Results of stereotactic radiosurgery in patients with hormone-producing pituitary adenomas: factors associated with endocrine normalization

Recurrent acromegaly: a systematic review on therapeutic approaches

BACKGROUND AND OBJECTIVE

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

METHOD

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

RESULTS

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

CONCLUSION

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

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

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

Effects on the Hypothalamo-Pituitary Axis in Patients with CNS or Head and Neck Tumors following Radiotherapy

BACKGROUND

Knowledge about the precise effects of radiotherapy on hypothalamo-pituitary functions is limited. Reduction of side effects is a major goal of advanced radiotherapy modalities. We assessed strategies for monitoring and replacement of hormone deficiencies in irradiated patients.

METHODS

A search strategy was systematically conducted on PubMed®. Additional articles were retrieved to describe endocrine mechanisms.

RESULTS

45 studies were evaluated from 2000 to 2022. They were predominantly retrospective and highly heterogeneous concerning patient numbers, tumor types, radiotherapy technique and follow-up. Endocrine deficiencies occurred in about 40% of patients within a median follow-up of 5.6 years without a clear difference between radiotherapy modalities. Somatotropic and thyrotropic axes were, respectively, the most and least radiosensitive.

CONCLUSIONS

Current pituitary gland dose constraints may underestimate radiation-induced endocrine deficiencies, thus impairing quality of life. Little difference might be expected between radiation techniques for PG tumors. For non-PG tumors, dose constraints should be applied more systematically.

Gamma Knife Radiosurgery for Indirect Dural Carotid-Cavernous Fistula: Long-Term Ophthalmological Outcome

Objective: The leading treatment option for dural carotid−cavernous sinus fistula is an endovascular approach with immediate improvement. Alternatively, radiosurgery is a slow response for obliterating the fistula and poses a radiation risk to the optic apparatus and the associated cranial nerves and blood vessels. In this study, we retrieved cases from a prospective database to assess the ophthalmological outcomes and complications in treating dural carotid cavernous sinus fistula with gamma knife radiosurgery (GKRS). Material and Methods: We retrieved a total of 65 cases of carotid cavernous sinus fistula treated with GKRS with margin dose of 18−20 Gy from 2003 to 2018 and reviewed the ophthalmological records required for our assessment. Results: The mean target volume was 2 ± 1.43 cc. The onset of symptom alleviated after GKRS was 3.71 ± 7.68 months. There were two cases with residual chemosis, two with cataract, two with infarction, one with transient optic neuropathy, and four with residual cranial nerve palsy, but none with glaucoma or dry eyes. In MRA analysis, total obliteration of the fistula was noted in 64 cases with no detectable ICA stenosis nor cavernous sinus thrombosis. In the Cox regression analysis, post-GKRS residual cranial nerve palsy was highly correlated to targeted volume (p < 0.05) and age (p < 0.05). The occurrence of post-GKRS cataract was related to the initial symptom of chemosis (p < 0.05). Conclusion: GKRS for carotid cavernous sinus fistula offers a high obliteration rate and preserves the cavernous sinus vascular structure while conferring a low risk of treatment complications such as adverse radiation risk to the optic apparatus and adjacent cranial nerves.

Gamma Knife Radiosurgery for Pituitary Tumors: A Systematic Review and Meta-Analysis

Simple Summary

Pituitary tumors represent approximately 10–15% of all brain neoplasms. Gamma Knife, the most commonly used stereotactic radiosurgery technique worldwide, plays an important role in the treatment of several pituitary neoplasm. It is currently used in cases of residual or recurrent tumors after surgery or as primary treatment when surgery is contraindicated. Its goals are long-term tumor control, preservation of visual function, and, for secreting pituitary adenomas, endocrine remission. Several retrospective case-series (level of evidence IV) on Gamma Knife for pituitary tumors have been published describing encouraging outcomes; only one systematic review and meta-analysis on non-functioning pituitary adenoma has been recently reported. We provide a systematic review of the literature and meta-analysis from the last two decades on Gamma Knife radiosurgery for several pituitary tumors with the aim of describing and confirming safety and effectiveness of this technique.

Abstract

To describe and evaluate outcomes of Gamma Knife radiosurgery (GK) for the treatment of pituitary tumors over the past twenty years, a systematic review and meta-analysis according to PRISMA statement was performed. Articles counting more than 30 patients were included. A weighted random effects models was used to calculate pooled outcome estimates. From 459 abstract reviews, 52 retrospective studies were included. Among them, 18 reported on non-functioning pituitary adenomas (NFPA), 13 on growth hormone (GH)-secreting adenomas, six on adrenocorticotropic hormone (ACTH)-secreting adenomas, four on prolactin hormone (PRL)-secreting adenomas, and 11 on craniopharyngiomas. Overall tumor control and five-year progression free survival (PFS) estimate after one GK procedure for NFPA was 93% (95% CI 89–97%) and 95% (95% CI 91–99%), respectively. In case of secreting pituitary adenomas, overall remission (cure without need for medication) estimates were 45% (95% CI 35–54%) for GH-secreting adenomas, 64% (95% CI 0.52–0.75%) for ACTH-secreting adenomas and 34% (95% CI: 19–48%) for PRL-secreting adenomas. The pooled analysis for overall tumor control and five-year PFS estimate after GK for craniopharyngioma was 74% (95% CI 67–81%) and 70% (95% CI: 64–76%), respectively. This meta-analysis confirms and quantifies safety and effectiveness of GK for pituitary tumors.

Internal carotid artery stenosis and risk of cerebrovascular ischemia following stereotactic radiosurgery for recurrent or residual pituitary adenomas

PURPOSE

To evaluate the incidence of internal carotid artery (ICA) stenosis and cerebrovascular accident in a series of patients treated with stereotactic radiosurgery (SRS) for recurrent or residual pituitary adenoma.

METHODS

All patients treated with single fraction SRS in our institution for recurrent or residual non-functioning-, growth hormone- and ACTH-secreting pituitary adenomas were retrospectively identified and reviewed. A comprehensive literature review to identify studies reporting on ICA steno-occlusive disease following SRS for pituitary adenomas and compare the risks of carotid stenosis and ischemic stroke in the SRS treated group to the general population figures.

RESULTS

528 patients [312 women and 216 men; median age at SRS 46 years old (range 12-80 years)] treated with SRS at our institution met study inclusion criteria. Mean clinical and radiologic follow-ups were 68.87 (SD ± 43.29) and 55.99 months (SD ± 38.03), respectively, and there were no clinically evident cerebral ischemic events noted. Asymptomatic, post-SRS, ICA stenosis occurred in two patients. A total of eight patients with ICA steno-occlusive disease following pituitary adenoma radiosurgery have been reported. Two of them suffered from ischemic stroke with however excellent recovery.

CONCLUSION

As compared to the general population, SRS for pituitary adenomas does not seem to confer appreciable increased risk for ICA steno-occlusive disease and ischemic stroke. However, post-SRS radiation vessel injuries do occur and physicians should be aware about this rare event. Prompt identification and management according to current guidelines are essential to prevent ischemic strokes.

Biological Effective Dose as a Predictor of Hypopituitarism After Single-Fraction Pituitary Adenoma Radiosurgery: Dosimetric Analysis and Cohort Study of Patients Treated Using Contemporary Techniques

BACKGROUND

Hypopituitarism is the most frequent complication after pituitary adenoma stereotactic radiosurgery (SRS) and is correlated with increasing radiation to the pituitary gland. Biological effective dose (BED) is a dosimetric parameter that incorporates a time component to adjust for mechanisms of deoxyribonucleic acid repair activated during treatment.

OBJECTIVE

To assess mean gland BED as a predictor of post-SRS hypopituitarism, as compared to mean gland dose, in a contemporary cohort study of patients undergoing single-fraction SRS for pituitary adenoma.

METHODS

Cohort study of 97 patients undergoing single-fraction SRS from 2007 to 2014. Eligible patients had no prior pituitary irradiation, normal pre-SRS endocrine function, and >24 mo of endocrine follow-up. Cox proportional hazards analysis was used to assess mean gland dose and BED as predictors of new post-SRS hypopituitarism.

RESULTS

Median post-SRS follow-up was 48 mo (interquartile range [IQR], 34-68). A total of 27 patients (28%) developed new hypopituitarism at a median 22 mo (IQR, 12-36). Actuarial rates of new endocrinopathy were 17% at 2 yr (95% CI 10%-25%) and 31% at 5 yr (95% CI 20%-42%). On univariate analysis, sex (P = .02), gland volume (P = .03), mean gland dose (P < .0001), and BED significantly predicted new hypopituitarism (P < .0001). After adjusting for sex and gland volume, BED > 45 Gy2.47 and mean gland dose > 10 Gy were significantly associated increased risk of hypopituitarism (hazard ratio [HR] = 14.32, 95% CI = 4.26-89.0, P < .0001; HR = 11.91, 95% CI = 3.54-74.0, P < .0001).

CONCLUSION

BED predicted hypopituitarism more reliably than mean gland dose after pituitary adenoma SRS, but additional studies are needed to confirm these results.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSION

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

Management of patients with persistent or recurrent Cushing's disease after initial pituitary surgery

INTRODUCTION

Treatment options for persistent and recurrent Cushing's disease (CD) include an individualized approach for repeat surgery, medical treatment, radiation therapy (RT), and bilateral adrenalectomy (BLA).

AREAS COVERED

In this expert opinion perspective, the authors review the latest treatment(s) for persistent/recurrent CD. A PubMed search was undertaken (English articles through May 2020) and relevant articles discussed. Repeat pituitary surgery should be considered in most patients with proven hypercortisolism; there is potential for cure with low risk of major complications. Medical therapy is valuable either alone, while awaiting the effects of RT, or in preparation for BLA. Medical therapy includes steroidogenesis inhibitors, agents that act at the pituitary or glucocorticoid receptor level, and novel agents in development. Radiation therapy has been used successfully to treat CD, but hypopituitarism risk and delayed efficacy (improved with radiosurgery) are major drawbacks. Laparoscopic BLA is safe and effective in patients with severe, difficult-to-manage hypercortisolism, but long-term follow-up is required as corticotroph tumor progression can develop.

EXPERT OPINION

Treatment of persistent/recurrent CD is challenging. Most patients require >1 therapy to achieve long-lasting remission. There is currently no ideal single treatment option that provides high and rapid efficacy, low adverse effects, and preserves normal pituitary-adrenal axis function.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Stereotactic radiosurgery for non-functioning pituitary adenomas: meta-analysis and International Stereotactic Radiosurgery Society practice opinion

BACKGROUND

This systematic review reports on outcomes and toxicities following stereotactic radiosurgery (SRS) for non-functioning pituitary adenomas (NFAs) and presents consensus opinions regarding appropriate patient management.

METHODS

Using the guidelines of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, a systematic review was performed from articles of ≥10 patients with NFAs published prior to May 2018 from the Medline database using the key words "radiosurgery" and "pituitary" and/or "adenoma." Weighted random effects models were used to calculate pooled outcome estimates.

RESULTS

Of the 678 abstracts reviewed, 35 full-text articles were included describing the outcomes of 2671 patients treated between 1971 and 2017 with either single fraction SRS or hypofractionated stereotactic radiotherapy (HSRT). All studies were retrospective (level IV evidence). SRS was used in 27 studies (median dose: 15 Gy, range: 5-35 Gy) and HSRT in 8 studies (median total dose: 21 Gy, range: 12-25 Gy, delivered in 3-5 fractions). The 5-year random effects local control estimate after SRS was 94% (95% CI: 93.0-96.0%) and 97.0% (95% CI: 93.0-98.0%) after HSRT. The 10-year local control random effects estimate after SRS was 83.0% (95% CI: 77.0-88.0%). Post-SRS hypopituitarism was the most common treatment-related toxicity observed, with a random effects estimate of 21.0% (95% CI: 15.0-27.0%), whereas visual dysfunction or other cranial nerve injuries were uncommon (range: 0-7%).

CONCLUSIONS

SRS is an effective and safe treatment for patients with NFAs. Encouraging short-term data support HSRT for select patients, and mature outcomes are needed before definitive recommendations can be made. Clinical practice opinions were developed on behalf of the International Stereotactic Radiosurgery Society (ISRS).

Risk of internal carotid artery stenosis or occlusion after single-fraction radiosurgery for benign parasellar tumors

OBJECTIVE

Stereotactic radiosurgery (SRS) is an accepted treatment option for patients with benign parasellar tumors. Here, the authors' objective was to determine the risk of developing new or progressive internal carotid artery (ICA) stenosis or occlusion after single-fraction SRS for cavernous sinus meningioma (CSM) or growth hormone-secreting pituitary adenoma (GHPA).

METHODS

The authors queried their prospectively maintained registry for patients treated with single-fraction SRS for CSM or GHPA in the period from 1990 to 2015. Study criteria included no prior irradiation and ≥ 12 months of post-SRS radiological follow-up. Pre-SRS grading of ICA involvement was applied according to the 1993 classification schemes of Hirsch for CSM or Knosp for GHPA.

RESULTS

The authors conducted a retrospective review of 283 patients, 155 with CSMs and 128 with GHPAs. Ninety-three (60%) CSMs were Hirsch category 2 and 3 tumors; 97 (76%) GHPAs were Knosp grade 2-4 tumors. Median follow-up after SRS was 6.6 years (IQR 1-24.9 years). No GHPA or category 1 CSM developed ICA stenosis or occlusion. Three (5.2%) patients with category 2 CSMs had asymptomatic ICA stenosis (n = 2) or occlusion (n = 1); 1 (1.1%) category 2 CSM patient had transient ischemic symptoms. Five (14.3%) category 3 CSMs progressed to ICA occlusion (4 asymptomatic, 1 symptomatic). The median time to stenosis/occlusion was 4.8 years (IQR 1.8-7.6). Five- and 10-year risks of ICA stenosis/occlusion in category 2 and 3 CSM patients were 7.5% and 12.4%, respectively. Five- and 10-year risks of ischemic stroke from ICA stenosis/occlusion in category 2 and 3 CSM patients were both 1.2%. Multivariate analysis showed patient age (HR 0.92, 95% CI 0.86-0.98, p = 0.01), meningioma pathology (HR and 95% CI not defined, p = 0.03), and pre-SRS carotid category (HR 4.51, 95% CI 1.77-14.61, p = 0.004) to be associated with ICA stenosis/occlusion. Internal carotid artery stenosis/occlusion was not related to post-SRS tumor growth (HR and 95% CI not defined, p = 0.41).

CONCLUSIONS

New or progressive ICA stenosis/occlusion was common after SRS for CSM but was not observed after SRS for GHPA, suggesting a tumor-specific mechanism unrelated to radiation dose. Pre-SRS ICA encasement or constriction increases the risk of ICA stenosis/occlusion; however, the risk of ischemic complications is very low.

The benefit and risk of stereotactic radiosurgery for prolactinomas: an international multicenter cohort study

OBJECTIVE

The most common functioning pituitary adenoma is prolactinoma. Patients with medically refractory or residual/recurrent tumors that are not amenable to resection can be treated with stereotactic radiosurgery (SRS). The aim of this multicenter study was to evaluate the role of SRS for treating prolactinomas.

METHODS

This retrospective study included prolactinomas treated with SRS between 1997 and 2016 at ten institutions. Patients' clinical and treatment parameters were investigated. Patients were considered to be in endocrine remission when they had a normal level of prolactin (PRL) without requiring dopamine agonist medications. Endocrine control was defined as endocrine remission or a controlled PRL level ≤ 30 ng/ml with dopamine agonist therapy. Other outcomes were evaluated including new-onset hormone deficiency, tumor recurrence, and new neurological complications.

RESULTS

The study cohort comprised 289 patients. The endocrine remission rates were 28%, 41%, and 54% at 3, 5, and 8 years after SRS, respectively. Following SRS, 25% of patients (72/289) had new hormone deficiency. Sixty-three percent of the patients (127/201) with available data attained endocrine control. Three percent of patients (9/269) had a new visual complication after SRS. Five percent of the patients (13/285) were recorded as having tumor progression. A pretreatment PRL level ≤ 270 ng/ml was a predictor of endocrine remission (p = 0.005, adjusted HR 0.487). An increasing margin dose resulted in better endocrine control after SRS (p = 0.033, adjusted OR 1.087).

CONCLUSIONS

In patients with medically refractory prolactinomas or a residual/recurrent prolactinoma, SRS affords remarkable therapeutic effects in endocrine remission, endocrine control, and tumor control. New-onset hypopituitarism is the most common adverse event.

Role of gamma knife radiosurgery in the treatment of prolactinomas

PURPOSE

Stereotactic radiosurgery is one of the treatment options for prolactinomas, the most commonly used being Gamma Knife Radiosurgery (GKRS). GKRS is indicated mainly in the treatment of dopamine agonist (DA)-resistant prolactinomas. In our study, we report on our experience in treating prolactinoma patients by GKRS.

METHODS

Twenty-eight patients were followed-up after GKRS for 26-195 months (median 140 months). Prior to GKRS, patients were treated with DAs and 9 of them (32.1%) underwent previous neurosurgery. Cavernous sinus invasion was present in 16 (57.1%) patients. Indications for GKRS were (i) resistance to DA treatment (17 patients), (ii) drug intolerance (5 patients), or (iii) attempts to reduce the dosage and/or shorten the length of DA treatment (6 patients).

RESULTS

After GKRS, normoprolactinaemia was achieved in 82.1% of patients, out of which hormonal remission (normoprolactinaemia after discontinuation of DAs) was achieved in 13 (46.4%), and hormonal control (normoprolactinaemia while taking DAs) in 10 (35.7%) patients. GKRS arrested adenoma growth or decreased adenoma size in all cases. Two patients (8.3%) developed hypopituitarism after GKRS. Prolactinoma cystic transformation with expansive behaviour, manifested by bilateral hemianopsia, was observed in one patient.

CONCLUSIONS

GKRS represents an effective treatment option, particularly for DA-resistant prolactinomas. Normoprolactinaemia was achieved in the majority of patients, either after discontinuation of, or while continuing to take, DAs. Tumour growth was arrested in all cases. The risk of the development of hypopituitarism can be limited if the safe dose to the pituitary and infundibulum is maintained.

Cerebral infarction after fractionated stereotactic radiation therapy of benign anterior skull base tumors

Background

The purpose of this study was to examine the occurrence of cerebral infarction (ischemic stroke), in a large combined cohort of patients with anterior skull base meningiomas, pituitary adenomas and craniopharyngiomas, after fractionated stereotactic radiation therapy (FSRT).

Material and Methods

All patients, 18 years and older, with anterior skull base meningiomas, pituitary adenomas and craniopharyngiomas, treated with fractionated stereotactic radiation, in our center, from January 1999 to December 2015 were identified. In total 169 patients were included. The prescription dose to the tumor was 54 Gy for 164 patients (97%) and 46.0-52.2 Gy for 5 patients (3%). Cases of cerebral infarctions subsequent to FSRT were identified from the Danish National Patient Registry and verified with review of case notes. The rate of cerebral infarction after FSRT was compared to the rate in the general population with a one sample t-test after standardization for age and year. We explored if age, sex, disease type, radiation dose and dose per fraction was associated with increased risk of cerebral infarction using univariate Cox models.

Results

At a median follow-up of 9.3 years (range 0.1-16.5), 7 of the 169 patients (4.1%) developed a cerebral infarction, at a median 5.7 years (range 1.2-11.5) after FSRT. The mean cerebral infarction rate for the general population was 0.0035 and 0.0048 for the FSRT cohort (p = 0.423). Univariate cox models analysis showed that increasing age correlated significantly with the cerebral infarction risk, with a hazard ratio of 1.090 (p = 0.013).

Conclusion

Increased risk of cerebral infarction after FSRT of anterior skull base tumors was associated with age, similar to the general population. Our study revealed that FSRT did not introduce an excess risk of cerebral infarction.

The role of Crooke's changes in recurrence and remission after gamma knife radiosurgery

PURPOSE

The objective of this study is to evaluate the role of Crooke's changes (CC) in normal the peri-tumoral anterior pituitary gland, in patients with Cushing's disease (CD) with a histopathological confirmed corticotroph adenoma, and determine if there is any difference in the recurrence and remission rates in CD patients after treatment with Gamma Knife Radiosurgery (GKRS).

METHODS

All patients treated with GKRS for CD from 2005 to 2016 at our institution were identified. Patients had a confirmed adrenocorticotropic (ACTH)-secreting adenoma, i.e. corticotroph adenoma, and normal pituitary gland included in the surgical specimen, and specimens were stained with hematoxylin and eosin and also immunostaining for cytokeratin and ACTH. Statistical analyses were performed in a total of 61 patients who met the inclusion criteria. Additionally, we analyzed 20 patients in each group, with and without CC, after they were matched in a propensity score fashion.

RESULTS

Endocrine remission defined as, a normal 24 h urine free cortisol while off suppressive medication, occurred in 48 patients (78.7%), with 76.9% in those with CC and 81.8% in those without CC. There was no statistical significant difference between the two groups in regarding remission (p = 0.312) or recurrence (p = 0.659) in either the unmatched or matched cohorts.

CONCLUSION

The presence or absence of CC in normal pituitary gland does not appear to confer a lower rate of remission or a higher rate of recurrence after GKRS. Patients with pituitary corticotroph adenomas that present with CC features may be well served by Stereotactic radiosurgery (SRS).

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.

Factors affecting early versus late remission in acromegaly following stereotactic radiosurgery

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

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

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

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

ABBREVIATIONS

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

Asymptomatic internal carotid artery occlusion after gamma knife radiosurgery for pituitary adenoma: Report of two cases and review of the literature

BACKGROUND

Gamma knife radiosurgery is an effective and safe treatment modality in the management of pituitary adenomas. Internal carotid occlusion is a rare but possible complication of Gamma Knife Radiosurgery for lesions within the cavernous sinus.

AIM

To stress the importance of considering the Internal carotid artery as an organ at risk in cavernous sinus invading adenomas and reduce the dose delivered to this structure whenever possible.

CASE DESCRIPTION

We report two cases of asymptomatic occlusion of the intracavernous segment of the internal carotid artery seven years after treatment in acromegalic patients. After trans-sphenoidal surgery, residual tumour was treated with gamma knife radiosurgery. The maximal doses to the affected artery were higher than 40 Gy and the 90% isodose was close to the arterial wall.

CONCLUSION

Every effort should be done to minimize the radiation dose to the internal carotid artery. If not possible, "hot spots" exceeding the 90% isodose close to this vessel should be avoided.

Advances in Gamma Knife radiosurgery for pituitary tumors

PURPOSE OF REVIEW

For the residual/recurrent pituitary adenomas, stereotactic radiosurgery (SRS) plays an important role in long-term tumor control and, for secretory adenomas, endocrine remission. The purpose of this review is to address the advances in SRS technique and detail the latest treatment strategies for various types of pituitary adenomas with a focus on recently published literature.

RECENT FINDINGS

From recent publications, SRS may be considered as an upfront treatment in patients with an adenoma that resides largely in the cavernous sinus and for whom resection is unlikely to produce substantial reduction in the overall tumor volume. Early treatment (<6 months after prior resection) with SRS appears to decrease the rate of tumor progression of subtotally resected nonfunctioning pituitary macroadenomas. Some types of adenomas may appear more aggressive with a high recurrence rate, for example, silent corticotroph pituitary adenomas, or sparsely granulated somatotroph-cell adenomas, may be indicated for a high-radiation dose. Finally, whole-sellar radiation and fractionated SRS are the alternative strategies, and may be indicated for challenging cases.

SUMMARY

The role of SRS for the pituitary adenoma is well established, and the treatment strategy is increasingly individualized based upon tumor histology, location, and volume. Hypopituitarism is the most complicated and can occur even years after SRS.

RADIOTHERAPY VERSUS RADIOSURGERY IN TREATING PATIENTS WITH ACROMEGALY: A SYSTEMATIC REVIEW AND META-ANALYSIS

OBJECTIVE

When patients with acromegaly have residual disease following surgery, adjuvant radiation therapy is considered. Both stereotactic radiosurgery (SRS) and conventional fractionated radiotherapy (RT) are utilized. We conducted a systematic review and meta-analysis to synthesize the existing evidence and compare outcomes for SRS and RT in patients with acromegaly.

METHODS

We searched Medline In-Process & Other Non-Indexed Citations, MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus through April 2014 for studies in which SRS or RT were used in patients with acromegaly. Outcomes evaluated were serum insulin-like growth factor-I (IGF-I) and growth hormone (GH) levels, biochemical remission, all-cause mortality, hypopituitarism, headaches, and secondary malignancies. We pooled outcomes using a random-effects model.

RESULTS

The final search yielded 30 eligible studies assessing 2,464 patients. Compared to RT, SRS was associated with a nonsignificant increase in remission rate at the latest follow-up period (52% vs. 36%; P = .14) and a significantly lower follow-up IGF-I level (-409.72 μg/L vs. -102 μg/L, P = .002). SRS had a lower incidence of hypopituitarism than RT; however, the difference was not statistically significant (32% vs. 51%, respectively; P = .05).

CONCLUSION

SRS may be associated with better biochemical remission, and it had a lower risk of hypopituitarism with at least 1 deficient axis when compared with RT; however, the confidence in such evidence is very low due to the noncomparative nature of the studies, high heterogeneity, and imprecision.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

[Retrospective analysis to evaluate efficacy and safety of stereotactic radiosurgery in Cushing's disease: 24 cases and a review]

BACKGROUND

In the past few years, stereotactic radiosurgery (SRS) has been suggested as a good alternative, second line therapy for the management of patients with ACTH-secreting pituitary adenomas. A retrospective study has been conducted in order to evaluate the efficacy and safety of this treatment in these patients.

MATERIAL AND METHODS

Data were collected on all patients treated with SRS for an ACTH-secreting pituitary adenoma between 1996 and 2008, and with at least one year of follow-up. An analysis was carried out by analysing the return to normal of the hormone levels and clinical improvement rates (including Cushing signs, arterial hypertension), as well as adverse effects, and disease relapse. A return to normal of the 24 hour urinary free cortisol (24-UFC) levels (<100 μg/day) without any ACTH-secretion suppressor drug treatment, was considered as cure or improvement.

RESULTS

A total of 30 patients were treated with SRS, of which 24 were included in the analysis. They all had high 24-UFC levels before the treatment. Cure was achieved in 12 (50%) in a mean of 28 months, and in other 3 patients 24-UFC levels returned to normal with treatment with ketoconazole after the SRS. Cushing signs improved in all cases, as well as arterial hypertension in 13 out of 14 cases. There were relapses after cure consolidation. As far as adverse effects, it should be mentioned that there were 9 cases of new pituitary hormonal dysfunction (the most frequent being hypothyroidism), one radionecrosis, and one case of visual field defect impairment. Radiation-related neoplasm was not detected in any of the cases.

CONCLUSIONS

SRS is an effective treatment for those patients with ACTH-secreting pituitary adenoma in whom surgery has failed, or in those that are not good candidates for it. It showed good rates of hormone levels returning to normal, as well as clinical disease control and a low level of adverse effects.

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.

HIGH-PRECISION CONFORMAL FRACTIONATED RADIOTHERAPY IS EFFECTIVE IN ACHIEVING REMISSION IN PATIENTS WITH ACROMEGALY AFTER FAILED TRANSSPHENOIDAL SURGERY

OBJECTIVE

Variable efficacy of pituitary radiotherapy in acromegaly is reported. Here we sought to assess the efficacy of high-precision conformal fractionated radiotherapy (CRT) in patients with acromegaly after failed TSS.

METHODS

A retrospective analysis was conducted a in tertiary care referral center between 1999 to 2013 on 36 acromegaly patients (M: 16, F: 20; median age: 36.0 years) with macroadenoma and mean growth hormone (GH) and insulin-like growth factor-1 (IGF1) upper limits of normal (ULN) of 15.9 ± 14.3 ng/mL and 1.74 ± 0.43, respectively. The cohort was divided into 2 groups: 30 patients (M: 13, F: 17) who were medical treatment naïve, and 6 patients (M: 3, F: 3) who received medical treatment after CRT.

RESULTS

Normalization of GH (fasting GH <1 ng/mL), normalization of IGF1 (ULN <1), and remission (normalization of GH and IGF1) were achieved in 20 (55%), 23 (63%) and 20 (55%) patients, respectively. The mean time required to achieve remission was 63 ± 33.4 months. Follow-up duration was the only predictor of achieving remission. GH level declined exponentially by 65% and 89% at 2 and 5 years, respectively. New onset hypopituitarism was noted in 33% of patients. Tumor control was achieved in 100% of patients. In groups 1 and 2, 18 (60%) and 2 (33.3%) achieved remission post-CRT, and the mean times required to achieve remission were 58.6 ± 30.7 months and 102 ± 42.4 months, respectively.

CONCLUSION

High-precision CRT is an effective modality to achieve remission in patients with acromegaly after failed TSS.

60 YEARS OF NEUROENDOCRINOLOGY: Acromegaly

Acromegaly (ACM) is a chronic, progressive disorder caused by the persistent hypersecretion of GH, in the vast majority of cases secreted by a pituitary adenoma. The consequent increase in IGF1 (a GH-induced liver protein) is responsible for most clinical features and for the systemic complications associated with increased mortality. The clinical diagnosis, based on symptoms related to GH excess or the presence of a pituitary mass, is often delayed many years because of the slow progression of the disease. Initial testing relies on measuring the serum IGF1 concentration. The oral glucose tolerance test with concomitant GH measurement is the gold-standard diagnostic test. The therapeutic options for ACM are surgery, medical treatment, and radiotherapy (RT). The outcome of surgery is very good for microadenomas (80-90% cure rate), but at least half of the macroadenomas (most frequently encountered in ACM patients) are not cured surgically. Somatostatin analogs are mainly indicated after surgical failure. Currently their routine use as primary therapy is not recommended. Dopamine agonists are useful in a minority of cases. Pegvisomant is indicated for patients refractory to surgery and other medical treatments. RT is employed sparingly, in cases of persistent disease activity despite other treatments, due to its long-term side effects. With complex, combined treatment, at least three-quarters of the cases are controlled according to current criteria. With proper control of the disease, the specific complications are partially improved and the mortality rate is close to that of the background population.

The Treatment of Cushing's Disease

Cushing's disease (CD), or pituitary-dependent Cushing's syndrome, is a severe endocrine disease caused by a corticotroph pituitary tumor and associated with increased morbidity and mortality. The first-line treatment for CD is pituitary surgery, which is followed by disease remission in around 78% and relapse in around 13% of patients during the 10-year period after surgery, so that nearly one third of patients experience in the long-term a failure of surgery and require an additional second-line treatment. Patients with persistent or recurrent CD require additional treatments, including pituitary radiotherapy, adrenal surgery, and/or medical therapy. Pituitary radiotherapy is effective in controlling cortisol excess in a large percentage of patients, but it is associated with a considerable risk of hypopituitarism. Adrenal surgery is followed by a rapid and definitive control of cortisol excess in nearly all patients, but it induces adrenal insufficiency. Medical therapy has recently acquired a more important role compared to the past, due to the recent employment of novel compounds able to control cortisol secretion or action. Currently, medical therapy is used as a presurgical treatment, particularly for severe disease; or as postsurgical treatment, in cases of failure or incomplete surgical tumor resection; or as bridging therapy before, during, and after radiotherapy while waiting for disease control; or, in selected cases, as primary therapy, mainly when surgery is not an option. The adrenal-directed drug ketoconazole is the most commonly used drug, mainly because of its rapid action, whereas the glucocorticoid receptor antagonist, mifepristone, is highly effective in controlling clinical comorbidities, mainly glucose intolerance, thus being a useful treatment for CD when it is associated with diabetes mellitus. Pituitary-directed drugs have the advantage of acting at the site responsible for CD, the pituitary tumor. Among this group of drugs, the dopamine agonist cabergoline and the somatostatin analog pasireotide result in disease remission in a consistent subgroup of patients with CD. Recently, pasireotide has been approved for the treatment of CD when surgery has failed or when surgery is not an option, and mifepristone has been approved for the treatment of Cushing's syndrome when associated with impairment of glucose metabolism in case of the lack of a surgical indication. Recent experience suggests that the combination of different drugs may be able to control cortisol excess in a great majority of patients with CD.

Gamma knife radiosurgery for Cushing's disease and Nelson's syndrome

PURPOSE

This paper presents our 18 years of experience in treating ACTH secreting adenomas (Cushing's disease and Nelson's syndrome) using the Leksell gamma knife (LGK) irradiation.

METHODS

Twenty-six patients with Cushing's disease were followed-up after LGK irradiation for 48-216 months (median 78 months). Seventeen patients had undergone previous surgery, in nine patients LGK irradiation was the primary therapy. Furthermore, 14 patients with Nelson's syndrome were followed-up for 30-204 months (median 144 months).

RESULTS

LGK treatment resulted in hormonal normalization in 80.7 % of patients with Cushing's disease. Time to normalization was 6-54 months (median 30 months). The volume of the adenoma decreased in 92.3% (in 30.7% disappeared completely). There was no recurrence of the disease. In all 14 patients with Nelson's syndrome ACTH levels decreased (in two patients fully normalized) their ACTH levels. When checked up 5-10 years after irradiation regrowth of the adenoma was only detected in one patient (9.1%), in 27.3% adenoma volume remained unchanged, in 45.4% adenoma volume decreased and in 18.2% adenoma completely disappeared. Hypopituitarism did not develop in any patient where the critical dose to the pituitary and distal infundibulum was respected.

CONCLUSION

LGK radiation represents an effective and well-tolerated option for the treatment of patients with Cushing's disease after unsuccessful surgery and may be valuable even as a primary treatment in patients who are not suitable for, or refuse, surgery. In the case of Nelson's syndrome it is possible to impede tumorous growth and control the size of the adenoma in almost all patients.

Radiotherapy vs. Radiosurgery in Treating Patients with Acromegaly: Systematic Review and Meta-Analysis

OBJECTIVE

When patients with acromegaly have residual disease following surgery, adjuvant radiation therapy is considered. Both stereotactic radiosurgery (SRS) and conventional fractionated radiotherapy (RT) are utilized. We conducted a systematic review and meta-analysis to synthesize the existing evidence to compare outcomes with SRS and RT in patients with acromegaly.

METHODS

We searched Medline In-Process & Other Non-Indexed Citations, MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus through April 2014 for studies in which SRS or RT were used in patients with acromegaly. Outcomes evaluated were serum IGF-1 and GH levels, biochemical remission, all-cause mortality, hypopituitarism, headaches and secondary malignancies. We pooled outcomes using the random-effects model.

RESULTS

The final search yielded 30 eligible studies enrolling 2464 patients. When compared to RT, SRS was associated with a non-significant increase in remission rate at the latest follow-up period (52% vs. 36%; p = 0.14), and a significantly lower follow-up IGF-1 level (decline of - 409.72 μg/1 vs. -102 μg/1; p = 0.002). SRS was associated with lower incidence of hypopituitarism than RT; however the difference was not statistically significant [(32% vs.51%, respectively; p = 0.05).

CONCLUSIONS

SRS may be associated with better biochemical remission and lower risk of hypopituitarism with at least one deficient axis when compared with RT; however, the confidence in such evidence is very low due to the non-comparative nature of the studies, high heterogeneity, and imprecision.

PITUITARY GIGANTISM--EXPERIENCE OF A SINGLE CENTER FROM WESTERN INDIA

OBJECTIVE

Limited data are available on pituitary gigantism, as it is a rare disorder. This study was carried out to assess the clinical, hormonal, and radiologic profiles and management outcomes of patients with pituitary gigantism.

METHODS

We conduced a retrospective analysis of 14 patients with pituitary gigantism who presented to a single tertiary care institute from 1990 to 2014.

RESULTS

Thirteen patients were male, and 1 was female. The mean age at diagnosis was 21.9 ± 6.1 years, with a mean lag period of 6.5 ± 5.6 years. The mean height SD score at the time of diagnosis was 3.2 ± 0.6. Symptoms of tumor mass effect were the chief presenting complaint in the majority (50%) of patients, while 2 patients were asymptomatic. Six patients had hyperprolactinemia. At presentation, the nadir PGGH (postglucose GH) and insulin-like growth factor (IGF 1)-ULN (× upper limit of normal) were 63.2 ± 94.9 ng/mL and 1.98 ± 0.5, respectively. All (except 1 with mild pituitary hyperplasia) had pituitary macroadenoma. Six patients had invasive pituitary adenoma. Transsphenoidal surgery (TSS) was the primary modality of treatment in 13/14 patients, and it achieved remission in 4/13 (30.76%) patients without recurrence over a median follow-up of 7 years. Post-TSS radiotherapy (RT) achieved remission in 3/5 (60%) patients over a median follow-up of 3.5 years. None of the patients received medical management at any point of time.

CONCLUSION

Gigantism is more common in males, and remission can be achieved in the majority of the patients with the help of multimodality treatment (TSS and RT).

Review of cranial radiotherapy-induced vasculopathy

Cranial radiation can impact the cerebral vasculature in many ways, with a wide range of clinical manifestations. The incidence of these late effects including cerebrovascular accidents (CVAs), lacunar lesions, vascular occlusive disease including moyamoya syndrome, vascular malformations, and hemorrhage is not well known. This article reviews the preclinical findings regarding the pathophysiology of late radiation-induced vascular damage, and discusses the clinical incidence and risk factors for each type of vasculopathy. The pathophysiology is complex and dependent on the targeted blood vessels, and upregulation of pro-inflammatory and hypoxia-related genes. The risk factors for adult CVAs are similar to those for patients not exposed to cranial radiotherapy. For children, risks for late vascular complications include young age at radiotherapy, radiotherapy dose, NF1, tumor location, chemotherapy, and endocrine abnormalities. The incidence of late vascular complications of radiotherapy may be impacted by improved technology, therapeutic interventions, and appropriate follow up.

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

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

Cranial stereotactic radiosurgery: current status of the initial paradigm shifter

The concept of stereotactic radiosurgery (SRS) was first described by Lars Leksell in 1951. It was proposed as a noninvasive alternative to open neurosurgical approaches to manage a variety of conditions. In the following decades, SRS emerged as a unique discipline involving a collegial partnership among neurosurgeons, radiation oncologists, and medical physicists. SRS relies on the precisely guided delivery of high-dose ionizing radiation to an intracranial target. The focused convergence of multiple beams yields a potent therapeutic effect on the target and a steep dose fall-off to surrounding structures, thereby minimizing the risk of collateral damage. SRS is typically administered in a single session but can be given in as many as five sessions or fractions. By providing an ablative effect noninvasively, SRS has altered the treatment paradigms for benign and malignant intracranial tumors, functional disorders, and vascular malformations. Literature on extensive intracranial radiosurgery has unequivocally demonstrated the favorable benefit-to-risk profile that SRS affords for appropriately selected patients. In a departure from conventional radiotherapeutic strategies, radiosurgical principles have recently been extended to extracranial indications such as lung, spine, and liver tumors. The paradigm shift resulting from radiosurgery continues to alter the landscape of related fields.

Silent corticotroph adenomas after stereotactic radiosurgery: a case-control study

PURPOSE

To investigate the safety and effectiveness of stereotactic radiosurgery (SRS) in patients with a silent corticotroph adenoma (SCA) compared with patients with other subtypes of non-adrenocorticotropic hormone staining nonfunctioning pituitary adenoma (NFA).

METHODS AND MATERIALS

The clinical features and outcomes of 104 NFA patients treated with SRS in our center between September 1994 and August 2012 were evaluated. Among them, 34 consecutive patients with a confirmatory SCA were identified. A control group of 70 patients with other subtypes of NFA were selected for review based on comparable baseline features, including sex, age at the time of SRS, tumor size, margin radiation dose to the tumor, and duration of follow-up.

RESULTS

The median follow-up after SRS was 56 months (range, 6-200 months). No patients with an SCA developed Cushing disease during the follow-up. Tumor control was achieved in 21 of 34 patients (62%) in the SCA group, compared with 65 of 70 patients (93%) in the NFA group. The median progression-free survival (PFS) was 58 months in the SCA group. The actuarial PFS was 73%, 46%, and 31% in the SCA group and was 94%, 87%, and 87% in the NFA group at 3, 5, and 8 years, respectively. Silent corticotroph adenomas treated with a dose of ≥17 Gy exhibited improved PFS. New-onset loss of pituitary function developed in 10 patients (29%) in the SCA group, whereas it occurred in 18 patients (26%) in the NFA group. Eight patients (24%) in the SCA group experienced worsening of a visual field deficit or visual acuity attributed to the tumor progression, as did 6 patients (9%) in the NFA group.

CONCLUSION

Silent corticotroph adenomas exhibited a more aggressive course with a higher progression rate than other subtypes of NFAs. Stereotactic radiosurgery is an important adjuvant treatment for control of tumor growth. Increased radiation dose may lead to improved tumor control in SCA patients.

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

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

Dose-Volume Analysis of Radiation-Induced Optic Neuropathy After Single-Fraction Stereotactic Radiosurgery

BACKGROUND:

The risk of radiation-induced optic neuropathy (RION) is the primary limitation of single-fraction stereotactic radiosurgery (SRS) for many patients with parasellar lesions.

OBJECTIVE:

To define the normal tissue complication probability of the anterior visual pathways (AVPs) after single-fraction SRS.

METHODS:

Retrospective review comparing visual function before and after SRS in 133 patients (266 sides) with pituitary adenomas having SRS between October 2007 and July 2012. Patients with prior radiation therapy or SRS were excluded. The median follow-up after SRS was 32 months.

RESULTS:

The median maximum point dose to the AVP was 9.2 Gy (interquartile range [IQR], 6.9-10.8). One hundred seventy-four sides (65%) received &gt;8 Gy: the median 8-Gy volume was 15.8 mm3 (IQR, 3.7-36.2). Ninety-four sides (35%) received &gt;10 Gy; the median 10-Gy volume was 1.6 mm3 (IQR, 0.5-5.3). Twenty-nine sides (11%) received &gt;12 Gy; the median 12-Gy volume was 0.1 mm3 (IQR, 0.1-0.6). No patient had a RION after SRS. The chances of developing a RION at the 8-Gy, 10-Gy, and 12-Gy volumes (95% confidence interval) in this series were 0% to 2.6%, 0% to 4.7%, and 0% to 13.9%, respectively.

CONCLUSION:

The AVP in patients without prior radiation treatments can safely receive radiation doses up to 12 Gy with a low risk of RION. Although additional studies are needed to better delineate the normal tissue complication probability of the AVP, adherence to the AVP radiation tolerance guidelines developed 20 years ago (8 Gy) limits the applicability and potentially the effectiveness of single-fraction SRS for patients with lesions in the parasellar region.

Whole-Sellar Stereotactic Radiosurgery for Functioning Pituitary Adenomas

BACKGROUND:

Functioning pituitary adenomas (FPAs) can be difficult to delineate on postoperative magnetic resonance imaging, making them difficult targets for stereotactic radiosurgery (SRS). In such cases, radiation delivery to the entire sella has been utilized as a radiosurgical equivalent of a total hypophysectomy.

OBJECTIVE:

To evaluate the outcomes of a cohort of patients with FPA who underwent SRS to the whole-sellar region.

METHODS:

This is a retrospective review of patients who underwent whole-sellar SRS for FPA between 1989 and 2012. Sixty-four patients met the inclusion criteria: they were treated with whole-sellar SRS following surgical resection for persistently elevated hormone levels, and (1) no visible lesions on imaging studies and/or (2) tumor infiltration of dura or adjacent venous sinuses observed at the time of a prior resection. The median radiosurgical volume covering sellar structures was 3.2 mL, with a median margin dose of 25 Gy.

RESULTS:

The median endocrine follow-up was 41 months; 22 (68.8%) patients with acromegaly, 20 (71.4%) patients with Cushing disease, and 2 (50.0%) patients with prolactinoma achieved endocrine remission. The 2-, 4-, and 6-year actuarial remission rates were 54%, 78%, and 87%, respectively. New-onset neurological deficit was found in 4 (6.3%) patients following treatment. New-onset hypopituitarism was observed in 27 (43.5%) patients, with panhypopituitarism in 2 (3.2%). Higher margin/maximum dose were significantly associated with a higher remission rate and development of post-SRS hypopituitarism.

CONCLUSION:

Whole-sellar SRS for invasive or imaging-negative FPA following failed resection can offer reasonable rates of endocrine remission. Hypopituitarism following whole-sellar SRS is the most common complication.

Gamma knife in the treatment of pituitary adenomas: results of a single center

INTRODUCTION

Gamma Knife (GK) radiosurgery for pituitary adenomas can offer a means of tumor and biologic control with acceptable risk and low complication rates.

METHODS

Retrospective review of all the patients treated at our center with GK for pituitary adenomas from Nov 2003 to June 2011.

RESULTS

We treated a total of 86 patients. Ten were lost to follow-up. Mean follow was 32.8 months. There were 21 (24.4%) growth hormone secreting adenomas (GH), 8 (9.3%) prolactinomas (PRL), 8 (9.3%) adrenocorticotropic hormone secreting (ACTH) adenomas, 2 (2.3%) follicle stimulating hormone/luteinizing hormone secreting (FSH/LH) adenomas, and 47 (54.7%) null cell pituitary adenomas that were treated. Average maximum tumor diameter and volume was 2.21cm and 5.41cm³, respectively. The average dose to the 50% isodose line was 14.2 Gy and 23.6 Gy for secreting and non-secreting adenomas respectively. Mean maximal optic nerve dose was 8.87 Gy. Local control rate was 75 of 76 (98.7%), for those with followup. Thirty-three (43.4%) patients experienced arrest of tumor growth, while 42 (55.2%) patients experienced tumor regression. Of the 39 patients with secreting pituitary tumors, 6 were lost to follow-up. Improved endocrine status occurred in 16 (50.0%), while 14 (43.8%) demonstrated stability of hormone status on continued pre-operative medical management. Permanent complications included: panhypopituitarism (4), hypothyroidism (4), hypocortisolemia (1), diabetes insipidus (1), apoplexy (1), visual field defect (2), and diplopia (1).

CONCLUSIONS

Gamma Knife radiosurgery is a safe and effective means of achieving tumor growth control and endocrine remission/stability in pituitary adenomas.

Gamma Knife radiosurgery for the management of nonfunctioning pituitary adenomas: a multicenter study

Object

Pituitary adenomas are fairly common intracranial neoplasms, and nonfunctioning ones constitute a large subgroup of these adenomas. Complete resection is often difficult and may pose undue risk to neurological and endocrine function. Stereotactic radiosurgery has come to play an important role in the management of patients with nonfunctioning pituitary adenomas. This study examines the outcomes after radiosurgery in a large, multicenter patient population.

Methods

Under the auspices of the North American Gamma Knife Consortium, 9 Gamma Knife surgery (GKS) centers retrospectively combined their outcome data obtained in 512 patients with nonfunctional pituitary adenomas. Prior resection was performed in 479 patients (93.6%) and prior fractionated external-beam radiotherapy was performed in 34 patients (6.6%). The median age at the time of radiosurgery was 53 years. Fifty-eight percent of patients had some degree of hypopituitarism prior to radiosurgery. Patients received a median dose of 16 Gy to the tumor margin. The median follow-up was 36 months (range 1–223 months).

Results

Overall tumor control was achieved in 93.4% of patients at last follow-up; actuarial tumor control was 98%, 95%, 91%, and 85% at 3, 5, 8, and 10 years postradiosurgery, respectively. Smaller adenoma volume (OR 1.08 [95% CI 1.02–1.13], p = 0.006) and absence of suprasellar extension (OR 2.10 [95% CI 0.96–4.61], p = 0.064) were associated with progression-free tumor survival. New or worsened hypopituitarism after radiosurgery was noted in 21% of patients, with thyroid and cortisol deficiencies reported as the most common postradiosurgery endocrinopathies. History of prior radiation therapy and greater tumor margin doses were predictive of new or worsening endocrinopathy after GKS. New or progressive cranial nerve deficits were noted in 9% of patients; 6.6% had worsening or new onset optic nerve dysfunction. In multivariate analysis, decreasing age, increasing volume, history of prior radiation therapy, and history of prior pituitary axis deficiency were predictive of new or worsening cranial nerve dysfunction. No patient died as a result of tumor progression. Favorable outcomes of tumor control and neurological preservation were reflected in a 4-point radiosurgical pituitary score.

Conclusions

Gamma Knife surgery is an effective and well-tolerated management strategy for the vast majority of patients with recurrent or residual nonfunctional pituitary adenomas. Delayed hypopituitarism is the most common complication after radiosurgery. Neurological and cranial nerve function were preserved in more than 90% of patients after radiosurgery. The radiosurgical pituitary score may predict outcomes for future patients who undergo GKS for a nonfunctioning adenoma.

Long-term outcome of gamma knife surgery using a retrogasserian petrous bone target for classic trigeminal neuralgia

BACKGROUND

Gamma knife surgery (GKS) is the prevailing method for treatment of medically intractable trigeminal neuralgia (TN), although there are some technical differences among radiosurgical centers. We assessed the long-term outcomes of GKS using retrogasserian petrous bone targeting and evaluated factors associated with the clinical outcomes.

METHODS

Between December 2003 and June 2009, a total of 91 GKS treatments were performed in 90 patients with classic TN. The surgical target was defined at the anterior portion of the trigeminal nerve, just above the retrogasserian petrous bone. A single 4-mm collimator was used to deliver a median 88.0 Gy (range 75-90 Gy) dose of radiation.

FINDINGS

During follow-up, which ranged from 24 to 90 months, 89 patients (97.8 %) reported initial pain relief, 75 (82.4 %) experienced pain control, and 47 (51.6 %) achieved a pain-free state without medications at the last follow-up. Barrow Neurological Institute (BNI) scores of I-III at 2, 3, 4, 5, and 7 years were observed in 84 of 91, 68 of 77, 46 of 53, 33 of 36, 17 of 19, and 7 of 7 patients, respectively. Trigeminal nerve dysfunction was experienced by 34 patients, with 12 having BNI facial numbness scores of III-IV (13.2 %). In all, 14 patients (15.4 %) experienced pain recurrence at a mean 32 months (range 10-62 months) after treatment. The actuarial rates of pain control at 2, 4, and 6 years were 93 %, 88 %, and 79 %, respectively.

CONCLUSIONS

Gamma Knife radiosurgery is an efficient option for intractable TN. Our results can help medical practitioners to counsel their patients on the likelihood of achieving successful pain control.

Gamma knife stereotactic radiosurgery for drug resistant or intolerant invasive prolactinomas

We evaluated the efficacy of Gamma knife stereotactic radiosurgery (GKSR) as an adjunctive management modality for patients with drug resistant or intolerant cavernous sinus invasive prolactinomas. Twenty-two patients with cavernous sinus invasive prolactinoma underwent GKSR between 1994 and 2009. Thirteen patients were dopamine agonist (DA) resistant. Six patients were intolerant to DA. Three patients chose GKSR as their initial treatment modality in hopes they might avoid life long suppression medication. The median tumor volume was 3.0 cm3 (range 0.3–11.6). The marginal tumor dose (median= 15 Gy, range 12–25 Gy) prescribed was based on the dose delivered to the optic apparatus. The median follow-up interval was 36 months (range, 12–185). Endocrine normalization was defined as a normal serum prolactin level off DA (cure) or on DA. Endocrine improvement was defined asa decreased but still elevated serum prolactin level. Endocrine deterioration was defined as an increased serum prolactin level. Endocrine normalization was achieved in six(27.3%) patients. Twelve (54.5%) patients had endocrine improvement. Four patients (18.2%) developed delayed increased prolactin. Imaging-defined local tumor control was achieved in 19 (86.4%) patients, 12 of whom had tumor regression. Three patients had a delayed tumor progression and required additional management. One patient developed a new pituitary axis deficiency after GKSR. Invasive prolactinomas continue to pose management challenges. GKSR is a non invasive adjunctive option that may reduce prolactin levels in patients who are resistant to or intolerant of suppression medication. In a minority of cases, patients may no longer require long term suppression therapy.