Radiotherapy for nonfunctional pituitary adenoma: analysis of long-term tumor control

Clinical and therapeutic implications of cavernous sinus invasion in pituitary adenomas

Invasion of the cavernous sinus by pituitary adenomas impedes complete surgical resection, compromises biochemical remission, and increases the risk of further tumor recurrence. Accurate preoperative MRI-based diagnosis or intraoperative direct inspection of cavernous sinus invasion are essential for optimal surgical planning and for tailoring postoperative therapeutic strategies, depending on whether a total resection has been achieved, or tumoral tissue has been left in surgically inaccessible locations. The molecular mechanisms underlying the invasive behavior of pituitary adenomas remain poorly understood, hindering the development of targeted therapies. Some studies have identified genes overexpressed in pituitary adenomas invading the cavernous sinus, offering insights into the acquisition of invasive behavior. Their main limitation however lies in comparing purely intrasellar specimens obtained from invasive and non-invasive adenomas. Further, precise anatomical knowledge of the medial wall of the cavernous sinus is crucial for grasping the mechanisms of invasion. Recently, alongside the standard intrasellar surgery, extended endoscopic intracavernous surgical procedures with systematic selective resection of the medial wall of the cavernous sinus have shown promising results for invasive secreting pituitary adenomas. The first- and second-generation somatostatin agonist ligands and cabergoline are used with variable efficacy to control secretory activity and/or growth of intracavernous remnants. Tumor regrowth usually requires surgical reintervention, sometimes combined with radiotherapy or radiosurgery which is applied despite their benign nature. Unraveling the molecular pathways driving invasive behavior of pituitary adenomas and their tropism to the cavernous sinuses is the key for developing efficient innovative treatment modalities that could reduce the need for repeated surgery or radiotherapy.

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.

[Secondary tumors following radiation therapy and chemotherapy : Incidence of cavernous hemangiomas]

PROBLEM

There is a risk of developing secondary central nervous system (CNS) tumors after cranial radiation therapy. Meningiomas and pituitary tumors are also increasingly treated with radiation therapy, which means that the risk of secondary tumors from radiation in children and adults must be communicated.

METHODS

Studies in children show that radiation causes a 7- to 10-fold increase in subsequent CNS tumors with a cumulative incidence over 20 years ranging from 1.03 to 28.9. The latency period for the occurrence of secondary tumors ranged from 5.5 to 30 years, with gliomas developing after 5-10 years and meningiomas around 15 years after irradiation. The latency period for secondary CNS tumors in adults ranged from 5 to 34 years.

CONCLUSION

After radiation treatment, tumors can rarely occur as secondary sequelae, mostly meningiomas and gliomas, but also cavernomas. The treatment and long-term results of radiation-induced CNS tumors showed no worse results than primary CNS tumors over the course of time.

Long-Term Changes in the Size of Pituitary Microadenomas

BACKGROUND

The estimated prevalence of pituitary lesions is 10% to 38.5% in radiologic studies. However, how frequently these incidental lesions should be monitored by serial pituitary magnetic resonance imaging (MRI) remains unclear.

OBJECTIVE

To evaluate changes in pituitary microadenomas over time.

DESIGN

Retrospective, longitudinal cohort study.

SETTING

Mass General Brigham, Boston, Massachusetts.

PATIENTS

Evidence of pituitary microadenoma from MRI.

MEASUREMENTS

Dimensions of pituitary microadenomas.

RESULTS

During the study period (from 2003 to 2021), 414 patients with pituitary microadenomas were identified. Of the 177 patients who had more than 1 MRI, 78 had no change in the size of the microadenoma over time, 49 had an increase in size, 34 had a decrease in size, and 16 had both an increase and decrease in size. By linear mixed model analysis, the estimated slope was 0.016 mm/y (95% CI, -0.037 to 0.069). In the subgroup analysis, pituitary adenomas with a baseline size of 4 mm or less tended to increase in size. The estimated slope was 0.09 mm/y (CI, 0.020 to 0.161). In contrast, in the subgroup with baseline tumor size greater than 4 mm, the size tended to decrease. The estimated slope was -0.063 mm/y (CI, -0.141 to 0.015).

LIMITATION

Retrospective cohort, some patients were lost to follow-up for unknown reasons, and data were limited to local large institutions.

CONCLUSION

During the study period, approximately two thirds of the microadenomas remained unchanged or decreased in size. The growth, if any, was slow. These findings suggest that less frequent pituitary MRI surveillance for patients with incidental pituitary microadenomas may be safe.

PRIMARY FUNDING SOURCE

None.

Proton Therapy for Intracranial Meningioma for the Treatment of Primary/Recurrent Disease Including Re-Irradiation

Meningeal tumors represent approximately 10-25% of primary brain tumors and occur usually in elderly female patients. Most meningiomas are benign (80-85%) and for symptomatic and/or large tumors, surgery, with or without radiation therapy (RT), has been long established as an effective means of local tumor control. RT can be delivered to inoperable lesions or to those with non-benign histology and for Simpson I-III and IV-V resection. RT can be delivered with photons or particles (protons or carbon ions) in stereotactic or non-stereotactic conditions. Particle therapy delivered for these tumors uses the physical properties of charged carbon ions or protons to spare normal brain tissue (i.e. Bragg peak), with or without or a dose-escalation paradigm for non-benign lesions. PT can substantially decrease the dose delivered to the non-target brain tissues, including but not limited to the hippocampi, optic apparatus or cochlea. Only a limited number of meningioma patients have been treated with PT in the adjuvant or recurrent setting, as well as for inoperable lesions with pencil beam scanning and with protons only. Approximately 500 patients with image-defined or WHO grade I meningioma have been treated with protons. The reported outcome, usually 5-year local tumor control, ranges from 85 to 99% (median, 96%). For WHO grade II or III patients, the outcome of only 97 patients has been published, reporting a median tumor local control rate of 52% (range, 38-71.1). Only 24 recurring patients treated previously with photon radiotherapy and re-treated with PT were reported. The clinical outcome of these challenging patients seems interesting, provided that they presented initially with benign tumors, are not in the elderly category and have been treated previously with conventional radiation dose of photons. Overall, the number of meningioma patients treated or-re-irradiated with this treatment modality is small and the clinical evidence level is somewhat low (i.e. 3b-5). In this review, we detail the results of upfront PT delivered to patients with meningioma in the adjuvant setting and for inoperable tumors. The outcome of meningioma patients treated with this radiation modality for recurrent tumors, with or without previous RT, will also be reviewed.

Glioblastoma multiforme as a secondary malignancy following stereotactic radiosurgery of a meningioma: case report

The documentation and exact incidence of stereotactic radiosurgery (SRS)-induced neoplasia is not well understood, with most literature restricted to single case reports and single-center retrospective reviews. The authors present a rare case of radiosurgery-induced glioblastoma multiforme (GBM) following radiosurgical treatment of a meningioma. A 74-year-old patient with a sporadic meningioma underwent radiosurgery following surgical removal of a WHO grade II meningioma. Eighteen months later she presented with seizures, and MRI revealed an intraaxial tumor, which was resected and proven to be a glioblastoma. As far as the authors are aware, this case represents the third case of GBM following SRS for a meningioma. This report serves to increase the awareness of this possible complication following SRS. The possibility of this rare complication should be explained to patients when obtaining their consent for radiosurgery.

Evaluation of radiological recurrence patterns following gamma knife radiosurgery for solitary meningioma previously treated via cranial surgery

The use of gamma knife radiosurgery (GKS) for meningiomas after cranial surgery has been extensively evaluated; however, studies on tumor progression, including recurrence out of the margin dose line, are scarce. Hence, we aimed to evaluate the meningioma recurrence after GKS within and out of the margin dose. We included 37 consecutive patients with World Health Organization (WHO) grade 1 meningiomas who were treated with GKS following cranial surgery. Radiologically indicated recurrences were classified into three patterns by their relationship to the margin dose and tumor. The median follow-up was 58.9 months; 2 (5.4%) patients died. Only 2 (5.4%) patients did not keep active daily lives because of tumor progression. Cumulative local control at 5 years was 85.2%. Local recurrence and recurrence out of the margin dose occurred in 5 (13.5%) and 13 (35.1%) patients, respectively. A larger preoperative maximum diameter was a risk factor for local recurrence (hazard ratio [HR]: 2.118; P = 0.033), adjacent progression (HR: 1.633; P = 0.015), and remote progression (HR: 2.016; P = 0.003). Symptomatic adverse radiation effects occurred in 1 patient. Salvage GKS and cranial surgery were performed in 9 (24.3%) and 8 (21.6%) patients, respectively. Progression to WHO grade 2-3 occurred in 5 (13.5%) patients. A larger preoperative maximum diameter was a risk factor for progression of WHO grade (HR: 2.016, P = 0.033). Progression out of the margin dose was associated with a larger preoperative tumor size.

Surgery of the lateral skull base: a 50-year endeavour

Disregarding the widely used division of skull base into anterior and lateral, since the skull base should be conceived as a single anatomic structure, it was to our convenience to group all those approaches that run from the antero-lateral, pure lateral and postero-lateral side of the skull base as “Surgery of the lateral skull base”. “50 years of endeavour” points to the great effort which has been made over the last decades, when more and more difficult surgeries were performed by reducing morbidity. The principle of lateral skull base surgery, “remove skull base bone to approach the base itself and the adjacent sites of the endo-esocranium”, was then combined with function preservation and with tailoring surgery to the pathology. The concept that histology dictates the extent of resection, balancing the intrinsic morbidity of each approach was the object of the first section of the present report. The main surgical approaches were described in the second section and were conceived not as a step-by-step description of technique, but as the highlighthening of the surgical principles. The third section was centered on open issues related to the tumor and its treatment. The topic of vestibular schwannoma was investigated with the current debate on observation, hearing preservation surgery, hearing rehabilitation, radiotherapy and the recent efforts to detect biological markers able to predict tumor growth. Jugular foramen paragangliomas were treated in the frame of radical or partial surgery, radiotherapy, partial “tailored” surgery and observation. Surgery on meningioma was debated from the point of view of the neurosurgeon and of the otologist. Endolymphatic sac tumors and malignant tumors of the external auditory canal were also treated, as well as chordomas, chondrosarcomas and petrous bone cholesteatomas. Finally, the fourth section focused on free-choice topics which were assigned to aknowledged experts. The aim of this work was attempting to report the state of the art of the lateral skull base surgery after 50 years of hard work and, above all, to raise questions on those issues which still need an answer, as to allow progress in knowledge through sharing of various experiences. At the end of the reading, if more doubts remain rather than certainties, the aim of this work will probably be achieved.

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.

Non-invasive radiomics approach potentially predicts non-functioning pituitary adenomas subtypes before surgery

PURPOSE

To make individualised preoperative prediction of non-functioning pituitary adenoma (NFPAs) subtypes between null cell adenomas (NCAs) and other subtypes using a radiomics approach.

METHODS

We enrolled 112 patients (training set: n = 75; test set: n = 37) with complete T1-weighted magnetic resonance imaging (MRI) and contrast-enhanced T1-weighted MRI (CE-T1). A total of 1482 quantitative imaging features were extracted from T1 and CE-T1 images. Support vector machine trained a predictive model that was validated using a receiver operating characteristics (ROC) analysis on an independent test set. Moreover, a nomogram was constructed incorporating clinical characteristics and the radiomics signature for individual prediction.

RESULTS

T1 image features yielded area under the curve (AUC) values of 0.8314 and 0.8042 for the training and test sets, respectively, while CE-T1 image features provided no additional contribution to the predictive model. The nomogram incorporating sex and the T1 radiomics signature yielded good calibration in the training and test sets (concordance index (CI) = 0.854 and 0.857, respectively).

CONCLUSION

This study focused on the preoperative prediction of NFPA subtypes between NCAs and others using a radiomics approach. The developed model yielded good performance, indicating that radiomics had good potential for the preoperative diagnosis of NFPAs.

KEY POINTS

• MRI may help in the pre-operative diagnosis of NFPAs subtypes • Retrospective study showed T1-weighted MRI more useful than CE-T1 in NCAs diagnosis • Treatment decision making becomes more individualised • Radiomics approach had potential for classification of NFPAs.

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.

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.

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.

Post-surgical management of non-functioning pituitary adenoma

Post-surgical surveillance of non-functioning pituitary adenoma (NFPA) is based on magnetic resonance imaging (MRI) at 3 or 6 months then 1 year. When there is no adenomatous residue, annual surveillance is recommended for 5 years and then at 7, 10 and 15 years. In case of residue or doubtful MRI, prolonged annual surveillance monitors any progression. Reintervention is indicated if complete residue resection is feasible, or for symptomatic optic pathway compression, to create a safety margin between the tumor and the optic pathways ahead of complementary radiation therapy (RT), or in case of post-RT progression. In case of residue, unless the tumor displays elevated growth potential, it is usually recommended to postpone RT until progression is manifest, as efficacy is comparable whether treatment is immediate or postponed. The efficacy of the various RT techniques in terms of tumor volume control is likewise comparable. RT-induced hypopituitarism is frequent, whatever the technique. The choice thus depends basically on residue characteristics: size, delineation, and proximity to neighboring radiation-sensitive structures. Reduced rates of vascular complications and secondary brain tumor can be hoped for with one-dose or hypofractionated stereotactic RT, but there has been insufficient follow-up to provide evidence. Somatostatin analogs and dopaminergic agonists have yet to demonstrate sufficient efficacy. Temozolomide is an option in aggressive NFPA resistant to surgery and RT.

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.

Radiation-associated secondary brain tumors after conventional radiotherapy and radiosurgery

Although there is not enough strong molecular evidence for radiation to be a causal factor for the development of secondary brain tumors, a relationship has still been found. There is a slight but significant 2-2.7% increased risk of secondary brain tumors after conventional radiotherapy. However, this risk is small and should not preclude the use of radiotherapy as an effective treatment for uncontrolled pituitary tumors. The risk of radiosurgery-associated secondary brain tumors has not been precisely determined. Taking into account the considerable number of patients who received radiosurgery worldwide and the small number of secondary brain tumors, radiosurgery seems to be a safe treatment modality. This review summarizes the pathogenesis, prevalence and characteristics of secondary brain tumors after conventional radiotherapy and stereotactic radiosurgery for pituitary adenomas.

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.

Fractionated stereotactic radiosurgery using the Novalis system for the management of pituitary adenomas close to the optic apparatus

Radiosurgery has been proven to be an effective treatment for residual or recurrent pituitary adenomas after surgery. However, it causes severe complications when the optic apparatus is irradiated over the tolerance dose. In this study, we analyzed the feasibility of fractionated stereotactic radiosurgery to treat pituitary tumors close to the optic apparatus. Thirty-four patients from June 2006 to June 2011 with recurrent or residual pituitary adenomas close to (<3 mm) the optic apparatus were treated with fractionated stereotactic radiosurgery. Three fractions with a total dose of 2100 cGy were applied to the tumors. Imaging, examination of vision, and estimation of hormone level were regularly performed before and after radiosurgery. The mean tumor volume before fractioned stereotactic radiosurgery was 5.06±3.08 cm3 (range: 0.82-12.69 cm3). After a mean follow up of 36.8±15.7 months (range: 16-72 months), tumor size was reduced in seven (20.6%) patients and remained the same in the other 27 (79.4%) patients. Vision was improved in one patient and remained stable in the rest. Only one patient developed transient post-treatment diplopia. This study suggests that fractionated stereotactic radiosurgery is safe for treating pituitary adenomas close to the optic apparatus. Studies with more patients and longer follow-up are required to draw definite conclusions.

Multi-session radiosurgery of benign intracranial tumors

Multi-session stereotactic radiosurgery (SRS) enables a high dose per fraction to be delivered to the tumor bed with rapid dose falloff that allows for sparing of critical structures, resulting in less radiation-associated toxicity. In this article, the authors review the basic concepts and techniques of multi-session SRS, indications for this technique, outcomes from single-session and multi-session SRS using 3 commonly treated benign intracranial tumors (meningiomas, vestibular schwannomas, pituitary adenomas), and discuss why multi-session SRS is an attractive approach for the treatment of these tumors.

The prognostic value of tumor necrosis in patients undergoing stereotactic radiosurgery of brain metastases

Background

This retrospective study investigated the outcome of patients with brain metastases after radiosurgery with special emphasis on prognostic impact of visible intratumoral necrosis on survival and local control.

Methods

From 1998 through 2008, 149 patients with brain metastases from solid tumors were treated with stereotactic radiotherapy at Luebeck University. Median age was 58.4 years with 11%, 78%, 10% in recursive partitioning analysis (RPA) classes I, II, III, respectively. 70% had 1 metastasis, 29% 2-3 metastases, 2 patients more than 3 metastases, 71% active extracranial disease. Median volume of metastatic lesions was 4.7 cm³, median radiosurgery dose 22 Gy (single fraction). 71% of patients received additional whole-brain irradiation (WBI). All patients were analyzed regarding survival, local, distant failure and prognostic factors, side effects and changes in neurologic symptoms after radiotherapy. The type of contrast-enhancement in MR imaging was also analyzed; metastatic lesions were classified as containing necrosis if they appeared as ring-enhancing with central areas of no or minimal contrast enhancement.

Results

Median survival was 7.0 months with 1-year and 5-year survival rates of 33% and 0.4%, respectively. Tumor necrosis (ring-enhancement) was visible on pretreatment MRI scans in 56% of all lesions and lesions with necrosis were larger than non-necrotic lesions (6.7 cm³ vs. 3.2 cm³, p = 0.01). Patients with tumor necrosis had a median survival of 5.4 months, patients without tumor necrosis 7.2 months. Local control rate in the irradiated volume was 70%, median survival without local failure 17.8 months. Control in the brain outside the irradiated volume was 60%, median survival without distant failure 14.0 months. Significant prognostic factors for overall survival were KPS (p = 0.001), presence of tumor necrosis on pretreatment MRI (p = 0.001) with RPA-class and WBI reaching marginal significance (each p = 0.05). Prognostic impact of tumor necrosis remained significant if only smaller tumors with a volume below 3.5 cm³ (p = 0.03). Side effects were rare, only one patient suffered from serious acute side effects.

Conclusions

Results of this retrospective study support that stereotactic radiotherapy is an effective treatment option for patients with metastatic brain lesions. The prognostic impact of visible tumor necrosis (ring-enhancement) on pretreatment MRI scans should be further investigated.

Salvage surgery of vestibular schwannoma after failed radiotherapy: the Gruppo Otologico experience and review of the literature

OBJECTIVES

The use of radiation therapy has largely widespread and becomes in many centers the preference modality of treatment for symptomatic patients who are old, medically unfit for surgical therapy, those who refuse surgery and in some recurrent or residual growing tumors. The risk of radiotherapy failure in the treatment of vestibular schwannoma might be underestimated in the literature. The purpose of this study is to show the Gruppo Otologico experience with salvage surgery to better understand the surgical outcomes and difficulties in treating vestibular schwannoma after failed radiotherapy.

STUDY DESIGN

Retrospective chart review of patients who required salvage surgery of vestibular schwannoma after failed radiotherapy.

SETTINGS

Quaternary referral otology and skull base center.

RESULTS

Between 1987 and 2010, 2500 cases of VS underwent surgical treatment at the Gruppo Otologico. Nineteen patients had received stereotactic radiation therapy before the surgical treatment. The interval time between radiotherapy and surgical salvage ranged from 1 to 10 years. In all the cases decision of surgery was taken following an increase in tumor size with or without new onset of symptoms. Complete tumor removal was achieved in 86.6% of the cases through a transotic, transcochlear or enlarged translabyrinthine approach with trans-apical extension. Difficult dissection of the tumor was encountered in 93.3% the cases. The facial nerve was anatomically preserved in 93.3% but its function was worsened in 73.3% of patients after at least 6 months of follow up. Malignant transformation of the vestibular schwannoma was encountered in one patient.

CONCLUSION

Complete surgical resection of VS is more difficult after radiotherapy with relatively poor facial nerve outcomes and nearly impossible hearing preservation. Patients who receive radiation therapy for the treatment of vestibular schwannoma should be made aware of its potential complications and risk of failure, especially in young patients and NF2 cases.

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.

Long-term outcomes after gamma knife stereotactic radiosurgery for nonfunctional pituitary adenomas

BACKGROUND

Nonfunctional pituitary adenomas (NFPAs) represent approximately 50% of all pituitary tumors.

OBJECTIVE

To evaluate the long-term outcomes of stereotactic radiosurgery for NFPAs.

METHODS

We evaluated the management outcomes of Gamma Knife radiosurgery in 125 patients with NFPAs over an interval of 22 years. The median patient age was 54 years (range, 16-88 years). One hundred ten patients (88%) had residual or recurrent tumors after ≥ 1 surgical procedures, and 17 (14%) had undergone prior fractionated radiation therapy. The median target volume was 3.5 cm3 (range, 0.4-28.1 cm3), and the median tumor margin dose was 13.0 Gy (range, 10-25 Gy).

RESULTS

Tumor volume decreased in 66 patients (53%), remained stable in 46 (37%), and increased in 13 (10.4%) during a median of 62 months (maximum, 19 years) of imaging follow-up. The actuarial tumor control rates at 1, 5, and 10 years were 99%, 94%, and 76%, respectively. Factors associated with a reduced progression-free survival included larger tumor volume (≥ 4.5 cm3) and ≥ 2 prior recurrences. Of 88 patients with residual pituitary function, 21 (24%) suffered new hormonal deficits at a median of 24 months (range, 3-114 months). Prior radiation therapy increased the risk of developing new pituitary hormonal deficits. One patient (0.8%) had a decline in visual function, and 2 (1.6%) developed new cranial neuropathies without tumor progression.

CONCLUSION

Stereotactic radiosurgery can provide effective management for patients with newly diagnosed NFPAs and for those after prior resection and/or radiation therapy.

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.

Adjuvant or radical fractionated stereotactic radiotherapy for patients with pituitary functional and nonfunctional macroadenoma

Purpose

To evaluate the efficacy and toxicity of stereotactic fractionated radiotherapy (SFRT) for patients with pituitary macroadenoma (PMA).

Methods and Materials

Between March 2000 and March 2009, 27 patients (male to female ratio, 1.25) with PMA underwent SFRT (median dose, 50.4 Gy). Mean age of the patients was 56.5 years (range, 20.3 - 77.4). In all but one patient, SFRT was administered for salvage treatment after surgical resection (transphenoidal resection in 23, transphenoidal resection followed by craniotomy in 2 and multiple transphenoidal resections in another patient). In 10 (37%) patients, the PMAs were functional (3 ACTH-secreting, 3 prolactinomas, 2 growth hormone-secreting and 2 multiple hormone-secretion). Three (11.1%) and 9 (33.3%) patients had PMA abutting and compressing the optic chiasm, respectively. Mean tumor volume was 2.9 ± 4.6 cm³. Eighteen (66.7%) patients had hypopituitarism prior to SFRT. The mean follow-up period after SFRT was 72.4 ± 37.2 months.

Results

Tumor size decreased for 6 (22.2%) patients and remained unchanged for 19 (70.4%) other patients. Two (7.4%) patients had tumor growth inside the prescribed treatment volume. The estimated 5-year tumor growth control was 95.5% after SFRT. Biochemical remission occurred in 3 (30%) patients with functional PMA. Two patients with normal anterior pituitary function before SFRT developed new deficits 25 and 65 months after treatment. The 5-year survival without new anterior pituitary deficit was thus 95.8%. Five patients with visual field defect had improved visual function and 1 patient with no visual defect prior to SFRT, but an optic chiasm abutting tumor, had a decline in visual function. The estimated 5-year vision and pituitary function preservation rates were 93.2% and 95.8%, respectively.

Conclusions

SFRT is a safe and effective treatment for patients with PMA, although longer follow-up is needed to evaluate long-term outcomes. In this study, approximately 1 patient with visual field defect out of two had an improved visual function.

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.

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.

Oncocytic carcinoma of the breast: frequency, morphology and follow-up

Oncocytic breast carcinomas are tumors composed of no fewer than 70% of oncocytic cells (World Health Organization). The purpose of this study was to determine the frequency, morphologic, immunohistochemical, and clinical features of invasive oncocytic carcinoma in a large series. Twenty-eight cases of putative oncocytic breast carcinoma (selected cases group) and 76 consecutive cases of invasive breast carcinoma (consecutive cases group) were analyzed. Immunohistochemistry for mitochondria, gross cystic disease fluid protein 15, chromogranin, estrogen receptor, progesterone receptor, androgen receptor, HER2/Neu, cytokeratin 7, cytokeratin 14, epithelial membrane antigen, and differentiation cluster 68 was performed. Score for mitochondria was based on intensity and percentage of immunopositive cells. Classes were as follows: (1) oncocytic carcinoma: at least 70%, 3+; (2) mitochondrion-rich carcinoma: 50% to 70%, 3+, or more than 50%, 2+; and (3) all the other cases were referred to as invasive breast carcinoma. Ultrastructural examination was available for 6 cases of oncocytic carcinoma. Morphologic and immunohistochemical features of the 3 groups were compared using Fisher exact test (P < .05). For overall survival analysis, Kaplan-Maier curves were compared using log-rank and Wilcoxon tests (P < .05). Our results suggest that oncocytic breast carcinoma is a morphologic entity with distinctive histologic and ultrastructural features. Mitochondrion-rich carcinomas are histologically similar to oncocytic carcinomas and constitute 19.7% of all invasive carcinomas, indicating that cytoplasmic eosinophilia in breast cancer cells is often due to accumulation of mitochondria. Oncocytic carcinomas and mitochondrion-rich carcinomas are more often grade III tumors and show human epidermal growth factor receptor 2 overexpression. Clinical features and overall survival of oncocytic carcinomas are not distinctive because they are similar to those of the other cases when matched for grade and stage.

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.

Mortality in patients with pituitary disease

Pituitary disease is associated with increased mortality predominantly due to vascular disease. Control of cortisol secretion and GH hypersecretion (and cardiovascular risk factor reduction) is key in the reduction of mortality in patients with Cushing's disease and acromegaly, retrospectively. For patients with acromegaly, the role of IGF-I is less clear-cut. Confounding pituitary hormone deficiencies such as gonadotropins and particularly ACTH deficiency (with higher doses of hydrocortisone replacement) may have a detrimental effect on outcome in patients with pituitary disease. Pituitary radiotherapy is a further factor that has been associated with increased mortality (particularly cerebrovascular). Although standardized mortality ratios in pituitary disease are falling due to improved treatment, mortality for many conditions are still elevated above that of the general population, and therefore further measures are needed. Craniopharyngioma patients have a particularly increased risk of mortality as a result of the tumor itself and treatment to control tumor growth; this is a key area for future research in order to optimize the outcome for these patients.

Modern techniques for pituitary radiotherapy

Radiotherapy (RT) remains an effective treatment for residual or recurrent pituitary adenomas with excellent rates of tumour control and normalisation of excess hormone secretion. The main late toxicity is hypopituitarism: other side effects are rare. We discuss technical developments in the delivery of radiotherapy (stereotactic conformal radiotherapy (SCRT) and stereotactic radiosurgery (SRS)), all aiming to reduce the amount of normal brain receiving significant doses of radiation. We provide a comprehensive review of published data on outcome of conventional fractionated radiotherapy and modern RT techniques. SCRT is a suitable treatment technique for all sizes of pituitary adenoma and efficacy is comparable to conventional RT; the lack of long term follow up means that currently there is no information on potential reduction in the incidence of late radiation induced toxicity. Single fraction SRS can only be safely delivered to small tumours away from critical structures. There is no evidence that it produces faster decline of elevated hormone levels than fractionated treatment and is not associated with lesser morbidity.

Radiologic follow-up of non-functioning pituitary adenomas: rationale and cost effectiveness

Patients with non-functioning pituitary adenomas (NFPAs) are followed-up with serial endocrine, ophthalmologic and radiological assessment. There is a lack of evidence based guidance regarding the frequency and duration of radiological assessment during follow-up. We retrospectively analysed the details of follow-up radiological scanning in a cohort of patients diagnosed with NFPAs in an attempt to devise a rational and cost effective scanning schedule for use in routine clinical practice. 49 patients were identified using the hospital endocrine register. A detailed review of the case notes and follow up scans was undertaken. The data was analysed using descriptive statistics and Kaplan-Meier survival analysis using SPSS ver 13.0 (SPSS Inc. Chicago, IL). The time in which the tumor size in the followed up patients reached a state of 'no change' which persisted for at least two further scans was calculated. 41 patients, followed up for a median duration of 70 months were ultimately analysed. 33 patients had surgery while eight were conservatively managed. The time taken by 50% of tumors to achieve a steady state of 'no change' in tumor size on scans was 30 months. 90% of tumours achieved this state in 88 months. Surgical management did not significantly influence the time required to attain the steady state on a Kaplan-Meier analysis (Log rank test P = 0.06). NFPAs need extended follow-up since late recurrences after treatment are known. Routine radiologic follow up may be uneconomical after the steady state is achieved. Regular Goldmann perimetry beyond this time may be of greater use in selecting patients who actually need repeat surgical debulking. This method of follow up is likely to be more cost effective and reduce the number of scans performed.

Stereotactic Radiosurgery with the CyberKnife for Pituitary Adenomas

OBJECTIVE

In recent years, CyberKnife has emerged as an important treatment modality in the management of pituitary adenomas. Treatment results after performing CyberKnife and the complications of this procedure are reviewed.

METHODS

Twenty-six patients with pituitary adenomas received stereotactic radiosurgery with the CyberKnife (CKRS). The follow-up periods ranged from 7 months to 47 months (mean+/-SD : 30+/-12.7 months). The patients consisted of 17 with non-functioning adenomas, 3 with prolactinomas and 6 with acromegaly. The change in the tumor volume, visual acuity, hormonal function, and complications by this therapy were analyzed in each case.

RESULTS

The tumor control rate was 92.3%. Hormonal function was improved in all of the 9 (100%) functioning adenomas. Hormonal normalization was observed in 4 of the 9 (44%) patients with a mean duration of 16 months. In two patients (7.6%), visual acuity worsened due to cystic enlargement of the tumor after CKRS. No other complications were observed.

CONCLUSION

CyberKnife is considered safe and effective in selected patients with pituitary adenomas. However, longer follow-up is required for a more complete assessment of late toxicity and treatment efficacy.

Radiotherapy of nonfunctioning and gonadotroph adenomas

Transsphenoidal surgery is the treatment of choice for NFPA but is seldom curative. The management of patients in whom residual tumor is detected after surgery is not clear-cut. Radiation therapy is effective in controlling tumor mass in the majority of patients, but is associated with long term complications that call for restriction of its use to patients at high risk for tumor growth. New radiation techniques may prove to be safer while retaining the effectiveness of conventional radiotherapy, however longer follow-up is necessary to confirm this assumption. For now, it appears to be safe to withhold radiation and carefully follow patients with small tumor remnants, whereas large remnants from invasive tumors should be considered for radiotherapy. Nevertheless, there are no prospective controlled studies that support this empirical approach.

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.

Pituitary adenomas in northern Sweden: a study on therapy choices and the risk of second primary tumours

OBJECTIVES

To present the incidence of pituitary adenomas in northern Sweden and to determine whether the incidence of second primary tumours differs from the incidence in the general population or might be related to radiotherapy.

DESIGN

A retrospective register study.

PATIENTS

A total of 546 patients with pituitary adenomas were identified in the Cancer Registry of northern Sweden between 1958 and 2004. Only patients with histopathological verification and/or endocrine activity of the adenoma and more than 12 months of follow-up were included, resulting in 376 patients in the study.

MEASUREMENTS

The number of patients receiving surgery and/or radiotherapy and presenting second primary tumours were registered. Standard incidence ratios (SIRs) between the observed and the expected incidence of second primary tumours were calculated.

RESULTS

The total number of person-years at risk for a second primary tumour was 4730. Fifty-four out of 376 (14%) patients had 63 second primary tumours. Forty patients had second primary tumours diagnosed more than 12 months after diagnosis of the pituitary adenoma (expected 42.6, SIR 0.94, 95% CI 0.67-1.28). A significantly increased incidence of second primary tumours was seen in 42 men with GH-secreting adenomas. Ten second tumours were found (expected 4.55, SIR 2.20, 95% CI 1.05-4.04). A total of 261 patients received radiotherapy and 31 second primary tumours occurred after radiotherapy (expected 32.9, SIR 0.94, 95% CI 0.64-1.34). Three second primary intracranial tumours appeared within the irradiation volume (expected 0.85, SIR 3.51, 95% CI 0.71-10.36).

CONCLUSIONS

No significant increase was found in the incidence of second primary tumours in general in patients with pituitary adenomas. An increased incidence of second primary tumours was seen in men with GH-secreting adenomas.

Early results of surgery in patients with nonfunctioning pituitary adenoma and analysis of the risk of tumor recurrence

OBJECT

Nonfunctioning pituitary adenomas (NFPAs) are benign tumors of the pituitary gland that typically cause visual and/or hormonal dysfunction. Surgery is the treatment of choice, but patients remain at risk for tumor recurrence for several years afterwards. The authors evaluate the early results of surgery and the long-term risk of tumor recurrence in patients with NFPAs.

METHODS

Between 1990 and 2005, 491 previously untreated patients with NFPA underwent surgery at the Università Vita-Salute. Determinations of recurrence or growth of the residual tumor tissue during the follow-up period were based on neuroradiological criteria.

RESULTS

Residual tumor after surgery was detected in 173 patients (36.4%). Multivariate analysis showed that invasion of the cavernous sinus, maximum tumor diameter, and absence of tumor apoplexy were associated with an unfavorable surgical outcome. At least 2 sets of follow-up neuroimaging studies were obtained in 436 patients (median follow-up 53 months). Tumors recurred in 83 patients (19.0%). When tumor removal appeared complete, younger age at surgery was associated with a risk of tumor recurrence. In patients with incomplete tumor removal, adjunctive postoperative radiotherapy had a marked protective effect against growth of residual tumor.

CONCLUSIONS

Complete surgical removal of NFPAs can be safely achieved in > 50% of cases. Visual symptoms and, less frequently, pituitary function may improve after surgery. However, tumor can recur in patients after apparently complete surgical removal. In patients with incomplete tumor removal, radiation therapy is the most effective adjuvant therapy for preventing residual tumor growth.

Radiotherapy for pituitary adenomas

This article describes the technical aspects and the clinical results of conventional radiotherapy and modern stereotactic radiotherapy for pituitary adenomas. Systematic review of the published literature provides a factual basis for the comparison and the selection of appropriate radiation technique in patients who have secreting and nonfunctioning pituitary adenomas not cured with surgery and medical therapy.