Stereotactic radiosurgery for recurrent surgically treated acromegaly: comparison with fractionated radiotherapy

Recurrent acromegaly: a systematic review on therapeutic approaches

BACKGROUND AND OBJECTIVE

Management of recurrent acromegaly is challenging for both neurosurgeons and endocrinologists. Several treatment options including repeat surgery, medical therapy, and radiation are offered for such patients. The efficacy of these modalities for the treatment of recurrence has not been studied previously in the literature. In this study, we aim to systematically review the existing cases of recurrence and come to a conclusion regarding the appropriate treatment in such cases.

METHOD

A systematic review was performed through PubMed, Scopus, Web of Science, and Cochrane database to identify studies reporting the treatment outcome of recurrent acromegaly patients. Using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, the included studies were reviewed for primary and secondary treatment, complications, and outcomes of the secondary treatment.

RESULTS

The systematic review retrieved 23 records with 95 cases of recurrent acromegaly. The mean time of recurrence was 4.16 years after the initial treatment. The most common primary treatment was surgery followed by radiotherapy. The remission rate was significantly higher in medical and radiotherapy compared to surgical treatment.

CONCLUSION

In cases of recurrent acromegaly, the patient may benefit more from radiotherapy and medical therapy compared to surgery. As the quality of evidence is low on this matter feature studies specifically designed for recurrent patients are needed.

Stereotactic Radiosurgery Outcomes in Medically and Surgically Failed or Nonsurgical Candidates with Medically Failed Prolactinomas: A Systematic Review and Meta-Analysis

Objective  Prolactinomas are treated with dopamine agonists (DAs) as first-line therapy and transsphenoidal surgery as an alternative approach for medically failed tumors. We sought to summarize the efficacy of stereotactic radiosurgery (SRS) in the medically and surgically failed prolactinomas as well as in nonsurgical candidates with medically failed prolactinomas by systematic review and meta-analysis. Method  A literature search was conducted according to the Preferred Reporting Items for Systematic Review and Meta-Analyses guideline. Results  A total of 11 articles (total N  = 709) met inclusion criteria. Thirty-three percent of patients were able to achieve endocrine remission at a mean follow-up of 54.2 ± 42.2 months with no association between stopping DA and endocrine remission. Sixty-two percent of patients were able to achieve endocrine control with DA therapy and 34% of patients were able to decrease the dose of DA dose when compared with pre-SRS DA dose at the end of the follow-up period. However, 54% of patients required DA at the end of the follow-up to control hyperprolactinemia. Ninety percent of patients were able to achieve radiologic control at the end of the follow-up in comparison to pre-SRS imagings. Furthermore, 26% of patients newly developed hypopituitarism (one or more pituitary hormones) post-SRS throughout the follow-up period. Conclusion  This systematic review and meta-analysis demonstrates SRS as an effective adjunct therapy in medically failed nonsurgical candidates or surgically and medically recalcitrant prolactinomas with a 33% chance of achieving endocrine remission, 62% of patients achieved hormonal control with DA and GKRS (gamma knife radio-surgery), with a 34% chance of decreasing DA dose and 90% chance of achieving radiologic control.

Recent Therapeutic Advances in Pituitary Carcinoma

Pituitary carcinoma (PC) is a rare, aggressive malignancy that comprises 0.1-0.2% of all pituitary tumors. PC is defined anatomically as a pituitary tumor that metastasizes outside the primary intrasellar location as noncontiguous lesions in the central nervous system or as metastases to other organs. Similar to pituitary adenoma, PC originates from various cell types of the pituitary gland and can be functioning or nonfunctioning, with the former constituting the majority of the cases. Compression of intricate skull-based structures, excessive hormonal secretion, impaired pituitary function from therapy, and systemic metastases lead to debilitating symptoms and a poor survival outcome in most cases. PC frequently recurs despite multimodality treatments, including surgical resection, radiotherapy, and biochemical and cytotoxic treatments. There is an unmet need to better understand the pathogenesis and molecular characterization of PC to improve therapeutic strategies. As our understanding of the role of signaling pathways in the tumorigenesis of and malignant transformation of PC evolves, efforts have focused on targeted therapy. In addition, recent advances in the use of immune checkpoint inhibitors to treat various solid cancers have led to an interest in exploring the role of immunotherapy for the treatment of aggressive refractory pituitary tumors. Here, we review our current understanding of the pathogenesis, molecular characterization, and treatment of PC. Particular attention is given to emerging treatment options, including targeted therapy, immunotherapy, and peptide receptor radionuclide therapy.

Efficiency and Safety of CyberKnife Robotic Radiosurgery in the Multimodal Management of Patients with Acromegaly

OBJECTIVE

To analyze, in a cohort of acromegalic patients, the results of the efficiency and safety of radiosurgery (CyberKnife), as well as the prognostic factors associated with disease remission.

MATERIAL AND METHODS

Observational, retrospective, longitudinal, and analytical study that included acromegalic patients with persistent biochemical activity after initial medical-surgical treatment, who received treatment with CyberKnife radiosurgery. GH and IGF-1 levels at baseline after one year and at the end of follow-up were evaluated.

RESULTS

57 patients were included, with a median follow-up of four years (IQR, 2-7.2 years). The biochemical remission rate was 45.6%, 33.33% achieved biochemical control, and 12.28% attained biochemical cure at the end of follow-up. A progressive and statistically significant decrease was observed in the comparison of the concentrations of IGF-1, IFG-1 x ULN, and baseline GH at one year and at the end of follow-up. Both cavernous sinus invasion and elevated baseline IGF-1 x ULN concentrations were associated with an increased risk of biochemical non-remission.

CONCLUSION

Radiosurgery (CyberKnife) is a safe and effective technique in the adjuvant treatment of GH-producing tumors. Elevated levels of IGF x ULN before radiosurgery and invasion of the cavernous sinus by the tumor could be predictors of biochemical non-remission of acromegaly.

Dose to neuroanatomical structures surrounding pituitary adenomas and the effect of stereotactic radiosurgery on neuroendocrine function: an international multicenter study

OBJECTIVE

Stereotactic radiosurgery (SRS) provides a safe and effective therapeutic modality for patients with pituitary adenomas. The mechanism of delayed endocrine deficits based on targeted radiation to the hypothalamic-pituitary axis remains unclear. Radiation to normal neuroendocrine structures likely plays a role in delayed hypopituitarism after SRS. In this multicenter study by the International Radiosurgery Research Foundation (IRRF), the authors aimed to evaluate radiation tolerance of structures surrounding pituitary adenomas and identify predictors of delayed hypopituitarism after SRS for these tumors.

METHODS

This is a retrospective review of patients with pituitary adenomas who underwent single-fraction SRS from 1997 to 2019 at 16 institutions within the IRRF. Dosimetric point measurements of 14 predefined neuroanatomical structures along the hypothalamus, pituitary stalk, and normal pituitary gland were made. Statistical analyses were performed to determine the impact of doses to critical structures on clinical, radiographic, and endocrine outcomes.

RESULTS

The study cohort comprised 521 pituitary adenomas treated with SRS. Tumor control was achieved in 93.9% of patients over a median follow-up period of 60.1 months, and 22.5% of patients developed new loss of pituitary function with a median treatment volume of 3.2 cm3. Median maximal radiosurgical doses to the hypothalamus, pituitary stalk, and normal pituitary gland were 1.4, 7.2, and 11.3 Gy, respectively. Nonfunctioning adenoma status, younger age, higher margin dose, and higher doses to the pituitary stalk and normal pituitary gland were independent predictors of new or worsening hypopituitarism. Neither the dose to the hypothalamus nor the ratio between doses to the pituitary stalk and gland were significant predictors. The threshold of the median dose to the pituitary stalk for new endocrinopathy was 10.7 Gy in a single fraction (OR 1.77, 95% CI 1.17-2.68, p = 0.006).

CONCLUSIONS

SRS for the treatment of pituitary adenomas affords a high tumor control rate with an acceptable risk of new or worsening endocrinopathy. This evaluation of point dosimetry to adjacent neuroanatomical structures revealed that doses to the pituitary stalk, with a threshold of 10.7 Gy, and doses to the normal gland significantly increased the risk of post-SRS hypopituitarism. In patients with preserved pre-SRS neuroendocrine function, limiting the dose to the pituitary stalk and gland while still delivering an optimal dose to the tumor appears prudent.

Stereotactic radiosurgery for secretory pituitary adenomas: systematic review and International Stereotactic Radiosurgery Society practice recommendations

OBJECTIVE

A systematic review was performed to provide objective evidence on the use of stereotactic radiosurgery (SRS) in the management of secretory pituitary adenomas and develop consensus recommendations.

METHODS

The authors performed a systematic review of the English-language literature up until June 2018 using the PRISMA guidelines. The PubMed (Medline), Embase, and Cochrane databases were searched. A total of 45 articles reporting single-institution outcomes of SRS for acromegaly, Cushing's disease, and prolactinomas were selected and included in the analysis.

RESULTS

For acromegaly, random effects meta-analysis estimates for crude tumor control rate, crude endocrine remission rate, and any new hypopituitarism rates were 97.0% (95% CI 96.0%-98.0%), 44.0% (95% CI 35.0%-53.0%), and 17.0% (95% CI 13.0%-23.0%), respectively. For Cushing's disease, random effects estimates for crude tumor control rate, crude endocrine remission rate, and any new hypopituitarism rate were 92.0% (95% CI 87.0%-95.0%), 48.0% (95% CI 35.0%-61.0%), and 21.0% (95% CI 13.0%-31.0%), respectively. For prolactinomas, random effects estimates for crude tumor control rate, crude endocrine remission rate, and any new hypopituitarism rate were 93.0% (95% CI 90.0%-95.0%), 28.0% (95% CI 19.0%-39.0%), and 12.0% (95% CI 6.0%-24.0%), respectively. Meta-regression analysis did not show a statistically significant association between mean margin dose with crude endocrine remission rate or mean margin dose with development of any new hypopituitarism rate for any of the secretory subtypes.

CONCLUSIONS

SRS offers effective tumor control of hormone-producing pituitary adenomas in the majority of patients but a lower rate of endocrine improvement or remission.

Efficacy of Gamma Knife radiosurgery in the management of pituitary prolactinoma

Background:

Gamma Knife radiosurgery (GKR) has been widely used in the management of a variety of intracranial tumors, including pituitary adenomas. Pituitary prolactinoma (Prs) is one of the most common types of these adenomas.

Methods:

This prospective study included 50 patients with pituitary Prs over a period from June 2017 to June 2018 at the Neurosciences Hospital, Baghdad/Iraq. The GKR procedure was performed using the Leksell Gamma Knife^® Perfexion™, 192 beams of Cobalt 60 radiation were delivered through the intact skull to the pituitary Prs.

Results:

There is a significant female predominance 32 (72%). The results after 6 months of GKR showed significant improvement regarding the size of adenoma, prolactin hormone level, contrast enhancement on MRI, and medical treatment.

Conclusion:

The study showed that the GKR is a safe and effective modality of treatment in the management of pituitary Prs.

Gamma Knife radiosurgery for acromegaly: Evaluating the role of the biological effective dose associated with endocrine remission in a series of 42 consecutive cases

INTRODUCTION

Stereotactic radiosurgery (SRS) is a valuable treatment option for persistent and/or recurrent acromegaly secondary to growth hormone (GH) secreting pituitary adenoma (PA). Here, we assess the role of biological effective dose (BED) received by PA treated with SRS in relation with endocrine remission.

METHODS

Forty-two patients (minimum 6 months follow-up) were included. Mean marginal dose was 27.7 (median 28, 20-35), and mean BED received by tumour was 193.1 Gy_2.47 (median 199.7, 64.1-237.1). Based on the median values, we divided the patients in high tumour BED group (H-BEDtm, 199.7-237.1 Gy_2.47, n = 12) and low BED one (L- BEDtm, 64.1-199.7 Gy_2.47 , n = 10). The two groups did not differ by pretherapeutic IGF-1 levels (p = .1) or by the prescribed dose (p = .6).

RESULTS

Mean follow-up period was 62.5 months (median 60.5, 9-127). Probability of IGF-1 normalization was 65% at 3 years and 72.4% at 4 years, remaining stable until last follow-up. Twenty-two (52.4%) patients had complete endocrine remission in absence of any Somatostatin analogues. Actuarial rates were 33% at 3 years and 57.4% at 7 years, further remaining stable during follow-up course. In univariate analysis, only statistically significant parameter was pretherapeutic serum IGF-1 and IGF-1 index (p = .01). Five patients (5/26, 19.3%) without previous hypopituitarism developed new pituitary insufficiency. H-BEDtm was associated with higher rates of endocrine remission compared with L-BEDtm, with actuarial probability of 70.2% versus 48.2% at 9 years, although this did not reach statistical significance (p > .05).

CONCLUSION

Our study confirms that SRS by Gamma Knife is safe and effective for GH-secreting PA. Pretherapeutic serum levels of IGF-1 were only statistically significant parameter for endocrine remission.

Robotic Radiosurgery for Persistent Postoperative Acromegaly in Patients with Cavernous Sinus-Invading Pituitary Adenomas-A Multicenter Experience

Simple Summary

Growth hormone-secreting tumors of the pituitary gland which infiltrate surrounding tissue structures may not be fully resectable. This causes many patients to suffer from acromegaly after an unsuccessful surgery. To limit the considerable morbidity and mortality of such patients, effective and safe treatment options are needed. Fractionated radiotherapy and growth hormone-lowering medication are possible treatment options. Robotic radiosurgery (RRS) may be a suitable treatment modality as well. However, only sparse and heterogeneous data are available. This first retrospective multicenter study investigated the efficacy and safety of RRS for this patient group. Outcomes provide evidence that RRS may achieve biochemical disease control or remission in most of the patients. The hormone levels are decreasing after treatment, whereas favorable risk and safety profiles of RRS were shown. No new tumor growth was observed throughout the available follow-up. These findings may guide future care for this challenging patient population.

Abstract

Background: The rates of incomplete surgical resection for pituitary macroadenomas with cavernous sinus invasion are high. In growth hormone-producing adenomas, there is a considerable risk for persistent acromegaly. Thus, effective treatment options are needed to limit patient morbidity and mortality. This multicenter study assesses the efficacy and safety of robotic radiosurgery (RRS) for patients with cavernous sinus-invading adenomas with persistent acromegaly. Methods: Patients who underwent RRS with CyberKnife for postoperative acromegaly were eligible. Results: Fifty patients were included. At a median follow-up of 57 months, the local control was 100%. The pretreatment insulin-like growth factor 1 (IGF-1) levels and indexes were 381 ng/mL and 1.49, respectively. The median dose and prescription isodose were 18 Gy and 70%, respectively. Six months after RRS, and at the last follow-up, the IGF-1 levels and indexes were 277 ng/mL and 1.14, as well as 196 ng/mL and 0.83, respectively (p = 0.0001 and p = 0.0002). The IGF-1 index was a predictor for biochemical remission (p = 0.04). Nine patients achieved biochemical remission and 24 patients showed biochemical disease control. Three patients developed a new hypopituitarism. Conclusions: RRS is an effective treatment for this challenging patient population. IGF-1 levels are decreasing after treatment and most patients experience biochemical disease control or remission.

The Impact of Insulin-Like Growth Factor Index and Biologically Effective Dose on Outcomes After Stereotactic Radiosurgery for Acromegaly: Cohort Study

BACKGROUND

Stereotactic radiosurgery (SRS) is a safe and effective treatment for acromegaly.

OBJECTIVE

To improve understanding of clinical and dosimetric factors predicting biochemical remission.

METHODS

A single-institution cohort study of nonsyndromic, radiation-naïve patients with growth hormone-producing pituitary adenomas (GHA) having single-fraction SRS between 1990 and 2017. Exclusions were treatment with pituitary suppressive medications at the time of SRS, or <24 mo of follow-up. The primary outcome was biochemical remission-defined as normalization of insulin-like growth factor-1 index (IGF-1i) off suppression. Biochemical remission was assessed using Cox proportional hazards. Prior studies reporting IGF-1i were assessed via systematic literature review and meta-analysis using random-effect modeling.

RESULTS

A total of 102 patients met study criteria. Of these, 46 patients (45%) were female. The median age was 49 yr (interquartile range [IQR] = 37-59), and the median follow-up was 63 mo (IQR = 29-100). The median pre-SRS IGF-1i was 1.66 (IQR = 1.37-3.22). The median margin dose was 25 Gy (IQR = 21-25); the median estimated biologically effective dose (BED) was 169.49 Gy (IQR = 124.95-196.00). Biochemical remission was achieved in 58 patients (57%), whereas 22 patients (22%) had medication-controlled disease. Pre-SRS IGF-1i ≥ 2.25 was the strongest predictor of treatment failure, with an unadjusted hazard ratio (HR) of 0.51 (95% CI = 0.26-0.91, P = .02). Number of isocenters, margin dose, and BED predicted remission on univariate analysis, but after adjusting for sex and baseline IGF-1i, only BED remained significant-and was independently associated with outcome in continuous (HR = 1.01, 95% CI = 1.00-1.01, P = .02) and binary models (HR = 2.27, 95% CI = 1.39-5.22, P = .002). A total of 24 patients (29%) developed new post-SRS hypopituitarism. Pooled HR for biochemical remission given subthreshold IGF-1i was 2.25 (95% CI = 1.33-3.16, P < .0001).

CONCLUSION

IGF-1i is a reliable predictor of biochemical remission after SRS. BED appears to predict biochemical outcome more reliably than radiation dose, but confirmatory study is needed.

Fundamentals of Radiation Oncology for Neurologic Imaging

Although the physical and biologic principles of radiation therapy have remained relatively unchanged, a technologic renaissance has led to continuous and ever-changing growth in the field of radiation oncology. As a result, medical devices, techniques, and indications have changed considerably during the past 20-30 years. For example, advances in CT and MRI have revolutionized the treatment planning process for a variety of central nervous system diseases, including primary and metastatic tumors, vascular malformations, and inflammatory diseases. The resultant improved ability to delineate normal from abnormal tissue has enabled radiation oncologists to achieve more precise targeting and helped to mitigate treatment-related complications. Nevertheless, posttreatment complications still occur and can pose a diagnostic challenge for radiologists. These complications can be divided into acute, early-delayed, and late-delayed complications on the basis of the time that they manifest after radiation therapy and include leukoencephalopathy, vascular complications, and secondary neoplasms. The different irradiation technologies and applications of these technologies in the brain, current concepts used in treatment planning, and essential roles of the radiation oncologist in the setting of brain disease are reviewed. In addition, relevant imaging findings that can be used to delineate the extent of disease before treatment, and the expected posttreatment imaging changes are described. Common and uncommon complications related to radiation therapy and the associated imaging manifestations also are discussed. Familiarity with these entities may aid the radiologist in making the diagnosis and help guide appropriate management. ^©RSNA, 2020.

Current perspectives on recurrent pituitary adenoma: The role and timing of surgery vs adjuvant treatment

The clinical course of pituitary adenoma can be highly variable. Aggressive pituitary tumours may require multimodal therapy with multiple operations. Even standard pituitary adenomas exhibit relatively high long-term recurrence rates and delayed intervention is often required. The indications for revision surgery in the endoscopic era are expanding for both functioning and nonfunctioning tumours, including access to the cavernous sinus and intracranial compartments. Although revision surgery can be challenging, it has been demonstrated to be both safe and effective. The question of the use of early radiotherapy in pituitary adenoma remains controversial. Our increasing understanding of pituitary tumour biology facilitates individualized treatment and surveillance protocols, with early intervention in high-risk adenoma subtypes. In this review, we discuss the treatment options for recurring pituitary tumours and focus on the role of revision surgery.

Factors Associated with and Temporal Trends in the Use of Radiation Therapy for the Treatment of Pituitary Adenoma in the National Cancer Database

Objective  Radiation therapy represents an uncommon but important component of treatment plans for some pituitary adenomas (PAs). Although radiation therapy has been used to treat pituitary adenomas for over a century, general trends in the usage of radiation therapy for this purpose have not been reviewed. Additionally, there are few large studies evaluating how radiation therapy is used for the treatment of these benign tumors. Investigating these trends and identifying any variations in radiation therapy utilization would help to better inform treatment decisions and improve patient outcomes. Design  Present study is a retrospective analysis of cases using the National Cancer Database. Setting  The research was organized at a tertiary academic medical center. Participants  Patients were diagnosed with pituitary adenoma between 2004 and 2014 within the National Cancer Database (NCDB). Methods  Temporal trends in the usage of radiation therapy to treat pituitary adenoma were analyzed through a retrospective analysis of 77,142 pituitary adenoma cases from the NCDB between 2004 and 2014. Univariate and multivariate analyses were to examine the relationship between patient, tumor, and treatment factors, and the incorporation of radiation therapy into the treatment of pituitary adenomas. We adjusted for potential confounders such as age, sex, race, comorbidity score, facility type, and year of diagnosis. Results  A total of 77,142 patients met inclusion criteria. Inclusion of radiation therapy in pituitary adenoma treatment was 8.0% in 2004 and steadily declined to a low of 3.1% in 2014. Overall, patients were less likely to receive radiation for their pituitary adenoma over time ( p  < 0.001). Similarly, patients were found to be less likely to receive any type of treatment for PA over time ( p  < 0.001). Multivariable evaluation found patients who were female, between 54 and 64 years of age, or treated at either a Comprehensive Community Cancer Program or an Integrated Network Cancer Program were more likely to receive radiation as part of their pituitary adenoma treatment ( p  < 0.001, odds ratio [OR] = 2.01, confidence interval [CI]: 1.54-2.63; p  < 0.001, OR = 1.84, CI: 1.38-2.44, respectively). Patients were less likely to receive radiation for their PA if they were African American ( p  < 0.001, OR = 0.81, CI: 0.72-0.91). Logistic regression also identified a progressive increase in the likelihood of receiving radiation after a PA diagnosis with increasing tumor size starting with microscopic tumors, peaking at 4 to 5 cm ( p  < 0.001; OR = 15.57; CI: 12.20-19.87). Conclusion  In this sample of pituitary adenoma patients treated at NCDB institutions between 2004 and 2014, we found a steady decline in the incorporation of radiation therapy in treatment, as well as in the use of any type of intervention for PA treatment, suggesting a rise in noninterventional observation of PA.

Outcomes of Pituitary Radiation for Cushing's Disease

Achievement of biochemical remission with preservation of normal pituitary function is the goal of treatment for Cushing's disease. For patients with persistent or recurrent Cushing's disease after transsphenoidal resection, radiation therapy may be a safe and effective treatment. Stereotactic radiosurgery is favored over conventional fractionated external beam radiation. Hormonal recurrence rates range from 0% to 36% at 8 years after treatment. Tumor control rates are high. New pituitary hormone deficiency is the most common adverse effect after stereotactic radiosurgery and external beam radiation. The effects of radiation planning optimization and use of adjuvant medication on endocrine remission rates warrant investigation.

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

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

Fractionated Stereotactic Radiotherapy for Pituitary Adenomas: Single-Center Experience in 75 Consecutive Patients

BACKGROUND

Early results of postoperative fractionated stereotactic radiotherapy (FSRT) for functional and nonfunctional pituitary adenomas appear promising, but the majority of available evidence draws from small series with insufficient follow-up data to draw meaningful conclusions.

OBJECTIVE

To evaluate the long-term outcomes of a large series of patients undergoing FSRT for both functional and nonfunctional pituitary adenomas with the Novalis system (BrainLAB, Heimstetten, Germany).

METHODS

Chart data for 75 consecutive patients undergoing FSRT for a pituitary tumor (21 functional and 54 nonfunctional adenomas) at our institution between January 2004 and June 2013 were reviewed.

RESULTS

Radiographic progression-free survival was 100% over a mean of 47.8 months of radiographic follow-up (range, 12.0-131.2 months). Hormonal normalization was seen in 69.2% of patients with functional adenomas after FSRT, whereas 30.8% experienced partial hormonal control. Mild, grade I acute adverse effects were observed during radiotherapy treatment in 36 patients (48%), and objective, persistent worsening of vision occurred in a single patient (1.5%) after FSRT. New hormonal deficits were seen in 28.0% of patients after FSRT. Radiographic responses were inversely related to tumor volume.

CONCLUSION

FSRT delivers radiographic and functional outcomes similar to those seen with stereotactic radiosurgery and conventional radiotherapy with less resultant toxicity. FSRT is most beneficial for smaller tumors (those <3 cm in diameter).

ABBREVIATIONS

EBRT, external beam radiotherapyFSRT, fractionated stereotactic radiotherapyOR, odds ratioPTV, planning target volumeSRS, stereotactic radiosurgery.

Updates in outcomes of stereotactic radiation therapy in acromegaly

Purpose Treatment of acromegaly has undergone important progress in the last 20 years mainly due to the development of new medical options and advances in surgical techniques. Pituitary surgery is usually first-line therapy, and medical treatment is indicated for persistent disease, while radiation (RT) is often used as third-line therapy. The benefits of RT (tumor volume control and decreased hormonal secretion) are hampered by the long latency of the effect and the high risk of adverse effects. Stereotactic RT methods have been developed with the aim to provide more precise targeting of the tumor with better control of the radiation dose received by the adjacent brain structures. The purpose of this review is to present the updates in the efficacy and safety of pituitary RT in acromegalic patients, with an emphasis on the new stereotactic radiation techniques. Methods A systematic review was performed using PubMed and articles/abstracts and reviews detailing RT in acromegaly from 2000 to 2016 were included. Results Stereotactic radiosurgery and fractionated stereotactic RT (FSRT) for patients with persistent active acromegaly after surgery and/or during medical therapy provide comparable high rates of tumor control, i.e. stable or decrease in size of the tumor in 93-100% of patients at 5-10 years and endocrinological remission in 40-60% of patients at 5 years. Hypofractionated RT is an optimal option for tumors located near the optic structures, due to its lower toxicity for the optic nerves compared to single-dose radiosurgery. The rate of new hypopituitarism varies from 10 to 50% at 5 years and increases with the duration of follow-up. The risk for other radiation-induced complications is usually low (0-5% for new visual deficits, cranial nerves damage or brain radionecrosis and 0-1% for secondary brain tumors) and risk of stroke may be higher in FSRT. Conclusion Although the use of radiotherapy in patients with acromegaly has decreased with advances in medical treatments, it remains an effective treatment option after unsuccessful surgery and/or resistance or unavailability of medical therapy. Long-term studies evaluating secondary morbidity and mortality rate after the new stereotactic techniques are needed, in order to evaluate their potential brain-sparing effect.

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.

Target delineation and optimal radiosurgical dose for pituitary tumors

Stereotactic radiosurgery (SRS) delivered as either single-fraction or multi-fraction SRS (2–5 fractions) is frequently employed in patients with residual or recurrent pituitary adenoma. The most common delivery systems used for SRS include the cobalt-60 system Gamma Knife, the CyberKnife (CK) robotic radiosurgery system, or a modified conventional radiotherapy machine (linear accelerator, LINAC). Tumor control and normalization of hormone hypersecretion have been reported in 75–100 % and 25–80 % of patients, respectively. Hypopituitarism is the most commonly reported late complication of radiation treatment, whereas other toxicities occur less frequently. We have provided an overview of the recent available literature on SRS in patients with a pituitary adenoma. Critical aspects of pituitary irradiation, including target delineation and doses to organs at risk, optimal radiation dose, as well as the long-term efficacy and toxicity of SRS for either nonfunctioning or secreting pituitary adenomas are discussed. Single-fraction SRS represents an effective treatment for patients with a pituitary adenoma; however, caution should be used for lesions > 2.5–3 cm in size and/or involving the anterior optic pathway. Future studies will be necessary to optimize target doses and critical organ dose constrains in order to reduce the long-term toxicity of treatments while maintaining high efficacy.

Gamma knife radiosurgery in patients with persistent acromegaly or Cushing's disease: long-term risk of hypopituitarism

INTRODUCTION

For patient with a recurrent or residual acromegaly or Cushing's disease (CD) after resection, gamma knife radiosurgery (GKRS) is often used. Hypopituitarism is the most common adverse effect after GKRS treatment. The paucity of studies with long-term follow-up has hampered understanding of the latent risks of hypopituitarism in patients with acromegaly or CD. We report the long-term risks of hypopituitarism for patients treated with GKRS for acromegaly or CD.

METHODS

From a prospectively created, IRB-approved database, we identified all patients with acromegaly or CD treated with GKRS at the University of Virginia from 1989 to 2008. Only patients with a minimum endocrine follow-up of 60 months were included. The median follow-up is 159·5 months (60·1-278). Thorough radiological and endocrine assessments were performed immediately before GKRS and at regular follow-up intervals. New onset of hypopituitarism was defined as pituitary hormone deficits after GKRS requiring corresponding hormone replacement.

RESULTS

Sixty patients with either acromegaly or CD were included. Median tumour volume at time of GKRS was 1·3 cm(3) (0·3-13·4), and median margin dose was 25 Gy (6-30). GKRS-induced new pituitary deficiency occurred in 58·3% (n = 35) of patients. Growth hormone deficiency was most common (28·3%, n = 17). The actuarial overall rates of hypopituitarism at 3, 5 and 10 years were 10%, 21·7% and 53·3%, respectively. The median time to hypopituitarism was 61 months after GKRS (range, 12-160). Cavernous sinus invasion of the tumour was found to correlate with the occurrence of a new or progressive hypopituitarism after GKRS (P = 0·018).

CONCLUSIONS

Delayed hypopituitarism increases as a function of time after radiosurgery. Hormone axes appear to vary in terms of radiosensitivity. Patients with adenoma in the cavernous sinus are more prone to develop loss of pituitary function after GKRS.

Gamma Knife radiosurgery for medically and surgically refractory prolactinomas: long-term results

INTRODUCTION

Prolactinomas are the most common functioning pituitary adenomas. Dopamine agonists (DA) are generally very effective in treating prolactinomas by inducing tumor volume regression and endocrine remission. A minority of patients do not respond to DA or are intolerant because of side-effects. Microsurgical resection when possible is the next treatment option, but cavernous sinus, dural, or bone involvement may not allow for complete resection.

OBJECTIVE

We reviewed the outcome of patients with medically and surgically refractory prolactinomas treated with Gamma Knife radiosurgery (GKRS) during a 22 years follow-up period.

METHODS

We reviewed the patient database at the University of Virginia Gamma Knife center during a 25-year period (1989-2014), identifying 38 patients having neurosurgical, radiological and endocrine follow-up.

RESULTS

Median age at GKRS treatment was 43 years. Median follow-up was 42.3 months (range 6-207.9). 55.3 % (n = 21) were taking a dopamine agonist at time of GKRS. 63.2 % (n = 24) had cavernous sinus tumor invasion. Endocrine remission (normal serum prolactin off of a dopamine agonist) was achieved in 50 % (n = 19). GKRS induced hypopituitarism occurred in 30.3 % (n = 10). Cavernous sinus involvement was shown to be a significant negative prognosticator of endocrine remission. Taking a dopamine agonist drug at the time of GKRS showed a tendency to decrease the probability for endocrine remission.

CONCLUSION

GKRS for refractory prolactinomas can lead to endocrine remission in many patients. Hypopituitarism is the most common side effect of GKRS.

Outcome of Stereotactic Radiotherapy for Patients with Uncontrolled Acromegaly

Objective:

Linear accelerator based stereotactic radiation therapy (SRT) has been used for the treatment of pituitary tumours; however, little is known concerning the use of this modality for the treatment of patients with acromegaly. We have prospectively studied the short-term outcome of SRT in 12 acromegaly patients who failed to achieve biochemical remission despite surgery and/or pharmacologic therapy.

Methods:

We identified all patients who had biochemically uncontrolled acromegaly and were treated with SRT between April 2003 and December 2006. All patients were followed prospectively based on a pre-defined protocol that included Goldman visual field examination, MRI of the sella, and pituitary hormone testing at 3, 6, 12 months, and then yearly.

Results:

A total of 12 patients with acromegaly were treated with SRT. There were 9 females and the median age of the group was 50 years. The median follow-up was 28.5 months during which time the mean tumor volume decreased by 40%, the median GH fell from 4.1 μg/L to 1.3 μg/L (p=0.003) and the median IGF-1 dropped more than half from 545.5 μg/L to 260.5 μg/L (p=0.002). Four patients achieved normal, while an additional 2 achieved near-normal, IGF-1 levels. One patient was able to discontinue and two were able to reduce their acromegaly medications while maintaining a normal IGF-1. A new pituitary hormonal deficit was found at 24 months in one patient who developed hypoadrenalism requiring corticosteroid replacement.

Conclusion:

Based on our early experience, we believe that SRT should be considered in treating patients with uncontrolled acromegaly.

Feasibility and outcome of re-irradiation in the treatment of multiply recurrent pituitary adenomas

PURPOSE

This study evaluates the toxicity and outcomes of re-irradiation to the sella for pituitary adenomas.

METHODS

Patients diagnosed with a pituitary adenoma and treated with two or more courses of radiation treatment (RT) to the sella were retrospectively analyzed for: initial diagnosis, including histological type and functional status; RT modality, technique, dose, and fractionation; treatment with surgery, endocrine agents, and chemotherapy; toxicity of RT including radiation-induced optic neuropathy, radionecrosis, and radiation-induced neoplasms; and outcomes including local control, distant metastasis, biochemical control of functional tumors, and vital status at last follow-up.

RESULTS

We identified 15 patients with non-functioning pituitary adenoma (n = 6), Cushing's disease (CD) (n = 5), acromegaly (n = 3), and prolactinoma (n = 1). Initial RT was delivered using opposed lateral fields in 8 (53%), intensity-modulated radiation therapy (IMRT) in 4 (27%), fractionated stereotactic radiation therapy (FSRT) in 1 (6.7%), and stereotactic radiosurgery (SRS) in 2. The median dose was 49.5 Gy for fractionated RT and 15-25 Gy for SRS. Re-irradiation was performed a median of 5.8 years after initial RT, and delivered using lateral opposed beams (n = 1), IMRT (n = 4), linear-accelerator based SRS (n = 3), FSRT (n = 3), gamma knife surgery (n = 2), and yttrium-90 brachytherapy (n = 1). The median dose of re-irradiation was 45 Gy (range 27.9-54 Gy) for fractionated RT and 18 Gy for SRS. Radiation-induced optic neuropathy (RION) was observed in 2 (13.3%) patients, 6 months and 14 years after re-irradiation; the 5-year rate of RION was 9 %. Temporal lobe necrosis (TLN) occurred in two patients (13.3%), both of whom had received SRS. The 2- and 5-year rates of TLN were 10 and 28%. Actuarial local control rates at 2 and 5 years were 80 and 58%, respectively. Biochemical remission occurred in one of three patients with CD. Four patients (27%) ultimately developed pituitary carcinoma.

CONCLUSIONS

Re-irradiation is a feasible treatment option for local control in patients with recalcitrant pituitary adenomas, with acceptable rates of RION and TLN given the lack of options that may be available otherwise. Re-irradiation, however, did not control hormonal hypersecretion.

Stereotactic radiotherapy and radiosurgery for non-functioning and secreting pituitary adenomas

Radiotherapy (RT) is frequently employed in patients with residual or recurrent pituitary adenoma with excellent rates of tumor control and remission of hormonal hypersecretion. Advances in RT have improved with the use of stereotactic techniques either as fractionated stereotactic radiotherapy (FSRT) or stereotactic radiosurgery (SRS), all aiming to improve the dose distribution to the tumor while reducing the amount of normal brain receiving significant doses of radiation. We provide an overview of the recent published literature on the long-term efficacy and adverse effects of stereotactic irradiation in nonfunctioning and secreting pituitary adenomas. Both techniques are associated with excellent clinical outcomes; however, advantages and drawbacks of each of these techniques in terms of local control, hormonal excess normalization, and radiation-induced toxicity remain a matter of debate. In clinical practice, single-fraction SRS may represent a convenient approach to patients with small and medium-sized pituitary adenoma away at least 2 mm from the optic chiasm, whereas FSRT is preferred over SRS for lesions >2.5-3 cm in size and/or involving the anterior optic pathway.

Unyielding progress: recent advances in the treatment of central nervous system neoplasms with radiosurgery and radiation therapy

In the past decade, our understanding of the roles of external beam radiotherapy (EBRT) and stereotactic radiosurgery (SRS) in the management of brain tumors has dramatically improved. To highlight the changes and contemporary treatment approaches, we review the indications and outcomes of ionizing radiation for benign intracranial tumors and brain metastases. For nonfunctioning pituitary adenomas, SRS is able to achieve radiographic tumor control in at least 90 % of cases. The rate of SRS-induced endocrine remission for functioning pituitary adenomas depends on the tumor subtype, but it is generally lower than the rate of radiographic tumor control. The most common complications from pituitary adenoma SRS treatment are hypopituitarism and cranial neuropathies. SRS has become the preferred treatment modality for vestibular schwannomas and skull base meningiomas less than 3 cm in size. Large vestibular schwannomas and meningiomas remain best managed with initial surgical resection or EBRT for surgically ineligible patients. For small to moderately sized brain metastases, there has been a shift toward treatment of newly diagnosed patients with SRS alone due to similar local control rates compared with surgical resection. RCTs have shown combined SRS and whole brain radiation therapy (WBRT) for brain metastases to decrease rates of local and distant intracranial recurrence compared to SRS alone. However, the improved intracranial control comes at the expense of poorer neurocognitive outcomes and without prolonging overall survival. Therefore, WBRT is generally reserved for salvage therapy. While EBRT has been frequently supplanted by SRS for the treatment pituitary adenomas and brain metastases, it still proves useful in selected cases of large lesions which are not amenable to surgical debulking or for those with widespread disease, poor performance status, and short life expectancy. In recent years, the scope of SRS has extended beyond the intracranial space to include extradural and intradural spinal tumors.

Thyrotropin-secreting pituitary adenomas: outcome of pituitary surgery and irradiation

OBJECTIVE

Our objective was to describe the effects of surgery and radiotherapy on hormonal control and tumor mass in short- and long-term follow-up of TSH-secreting pituitary adenomas (TSHomas).

METHODS

This was a retrospective multicenter study.

RESULTS

We collected data of 70 TSHomas (70% macroadenomas). The mean follow-up was 64.4 (range 3-324) months. Overall, 97% of patients were treated with surgery; in 27% of them radiotherapy was associated. After surgery, 75% of patients normalized thyroid function, 58% normalized both pituitary imaging and hormonal profile, 9% developed pituitary deficiencies, and 3% had tumor or hormonal recurrence, all within the first 2 years after surgery. Presurgical medical treatment did not significantly improve surgical outcome (63% vs 57%). Radiotherapy controlled hypersecretion in 37% of patients within 2 years, whereas 32% of patients developed new pituitary deficiencies from 18 to 96 months from treatment. At last follow-up, 80% of patients normalized thyroid function, whereas 20% were currently on medical treatment: 85% with somatostatin analog (SSA) alone and 15% with SSA combined with methimazole. Subjects who achieved disease control had surgery as the only treatment in 80% of cases and surgery combined with irradiation in 20%.

CONCLUSIONS

Surgery remains the first-choice treatment for TSHoma. If surgery is successful, recurrence is rare. When surgery is unsuccessful or contraindicated, SSA and radiotherapy are effective in controlling hyperthyroidism and tumor growth in the majority of patients. The effects of radiotherapy on TSH secretion and tumor mass are greater within the first years after treatment, whereas pituitary deficiencies may occur several years later.

Radiation therapy in the management of pituitary adenomas

Radiation therapy in the form of fractionated treatment or radiosurgery has an important role in the management of pituitary adenomas. Radiation is a reliable way of gaining local control for radiographically progressing pituitary adenomas. For functioning adenomas that are biochemically recurrent or persistent, radiation therapy is less consistent in offering biochemical normalization and often requires a latency period of years or decades. The decision of when to use radiation therapy is a delicate balance between its benefits and late sequelae, especially in the context of benign disease. Recent technological advances in radiation oncology hold the potential to minimize dose to uninvolved normal tissue and therefore reduce the risk of toxicity.

Hypopituitarism after stereotactic radiosurgery for pituitary adenomas

BACKGROUND

Studies of new-onset Gamma Knife stereotactic radiosurgery (SRS)-induced hypopituitarism in large cohort of pituitary adenoma patients with long-term follow-up are lacking.

OBJECTIVE

We investigated the outcomes of SRS for pituitary adenoma patients with regard to newly developed hypopituitarism.

METHODS

This was a retrospective review of patients treated with SRS at the University of Virginia between 1994 and 2006. A total of 262 patients with a pituitary adenoma treated with SRS were reviewed. Thorough endocrine assessment was performed immediately before SRS and in regular follow-ups. Assessment consisted of 24-hour urine free cortisol (patients with Cushing disease), serum adrenocorticotropic hormone, cortisol, follicle-stimulating hormone, luteinizing hormone, insulin-like growth factor-1, growth hormone, testosterone (men), prolactin, thyroid-stimulating hormone, and free T(4).

RESULTS

Endocrine remission occurred in 144 of 199 patients with a functioning adenoma. Tumor control rate was 89%. Eighty patients experienced at least 1 axis of new-onset SRS-induced hypopituitarism. The new hypopituitarism rate was 30% based on endocrine follow-up ranging from 6 to 150 months; the actuarial rate of new pituitary hormone deficiency was 31.5% at 5 years after SRS. On univariate and multivariate analyses, variables regarding the increased risk of hypopituitarism included suprasellar extension and higher radiation dose to the tumor margin; there were no correlations among tumor volume, prior transsphenoidal adenomectomy, prior radiation therapy, and age at SRS.

CONCLUSION

SRS provides an effective and safe treatment option for patients with a pituitary adenoma. Higher margin radiation dose to the adenoma and suprasellar extension were 2 independent predictors of SRS-induced hypopituitarism.

Orbital metastasis of pituitary growth hormone secreting carcinoma causing lateral gaze palsy

Background:

Although pituitary adenoma is one of the most common intracranial tumors, it rarely progresses secondarily into a metastatic carcinoma. Commonalities in reported cases include subtotal resection at presentation, treatment with radiation therapy, and delayed metastatic progression. Pathologic descriptions of these lesions are varying and inconsistent.

Case Description:

A 52-year-old male was diagnosed with acromegaly and pituitary tumor in 1996. He underwent four subtotal resections and five courses of stereotactic radiosurgery over 14 years. He developed left eye lateral gaze palsy, and was found to have a distant orbital metastasis with involvement of the left lateral rectus and lateral orbital wall. He underwent left orbital craniotomy via eyebrow incision for resection of this lesion. Pathologic evaluation showed a markedly elevated Ki67 level of 30%.

Conclusion:

While overall incidence of metastatic progression of pituitary adenoma after radiotherapy appears to be low, it appears to be a possible complication, and could be more likely in patients receiving multiple doses of radiotherapy. Our review of reported cases showed that 45/46 (97.8%) of patients developing carcinoma had prior radiation exposure. These patients may also have more aggressive pathologic characteristics of their lesions.

Meningiomas, nerve sheath tumors, and pituitary tumors: diagnosis and treatment

This article gives an overview of meningiomas, pituitary tumors, and intracranial nerve sheath tumors as regards epidemiology, diagnosis, and treatment. Discussion includes the definition of these tumors and their symptomatology, diagnostic procedures, treatment options, surgical techniques, and outcomes.

Gamma knife radiosurgery for clinically persistent acromegaly

Gamma knife radiosurgery (GKRS) is an important additional strategy for unresected clinically active pituitary adenomas. Radiosurgery for acromegaly aims to achieve tumor growth control and endocrine remission, potentially obviating the need for lifetime medication suppression therapy. Forty patients with clinically active acromegaly underwent GKRS between 1988 and 2009. Thirty-four patients had undergone prior surgical resection. The median follow-up interval was 72 months (range 24-145). Endocrine remission was defined as growth hormones (GH) level <2.5 ng/ml and a normal insulin-like growth factor 1 (IGF-1) level (age and sex adjusted) off growth hormone inhibiting drugs for at least 3 months. Endocrine control was defined as normal GH and IGF-1 levels on suppression medication. Endocrine remission was achieved in 19 (47.5 %) patients and endocrine control in four additional (10.0 %) patients. Patients with lower IGF-1 level and with tumors that were less invasive of the cavernous sinus before GKRS were associated with better GH remission rates. Imaging-defined local tumor control was achieved in 39 (97.5 %) patients (27 had tumor regression). One patient with delayed tumor progression underwent a second GKRS procedure. Three other patients had repeat GKRS because of persistently elevated and clinically symptomatic GH and IGF-1 levels. Sixteen (40.0 %) patients eventually developed a new pituitary axis deficiency at a median onset of 36 months after radiosurgery. No patient developed new visual dysfunction. Gamma knife radiosurgery, which is most often applied in clinically symptomatic acromegaly persistent after initial microsurgery, was most effective when the tumor was less invasive of the cavernous sinus and when patients had lower IGF-1 levels before GKRS. Almost one half of the patients no longer required long term medication suppression.

Comprehensive review of stereotactic radiosurgery for medically and surgically refractory pituitary adenomas

Despite advances in surgical techniques and medical therapies, a significant proportion of pituitary adenomas remain endocrinologically active, demonstrate persistent radiographic disease, or recur when followed for long periods of time. While surgical intervention remains the first-line therapy, stereotactic radiosurgery is increasingly recognized as a viable treatment option for these often challenging tumors. In this review, we comprehensively review the literature to evaluate both endocrinologic and radiographic outcomes of radiosurgical management of pituitary adenomas. The literature clearly supports the use of radiosurgery, with endocrinologic remission rates and time to remission varying by tumor type [prolactinoma: 20–30%, growth hormone secreting adenomas: ~50%, adrenocorticotrophic hormone (ACTH)-secreting adenomas: 40–65%] and radiographic control rates almost universally greater than 90% with long-term follow-up. We stratify the outcomes by tumor type, review the importance of prognostic factors (particularly, pre-treatment endocrinologic function and tumor size), and discuss the complications of treatment (with special attention to endocrinopathy and visual complications). We conclude that the literature supports the use of radiosurgery for treatment-refractory pituitary adenomas, providing the patient with a minimally invasive, safe, and effective treatment option for an otherwise resistant tumor. As such, we provide literature-based treatment considerations, including radiosurgical dose, endocrinologic, radiographic, and medical considerations for each adenoma type.

Results of gamma knife radiosurgery in acromegaly

Objective. Single-session radiosurgery with Gamma Knife (GK) may be a potential adjuvant treatment in acromegaly. We analyzed the safety and efficacy of GK in patients who had previously received maximal surgical debulking at our hospital. Methods. The study was a retrospective analysis of hormonal, radiological, and ophthalmologic data collected in a predefined protocol from 1994 to 2009. The mean age at treatment was 42.3 years (range 22-67 yy). 103 acromegalic patients participated in the study. The median follow-up was 71 months (IQ range 43-107). All patients were treated with GK for residual or recurrent GH-secreting adenoma. Results. Sixty-three patients (61.2%) reached the main outcome of the study. The rate of remission was 58.3% at 5 years (95% CI 47.6-69.0%). Other 15 patients (14.6%) were in remission after GK while on treatment with somatostatin analogues. No serious side effects occurred after GK. Eight patients (7.8%) experienced a new deficit of pituitary function. New cases of hypogonadism, hypothyroidism, and hypoadrenalism occurred in 4 of 77 patients (5.2%), 3 of 95 patients (3.2%), and 6 of 100 patients at risk (6.0%), respectively. Conclusion. In a highly selected group of acromegalic patients, GK treatment had good efficacy and safety.

Stereotactic Irradiation of GH-Secreting Pituitary Adenomas

Radiotherapy (RT) is often employed in patients with acromegaly refractory to medical and/or surgical interventions in order to prevent tumour regrowth and normalize elevated GH and IGF-I levels. It achieves tumour control and hormone normalization up to 90% and 70% of patients at 10-15 years. Despite the excellent tumour control, conventional RT is associated with a potential risk of developing late toxicity, especially hypopituitarism, and its role in the management of patients with GH-secreting pituitary adenomas remains a matter of debate. Stereotactic techniques have been developed with the aim to deliver more localized irradiation and minimize the long-term consequences of treatment, while improving its efficacy. Stereotactic irradiation can be given in a single dose as stereotactic radiosurgery (SRS) or in multiple doses as fractionated stereotactic radiotherapy (FSRT). We have reviewed the recent published literature on stereotactic techniques for GH-secreting pituitary tumors with the aim to define the efficacy and potential adverse effects of each of these techniques.

Radiation techniques for acromegaly

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.

Gamma knife radiosurgery for patients with prolactin-secreting pituitary adenomas

OBJECTIVE

To evaluate the efficacy of stereotactic radiosurgery (SRS) for patients with prolactin (PRL)-secreting pituitary adenomas that were refractory to medical management.

METHODS

Retrospective review of 22 patients treated with SRS from 1994 until 2006. All patients were either intolerant or their tumors were unresponsive to dopamine agonist therapy. Nine patients (41%) had undergone prior transsphenoidal surgery. The median serum PRL concentration before SRS was 88.4 ng/mL (range, 25-943). The median treatment volume was 2.2 cm(3) (range, 0.4-29.0); the median margin radiation dose was 25 Gy (range, 16-30). The median endocrinologic follow-up was 60 months (range, 16-129).

RESULTS

Tumor control after SRS was 100%. Serum PRL concentration was significantly lower (median, 28.4 ng/mL) (P = 0.006) at last follow-up, but the 4-year actuarial rate of biochemical remission off medications was only 17%. No tested variable was associated with biochemical remission off medications. Overall, four patients (18%) had biochemical remission off medications and clinical improvement, three patients (14%) had normal serum PRL concentrations and clinical improvement on dopamine agonist therapy, seven patients (32%) had improved symptoms off medications but continued to have elevated serum PRL levels, and eight patients (36%) continued to be symptomatic with elevated PRL levels either on (n = 3) or off (n = 5) dopamine agonist therapy. The incidence of new anterior pituitary deficits was 42% at 4 years.

CONCLUSIONS

SRS was effective in controlling tumor growth for patients with PRL-secreting pituitary adenomas, and the majority of patients were clinically improved.

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.

Radiosurgery for pituitary adenomas: evaluation of its efficacy and safety

Object

To assess the effects of radiosurgery (RS) on the radiological and hormonal control and its toxicity in the treatment of pituitary adenomas.

Methods

Retrospective analysis of 42 patients out of the first 48 consecutive patients with pituitary adenomas treated with RS between 1999 and 2008 with a 6 months minimum follow-up. RS was delivered with Gamma Knife as a primary or adjuvant treatment. There were 14 patients with non-secretory adenomas and, among functioning adenomas, 9 were prolactinomas, 9 were adrenocorticotropic hormone-secreting and 10 were growth hormone-secreting tumors. Hormonal control was defined as hormonal response (decline of more than 50% from the pre-RS levels) and hormonal normalization. Radiological control was defined as stasis or shrinkage of the tumor. Hypopituitarism and visual deficit were the morbidity outcomes. Hypopituitarism was defined as the initiation of any hormone replacement therapy and visual deficit as loss of visual acuity or visual field after RS.

Results

The median follow-up was 42 months (6-109 months). The median dose was 12,5 Gy (9 - 15 Gy) and 20 Gy (12 - 28 Gy) for non-secretory and secretory adenomas, respectively. Tumor growth was controlled in 98% (41 in 42) of the cases and tumor shrinkage ocurred in 10% (4 in 42) of the cases. The 3-year actuarial rate of hormonal control and normalization were 62,4% and 37,6%, respectively, and the 5-year actuarial rate were 81,2% and 55,4%, respectively. The median latency period for hormonal control and normalization was, respectively, 15 and 18 months. On univariate analysis, there were no relationships between median dose or tumoral volume and hormonal control or normalization. There were no patients with visual deficit and 1 patient had hypopituitarism after RS.

Conclusions

RS is an effective and safe therapeutic option in the management of selected patients with pituitary adenomas. The short latency of the radiation response, the highly acceptable radiological and hormonal control and absence of complications at this early follow-up are consistent with literature.

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.

Factors Associated With Endocrine Deficits After Stereotactic Radiosurgery of Pituitary Adenomas

OBJECTIVE

To analyze the factors associated with anterior pituitary deficits after pituitary adenoma stereotactic radiosurgery (SRS).

METHODS

The tumor, pituitary stalk, and pituitary gland were segmented on the dose plans of 82 patients (secreting tumors, n = 53; nonsecreting tumors, n = 29) for dose-volume analysis. No patient had undergone prior radiation therapy and all patients had at least 12 months of endocrinological follow-up (median, 63 months; mean, 69 months; range, 13–134).

RESULTS

Thirty-four patients (41%) developed new anterior pituitary deficits at a median of 32 months (range, 2–118) after SRS. The risk of developing new anterior pituitary deficits was 16% and 45% at 2 and 5 years, respectively. Multivariate analysis of the entire group showed that poor visualization of the pituitary gland (hazard ratio [HR] = 2.63, 95% confidence interval [CI] = 1.10–6.25, P = .03) was associated with a higher rate of new anterior pituitary deficits. Dosimetric analysis of 60 patients whose pituitary gland could be clearly identified showed that increasing mean pituitary gland radiation dose correlated with new anterior pituitary deficits (HR = 1.11, 95% CI = 1.02–1.20, P = .02). New anterior pituitary deficits stratified by mean pituitary gland radiation dose: ≤7.5 Gy, 0% (0/7); 7.6 to 13.2 Gy, 29% (7/24); 13.3 to 19.1 Gy, 39% (9/23); &gt;19.1 Gy, 83% (5/6).

CONCLUSION

New endocrine deficits after pituitary adenoma radiosurgery were correlated with increasing radiation dose to the pituitary gland. Methods that limit the radiation dose to the pituitary gland during SRS may increase the probability of preserving pituitary function.

Endonasal transsphenoidal surgery and multimodality treatment for giant pituitary adenomas

OBJECTIVE

Giant pituitary adenomas (> or =40 mm) pose a major management challenge. We describe the experience of a single surgeon and a dedicated neuro-endocrine team with multimodality treatment of these tumours in three specialized institutions.

DESIGN

Retrospective data set analyses.

PATIENTS

Fifty-one consecutive patients with a giant adenoma (39 endocrine-inactive, 12 endocrine-active; mean tumour diameter 45 mm) treated over 10 years by an endonasal transsphenoidal approach were included. All patients had surgical resection followed by radiotherapy and/or medical therapy as judged necessary.

MEASUREMENTS

Hormonal and visual status, extent of resection, tumour control rates, complications and use of medical and radiotherapy were evaluated.

RESULTS

Surgery resulted in gross total, near total and subtotal removal in21 (41%), 10 (20%) and 20 (39%) patients respectively. Complete tumour removal was associated with absence of cavernous sinus invasion (P < 0.001). Long-term endocrine function improved in 49% of patients and new endocrinopathy occurred in 14.6%; 76% required long-term hormone replacement therapy. Vision improved in 81.5% of the patients and there was no visual worsening. At the last follow up (median 30 months), tumour control was achieved in 96% of patients: 59% with surgery alone, 20% with surgery plus focussed radiotherapy, 18% with surgery and medical therapy and two with all three modalities.

CONCLUSIONS

Endonasal surgery provides effective initial treatment for patients with giant adenomas. Multimodality therapy was needed in almost 50% of patients and this rate will likely increase with longer follow up. Close collaboration of neurosurgeons with endocrinologists and radiation oncologists is essential for optimal treatment of patients with these challenging tumours.

Gamma knife radiosurgery for growth hormone-producing adenomas

We evaluated the endocrinological outcomes of gamma knife radiosurgery (GKS) for the treatment of growth hormone (GH)-producing pituitary adenomas. Twenty-six patients treated with GKS (median treatment [tumour] volume: 0.8 mL; median marginal radiation dose: 20Gy) were followed for a median of 84 months. "Disease remission" was defined as either nadir levels of GH <1 microg/L during an oral glucose load, or random GH levels <2 microg/L and normal age-adjusted and sex-adjusted levels of insulin-like growth factor without pituitary suppressive medications. The remission rate was 38% (10/26) and the 5-year and 10-year actuarial remission rates were 16.9% and 47.4%, respectively. Two patients (8%) suffered hypopituitarism requiring medication, but no other serious deficits were observed. Although GKS requires a relatively long time to achieve hormonal remission, it is a very useful, long-term treatment for GH-producing adenomas. We propose that compared to continuing life-long medication, GKS is less invasive and more cost effective.