Radiotherapy for nonfunctioning pituitary adenomas: from conventional to modern stereotactic radiation techniques

The Impact of Surgical Telementoring on Reducing the Complication Rate in Endoscopic Endonasal Surgery of the Skull Base

BACKGROUND

Pituitary adenomas represent the most common pituitary disorder, with an estimated prevalence as high as 20%, and they can manifest with hormone hypersecretion or deficiency, neurological symptoms from mass effect, or incidental findings on imaging. Transsphenoidal surgery, performed either microscopically or endoscopically, allows for a better extent of resection while minimising the associated risk in comparison to the transcranial approach. Endoscopy allows for better visualisation and improvement in tumour resection with an improved working angle and less nasal morbidity, making it likely to become the preferred surgical treatment for pituitary neoplasms. The learning curve can be aided by telementoring.

METHODS

We retrospectively analysed the clinical records of 94 patients who underwent an endoscopic endonasal resection of a pituitary neoplasm between the years 2011 and 2023 at Maribor University Medical Centre in Slovenia. Remote surgical telementoring over 3 years assisted with the learning curve.

RESULTS

The proportion of complication-free patients significantly increased over the observed period (60% vs. 79%). A gradual but insignificant increase in the percentage of patients with improved endocrine function was observed. Patients' vision improved significantly over the observed period. By gaining experience, the extent of gross total tumour resection increased insignificantly (67% vs. 79%).

CONCLUSIONS

Telementoring for the endoscopic endonasal approach to pituitary neoplasms enables low-volume centres to achieve efficiency, decreasing rates of postoperative complications and increasing the extent of tumour resection.

[Differential diagnosis and tactics of managing a patient with primary hypophysitis on the example of a clinical case]

In recent years, there has been a significant increase in the prevalence of autoimmune endocrinopathies, which are known to affect various levels of the endocrine system, including the pituitary gland. Hypophysitis is a general term used to describe any form of sellar and suprasellar inflammation that leads to structural changes in the hypothalamic-pituitary region and manifests itself in varying degrees of hormonal deficiency of the anterior and posterior pituitary glands. To date, there is a primary form of hypophysitis, which occurs as a result of an autoimmune lesion directly to the pituitary gland, and a secondary form of hypophysitis, which occurs as a result of the presence of a systemic autoimmune disease. Regardless of the etiology, patients with hypophysitis show various signs and symptoms caused by an inflammatory process in the pituitary gland, which can lead to the development of hypopituitarism, compression of the sellar and parasellar structures. MRI is currently the best non-invasive diagnostic tool for diagnosing hypopituitarism, however, the diagnosis can be made with certainty only by histological examination of the pituitary tissue, which requires an invasive approach, which greatly reduces the feasibility of this procedure. In this article, we present a patient with MRI showing signs of hypophysitis in the absence of clear clinical symptoms.

Craniopharyngiomas

Craniopharyngiomas are difficult to treat because of their dense adherence to surrounding structures and the frequent presence of cysts which obscure the anatomy. The introduction of endonasal endoscopic approaches has enabled microsurgery to be performed without mortality. The high recurrence rate requires other forms of treatment of which GKNS has currently been shown to be perhaps the most effective. Difficulties include poorly visualized visual pathways despite which a high degree of tumor control is achievable with surprisingly little damage to vision.

Endocrine Function after Transsphenoidal Surgery in Patients with Non-Functioning Pituitary Adenomas: A Systematic Review and Meta-Analysis

INTRODUCTION

Transsphenoidal surgery is the current treatment for mass reduction in patients with non-functional pituitary adenomas (NFPAs). The surgical procedure may deteriorate or recover pituitary endocrine function. The aim of this study was to systematically assess the benefits and harms of transsphenoidal surgery on pituitary endocrine function in patients with NFPAs.

METHODS

This systematic review and meta-analysis was registered with PROSPERO (registration No. CRD42020210853). We searched Pubmed and EMBASE for studies reporting on pituitary function before and after transsphenoidal surgery in patients with NFPAs having a minimum follow-up of 1 month. The prespecified primary outcomes were the proportions of patients with improved or deteriorated pituitary function after surgery reported as weighted mean using random effects meta-analysis or in case of considerable heterogeneity, i.e., I2 ≥ 75%, as a range of reported proportions. Subgroup analyses were planned for the primary outcomes on study level.

RESULTS

Of the 6,597 identified records, 24 studies enrolling 3,816 participants were eligible for assessment. Twenty-three studies were judged to have serious or critical risk of bias. The range of proportions of patients with recovery of at least one pituitary axis was between 10.2% and 97.7% (I2 = 93%), while the range of proportions of patients experiencing loss of at least one axis after pituitary surgery was between 0.0% and 36.6% (I2 = 91%). None of the a priori planned subgroup analyses explained the observed heterogeneity associated with deterioration of pituitary function after surgery, and the proportion of patients may be underestimated due to publication bias.

CONCLUSIONS

The current systematic review finds that the endocrine effect of pituitary surgery is unclear both in terms of the chance of recovery and in terms of the risk of pituitary failure and hypopituitarism should be considered only a relative indication for surgery. However, the range of effects does include potentially clinically relevant rates of pituitary recovery calling for more systematic collection of data in future studies.

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.

Pituitary Adenomas: From Diagnosis to Therapeutics

Pituitary adenomas are tumors that arise in the anterior pituitary gland. They are the third most common cause of central nervous system (CNS) tumors among adults. Most adenomas are benign and exert their effect via excess hormone secretion or mass effect. Clinical presentation of pituitary adenoma varies based on their size and hormone secreted. Here, we review some of the most common types of pituitary adenomas, their clinical presentation, and current diagnostic and therapeutic strategies.

Aggressive Pituitary Adenoma Not Fulfilling the New High-Risk Criteria with Progression after 18-Year Stable Clinical Course: Case Report

BACKGROUND

 The World Health Organization (WHO) classification of tumors of the endocrine organs was revised in 2017. The term atypical adenoma is no longer recommended, and tumors with rapid growth, radiologic invasion, and high K_i-67 labeling index are defined as high-risk adenomas. In this article, we present the case of an aggressive pituitary adenoma not fulfilling the new high-risk criteria with extraordinary rapid progression after very long stable disease, and discuss the remaining problem of the new criteria in terms of a complicated balance between pathologic findings and clinical features.

CASE DESCRIPTION

 A 67-year-old man was admitted with sellar tumor. Serum prolactin concentration was high at 4,552.2 ng/mL. Transsphenoidal surgery achieved subtotal removal. Histologic diagnosis was lactotroph cell adenoma, and K_i-67 labeling index was 2.6%. Postoperatively, magnetic resonance imaging revealed no evidence of tumor regrowth, but terguride or cabergoline administration was continued for slight hyperprolactinemia. Second surgery was performed 18 years after initial surgery because the tumor showed extraordinary rapid regrowth and hyperprolactinemia of 969 ng/mL. Histologic diagnosis was lactotroph cell adenoma with K_i-67 labeling index of 28.9% and positive immunoreactivity for p53. This case could be diagnosed as a high-risk adenoma from the beginning of treatment based on the WHO 2017 criteria, but the clinical course was unusually long and the indication of aggressive adjuvant therapy after initial surgery remained unsolved.

CONCLUSION

 Pathologic confirmation for the present definition would be expected to assess the cutoff between typical adenomas and aggressive tumors.

Therapeutic approach to non-functioning pituitary adenomas

The treatment of non-functioning pituitary adenomas raises two questions: when should they be treated and what role does each available treatment play. We review the usefulness of the different treatments and propose a therapeutic scheme based on the existing literature. Active treatment of pituitary adenomas should be performed when they produce symptoms, have contact with the optic tract, or have grown on imaging tests. The treatment is surgical, using radiotherapy for cases with significant non-removable postsurgical tumour remnants and for those in which histopathology studies show aggressive features. Medical treatment is reserved for situations in which surgical and radiotherapy treatments have been exhausted. The most advisable surgical treatment is endoscopic, although experienced neurosurgeons achieve results with microsurgery that are only slightly inferior.

Stereotactic Radiosurgery for Residual and Recurrent Nonfunctioning Pituitary Adenomas: A Contemporary Case Series of GammaKnife and CyberKnife Radiosurgery

BACKGROUND

In patients with residual or recurrent nonfunctioning pituitary adenomas (NFPAs) after transsphenoidal resection, both GammaKnife (GKRS) and CyberKnife (CKRS) stereotactic radiosurgery (SRS) are viable treatment options.

OBJECTIVES

We report a retrospective single center series comparing assessing the effectiveness and complications from of these 2 commonly used SRS techniques.

METHODS

A total of 53 patients with prior surgical resection and residual or recurrent NFPAs who underwent GKRS or CKRS and minimum 3-month follow-up between January 2002 and February 2017 at a single center were identified.

RESULTS

A total of 34 patients underwent GKRS and 19 received CKRS. CKRS patients had a larger maximal tumor diameter (P = 0.005) and tumor volume treated (P = 0.001). Differences between GKRS and CKRS treatment parameters included target volume, target volume treated, prescribed dose, maximum dose, prescription isodose line, and conformity index (P < 0.05). The mean follow-up time was 53.74 months for GKRS and 41.48 months for CKRS patients. Tumor progression developed in 6% of cases after GKRS versus 5% after CKRS. The mean progression-free survival was 48.44 months after GKRS and 38.57 months after CKRS (P = 0.61). Five-year actuarial tumor control rates were 91% after GKRS versus 89% after CKRS (P > 0.99). There were no differences in worsened vision or rates of hypopituitarism.

CONCLUSIONS

In patients undergoing single fraction GKRS versus fractionated CKRS for NFPAs, both modalities had similar rates of tumor control, new hypopituitarism, and visual morbidity despite varying indications. This study validates the versatile use of these 2 SRS modalities for patients meeting their relative criteria, especially based on proximity to the optic apparatus and normal pituitary gland.

Radiation dose to neuroanatomical structures of pituitary adenomas and the effect of Gamma Knife radiosurgery on pituitary function

OBJECTIVE

Gamma Knife radiosurgery (GKRS) provides a safe and effective management option for patients with all types of pituitary adenomas. The long-term adverse effects of targeted radiation to the hypothalamic-pituitary axis in relationship to radiation dose remain unclear. In this retrospective review, the authors investigated the role of differential radiation doses in predicting long-term clinical outcomes and pituitary function after GKRS for pituitary adenomas.

METHODS

A cohort of 236 patients with pituitary tumors (41.5% nonfunctioning, 58.5% functioning adenomas) was treated with GKRS between 1998 and 2015. Point dosimetric measurements, with no minimum volume, to 14 consistent points along the hypothalamus bilaterally, pituitary stalk, and normal pituitary were made. Statistical analyses were performed to determine the impact of doses to critical structures on clinical, radiological, and endocrine outcomes.

RESULTS

With a median follow-up duration of 42.9 months, 18.6% of patients developed new loss of pituitary function. The median time to endocrinopathy was 21 months (range 2-157 months). The median dose was 2.1 Gy to the hypothalamus, 9.1 Gy to the pituitary stalk, and 15.3 Gy to the normal pituitary. Increasing age (p = 0.015, HR 0.98) and ratio of maximum dose to the pituitary stalk over the normal pituitary gland (p = 0.013, HR 0.22) were independent predictors of new or worsening hypopituitarism in the multivariate analysis. Sex, margin dose, treatment volume, nonfunctioning adenoma status, or ratio between doses to the pituitary stalk and hypothalamus were not significant predictors.

CONCLUSIONS

GKRS offers a low rate of delayed pituitary insufficiency for pituitary adenomas. Doses to the hypothalamus are low and generally do not portend endocrine deficits. Patients who are treated with a high dose to the pituitary stalk relative to the normal gland are at higher risk of post-GKRS endocrinopathy. Point dosimetry to specific neuroanatomical structures revealed that a ratio of stalk-to-gland radiation dose of 0.8 or more significantly increased the risk of endocrinopathy following GKRS. Improvement in the gradient index toward the stalk and normal gland may help preserve endocrine function.

The Promise of Proton Therapy for Central Nervous System Malignancies

Radiation therapy plays a significant role in management of benign and malignant diseases of the central nervous system. Patients may be at risk of acute and late toxicity from radiation therapy due to dose deposition in critical normal structures. In contrast to conventional photon delivery techniques, proton therapy is characterized by Bragg peak dose deposition which results in decreased exit dose beyond the target and greater sparing of normal structure which may reduce the rate of late toxicities from treatment. Dosimetric studies have demonstrated reduced dose to normal structures using proton therapy as compared to photon therapy. In addition, clinical studies are being reported demonstrating safety, feasibility, and low rates of acute toxicity. Technical challenges in proton therapy remain, including full understanding of depth of proton penetration and the biological activity in the distal Bragg peak. In addition, longer clinical follow-up is required to demonstrate reduction in late toxicities as compared to conventional photon-based radiation techniques. In this review, we summarize the current clinical literature and areas of active investigation in proton therapy for adult central nervous system malignancies.

Pituitary Adenomas: What Are the Key Features? What Are the Current Treatments? Where Is the Future Taking Us?

Pituitary tumors are a heterogeneous group of lesions (usually benign) and proper understanding of the anatomy, physiology, and pathology of the hypothalamic/pituitary region is essential to make an accurate diagnosis and define the essential treatment options (i.e., surgery, medical therapies, and radiotherapy, alone or in combination). Surgery is the primary treatment for acromegaly, Cushing disease, thyroid-stimulating hormone-secreting adenomas, resistant prolactinomas, and nonfunctioning pituitary adenomas causing mass effect. Medical and radiation therapy are reserved in cases in which surgery is not possible or does not provide a complete cure. In the last decades, tremendous innovations (i.e., targeted drugs and refined surgical tools and techniques) have expanded the treatment strategies for pituitary adenomas. We herein report the current indications for and depiction of the surgical techniques in pituitary surgery, review current medical treatments, and provide a glimpse of future possibilities.

Hypopituitarism after Gamma Knife radiosurgery for pituitary adenomas: a multicenter, international study

OBJECTIVE

Recurrent or residual adenomas are frequently treated with Gamma Knife radiosurgery (GKRS). The most common complication after GKRS for pituitary adenomas is hypopituitarism. In the current study, the authors detail the timing and types of hypopituitarism in a multicenter, international cohort of pituitary adenoma patients treated with GKRS.

METHODS

Seventeen institutions pooled clinical data obtained from pituitary adenoma patients who were treated with GKRS from 1988 to 2016. Patients who had undergone prior radiotherapy were excluded. A total of 1023 patients met the study inclusion criteria. The treated lesions included 410 nonfunctioning pituitary adenomas (NFPAs), 262 cases of Cushing's disease (CD), and 251 cases of acromegaly. The median follow-up was 51 months (range 6-246 months). Statistical analysis was performed using a Cox proportional hazards model to evaluate factors associated with the development of new-onset hypopituitarism.

RESULTS

At last follow-up, 248 patients had developed new pituitary hormone deficiency (86 with NFPA, 66 with CD, and 96 with acromegaly). Among these patients, 150 (60.5%) had single and 98 (39.5%) had multiple hormone deficiencies. New hormonal changes included 82 cortisol (21.6%), 135 thyrotropin (35.6%), 92 gonadotropin (24.3%), 59 growth hormone (15.6%), and 11 vasopressin (2.9%) deficiencies. The actuarial 1-year, 3-year, 5-year, 7-year, and 10-year rates of hypopituitarism were 7.8%, 16.2%, 22.4%, 27.5%, and 31.3%, respectively. The median time to hypopituitarism onset was 39 months.In univariate analyses, an increased rate of new-onset hypopituitarism was significantly associated with a lower isodose line (p = 0.006, HR = 8.695), whole sellar targeting (p = 0.033, HR = 1.452), and treatment of a functional pituitary adenoma as compared with an NFPA (p = 0.008, HR = 1.510). In multivariate analyses, only a lower isodose line was found to be an independent predictor of new-onset hypopituitarism (p = 0.001, HR = 1.38).

CONCLUSIONS

Hypopituitarism remains the most common unintended effect of GKRS for a pituitary adenoma. Treating the target volume at an isodose line of 50% or greater and avoiding whole-sellar radiosurgery, unless necessary, will likely mitigate the risk of post-GKRS hypopituitarism. Follow-up of these patients is required to detect and treat latent endocrinopathies.

Non-functioning pituitary adenomas: indications for pituitary surgery and post-surgical management

PURPOSE

Non-functioning pituitary adenomas (NFPAs) are associated with impaired well-being, increased comorbidities, and reduced long-term survival. Data on optimal management of NFPAs around surgical treatment are scarce, and postoperative treatment and follow-up strategies have not been evaluated in prospective trials. Here, we review the preoperative, perioperative, and early postoperative management of patients with NFPAs.

METHODS

We searched Medline and the Cochrane Library for articles published in English with the following items "Pituitary neoplasms AND Surgery" and "Surgery AND Hypopituitarism". Studies containing detailed analyses of the management of NFPAs in adult patients, including pituitary surgery, endocrine care, imaging, ophthalmologic assessment and long-term outcome were reviewed.

RESULTS

Treatment options for NFPAs include active surveillance, surgical resection, and radiotherapy. Pituitary surgery is currently recommended as first-line treatment in patients with visual impairment due to adenomas compressing the optic nerves or chiasma. Radiotherapy is reserved for large tumor remnants or tumor recurrence following one or more surgical attempts. There is no consensus of optimal pre-, peri-, and postoperative management such as timing, frequency, and duration of endocrine, radiologic, and ophthalmologic assessments as well as management of smaller tumor remnants or tumor recurrence.

CONCLUSIONS

In clinical practice, there is a great variation in the treatment and follow-up of patients with NFPAs. We have, based on available data, suggested an optimal management strategy for patients with NFPAs in relation to pituitary surgery. Prospective trials oriented at drawing up strategies for the management of NFPAs are needed.

Recurrent non-functioning pituitary adenomas: a review on the new pathological classification, management guidelines and treatment options

At least 50% of surgically resected non-functioning pituitary adenomas (NFPA) recur. Either early or late adjuvant radiotherapy is highly efficacious in controlling recurrent NFPA but associates potentially burdensome complications like hypopituitarism, vascular complications or secondary neoplasm. Reoperation is indicated in bulky tumor rests compressing the optic pathway. To date, no standardized medical therapy is available for recurrent NFPA although cabergoline and temozolomide show promising results. Guidelines on the management of recurrent NFPAs are now available. The new 2017 WHO pituitary tumor classification, based on immunohistochemistry and transcription factor assessment, identifies a group of aggressive NFPA variants that may benefit from earlier adjuvant therapy. Nevertheless, NFPA patients exhibit a reduced overall life expectancy largely due to hypopituitarism and treatment-related morbidity. The management of recurrent NFPA benefits from a multidisciplinary teamwork of surgeons, endocrinologists, radiation oncologists, ophthalmologists, pathologists and neuro-radiologists in order to provide individualized therapy and anticipate deterioration.

Management of nonfunctioning pituitary tumors: radiotherapy

External beam radiotherapy (RT) is an essential part of the management of intracranial tumors and has been used in treating pituitary adenomas for more than five decades. It has been demonstrated that conventional RT for postoperative residual or progressive nonfunctioning pituitary adenomas (NFAs) present an excellent long-term local tumor control, although its use has been limited because of the potential late toxicity related to radiation treatments. Recent advances in radiation techniques have led to more accurate treatments, rendering obsolete many commonly held views of the "old" radiotherapy. New techniques include intensity modulated radiotherapy, volumetric-modulated arc therapy, and stereotactic techniques, either stereotactic radiosurgery or fractionated stereotactic radiotherapy. New techniques allow the delivering of higher radiation doses to the target with rapid dose fall-off in the surrounding normal tissues, and potentially limiting the long term toxicity of radiation. In this review, we present a critical analysis of the most recent available literature on the use of radiation in patients with NFAs, focusing particularly on the efficacy and safety of radiation stereotactic techniques.

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.

Early versus late Gamma Knife radiosurgery following transsphenoidal surgery for nonfunctioning pituitary macroadenomas: a multicenter matched-cohort study

OBJECTIVE Gamma Knife radiosurgery (GKRS) is frequently used to treat residual or recurrent nonfunctioning pituitary macroadenomas. There is no consensus as to whether GKRS should be used early after surgery or if radiosurgery should be withheld until there is evidence of imaging-defined progression of tumor. Given the high incidence of adenoma progression after subtotal resection over time, the present study intended to evaluate the effect of timing of radiosurgery on outcome. METHODS This is a multicenter retrospective review of patients with nonfunctioning pituitary macroadenomas who underwent transsphenoidal surgery followed by GKRS from 1987 to 2015 at 9 institutions affiliated with the International Gamma Knife Research Foundation. Patients were matched by adenoma and radiosurgical parameters and stratified based on the interval between last resection and radiosurgery. Operative results, imaging data, and clinical outcomes were compared across groups following early (≤ 6 months after resection) or late (> 6 months after resection) radiosurgery. RESULTS After matching, 222 patients met the authors' study criteria (from an initial collection of 496 patients) and were grouped based on early (n = 111) or late (n = 111) GKRS following transsphenoidal surgery. There was a greater risk of tumor progression after GKRS (p = 0.013) and residual tumor (p = 0.038) in the late radiosurgical group over a median imaging follow-up period of 68.5 months. No significant difference in the occurrence of post-GKRS endocrinopathy was observed (p = 0.68). Thirty percent of patients without endocrinopathy in the early cohort developed new endocrinopathies during the follow-up period versus 27% in the late cohort (p = 0.84). Fourteen percent of the patients in the early group and 25% of the patients in the late group experienced the resolution of endocrine dysfunction after original presentation (p = 0.32). CONCLUSIONS In this study, early GKRS was associated with a lower risk of radiological progression of subtotally resected nonfunctioning pituitary macroadenomas compared with expectant management followed by late radiosurgery. Delaying radiosurgery may increase patient risk for long-term adenoma progression. The timing of radiosurgery does not appear to significantly affect the rate of delayed endocrinopathy.

MANAGEMENT OF ENDOCRINE DISEASE: Present and future perspectives for medical therapy of nonfunctioning pituitary adenomas

In contrast to the clear indication for surgical treatment in symptomatic patients with clinically nonfunctioning pituitary adenomas (NFPA), there are no randomized controlled studies comparing therapeutic strategies such as watchful waiting, irradiation or medical therapy for the management of NFPA after surgery. Further, no medical therapy is currently approved for the treatment of NFPA. In this review, we summarize accumulating data on medications currently approved for secreting pituitary adenomas, used off-label in patients with NFPA. Perspectives on overall treatment optimization and potential future therapies are also detailed.

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.

A comparison of the doses received by normal cranial tissues during different simple model conventional radiotherapeutic approaches to pituitary tumours

This aim of this study was to compare the doses received by critical cranial organs when three different radiation techniques were used to treat pituitary tumours. Cranial computed tomography scans of a RANDO phantom and 30 patients were used for pituitary macroadenoma radiotherapy treatment planning. For each slice, target volumes and other critical organs were contoured and three techniques were applied: (A) two parallel-opposed lateral fields, (B) two oblique fields (45°) in coronal plane and (C) two parallel-opposed lateral and anterior fields while the head was tilted 45° in the sagittal plane. The doses received by the target volume and the critical organs for each technique were calculated for all patients. Irradiation was repeated three times for each technique. Finally, the doses that reached the organs of interest resulting from these techniques were compared. The dose delivered to the temporal lobes was 105, 9 and 72 % of the prescribed dose using techniques A, B and C, respectively. The dose received by the cochlea was the lowest in technique C (27 % of prescribed dose) compared with techniques A (79 %) and B (48 %). All techniques delivered 100 % of the prescribed dose to the chiasma. Technique A increased the dose to temporal lobes and the cochlea to such an extent that they exceeded the tolerance dose. Technique B spared the temporal lobes better than technique C; however, technique C was preferred since the dose received by the cochlea in this case was the lowest of all techniques. None of the techniques spared the chiasma.

Longitudinal evaluation of the natural history of conservatively managed nonfunctioning pituitary adenomas

CONTEXT

The optimal management of nonfunctioning pituitary adenomas presenting without symptomatic mass effect remains uncertain. The objective of this study was to elucidate the natural history of nonfunctioning pituitary adenomas managed conservatively.

DESIGN

Volumetric evaluation of tumour growth in serial pituitary MRI scans by a single observer and retrospective review of changes in pituitary function.

PATIENTS

Patients with nonfunctioning pituitary adenomas who underwent at least 2 serial pituitary MRI scans over ≥6 months between 2003 and 2013 prior to any intervention.

MEASUREMENTS

Primary end-point was a ≥20% increase in volume or surgery. Secondary end-points were rate of pituitary dysfunction and pituitary apoplexy.

RESULTS

Fifty nonfunctioning pituitary adenomas (23 macroadenomas and 27 microadenomas, mean age 49, range 17-85 years) were identified. Mean follow-up was 36 months (range 6-79). An increase in volume occurred in macroadenomas (P < 0·01) but not in microadenomas (P = 0·44). A ≥20% increase in volume occurred in nine of 23 macroadenomas compared with two of 27 microadenomas (P < 0·05). Five macroadenomas (one with new visual field defect) and one microadenoma proceeded to surgery (P = 0·08). Hormone deficiency was present in four of 24 macroadenomas vs 0 of 27 microadenomas (P < 0·05) at baseline, while new hormone deficiency developed in only two macroadenomas during follow-up. Pituitary apoplexy occurred in one microadenoma. A growth rate of >10 mm³ /month assessed at approximately 2 years of follow-up among the macroadenoma group was highly predictive (sensitivity and specificity of 90%) of a ≥20% increase in volume or surgery.

CONCLUSIONS

Nonfunctioning pituitary macroadenomas have a greater tendency to grow and require surgical intervention while microadenomas rarely progress.

Retrospective observational analysis of non-irradiated non-functioning pituitary adenomas

PURPOSE

The management of choice of non-functioning pituitary adenomas (NFPAs) remains debulking surgery when symptomatic. However, patient series systematically reporting the NFPAs outcome that were not treated either surgically, medically or with radiotherapy during long follow-up thereby giving an indication of their natural history are limited. Aim of the present study was to evaluate the natural course of presumed NFPAs, the outcome of confirmed NFPAs during a long follow-up period.

METHODS

Between 1993 and 2013, 84 patients with presumed NFPA were studied retrospectively. Patients were enrolled based on the following criteria: imaging suggestive of pituitary adenoma, absence of any biochemical/clinical evidence of hormonal excess, exclusion of prolactinomas and at least one sequential imaging during the follow-up. Repeated assessment of the pituitary function, visual fields and imaging was performed at regular intervals. The follow-up duration was evaluated from the first and last imaging dates.

RESULTS

In group F (follow-up without surgery, 33 patients), the macroadenomas showed a 15% probability of tumor growth and reduction. Similar tumor size alterations were observed also for the microadenomas. In group S (surgery, 51 patients), both residual tumors (>1 and <1 cm) following initial surgical resection remain mainly stable until the last imaging.

CONCLUSIONS

Based on the given lack of approved medical treatment and the possible risks of surgical intervention in presence of significant comorbidities, our study proposes a conservative approach with a careful follow-up in patients with NFPAs without visual or neurological abnormalities.

Early versus late Gamma Knife radiosurgery following transsphenoidal resection for nonfunctioning pituitary macroadenomas: a matched cohort study

OBJECT Gamma Knife radiosurgery (GKRS) is frequently employed to treat residual or recurrent nonfunctioning pituitary macroadenomas. There is no consensus as to whether GKRS should be used early after surgery or if radiosurgery should be withheld until there is evidence of radiographic progression of tumor. METHODS This is a retrospective review of patients with nonfunctioning pituitary macroadenomas who underwent transsphenoidal surgery followed by GKRS between 1996 and 2013 at the University of Virginia Health System. Patients were stratified based on the interval between resection and radiosurgery. Operative results and imaging and clinical outcomes were compared across groups following early (≤ 6 months) or late (> 6 months) radiosurgery. RESULTS Sixty-four patients met the study criteria and were grouped based on early (n = 32) or late (n = 32) GKRS following transsphenoidal resection. There was a greater risk of tumor progression after GKRS in the late radiosurgical group (p = 0.027) over a median radiographic follow-up period of 68.5 months. Furthermore, there was a significantly higher occurrence of post-GKRS endocrinopathy in the late radiosurgical cohort (p = 0.041). Seventeen percent of patients without endocrinopathy in the early cohort developed new endocrinopathies during the follow-up period versus 64% in the late cohort (p = 0.036). This difference was primarily due to a significantly higher rate of tumor growth during the observation period of the late treatment cohort (p = 0.014). Of these patients with completely new endocrinopathies, radiation-associated pituitary insufficiency developed in 1 of 2 patients in the early group and in 3 of 7 (42.9%) patients in the late group. CONCLUSIONS Early treatment with GKRS appears to decrease the rate of radiographic and symptomatic progression of subtotally resected nonfunctioning pituitary macroadenomas compared with late GKRS treatment after a period of expectant management. Delaying radiosurgery may place the patient at increased risk for adenoma progression and endocrinopathy.

Risk-adapted single or fractionated stereotactic high-precision radiotherapy in a pooled series of nonfunctioning pituitary adenomas: high local control and low toxicity

PURPOSE

The purpose of this work was to evaluate a prospectively initiated two-center protocol of risk-adapted single-fraction (SRS) or fractionated radiotherapy (SRT) in patients with nonsecretory pituitary adenomas (NSA).

PATIENTS AND METHODS

A total of 73 NSA patients (39 men/34 women) with a median age of 62 years were prospectively included in a treatment protocol of SRS [planning target volume (PTV) < 4 ccm, > 2 mm to optic pathways = low risk] or SRT (PTV ≥ 4 ccm, ≤ 2 mm to optic pathways = high risk) in two Novalis® centers. Mean tumor volume was 7.02 ccm (range 0.58-57.29 ccm). Based on the protocol guidelines, 5 patients were treated with SRS and 68 patients with SRT.

RESULTS

Median follow-up (FU) reached 5 years with 5-year overall survival (OS) of 90.4 % (CI 80.2-95 %) and 5-year local control and progression-free survival rates of 100 % (CI 93.3-100 %) and 90.4 % (CI 80.2-95 %), respectively. A post-SRS/SRT new visual disorder occurred in 2 patients (2.7 %), a new oculomotor nerve palsy in one pre-irradiated patient, in 3 patients (4.1 %) a pre-existing visual disorder improved. New complete hypopituitarism occurred in 4 patients (13.8 %) and in 3 patients (25 %) with pre-existing partial hypopituitarism. Pituitary function in 26 % of patients retained normal. Patients with tumor shrinkage (65.75 %) had a significantly longer FU (p = 0.0093). Multivariate analysis confirmed correlation of new hypopituitarism with duration of FU (p = 0.008) and correlation of new hypopituitarism and tumor volume (p = 0.023). No significant influence factors for occurrence of visual disorders were found.

CONCLUSION

Our SRS/SRT protocol proved to be safe and successful in terms of tumor control and protection of the visual system, especially for large tumors located close to optic pathways.

Gamma knife surgery for patients with volumetric classification of nonfunctioning pituitary adenomas: a systematic review and meta-analysis

OBJECTIVE

The aim of this study was to scrutinize the literature to determine the efficacy and safety of gamma knife surgery (GKS) for the treatment of nonfunctioning pituitary adenomas (NFPAs) with volumetric classification.

METHODS

Electronic databases including MedLine, PubMed, and Cochrane Central were searched. The literature related to patients with NFPAs treated with GKS was collected. Eligible studies reported on the rate of tumor control (RTC), the rate of radiosurgery-induced optic neuropathy injury (RRIONI), the rate of radiosurgery-induced endocrinological deficits (RRIED), and other parameters.

RESULTS

A total of 17 studies met the criteria. based on the tumor volume, nfpas were divided into three groups: the RTC of group I (93 patients) with tumor volumes <2 ml was 99% (95% CI 96-100%), the RRIONI was 1% (95% CI 0-4%), and the RRIED was 1% (95% CI 0-4%). The RTC of group II (301 patients) with volumes from 2 to 4 ml was 96% (95% CI 92-99%), the RRIONI was 0 (95% CI 0-2%), and RRIED was 7% (95% CI 2-14%). The RTC of group III (531 patients) with volumes larger than 4 ml was 91% (95% CI 89-94%), the RRIONI was 2% (95% CI 0-5%), and the RRIED was 22% (95% CI 14-31%). There were significant differences in the RTC and in the RRIED among the three groups (P<0.001), indicating that there were higher RRIED and lower RTC with the increase of tumor volume.

CONCLUSIONS

NFPAs, according to tumor volume classification, need stratification for GKS treatment. GKS is the optimal choice for the treatment of group II NFPAs. Patients with residual tumor volumes of <4 ml will benefit most from GKS treatment.

Pituitary disease mortality: is it fiction?

During the last 20 years a tremendous improvement in the care of patients with pituitary tumors and of hypopituitarism has been achieved. If we resolve most of the possible causes of the increased cardiovascular disease and stroke mortality a normal survival is expected in these patients. Recently, a large population based study showed a decline in the risk of non-fatal stroke and of non-fatal cardiac events in GH deficient patients. This improvement was achieved by complete hormone replacement, including long term GH replacement, together with prescription of cardio protective drugs. If we follow the latest achievements in pituitary imaging, surgery techniques, hormone substitutions, cardio protective medications, we would expect a normal longevity in these patients. This review will focus on; (1) pituitary insufficiencies and hormone substitutions, (2) modes of cranial radiotherapy, and (3) new techniques in the surgery of a pituitary adenoma.

Stereotactic radiosurgery/radiotherapy for pituitary adenomas: a review of recent literature

The recent clinical results are reviewed of stereotactic radiosurgery/radiotherapy for the treatment of pituitary adenomas. The outcomes of pituitary adenomas treated by stereotactic radiosurgery/radiotherapy with gamma knife, CyberKnife, or linear accelerator (LINAC) radiosurgery were evaluated from articles published after 2004. Each study was evaluated for the number of patients, radiosurgical parameter (marginal dose), length of follow up, tumor growth control, rate of hormonal normalization in secretary adenomas, and adverse events. After gamma knife radiosurgery, the tumor reduction rates varied from 42.3% to 89% in non-secreting adenomas. However, the tumor control rates in non-secreting adenomas were more than 90% in most studies. In growth hormone-secreting adenomas, the rates of insulin-like growth factor-1 normalization ranged from 36.9% to 82%. In adrenocorticotropin-secreting adenomas, the rates for 24-hour urine free cortisol normalization ranged from 27.9% to 54%. In prolactin-secreting adenomas, the prolactin normalization ranged from 17.4% to 50%. New hormonal deficits ranged from 0% to 34%. New visual deficits were relatively low. The number of patients treated with CyberKnife and LINAC radiosurgery/radiotherapy was small and follow-up periods were relatively short compared to those with gamma knife treatment, but the clinical outcomes after these therapies were similar to those after gamma knife therapy. Image-guided stereotactic radiosurgery/radiotherapy with the gamma knife, CyberKnife, or LINAC system is effective and safe against pituitary adenomas. Careful long-term follow up of the patients is necessary because of long-term anti-tumor effects and delayed adverse events.

Endoscopic endonasal transsphenoidal removal of recurrent and regrowing pituitary adenomas: experience on a 59-patient series

OBJECTIVE

The nature of the pituitary adenomas itself exposes the possibility of a recurrence of the tumor. The aim of this study was to evaluate the effectiveness of the endoscopic endonasal transsphenoidal approach for the removal of recurrent and residual pituitary adenomas, already treated by a microscopic or endoscopic transsphenoidal approach or by a transcranial route.

METHODS

A total of 59 adult patients with a recurrent or regrowing pituitary adenoma underwent surgery using a pure endoscopic endonasal transsphenoidal approach. Of these patients, 31 were previously operated on by a microsurgical transsphenoidal approach, 22 by means of an endoscopic transsphenoidal route, and 6 via a transcranial route. The patient series has been divided into 3 tiers according to the primary surgery, and the results were evaluated accordingly.

RESULTS

Gross total removal was achieved in 37 of our cases (62.7%). According to prior surgery at primary disease, we found that in the subgroup of patients who underwent a microsurgical transsphenoidal approach we achieved gross total removal in 23 cases (74.2%; 23 of 31), whereas in the group of patients who underwent the endoscopic endonasal approach, gross total removal was attained respectively in 13 cases (59.1%; 13 of 22) and in only 1 case of those who underwent the transcranial approach (16.7%; 1 of 6). Postoperative complications included 1 case (1.7%) of cerebrospinal fluid leak and meningitis, and 1 with an hematoma in the tumor field (1.7%); both needed surgical reoperation.

CONCLUSIONS

The endoscopic endonasal approach is a safe and effective procedure for the management of recurrent and/or regrowing pituitary tumors previously treated by either a microsurgical or an endoscopic approach.

Gamma Knife surgery for patients with nonfunctioning pituitary macroadenomas: predictors of tumor control, neurological deficits, and hypopituitarism

Object

Nonfunctioning pituitary macroadenomas often recur after microsurgery and thereby require further treatment. Gamma Knife surgery (GKS) has been used to treat recurrent adenomas. In this study, the authors evaluated outcomes following GKS of nonfunctioning pituitary macroadenomas and assessed predictors of tumor control, neurological deficits, and delayed hypopituitarism.

Methods

Between June 1989 and March 2010, 140 consecutive patients with nonfunctioning pituitary macroadenomas were treated using GKS at the University of Virginia. The median patient age was 51 years (range 21–82 years), and 56% of patients were male. Mean tumor volume was 5.6 cm3 (range 0.6–35 cm3). Thirteen patients were treated with GKS as primary therapy, and 127 had undergone at least 1 open resection prior to GKS. Ninety-three patients had a history of hormone therapy prior to GKS. The mean maximal dose of GKS was 38.6 Gy (range 10–70 Gy), the mean marginal dose was 18 Gy (range 5–25 Gy), and the mean number of isocenters was 9.8 (range 1–26). Follow-up evaluations were performed in all 140 patients, ranging from 0.5 to 17 years (mean 5 years, median 4.2 years).

Results

Tumor volume remained stable or decreased in 113 (90%) of 125 patients with available follow-up imaging. Kaplan-Meier analysis demonstrated radiographic progression free survival at 2, 5, 8, and 10 years to be 98%, 97%, 91%, and 87%, respectively. In multivariate analysis, a tumor volume greater than 5 cm3 (hazard ratio = 5.0, 95% CI 1.5–17.2; p = 0.023) was the only factor predictive of tumor growth. The median time to tumor progression was 14.5 years. Delayed hypopituitarism occurred in 30.3% of patients. No factor was predictive of post-GKS hypopituitarism. A new or worsening cranial nerve deficit occurred in 16 (13.7%) of 117 patients. Visual decline was the most common neurological deficit (12.8%), and all patients experiencing visual decline had evidence of tumor progression. In multivariate analysis, a tumor volume greater than 5 cm3 (OR = 3.7, 95% CI 1.2–11.7; p = 0.025) and pre-GKS hypopituitarism (OR = 7.5, 95% CI 1.1–60.8; p = 0.05) were predictive of a new or worsened neurological deficit.

Conclusions

In patients with nonfunctioning pituitary macroadenomas, GKS confers a high rate of tumor control and a low rate of neurological deficits. The most common complication following GKS is delayed hypopituitarism, and this occurs in a minority of patients.

Tumour recurrence and enlargement in patients with craniopharyngioma with and without GH replacement therapy during more than 10 years of follow-up

OBJECTIVE

Most patients who have been treated for craniopharyngioma (CP) are GH deficient (GHD). GH replacement therapy (GHRT) may stimulate tumour regrowth; and one of the concerns with long-term GHRT is the risk of tumour progression. Therefore, the objective was to study tumour progression in CP patients on long-term GHRT.

DESIGN

Case-control study.

PATIENTS AND METHODS

The criteria for inclusion of cases were: i) GHD caused by CP; ii) GHRT >3 years; and iii) regular imaging. This resulted in 56 patients (mean age at diagnosis 25±16 years) with a mean duration of GHRT of 13.6±5.0 years. As controls, 70 CP patients who had not received GHRT were sampled with regard to follow-up, gender, age at diagnosis and initial radiation therapy (RT).

RESULTS

The 10-year tumour progression-free survival rate (PFSR) for the entire population was 72%. There was an association (hazard ratio, P value) between PFSR and initial RT (0.13, 0.001) and residual tumour (3.2, 0.001). The 10-year PFSR was 88% for the GHRT group and 57% for the control group. Substitution with GHRT resulted in the following associations to PFSR: GHRT (0.57, 0.17), initial RT (0.16, <0.001), residual tumour (2.6, <0.01) and gender (0.57, 0.10). Adjusted for these factors, the 10-year PFSR was 85% for the GHRT group and 65% for the control group.

CONCLUSIONS

In patients with CP, the most important prognostic factors for the PFSR were initial RT and residual tumour after initial treatment. Long-term GHRT did not affect the PFSR in patients with CP.

Natural history of postoperative nonfunctioning pituitary adenomas: a systematic review and meta-analysis

OBJECTIVE

Previous studies attempting to define the natural history of postoperative nonfunctioning pituitary adenomas (pNFPAs) were somewhat limited by selection bias and/or small numbers and/or lack of consistency among the study findings. The aim of this study was to scrutinize the literature in order to analyze the natural history of pNFPAs.

METHODS

Electronic database including MEDLINE, PubMed and Cochrane CENTRAL were searched. The literature relating to the patients with pNFPAs without postoperative radiotherapy and pharmacotherapy was collected. Eligible studies reported on the rate of tumor recurrence, the tumor growth-free survival rate (TGFSR) at 5 and 10 years, and/or the residual tumor volume doubling time (TVDT).

RESULTS

19 studies met the criteria. The pNFPAs were divided into two groups: the pooled recurrence rate of group I without detectable residual tumor (371 patients) was 12% (95% CI 6-19%), the TGFSR at 5 and 10 years were 96% (95% CI 89-99%) and 82% (95% CI 65-94%), respectively. The pooled recurrence rate of group II with residual tumor (600 patients) was 46% (95% CI 36-56%), the TGFSR at 5 and 10 years were 56% (95% CI 41-71%) and 40% (95% CI 27-53%), respectively. The mean TVDT was 3.4 years (95% CI 2.4-4.5 years).

CONCLUSIONS

pNFPAs, with or without detectable residual tumor, need stratification of treatment and radiological/endocrinological follow-up strategy. According to the TVDT, residual tumor regrowth is very slow, which permits an extensive and safe follow-up program for most patients.

The role of radiation therapy in the management of non-functioning pituitary adenomas

Surgical removal of non-functioning pituitary adenoma (NFPA) is the first-choice therapeutic option, but radical removal of the tumor cannot be accomplished in all patients. The best strategy to prevent regrowth of NFPA is still a matter of debate. Adjuvant radiotherapy is very effective in reducing recurrence rate after incomplete removal of NFPA, but concerns still exist about long-term toxicity of radiation. Different modalities have been developed to irradiate the pituitary region. One major distinction is between radiation techniques that deliver the total dose in multiple sessions using 3 fixed radiation beams and radiosurgical equipment that delivers the total dose to the target volume in a single treatment session. Progression-free survival of patients with NFPA treated by adjuvant radiotherapy is well above 90% at 5 yr in most studies and diminishes only slightly at 10 yr. Very few studies have a more prolonged follow-up. In comparison, the 5- and 10-yr estimated recurrence rate without adjuvant radiotherapy ranged from 15% to 51% and from 44% to 78%, respectively. Complications of radiation include rare but severe side-effects, such as secondary brain neoplasm, optic neuropathy, cerebrovascular accidents, and more frequent but less severe complications, such as pituitary deficiency. Optimal management of patients with residual or recurring NFPA after surgical debulking can be achieved through the judicious use of different treatment options, necessitating close cooperation between neurosurgeons, endocrinologists, and radiation oncologists.

Endocrinological outcome after pituitary transposition (hypophysopexy) and adjuvant radiotherapy for tumors involving the cavernous sinus

Object

Stereotactic radiosurgery and fractionated stereotactic radiotherapy are commonly used in the treatment of residual or recurrent benign tumors of the skull base and cavernous sinus. A major risk associated with radiosurgical or radiotherapy treatment of residual or recurrent tumors adjacent to normal functional pituitary gland is radiation of the pituitary, which frequently leads to the development of hypopituitarism. The authors have used a technique of pituitary transposition to reduce the radiation dose to the normal pituitary gland in cases of planned radiosurgical treatment of residual tumor within the cavernous sinus. Here, the authors analyze the long-term endocrinological outcomes in patients with residual and recurrent tumors who undergo hypophysopexy and adjuvant radiosurgical or conformal fractionated radiotherapy treatment.

Methods

Pituitary transposition involves placement of a fat graft between the normal pituitary gland and residual tumor in the cavernous sinus. A sellar exploration for tumor resection is performed, the pituitary gland is transposed from the region of the cavernous sinus, and the graft is interposed between the pituitary gland and the residual tumor. The residual tumor may then be treated with stereotactic radiosurgery or conformal fractionated radiation therapy. The authors evaluated endocrinological outcome, safety of the procedure, and postoperative complications in patients who underwent this procedure during a 7-year period.

Results

Hypophysopexy has been used in 34 patients with nonfunctioning pituitary adenomas (19), functional pituitary adenomas (8), chordomas (2), meningiomas (2), chondrosarcoma (1), hemangiopericytoma (1), or hemangioma (1) involving the sella and cavernous sinus. Follow-up (radiographic and endocrinological) has been performed yearly in all patients. Two patients experienced postoperative endocrine deficits before radiosurgery (1 transient), but none of the patients developed new hypopituitarism during the median 4-year follow-up (range 1–8 years) after radiosurgery or fractionated stereotactic radiotherapy.

Conclusions

The increased distance between the normal pituitary gland and the residual tumor facilitates treatment of the tumor with radiosurgery or radiotherapy and effectively reduces the incidence of radiation injury to the normal pituitary gland when compared with historical controls.

Long-term Outcomes After Gamma Knife Radiosurgery for Patients With a Nonfunctioning Pituitary Adenoma

BACKGROUND:

Nonfunctioning pituitary adenomas recur after microsurgery. Gamma Knife radiosurgery (GKRS) has been used to treat recurrent adenomas.

OBJECTIVE:

To evaluate the long-term rates of tumor control and development of hypopituitarism in patients with nonfunctioning pituitary adenomas after GKRS.

METHODS:

Forty-eight patients with a nonfunctioning pituitary adenoma treated between 1991 and 2004 at the University of Virginia were studied. All patients had more than 4 years of clinical and imaging follow-up.

RESULTS:

All patients underwent follow-up imaging and endocrine evaluations, with a duration ranging from 50 to 215 months (median, 80.5 months) and 57 to 201 months (median, 95 months), respectively. New hormone deficiency after GKRS occurred in 19 of 48 patients (39%). Corticotropin/cortisol deficiency developed in 8% of patients, thyroid hormone deficiency in 20.8%, gonadotropin deficiency in 4.2%, growth hormone/insulin-like growth factor 1 in 16.7%, and diabetes insipidus in 2%. Panhypopituitarism including diabetes insipidus developed in 1 patient. Overall, control of tumor volume was 83%. Tumor volume decreased in 36 patients (75%), increased in 8 patients (17%), and was unchanged in 4 patients (8%). Tumor volumes greater than 5 mL at the time of GKRS were associated with a significantly greater rate of growth (P = .003) compared with an adenoma with a volume of 5 mL or less.

CONCLUSION:

GKRS resulted in a high and durable rate of tumor control in patients with a nonfunctioning pituitary adenoma. A higher preoperative tumor volume was associated with an increased rate of tumor growth.

Time course of hypothalamic-pituitary deficiency in adults receiving cranial radiotherapy for primary extrasellar brain tumors

BACKGROUND

No longitudinal data on hypothalamic-pituitary (HP) function are available in patients who had received cranial radiation therapy (CRT) for primary extrasellar brain tumors (PBT).

PURPOSE

To investigate the effects of CRT on HP function in adults with PBT.

PATIENTS AND METHODS

Twenty-six adults irradiated for PBT and six CRT naive controls were studied. CRT was delivered with 6 MV X-ray by a linear accelerator (2 Gy fraction schedule). Gross Tumor Volume (GTV) excluded the HP region that was contoured on the planning CT. Median dose to the HP region was 41.8 Gy (IQR: 30.7-49.8).

RESULTS

All controls maintained normal HP function. Hypopituitarism developed in 38% of CRT patients (GH deficiency 29%, ACTH 22%, TSH 14%, gonadotropin 4%, no abnormal prolactin level or diabetes insipidus). All HP failures occurred within 32 months after CRT.

CONCLUSIONS

Adults undergoing CRT for PBT are at increased risk for HP dysfunction within 3 years from CRT. Endocrine surveillance is recommended also in adults patients exposed to CRT for primary brain tumors distant from HP region.

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.

Future directions for surgery of the pituitary region

Pituitary surgery has evolved tremendously over the past century amidst a rapidly changing landscape of medical and radiosurgical therapies. One of the principal driving forces behind this transformation has been the benefit of minimal invasiveness, which is likely to further advance the specialty as higher-definition and more miniature optic systems and cameras, the use of robotics, and enhanced neuroimaging and neuronavigation, are further translated into the operating room. The emergence of nanotechnology will likely allow tumor-specific molecular ligands and nanoparticles to identify and differentiate tumors, and may permit manipulation of neural structures on the micron level with tools currently being developed, including the nanoknife, nanotweezers and femtosecond laser. Further advances in stereotactic radiosurgery may increase the prominence and safety associated with this technique for the treatment of pituitary pathology.

A prospective study of nonfunctioning pituitary adenomas: presentation, management, and clinical outcome

A prospective study was performed to evaluate the presentation, therapeutic management, and clinical outcome of nonfunctioning pituitary adenomas (NFPAs). In most of 385 consecutive patients, NFPAs were macroadenomas. The mean follow-up duration was 5.5 ± 1.4 years. Presentation was dominated by headache, visual disturbance, and hypopituitarism. Pituitary apoplexy (clinical and subclinical) was observed in 88 patients. Appropriate steroids replacement was given before surgery. Endoscope-assisted transsphenoidal surgery (TSS) was performed, and was well tolerated by all patients. At discharge, visual disturbances were improved in 215 (87.6%) patients who had complained of visual impairment preoperatively. The shorter the time from presentation of pituitary apoplexy to surgery, the better the outcome in visual function. Seventy-two (18.7%) patients developed transient diabetes insipidus (DI) and 85 (22.1%) patients developed hyponatremia, but all these improved within six weeks. Hypocortisolism was confirmed in 84 (21.8%) patients with an abnormal postoperative day 2 (POD2) 0800 serum cortisol level and in 122 (31.7%) patients with an abnormal POD6 0800 serum cortisol level. Hypothyroidism occurred in 135 (35.1%) patients. Steroids replacement was thus given immediately. Eight (2.1%) patients needed lifetime hormone substitution. No adrenal crisis occurred. Five (1.3%) patients died within six weeks. Residual tumors were confirmed in 79 patients (20.8%) by postoperative four-month enhanced MR imaging. Tumor recurrence or regrowth occurred in 56 patients (14.7%) during the follow-up period. These patients required repeat TSS or radiosurgery. The findings of this study support the use of TSS as a feasible initial treatment for NFPAs. With appropriate perioperative management of abnormal fluid, electrolyte, and endocrinological function, TSS was associated with minimum morbidity and was well tolerated by patients regardless of age. However, close screening of pituitary function and adequate neuroradiological follow-up should be performed after surgery for detection of tumor recurrence or regrowth. The indications for repeat TSS and postoperative radiosurgery in residual or recurrent NFPAs should be better defined.

A single-institution restrospective experience of brachytherapy in the treatment of pituitary tumors: transsphenoidal approach combined with (192)Ir-afterloading catheters

BACKGROUND AND AIM

Radiotherapy may be used as an adjuvant treatment of pituitary adenomas. The aim of our study was to present our experience of multimodal treatment of pituitary adenomas, consisting in temporary implantation of (192)Ir-labeled wires following transphenoidal surgery.

SUBJECTS AND METHODS

An observational investigation was performed on a series of 80 patients undergoing surgery (S) for pituitary adenomas between 1982 and 2000, some of whom received post-operative external beam radiotherapy (EBRT) (no.=19 between 1982 and 1990), brachytherapy (B) (no.=35, all after 1991), or both irradiation modalities (EBRT+B) (no.=14). The different treatments were compared in terms of hormonal normalization in the subgroup of patients with hypersecreting adenomas, tumor control, and side effects.

RESULTS

Hormonal normalization was obtained in 84% of S+B patients and in 61% of S+EBRT patients. Tumor control was obtained in 74.3% of S+B patients and in 63.1% of S+EBRT patients. Anterior pituitary hormones deficits ranged from 8.6-34% in S+B patients and from 15.8-47.4% in S+EBRT patients, after a mean follow-up of 14 yr. The latter group also showed a higher rate of multiple deficits (42.1% vs 22.8%). Diabetes insipidus and other major complications were rare events in all groups.

CONCLUSIONS

We presented one original experience regarding brachytherapy in the management of pituitary tumors, which turned out to be effective and safe. Additional prospective, and possibly randomized, studies should clarify whether in the era of 3-dimensional conformal radiotherapy and stereotactic radiotherapy this treatment modality may still have a role.

Fractionated stereotactic radiotherapy in the treatment of pituitary macroadenomas

Background

The use of fractionated stereotactic radiotherapy (fsrt) has evolved with technical advances in noninvasive immobilization, radiation delivery, and image guidance. The application of fsrt to pituitary tumours is aimed at reducing toxicity through improved dose conformality and reduced treatment margins. The aim of the present paper is to report our own experience and to review the published data on fsrt for pituitary macroadenomas.

Methods

Between September 2000 and October 2005, 13 patients with pituitary macroadenoma underwent fsrt at our institution. In 12 patients, radiotherapy treatment followed surgical resection (transsphenoidal resection in 8, frontal craniotomy in 3, and multiple transsphenoidal resections followed by craniotomy in 1). In 4 patients, the tumours were functional (2 adrenocorticotropic hormone–secreting, 1 prolactinoma, and 1 growth hormone–secreting); the tumours in the remaining patients were clinically non-secretory. Before radiation, 3 patients had panhypopituitarism, and 6 patients had visual field defects. All patients were treated with fsrt using non-coplanar micro–multileaf collimation portals. A median dose of 50.4 Gy (range: 45–60 Gy) was prescribed to the 76.9%–95.2% isodose surface and delivered in 1.8-Gy fractions. The median planning target volume (gross tumour plus 3 mm) was 33.5 cm3 (range: 3.2–75 cm3).

Results

After a median follow-up of 24 months (range: 6–60 months), local control was 100%. One patient achieved clinical complete response. Treatment was well tolerated acutely for all patients. Neither radiation-induced optic neuropathy nor any radiation-related endocrine dysfunction was observed in our patients.

Conclusions

In accordance with published series, we found fsrt to be safe and effective in the management of large pituitary macroadenomas.

Non-functioning pituitary adenomas

Non-functioning pituitary tumours are mostly of gonadotroph cell origin and are devoid of humoral hypersecretory syndromes. They are usually large at the time of diagnosis, commonly presenting with headaches, visual field defects and hypopituitarism. Trans-sphenoidal surgery remains the treatment of choice for rapid decompression of neighbouring structures, often bringing to normalisation or improvement of visual and pituitary function. The management of patients with postoperative residual tumours is still a matter of debate and may include observation alone, the use of dopamine agonists or radiation therapy. There are no controlled or comparative studies of the available therapeutic options; therefore, recommendations are not evidence based. Patients need long-term follow-up for the detection and treatment of hypopituitarism, visual dysfunction and tumour growth that may develop over time.

A radiologic score to distinguish autoimmune hypophysitis from nonsecreting pituitary adenoma preoperatively

BACKGROUND AND PURPOSE

Autoimmune hypophysitis (AH) mimics the more common nonsecreting pituitary adenomas and can be diagnosed with certainty only histologically. Approximately 40% of patients with AH are still misdiagnosed as having pituitary macroadenoma and undergo unnecessary surgery. MR imaging is currently the best noninvasive diagnostic tool to differentiate AH from nonsecreting adenomas, though no single radiologic sign is diagnostically accurate. The purpose of this study was to develop a scoring system that summarizes numerous MR imaging signs to increase the probability of diagnosing AH before surgery.

MATERIALS AND METHODS

This was a case-control study of 402 patients, which compared the presurgical pituitary MR imaging features of patients with nonsecreting pituitary adenoma and controls with AH. MR images were compared on the basis of 16 morphologic features besides sex, age, and relation to pregnancy.

RESULTS

Only 2 of the 19 proposed features tested lacked prognostic value. When the other 17 predictors were analyzed jointly in a multiple logistic regression model, 8 (relation to pregnancy, pituitary mass volume and symmetry, signal intensity and signal intensity homogeneity after gadolinium administration, posterior pituitary bright spot presence, stalk size, and mucosal swelling) remained significant predictors of a correct classification. The diagnostic score had a global performance of 0.9917 and correctly classified 97% of the patients, with a sensitivity of 92%, a specificity of 99%, a positive predictive value of 97%, and a negative predictive value of 97% for the diagnosis of AH.

CONCLUSIONS

This new radiologic score could be integrated into the management of patients with AH, who derive greater benefit from medical as opposed to surgical treatment.

O(6)-methylguanine DNA methyltransferase immunoexpression in nonfunctioning pituitary adenomas: are progressive tumors potential candidates for temozolomide treatment?

BACKGROUND

Currently, no effective alternative treatment exists for progressive, regrowing, nonfunctioning pituitary adenomas (NFPA) that are resistant to conventional multimodality therapy. Temozolomide (TMZ) was proposed as a treatment option for pituitary carcinomas and aggressive pituitary adenomas. Recently, it was suggested that the responsiveness of pituitary tumors to TMZ depends on the immunoexpression of O(6)-methylguanine DNA methyltransferase (MGMT). Therefore, the authors of this report assessed MGMT expression in a series of patients with progressive, regrowing NFPAs to evaluate whether TMZ may serve as alternative treatment option.

METHODS

On the basis of postoperative magnetic resonance imaging, 45 patients with NFPAs were allocated to either a group with progressive, regrowing tumors (n = 24) or a tumor-free group (n = 21), which served as a control. MGMT expression was assessed semiquantitatively by immunohistochemistry (low expression was defined as <or=50% immunostained adenoma cells, and high expression was defined as >50% immunostained adenoma cells) and was compared between the 2 groups.

RESULTS

At the time of initial surgery, low MGMT expression was observed in 12 of 24 patients (50%) in the study group with progressive, regrowing NFPAs. In the control group of tumor-free patients, only 5 of 21 patients (24%) exhibited low MGMT expression. A comparable distribution of MGMT expression was observed in the specimens from repeat surgeries. A shorter interval to second surgery was observed in patients who had low MGMT expression.

CONCLUSIONS

The current data has suggested that half of the patients with progressive, regrowing NFPAs exhibit low MGMT expression and are potential candidates for treatment with TMZ. These findings provide a rationale for the use of TMZ as an alternative treatment approach in this subgroup if conventional therapy, including reoperation, radiosurgery, and radiotherapy, fails.

Treatment and follow-up of clinically nonfunctioning pituitary macroadenomas

CONTEXT

Although the majority of pituitary macroadenomas are clinically nonfunctioning, treatments as well as follow-up strategy for this condition lack evidence from randomized studies.

EVIDENCE ACQUISITION

We evaluated the evidence of treatment and follow-up strategies for clinically nonfunctioning adenomas. PubMed was searched for articles on nonfunctioning adenomas in November 2007, and references of selected articles were assessed for potentially relevant articles.

EVIDENCE SYNTHESIS

All evidence for treatment and follow-up for nonfunctioning adenomas is based on observational studies. The most effective treatment is transsphenoidal surgery, indicated in patients with visual field defects. A wait-and-see approach may be considered in nonfunctioning macroadenomas not reaching to the optic chiasm. Some of these tumors ( approximately 10%) will show spontaneous regression, whereas in approximately 50% there will be progression within 5 yr observation. Postoperative radiotherapy should not be applied to all patients after surgery but can be considered in patients with large postoperative remnants of the tumor. During follow-up careful assessment and replacement of pituitary insufficiencies should be performed. Magnetic resonance imaging is advised with intervals of 1-3 yr and evaluation of visual fields when appropriate. Recurrence rates are reported to be 6-46% after transsphenoidal surgery, whereas after postoperative radiotherapy, recurrence rates of 0-36% are reported. Long-term sequelae of nonfunctioning macroadenomas are hypopituitarism, persistent visual field defects, and decreased quality of life. Whether nonfunctioning macroadenomas are associated with an increased mortality is still a matter of debate.

CONCLUSION

Clinically nonfunctioning pituitary macroadenomas, although benign in nature, need individualized treatment and lifelong radiological and endocrinological follow-up.

Radiation therapy in the treatment of pituitary tumors

✓ The treatment of pituitary tumors has progressed into a multidisciplinary approach that involves neurosurgeons, radiation oncologists, and endocrinologists. This has allowed improved outcomes in treatment of pituitary tumors due to a combination of surgical, medical, and radiation therapies. In this study, the authors review the role of radiation therapy in the treatment of pituitary adenomas.