 20-29 mm; IV 30-39 mm; and V ≥ 40 mm. Comparisons were made between the groups, and correlations of tumor size with disease parameters, ROC curves, and logistic regression analyses were performed to investigate tumor size and confounding factors that could impact the outcomes.

RESULTS

117 patients were studied [59 women, age at diagnosis 43 ± 13 years; group I = 11 patients (9%); group II 54 (46%); group III 34 (29%); group IV 10 (9%); group V 8 (7%)]. Hypopituitarism, cavernous sinus invasion, GH levels, and use of somatostatin receptor ligands had their prevalence increased according to the adenoma size. Age showed a negative correlation with tumor size. A tumor diameter around 20 mm was the best predictor for the presence of hypopituitarism, invasiveness, need of adjuvant therapies, and poorer disease control.

CONCLUSION

Adenomas < 20 mm showed lower morbidity and better therapeutic response in acromegaly, while those ≥ 20 mm had similar clinical, therapeutic, and prognostic behavior.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Changes in acromegaly comorbidities, treatment, and outcome over three decades: a nationwide cohort study

Objective

To study the time-dependent changes in disease features of Danish patients with acromegaly, including treatment modalities, biochemical outcome, and comorbidities, with a particular focus on cancer and mortality.

Methods

Pertinent acromegaly-related variables were collected from 739 patients diagnosed since 1990. Data are presented across three decades (1990-1999, 2000-2009, and 2010-2021) based on the year of diagnosis or treatment initiation.

Results

Adenoma size and insulin-like growth factor I (IGF-I) levels at diagnosis did not differ significantly between study periods. The risk of being diagnosed with diabetes, heart disease, sleep apnea, joint disease, and osteoporosis increased from the 1990s to the later decades, while the mortality risk declined to nearly half. The risk of cancer did not significantly change. Treatment changed toward the use of more medical therapy, and fewer patients underwent repeat surgeries or pituitary irradiation. A statistically significant increase in the proportion of patients achieving IGF-I normalization within 3-5 years was observed over time (69%, 83%, and 88%). The proportion of patients with three or more deficient pituitary hormones decreased significantly over time.

Conclusion

Modern medical treatment regimens of acromegaly as well as increased awareness and improved diagnostics for its comorbidities have led to better disease control, fewer patients with severe hypopituitarism, and declining mortality in the Danish cohort of acromegaly patients. The risk of cancer did not increase over the study period.

Current and Future Advances in Surgical Therapy for Pituitary Adenoma

The vital physiological role of the pituitary gland, alongside its proximity to critical neurovascular structures, means that pituitary adenomas can cause significant morbidity or mortality. While enormous advancements have been made in the surgical care of pituitary adenomas, numerous challenges remain, such as treatment failure and recurrence. To meet these clinical challenges, there has been an enormous expansion of novel medical technologies (eg, endoscopy, advanced imaging, artificial intelligence). These innovations have the potential to benefit each step of the patient's journey, and ultimately, drive improved outcomes. Earlier and more accurate diagnosis addresses this in part. Analysis of novel patient data sets, such as automated facial analysis or natural language processing of medical records holds potential in achieving an earlier diagnosis. After diagnosis, treatment decision-making and planning will benefit from radiomics and multimodal machine learning models. Surgical safety and effectiveness will be transformed by smart simulation methods for trainees. Next-generation imaging techniques and augmented reality will enhance surgical planning and intraoperative navigation. Similarly, surgical abilities will be augmented by the future operative armamentarium, including advanced optical devices, smart instruments, and surgical robotics. Intraoperative support to surgical team members will benefit from a data science approach, utilizing machine learning analysis of operative videos to improve patient safety and orientate team members to a common workflow. Postoperatively, neural networks leveraging multimodal datasets will allow early detection of individuals at risk of complications and assist in the prediction of treatment failure, thus supporting patient-specific discharge and monitoring protocols. While these advancements in pituitary surgery hold promise to enhance the quality of care, clinicians must be the gatekeepers of the translation of such technologies, ensuring systematic assessment of risk and benefit prior to clinical implementation. In doing so, the synergy between these innovations can be leveraged to drive improved outcomes for patients of the future.

Endocrine disorders after primary gamma knife radiosurgery for pituitary adenomas: A systematic review and meta-analysis

PURPOSE

Gamma Knife radiosurgery (GKRS) is feasible for pituitary adenomas, but post-surgery GKRS may cause severe hormone deficits. We reviewed the literature on primary GKRS for pituitary adenoma focusing on radiation-induced hormone deficiencies.

METHODS

PubMed, Web-of-Science, Scopus, and Cochrane were searched upon the PRISMA guidelines to include studies describing primary GKRS for pituitary adenomas. Pooled-rates of GKRS-induced hormone deficiencies and clinical-radiological responses were analyzed with a random-effect model meta-analysis.

RESULTS

We included 24 studies comprising 1381 patients. Prolactinomas were the most common (34.2%), and 289 patients had non-functioning adenomas (20.9%). Median tumor volume was 1.6cm³ (range, 0.01-31.3), with suprasellar extension and cavernous sinus invasion detected in 26% and 31.1% cases. GKRS was delivered with median marginal dose 22.6 Gy (range, 6-49), maximum dose 50 Gy (range, 25-90), and isodose line 50% (range, 9-100%). Median maximum point doses were 9 Gy (range, 0.5-25) to the pituitary stalk, 7 Gy (range, 1-38) to the optic apparatus, and 5 Gy (range, 0.4-12.3) to the optic chiasm. Pooled 5 year rates of endocrine normalization and local tumor control were 48% (95%CI 45-51%) and 97% (95%CI 95-98%). 158 patients (11.4%) experienced endocrinopathies at a median of 45 months (range, 4-187.3) after GKRS, with pooled 5-year rates of 8% (95%CI 6-9%). GKRS-induced hormone deficiencies comprised secondary hypothyroidism (42.4%) and hypogonadotropic hypogonadism (33.5%), with panhypopituitarism reported in 31 cases (19.6%).

CONCLUSION

Primary GKRS for pituitary adenoma may correlate with lower rates of radiation-induced hypopituitarism (11.4%) than post-surgery GKRS (18-32%). Minimal doses to normal pituitary structures and long-term endocrine follow-up are of primary importance.

Long-term safety of gamma knife radiosurgery (SRS) for acromegaly

PURPOSE

Acromegaly has high morbidity and mortality when growth hormone secretion remains uncontrolled. Stereotactic radiosurgery (SRS) may be used when pituitary surgery is not suitable or unsuccessful, but there are few very long-term safety data available, especially for significant adverse events such as stroke.

METHODS

118 patients with acromegaly were treated with SRS between 1985 and 2015, at the National Centre for Stereotactic Radiosurgery, Sheffield, UK. Data were gathered from case notes, hospital databases, and patient questionnaires. Stroke incidence in comparison to the normal population was quantified using the standardised incidence ratio (SIR), and visual complications assessed.

RESULTS

88% (104/118) had complete morbidity follow up data for analysis. The mean follow-up was 134 months, and median SRS dose was 30 Gy. 81% of tumours had cavernous sinus invasion. There was no excess stroke rate relative to that seen in two age- and sex-matched large population studies (SIR = 1.36, 95% CI 0.27-3.96; SIR = 0.52, 95% CI 0.06-1.89). In 68/104 patients who had MRI-guided SRS with no further radiation treatment (SRS or fractionated radiotherapy) there was no loss of visual acuity and 3% developed ophthalmoplegia. There was a positive correlation between > 1 radiation treatment and both ophthalmoplegia and worsening visual acuity.

CONCLUSION

Stroke rate is not increased by SRS for acromegaly. Accurate MRI-based treatment planning and single SRS treatment allow the lowest complication rates. More than one radiation treatment (SRS or fractionated radiotherapy) was associated with increased visual complications.

Intensity-modulated Radiotherapy for Pituitary Somatotroph Adenomas

OBJECTIVE

To summarize our experience in the treatment of pituitary somatotroph adenomas by fractionated intensity-modulated radiotherapy (IMRT), describe the treatment outcomes, and determine predictors.

METHODS AND MATERIALS

Patients with pituitary somatotroph adenoma treated by IMRT in our institution from August 2009 to January 2019 were reviewed. A total of 113 patients (37 male) were included in this study. The median age was 33 years (range 12-67 years). A total of 112 patients had not achieved complete remission after surgery, and 1 patient was treated by radiotherapy (RT) alone because she refused to surgery. The median growth hormone level was 8.6 ng/mL (range 2-186 ng/mL) and the median insulin-like growth factor (IGF)-1 level was 732 ng/mL (range 314-1485 ng/mL) pre-RT. The radiation doses to clinical target volume were usually 50-56 Gy in 25 to 30 fractions and to gross tumor volume were 60.2 Gy in 28 fractions while simultaneous integrated boost-IMRT used. After RT, the patients were followed up with endocrine testing every 6 to 12 months and magnetic resonance imaging annually. Endocrine complete remission was defined as a normal sex- and age-adjusted IGF-1 level without any pituitary suppressive medications. The outcomes including endocrine remission and new hypopituitarism after RT were recorded. The median follow-up time was 36 months (range 6-105.5 months).

RESULTS

The endocrine complete remission rates of IGF-1 at 1, 2, 3, and 5 years were 6%, 22.8%, 48.6%, and 74.3%, respectively. The median time to complete remission was 36.2 ± 3.8 months. The tumor control rate was 99% during the follow-up. The overall incidence of RT-induced hypopituitarism was 28.3% at the last follow-up. Univariate and multivariate analysis demonstrated that tumor sizes before RT, pre-RT IGF-1 level, and age significant predicted the endocrine remission.

CONCLUSIONS

IMRT is a highly effective treatment for pituitary somatotroph adenoma. Endocrine remission rate, tumor control rate, the median time to remission and hypopituitarism incidence are similar to stereotactic radiosurgery. Age and IGF-1 level before RT were significant predictive factors in endocrine remission.

Radiosurgery as primary management for acromegaly

OBJECTIVE

Transsphenoidal surgery (TSS) remains the recommended primary treatment for acromegaly. Long-term outcome data are not available for patients treated with gamma knife radiosurgery (STRS) as a primary treatment.

DESIGN

Retrospective cohort study.

DATA COLLECTION

notes review, laboratory results, general physician notes, patient questionnaire and death certification.

PATIENTS

Twenty acromegaly patients underwent primary STRS at the National Centre for Radiosurgery, Sheffield, UK, between 1985 and 2015.

MEASUREMENTS

Biochemical control (GH/IGF1), hypopituitarism, morbidity and mortality were all recorded.

RESULTS

At 20 years of follow-up, control was seen in all on acromegaly-specific medication (n = 12) and 75% of those off medication (3/4). Time for 50% to achieve control on medication was 3 years, and 7.4 years off medication. Median marginal radiation dose was 27.5 Gy, and median follow-up was 166.5 months. 53% of patients developed new hypopituitarism at a median follow-up of 146 months, and the development of first onset of hypopituitarism occurred as late as 20 years after treatment. With MRI planning, no other complications were noted. Three patients underwent subsequent TSS due to poor biochemical control. During follow-up, 7 patients died at a median age of 65 years. There were no STRS-related deaths.

CONCLUSION

This is the longest follow-up of patients who have undergone primary STRS for acromegaly. It shows low morbidity, but significant latency to biochemical control and new-onset hypopituitarism. This mandates very long-term follow-up for these patients. STRS has shown good long-term efficacy providing initial control can be afforded by optimal medical management. While TSS remains best practice, STRS offers an alternative for those in whom surgery is not an option.

Malaysian Consensus Statement for the Diagnosis and Management of Acromegaly

In Malaysia, acromegaly is under-recognised with only 10-15% of the expected number of cases from prevalence estimates, having been diagnosed and managed in established endocrine centres with access to multidisciplinary care. This is mainly due to lack of awareness and standardised approach in diagnosing this disease resulting in delay in diagnosis and management with suboptimal treatment outcomes. This first Malaysian consensus statement on the diagnosis and management of acromegaly addresses these issues and is based on current best practices and latest available evidence so as to reduce the disease burden on acromegaly patients managed in the Malaysian healthcare system.

Factors affecting early versus late remission in acromegaly following stereotactic radiosurgery

Stereotactic radiosurgery (SRS) is a well-established treatment modality for patients with acromegaly. Our previously published study demonstrated a median time to remission of 29 months. This study aims to identify factors affecting the timing of remission and also to quantify the rate of late remission. This is a retrospective analysis of acromegaly patients who underwent SRS between 1988 and 2016. Early and late remissions were defined based on our prior median remission time of 29 months. The median imaging and endocrine follow-ups are 66 and 104.8 months, respectively. Multivariate analysis was conducted to analyze factors leading to late remission. A total number of 157 patients, of those 102 (64.9%) patients achieved remission. of those 102 patients, 62 patients (60.7%) had remission in less than 29 months (early remission) whereas 40 patients (39.3%) achieved remission later than (late remission) 29 months. The two groups differed significantly in the time interval between the last resection and the first SRS (p = 0.040) whole sella radiosurgery (p = 0.025) or radiosurgery to the cavernous sinus (p = 0.041). Competing risk analysis showed the interval between resection and SRS was significantly longer in the late remission group (HR 1.013, 95% CI 1.004-1.02; p = 0.007). Fifty-one of 157 patients (32.5%) developed a new endocrine deficiency following SRS. Those with shorter time between resection and SRS were more likely to achieve early remission. While most patients achieve remission in less than 4 years, the latency of effect with SRS yields a small percentage of patients achieving remission beyond that time point.

STEREOTACTIC RADIATION THERAPY IN PITUITARY ADENOMAS, IS IT BETTER THAN CONVENTIONAL RADIATION THERAPY?

Pituitary radiotherapy (RT) has undergone important progress in the last decades due to the development of new stereotactic techniques which provide more precise tumour targeting with less overall radiation received by the adjacent brain structures. Pituitary surgery is usually first-line therapy in most patients with nonfunctioning (NFPA) and functioning adenomas (except for prolactinomas and large growth hormone (GH) secreting adenomas), while RT is used as second or third-line therapy. The benefits of RT (tumour volume control and, in functional tumours, decreased hormonal secretion) are hampered by the long latency of the effect and the potential side effects. This review presents the updates in the efficacy and safety of the new stereotactic radiation techniques in patients with NFPA, GH-, ACTH- or PRL-secreting pituitary adenomas.

Methods

A systematic review was performed using PubMed and articles/abstracts and reviews detailing RT in pituitary adenomas from 2000 to 2017 were included.

Results

Stereotactic radiosurgery (SRS) and fractionated stereotactic RT (FSRT) provide high rates of tumour control i.e. stable or decrease in tumour size, in all types of pituitary adenomas (median 92 - 98%) at 5 years. Endocrinological remission is however significantly lower: 44-52% in acromegaly, 54-64% in Cushing's disease and around 30% in prolactinomas at 5 years. The rate of new hypopituitarism varies from 10% to 50% at 5 years in all tumour types and as expected increases with the duration of follow-up (FU). The risk for other radiation-induced complications is usually low (0-5% for new visual deficits, cranial nerves damage or brain radionecrosis and extremely low for secondary brain tumours), however longer FU is needed to determine rates of secondary tumours. Notably, in acromegaly, there may be a higher risk for stroke with FSRT.

Conclusion

Stereotactic radiotherapy can be an effective treatment option for patients with persistent or recurrent pituitary adenomas after unsuccessful surgery (especially if residual tumour is enlarging) and/or resistance or unavailability of medical therapy. Comparison with conventional radiation therapy (CRT) is rather difficult, due to the substantial heterogeneity of the studies. In order to evaluate the potential brain-sparing effect of the new stereotactic techniques, suggested by the current data, long-term studies evaluating secondary morbidity and mortality are needed.

Treatment Factors That Influence Mortality in Acromegaly

Acromegaly is a rare condition characterized by excessive secretion of growth hormone (GH), which is almost always due to a pituitary adenoma. Acromegaly is associated with significant morbidity such as hypertension, type 2 diabetes, cardiomyopathy, obstructive sleep apnoea, malignancy and musculoskeletal abnormalities. Acromegaly has also been associated with increased mortality in several retrospective studies. This review will focus on the epidemiological data relating to mortality rates in acromegaly, the relationship between acromegaly and malignancy, the role of GH and insulin-like growth factor-I in assessing the risk of future mortality, and the impact of radiotherapy and hypopituitarism on mortality.

Update on prognostic factors in acromegaly: Is a risk score possible?

Certain clinical conditions and markers have recently been demonstrated to modify the natural history of acromegaly in affected patients. Thus, some clinical, histological, radiological and molecular factors are associated with more aggressive pituitary tumors that have higher biochemical activity, higher tumor volumes and decreased tumoral and biochemical responses to current therapies. However, these factors do not seem to have an equal influence on the prognosis of patients with acromegaly. We present a review of the factors that influence the clinical course of patients with acromegaly and propose a risk value for each factor that will allow prognostic scoring for affected patients by considering a combination of these factors.

Efficacy and complications of pituitary irradiation

Radiation therapy is widely used in the management of intracranial (including sellar and parasellar) and systemic disorders. Although in many cases the irradiation aims to prevent the growth or regrowth and to control the hormonal hypersecretion of a pituitary tumor, in many others it adversely affects the hypothalamo-pituitary function simply because this area receives significant doses of radiation delivered for non-hypothalamo-pituitary disorders. The main long-term complications include hypopituitarism, optic neuropathy, cerebrovascular morbidity, and second brain tumors. Radiation technique and schedule are important determinants of these adverse effects.

Pegvisomant and cabergoline combination therapy in acromegaly

Combination with cabergoline may offer additional benefits to acromegalic patients on pegvisomant monotherapy. We evaluated the safety and efficacy profile of this combination and investigated the determinants of response. An observational, retrospective, cross-sectional study. Fourteen acromegalic patients (9 females), who were partially resistant to somatostatin analogs and on pegvisomant monotherapy. Cabergoline was added because of the presence of persistent mildly increased IGF-I. The mean follow-up time was 18.3 ± 10.4 months. The efficacy and safety profile was assessed. The influence of clinical and biochemical characteristics on treatment efficacy was studied. IGF-I levels returned to normal in 4 patients (28%) at the end of the study. In addition, some decline in IGF-I levels was observed in a further 5 patients. The % IGF-I decreased from 158 ± 64% to 124 ± 44% (p = 0.001). The average change in IGF-I was -18 ± 27% (range -67 to +24%). Lower baseline IGF-I (p = 0.007), female gender (p = 0.013), lower body weight (p = 0.031), and higher prolactin (PRL) levels (p = 0.007) were associated with a better response to combination therapy. There were no significant severe adverse events. Significant tumour shrinkage was observed in 1 patient. Combination therapy with pegvisomant and cabergoline could provide better control of IGF-I in some patients with acromegaly. Baseline IGF-I levels, female gender, body weight, and PRL levels affect the response to this combination therapy.

Efficacy and safety of higher dose stereotactic radiosurgery for functional pituitary adenomas: a preliminary report

OBJECTIVE

Single fraction stereotactic radiosurgery (SRS) is a common adjuvant therapy for hormonally active pituitary adenomas when surgical resection fails to control tumor growth or normalize hypersecretory activity. Marginal doses of 20-24 Gy are used at many centers and here we report our outcome data in patients treated with a higher marginal dose of 35 Gy.

METHODS

Thirty-one patients with secretory pituitary adenomas (adrenocorticotropic hormone, n = 15; growth hormone, n = 13; prolactin, n = 2; thyroid-stimulating hormone, n = 1) were treated with 35 Gy to the 50% isodose line, and had a mean follow-up time of 40.2 months (range = 12-96). All patients were evaluated post-SRS for time to hormonal normalization, time to relapse, as well as incidence and time course of radiation-induced hypopituitarism and cranial neuropathies.

RESULTS

Initial normalization of hypersecretion was achieved in 22 patients (70%) with a median time to remission of 17.7 months. After initial hormonal remission, 7 patients (32%) experienced an endocrine relapse, with a mean time to relapse of 21 months. New endocrine deficiency within any of the five major hormonal axes occurred in 10 patients (32%). One patient (3%) developed new-onset unilateral optic nerve pallor within the temporal field 3 years after SRS. Three patients (10%) reported transient new or increasing frontal headaches of unclear etiology following their procedures.

CONCLUSION

Time to endocrine remission was more rapid in patients treated with 35 Gy, as compared to previously reported literature using marginal doses of 20-24 Gy. Rates of endocrine remission and relapse, post-SRS hypopituitarism, and radiation-induced sequelae were not increased following higher dose treatment.

Comparative effectiveness review of treatment options for pituitary microadenomas in acromegaly

OBJECT

Acromegaly, a syndrome of excess growth hormone (GH) secretion typically caused by a GH-secreting pituitary adenoma, reduces life expectancy by approximately 10 years when left untreated. Treatment of acromegaly involves combinations of one or more discrete therapeutic modalities to achieve biochemical control. Unfortunately, data capable of informing decisions among alternate management strategies are presently lacking.

METHODS

The authors performed a comparative effectiveness research (CER) review integrating efficacy, cost, and quality of life (QOL) analysis for treatment strategies comprising various combinations of surgery, radiotherapy, stereotactic radiosurgery, and pharmacotherapy in patients with acromegaly caused by a pituitary microadenoma. A management decision tree was used to identify 5 treatment strategies, each with up to 4 potential treatment steps. Efficacy was assessed using recent literature reports of biochemical control rates for each modality. Cost estimations were derived from wholesale drug prices and from the Healthcare Cost and Utility Project. Quality of life data were obtained from studies utilizing the Acromegaly Quality of Life Questionnaire.

RESULTS

Individual treatment modalities were analyzed and ranked in each of 3 domains: highest rate of success, lowest cost, and highest QOL, and these scores were combined to facilitate comparison of overall effectiveness of each of the management strategies. These aggregate effectiveness scores were used to compare the 5 strategies from the decision tree, and a novel strategy was also proposed.

CONCLUSIONS

The choice of management strategy must be individualized for each patient with acromegaly. This CER analysis provides a comprehensive framework to inform clinical decisions among alternate management strategies in patients with GH-secreting pituitary microadenomas.

[Treatment of acromegaly: a critical analysis of the last ten years]

The ten previous years in terms of acromegaly treatment were essentially characterized by the experience accumulated with new formulations of somatostatin analogues or new drugs such GH-receptor antagonists recently available. Surgery remains the first-line treatment and its results did not change despite the generalization of endoscopy, which mainly seems to decrease local side-effects. The setting of radiotherapy was essentially modified by the increasing use of gamma-knife or stereotactic radiotherapy; however, their results are essentially the same as the classic fractionated, conventional radiotherapy and nobody knows if it will decrease the side-effects of this therapeutic modality. Nevertheless, thanks to a multistep therapeutic strategy, combining the different therapeutic modalities, it has become very rare for acromegaly not to be controlled in a patient.

Surgery and radiosurgery for acromegaly: a review of indications, operative techniques, outcomes, and complications

Among multimodality treatments for acromegaly, the goals of surgical intervention are to balance maximal tumor resection while preserving normal pituitary function and maintaining patient safety. The resection of growth hormone-(GH-) secreting pituitary adenomas in the hands of experienced surgeons results in hormonal remission in 50-70% of patients. Acromegalic patients often have medical comorbidities and anatomical variations complicating anesthesia and surgical management. Despite these challenges, complications such as CSF leak or new hypopituitarism following surgery remain uncommon. Over the past decade, endoscopic approaches to pituitary tumors have improved visualization and facilitated identification of additional tumor using angled telescopes. Patients with persistent acromegaly following surgery require continued medical and/or radiation-based interventions. The adjunctive use of stereotactic radiosurgery offers hormonal remission in 40-50% of patients. In this article, the current preoperative evaluation, indications for surgery, surgical approaches, role of radiosurgery, complications, and remission criteria following operative resection of GH adenomas are reviewed.

Conversion of daily pegvisomant to weekly pegvisomant combined with long-acting somatostatin analogs, in controlled acromegaly patients

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.

Effect of rosiglitazone on serum IGF-I concentrations in uncontrolled acromegalic patients under conventional medical therapy: results from a pilot phase 2 study

OBJECTIVE

Current therapies for acromegaly are unsatisfactory for some patients. High-dose thiazolidinediones have been reported to reduce serum GH levels in animal models of acromegaly. The objective of the study was to evaluate the effect of increasing doses of rosiglitazone on serum GH and IGF-I concentrations in acromegalic patients.

DESIGN

Phase 2 clinical trial.

PATIENTS AND METHODS

Five consecutive patients with active and uncontrolled acromegaly under conventional medical therapies were treated with increasing doses of rosiglitazone [4 mg/day every month, starting from 8 up to 20 mg/day] added to previous medical therapies for acromegaly.

RESULTS

Mean serum IGF-I concentrations decreased from 547 ± 91 to 265 ± 126 μg/l (p<0,001) during rosiglitazone treatment: 4 patients had normal serum IGF-I concentrations, and a patient had lowered serum IGF-I values, although still abnormal, at the end of the study. On the contrary, serum GH concentrations did not significantly changed during rosiglitazone therapy as well as other pituitary hormones. No relevant side effects of rosiglitazone were observed during the study period. Quantitative real time PCR and Western blotting showed that rosiglitazone lowered GH-dependent hepatic generation of IGF-I in HepG2 cell line.

CONCLUSIONS

Rosiglitazone reduces serum IGF-I concentrations in patients with uncontrolled acromegaly under conventional medical therapies, likely acting on the GH-dependent hepatic synthesis of IGF-I. Large studies are necessary to confirm the role of rosiglitazone as an adjunctive therapy for uncontrolled acromegalic patients under conventional medical therapies.

Radiation treatment strategies for acromegaly

The high morbidity and mortality associated with acromegaly can be addressed with multiple treatment modalities, including surgery, medicines, and radiation therapy. Radiation was initially delivered through conventional fractionated radiotherapy, which targets a wide area over many treatment sessions and has been shown to induce remission in 50%&#x2013;60% of patients with acromegaly. However, conventional fractionated radiotherapy takes several years to achieve remission in patients with acromegaly and carries a risk of hypopituitarism that may limit its use. Stereotactic radiosurgery, of which there are several forms, including Gamma Knife surgery, CyberKnife therapy, and proton beam therapy, offers slightly attenuated efficacy but achieves remission in less time and provides more precise targeting of the adenoma with better control of the dose of radiation received by adjacent structures such as the pituitary stalk, pituitary gland, optic chiasm, and cranial nerves in the cavernous sinus. Of the forms of stereotactic radiosurgery, Gamma Knife surgery is the most widely used and, because of its long-term follow-up in clinical studies, is the most likely to compete with medical therapy for first-line adjuvant use after resection. In this review, the authors outline the major modes of radiation therapies in clinical use today, and they critically assess the feasibility of these modalities for acromegaly treatment. Acromegaly is a multisystem disorder that demands highly specialized treatment protocols including neurosurgical and endocrinological intervention. As more efficient forms of pituitary radiation develop, acromegaly treatment options may continue to change with radiation therapies playing a more prominent role.

A systematic analysis of disease control in acromegaly treated with radiosurgery

Object

Stereotactic radiosurgery (SRS) has emerged as an adjuvant radiation-based therapy for pituitary adenomas. Here, the authors present a systematic analysis of SRS for growth hormone–secreting adenomas to characterize the efficacy of SRS in the treatment of acromegaly.

Methods

A comprehensive search of the English language literature revealed 970 patients with new, recurrent, or persistent acromegaly that had been treated using SRS along with assessable and quantifiable outcome data. Articles published between June 1998 and September 2009 were included in the analysis. Patient outcome data were aggregated and investigated based on tumor size, radiosurgery dose, and clinical outcomes both with and without medication.

Results

The overall disease control rate without medication was 48%–53%, and the overall disease control rate with or without medication was 73%. The overall mean duration of the reported follow-up was 48.5 ± 25.8 months. The mean overall tumor volume in this analysis was 2.11 ± 1.16 cm3. The Pearson product-moment correlation coefficient for tumor volume and cure rate was not significant (r = 0.0668, p = 0.8546).

Conclusions

Data from this analysis suggest that tumor size may not be a significant prognostic factor in disease control after radiosurgery for acromegaly. The overall disease control rate was approximately 48% without suppressive medications after radiosurgery for acromegaly. With the advancement of increasingly sophisticated stereotactic planning and tumor targeting, the precision of radiosurgery may continue to improve in the treatment of acromegaly.

The role of stereotactic radiosurgery in the multimodal management of growth hormone–secreting pituitary adenomas

Growth hormone (GH)–secreting pituitary adenomas represent a common source of GH excess in patients with acromegaly. Whereas surgical extirpation of the culprit lesion is considered first-line treatment, as many as 19% of patients develop recurrent symptoms due to regrowth of previously resected adenomatous tissue or to continued growth of the surgically inaccessible tumor. Although medical therapies that suppress GH production can be effective in the management of primary and recurrent acromegaly, these therapies are not curative, and lifelong treatment is required for hormonal control. Stereotactic radiosurgery has emerged as an effective adjunctive treatment modality, and is an appealing alternative to conventional fractionated radiation therapy. The authors reviewed the growing body of literature concerning the role of radiosurgical procedures in the treatment armamentarium of acromegaly, and identified more than 1350 patients across 45 case series. In this review, the authors report that radiosurgery offers true hormonal normalization in 17% to 82% of patients and tumor growth control in 37% to 100% of cases across all series, while minimizing adverse complications. As a result, stereotactic radiosurgery represents a safe and effective treatment option in the multimodal management of primary or recurrent acromegaly secondary to GH-secreting pituitary adenomas.

Acromegaly per se does not increase the risk for coronary artery disease

CONTEXT

Information about the risk and course of coronary artery disease (CAD) in acromegaly is limited.

OBJECTIVE

To evaluate CAD risk in acromegalic patients at diagnosis and after successful treatment during follow-up.

SUBJECTS AND METHODS

Twenty-five consecutive patients (age 45.1+/-10.6 years, 15 women) were studied at the time of diagnosis, and 19 patients were re-evaluated after 4.6+/-1.1 years. The European Society of Cardiology (ESC) risk score was calculated, and a cardiac computed tomography was performed for detection and quantification (Agatston score (AS)) of coronary artery calcium (CACs). Fifty age-, sex-, and CAD risk-matched subjects and CAC data from the population-based Heinz Nixdorf Recall (HNR) study served as controls.

RESULTS

In 21 of the 25 patients, the 10-year risk of developing CAD according to the ESC risk score was low (<10%) and high (>20%) in four patients. The AS was lower than in controls (2.6+/-7.9 vs 66+/-182; P=0.014) and less patients had a positive CAC (AS>0) (20 vs 48%, P=0.024), which in the acromegalic patients was less than expected from the HNR study. The AS did not correlate with GH excess or disease duration. In 19 acromegalic patients, who were in remission and re-evaluated after 4.6+/-1.1 years, the ESC risk (P=0.102) and the AS (P=0.173) did not change significantly and no symptomatic CAD event occurred.

CONCLUSION

CAD risk in newly diagnosed acromegalic patients was low and remained stable after successful treatment. CAC was lower than in controls suggesting that GH excess per se does not carry an additional CAD risk.

Fractionated stereotactic radiotherapy in patients with acromegaly: an interim single-centre audit

AIM

To evaluate the effect of fractionated stereotactic radiotherapy (FSRT) in acromegaly in a retrospective analysis.

PATIENTS AND METHODS

Thirty-four patients (17 females, median 43 years (range 30-74)) with acromegaly were treated with FSRT (conformal dynamic arcing, dose 54 Gy, 27-30 fractions) between January 1998 and April 2007. Of the 34 patients, 32 had undergone transsphenoidal adenotomy, and 28 were on medical therapy before FSRT. Patients on medical therapy continued this during and after the irradiation. The treatment was gradually decreased/withdrawn after careful assessment.

RESULTS

Magnetic resonance scanning of the pituitary gland 34 months (median, range 11-95) after irradiation showed stable or reduced volume of the remaining tumour tissue in 31 of 34 patients (91%). Seventeen patients (50%) were biochemically controlled (normalised nadir GH during oral glucose tolerance test and IGF1 <+2 S.D.) 30 months after FSRT (median, range 6-60), and ten of them had true biochemical remission (off medical therapy) 30 months after FSRT (median, range 12-69). Of 28 patients with one or more functioning pituitary axes before irradiation, 8 (29%) developed further deficit of one or two pituitary axes 48 months (median, range 6-102) after FSRT. Of 34 patients, 20 still required medical treatment for acromegaly at the end of this study, mainly those with a short follow-up period after irradiation.

CONCLUSION

The FSRT seems promising in terms of treatment of acromegaly. Longer follow-up is, however, needed to assess the overall efficacy and safety of FSRT for acromegaly.

Role of stereotactic radiosurgery in the management of pituitary adenomas

Trans-sphenoidal neurosurgery is the gold standard treatment for pituitary adenomas, but it can be contraindicated or ineffective. Stereotactic radiosurgery is a procedure aimed at controlling hormone hypersecretion and tumor size of pituitary adenomas. This Review discusses the long-term efficacy and adverse effects of stereotactic radiosurgery with the Gamma Knife((R)) in secreting and nonsecreting pituitary adenomas. Long-term data confirm the antisecretory efficacy of the procedure (about 50% remission in hypersecreting tumors) but also a previously unknown low risk of recurrence (2-10% of cases). The time to remission is estimated to range from 12 to 60 months. The antitumoral efficacy of this treatment against nonsecreting tumors is observed in about 90% of cases. Hypopituitarism is the main adverse effect, observed in 20-40% of cases. Comparisons with conventional fractionated radiotherapy reveal a lower rate of remission with Gamma Knife((R)) radiosurgery, counterbalanced by a more rapid efficacy and a lower rate of hypopituitarism. Short-term follow-up results on stereotactic fractionated radiotherapy suggest a risk of hypopituitarism similar to the one observed with radiosurgery. Therefore, stereotactic radiosurgery is probably still useful to treat some cases of pituitary adenoma, despite the fact that antisecretory drugs, particularly for acromegaly and prolactinomas, are becoming more effective and are well tolerated, thus increasing the probability of success with nonsurgical therapy.

Which patients with acromegaly are treated with pegvisomant? An overview of methodology and baseline data in ACROSTUDY

Context Pegvisomant (Somavert, Pfizer Inc.) is the first and only available GH receptor antagonist. ACROSTUDY is an international surveillance study that offers inclusion in a web-based registry to all patients with acromegaly treated with pegvisomant; it aims at monitoring long-term safety and efficacy of this compound. Patients and methods This report summarizes the main baseline characteristics of this particular population of patients. In February 2009, over 300 centres in 10 countries had contributed 792 patients. A gradual increase in cumulative patient recruitment was observed since the launching of ACROSTUDY in 2004: from 116 patients in 2005, it steeply increased to 792 at the latest data freeze in February 2009. At the time of enrolment, 91.8% of patients were already treated with pegvisomant but baseline was considered at the time of pegvisomant start. IGF1 concentrations were measured at local laboratories. Results Of all patients, 80% were reported to have had surgery and 33% to have received radiation therapy. Of the 792 patients, 14% had received no prior medical treatment before pegvisomant start, 65.9% had received somatostatin analogues and 18.6% dopamine agonists. Interestingly, 66.7% had received only pegvisomant at study start, while it was taken in association with dopamine agonists in 5.7%, with somatostatin analogues in 23.4% and with both types of agents in 3.8%. Mean IGF1 at baseline was 522 ng/ml. Conclusion Analysis of the baseline features of these patients treated with pegvisomant and reported in the ACROSTUDY database underscores the severity of the disease in this subset of the population of patients with acromegaly previously unresponsive to several medical, surgical or radiation treatment approaches.

Long-term results of stereotactic radiosurgery in secretory pituitary adenomas

CONTEXT

To date, no study reported long-term follow-up results of gamma knife stereotactic radiosurgery (SR).

OBJECTIVE

The aim of the study was to determine long-term efficacy and adverse effects of SR in secreting pituitary adenomas.

DESIGN

We conducted a retrospective study of patients treated by SR in the center of Marseille, France, with a follow-up of at least 60 months.

PATIENTS

A total of 76 patients were treated by SR for acromegaly (n = 43), Cushing's disease (CD; n = 18), or prolactinoma (n = 15) as a primary (n = 27) or adjunctive postsurgical treatment (n = 49).

MAIN OUTCOME MEASURES

After withdrawal of antisecretory drugs, patients were considered in remission if they had mean GH levels below 2 ng/ml and normal IGF-I (acromegaly), normal 24-h urinary free cortisol, and cortisol less than 50 nmol/liter after low-dose dexamethasone test (CD) or two consecutive normal samplings of prolactin levels (prolactinoma).

RESULTS

After a mean follow-up of 96 months, 44.7% of the patients were in remission. Mean time to remission was 42.6 months. Twelve patients presented late remission at least 48 months after SR. Two patients with CD presented late recurrence 72 and 96 months after SR. Forty percent of patients treated primarily with SR were in remission. Target volume and initial hormone levels were significant predictive factors of remission in univariate analysis. Radiation-induced hypopituitarism was observed in 23% patients; in half of them, hypopituitarism was observed after a mean time of 48 to 96 months. Twenty-four patients were followed for more than 120 months; rates of remission and hypopituitarism were similar to the whole cohort.

CONCLUSIONS

SR is an effective and safe primary or adjunctive treatment in selected patients with secreting pituitary adenomas.

Cost-effectiveness of lanreotide Autogel in treatment algorithms of acromegaly

The introduction of effective pharmacological treatments has changed the management of acromegaly. However, chronic, life-long treatment with somatostatin analogues and/or growth hormone receptor antagonists is very expensive. We estimated the costs of treatment algorithms to control acromegaly from a Dutch perspective. We used the following assumptions: after the diagnosis of acromegaly there is a mean remaining lifespan of approximately 33 years; the success rates of surgery and somatostatin analogues in controlling the disease are approximately 60%; and the lifelong costs of different algorithms to control acromegaly in 100 patients ranged from 43 million euros (primary surgery and secondary somatostatin analogues) to 57 million euros (primary somatostatin analogues and secondary surgery) and even reached 95 million euros (medical treatment only). In algorithms that include trans-sphenoidal surgery, the lifetime treatment costs are almost 46-59% cheaper per 100 patients than in algorithms with medical treatment but without trans-sphenoidal surgery. Algorithms with primary surgery and secondary somatostatin analogs are 30% cheaper per 100 patients than algorithms with primary somatostatin analogues and secondary surgery. Per 100 patients, algorithms including lanreotide Autogel are 14-34% more expensive than algorithms including octreotide long-acting release. These life-long costs should be taken into consideration when making choices between treatment algorithms.

Growth hormone deficiency is associated with decreased quality of life in patients with prior acromegaly

CONTEXT

Both GH deficiency (GHD) and GH excess are associated with a decreased quality of life. However, it is unknown whether patients with GHD after treatment for acromegaly have a poorer quality of life than those with normal GH levels after cure of acromegaly.

OBJECTIVE

The aim of the study was to determine whether patients with GHD and prior acromegaly have a poorer quality of life than those with GH sufficiency after cure of acromegaly.

DESIGN AND SETTING

We conducted a cross-sectional study in a General Clinical Research Center.

STUDY PARTICIPANTS

Forty-five patients with prior acromegaly participated: 26 with GHD and 19 with GH sufficiency.

INTERVENTION

There were no interventions.

MAIN OUTCOME MEASURES

We evaluated quality of life, as measured by 1) the Quality of Life Adult Growth Hormone Deficiency Assessment (QoL-AGHDA); 2) the Short-Form Health Survey (SF-36); and 3) the Symptom Questionnaire.

RESULTS

Mean scores on all subscales of all questionnaires, except for the anger/hostility and anxiety subscales of the Symptom Questionnaire, showed significantly impaired quality of life in the GH-deficient group compared with the GH-sufficient group. Peak GH levels after GHRH-arginine stimulation levels were inversely associated with QoL-AGHDA scale scores (R = -0.53; P = 0.0005) and the Symptom Questionnaire Depression subscale scores (R = -0.35; P = 0.031) and positively associated with most SF-36 subscale scores.

CONCLUSIONS

Our data are the first to demonstrate a reduced quality of life in patients who develop GHD after cure of acromegaly compared to those who are GH sufficient. Further studies are warranted to determine whether GH replacement would improve quality of life for patients with GHD after cure from acromegaly.

Lanreotide for the treatment of acromegaly

Lanreotide is an eight-amino acid peptide, which is an analog of the native somatostatin peptide, physiological inhibitor of growth hormone (GH). The drug shows high binding affinity for somatostatin receptors, SSTR2 and SSTR5, which is the primary mechanism considered to be responsible for decreasing GH secretion and GH cell proliferation in acromegaly. Two different formulations of lanreotide are currently available: lanreotide slow release, which requires intramuscular injection every 7-14 days, and lanreotide autogel, which requires deep subcutaneous injection every 4-8 weeks. Several studies have been published to date on the use of lanreotide in acromegaly. Antisecretory efficacy has been reported in 35%-70% of cases; this huge variability is probably explained by different indications (eg, primary or adjunctive postsurgical treatment), or the fact that some studies were based on patients known to be responders to somatostatin analogs. As a primary treatment, antisecretory efficacy was very similar, confirming the possibility of lanreotide as an option in cases of unsuccessful surgery, contraindication, or surgery refusal. Lanreotide also has antitumoral effects as it induces a decrease in tumor volume of [Symbol: see text]25% in 30%-70% of patients. This could be beneficial before transsphenoidal surgery, as a pretreatment, to decrease tumor volume and ease surgery; however, to date, advantages in terms of final remission or uncured status remain a matter of debate. Side effects are rare; the most frequent being gastrointestinal discomfort and increased risk of gallstone formation, and glucose metabolism modifications. Comparison with the other somatostatin analog, octreotide, tends to show identical levels of efficacy between both drugs. Lanreotide thus seems to be an effective treatment in acromegaly. To date, however, lanreotide is still considered as only suspending GH secretion, thus requiring prolonged and costly treatment.

[Radiotherapy and radiosurgery of pituitary adenomas]

There are two principal types of treatment for pituitary adenomas: fractionated conventional radiation therapy, based on biological selectivity, and radiosurgery, which is delivered in a single dose, based on anatomic selectivity and indicated preferentially for small tumors sufficiently distant from the optic chiasm. Conventional radiation therapy is effective against secretion in 60-80% of cases and radiosurgery in 40-50%, depending on the type of secretion. Maximum antisecretory efficacy is not reached immediately: this delay is longer for conventional radiation therapy (5-10 years) than for radiosurgery (2-3 years). In both cases, antisecretory treatment must be started, while awaiting remission. Radiation therapy and radiosurgery make it possible to stabilize or diminish tumor volume in 70-100% of cases. This is especially useful in the case of an active residue after surgery for non-secreting adenoma, but the long-term side effects of radiation must be borne in mind. The principal side effect is the onset of a pituitary deficiency (in more than 50% of cases after radiation therapy, 20% after radiosurgery). The risk increases with time since treatment. Other very long-term side effects have been described with radiation therapy: radiation-induced tumors, cerebral necrosis, strokes, etc. The role of radiosurgery and radiation therapy is growing ever more limited, because of the increasing efficacy of drug treatments and the excellent surgical results of experienced teams.