Gamma knife radiosurgery is effective in patients with thyrotropin-secreting pituitary adenomas

PURPOSE

Thyrotropin (TSH)-secreting pituitary adenoma (TSHoma) is a rare cause of TSH-dependent hyperthyroidism. The first therapeutic option is surgery. Medical treatment with somatostatin analogs is also effective. To obviate the need for lifelong drug therapy, gamma knife radiosurgery (GKRS) might be considered in selected patients. We report the largest series of patients with TSHoma treated by GKRS at a single center.

METHODS

This study was a retrospective analysis of 18 consecutive patients with TSHoma treated by GKRS between 1994 and 2022. Normalization of hyperthyroidism, when present at the time of surgery, and control of tumor growth were the main outcomes of the study.

RESULTS

The median follow-up after GKRS treatment was 114 months (IQR, 57-213 months; range 17-285 months). No patients had growth of the residual tumor after GKRS. Remission of hyperthyroidism occurred in 9 of the 11 (81.8%) patients who were hyperthyroid before GKRS. The probability of hyperthyroidism remission three years after GKRS was 59.1% (95% CI 27.9-90.3%). No major side effects occurred after GKRS. One patient out of the 15 patients (6.7%) with normal baseline adrenal function and follow-up longer than 3 years developed new onset hypoadrenalism, while hypogonadism did not occur in the 13 patients with baseline normal function.

CONCLUSION

Our study shows that GKRS is an effective and safe adjuvant treatment for selected patients with residual or recurring TSHoma. The option of GKRS as an alternative treatment to lifelong medical treatment with somatostatin analogs should be thoroughly discussed with the patients.

Intranasal oxytocin as a treatment for obesity: safety and efficacy

INTRODUCTION

Known for its effect on labor and lactation and on emotional and social functions, oxytocin has recently emerged as a key modulator of feeding behavior and indeed suggested as a potential treatment for obesity. The potential positive effect of oxytocin on both metabolic and psychological-behavioral complications of hypothalamic lesions makes it a promising tool in the management of these conditions.

AREAS COVERED

The aim of the present review article is to provide an overview of the mechanism of action and clinical experience of the use of oxytocin in different forms of obesity.

EXPERT OPINION

Current evidence suggests a potential role of oxytocin in the treatment of obesity with different causes. Several challenges remain: an improved understanding of the physiological regulation, mechanisms of action of oxytocin, and interplay with other endocrine axes is fundamental to clarify its role. Further clinical trials are needed to determine the safety and efficacy of oxytocin for the treatment of different forms of obesity. Understanding the mechanism(s) of action of oxytocin on body weight regulation might also improve our understanding of obesity and reveal possible new therapeutic targets - as well as promoting advances in other fields in which oxytocin might be used.

P14.03.B Glutamate excitotoxicity in brain metastases from lung, breast, and melanoma treated with stereotactic radiosurgery

Background

Brain metastases (BM) are the most frequent neoplasm in the central nervous system (CNS) and primary tumors frequently involved are melanoma, lung cancer and breast cancer. CNS localisation is associated with poor prognosis, and stereotactic radiosurgery (SRS) represents a treatment option for patients with a good performance status. Glutamate (Glu) is a neurotransmitter which plays a facilitating role in carcinogenesis and progression of malignant tumors, as well as in excitotoxicity. Glu efflux from the brain is regulated by scavengers glutamic oxaloacetic transaminase (GOT), glutamate-pyruvate transaminase (GPT) and lactate dehydrogenase (LDH), with aspartate and lactate as catabolites. Glu efflux from the brain seems to be impaired in advanced-stage cancers, resulting in increased blood Glu levels where scavengers exert a protective role. Our hypothesis is that serum Glu and scavengers’ levels are related to neuroinvasion and treatment response in patients with BM and may represent potential biomarkers for BM course and prognosis.

Material and Methods

Serum Glu scavengers (GOT1, GPT and LDH), serum Glu, aspartate and lactate levels are collected in included patients treated and grouped in A) BM group of patients affected by BM from lung or breast cancer or melanoma, treated with SRS; B) Control-1 group of patients affected by lung cancer, breast cancer or melanoma but without BM and C) Control-2 group of patients with benign intracranial lesions (meningiomas, acoustic schwannomas) treated with SRS.In A) and C) serum metabolites and scavengers will be analyzed before and after SRS treatment (at 3, 6, 9 months) while in B) analyzed once. Blood levels in A) and C) help in identifying differences related to malignancy, the role of SRS and the association with disease control, while blood levels in A) and B) help in detecting differences related to BMs. Exclusion criteria are surgical or previous radiosurgical treatment for BM. This study has received Institutional Ethical Committee approval on 3rd August 2020 (Project NCH04-2020, Clinicaltrials.gov identifier: NCT04785521).

Preliminary results

Comparison between BM group (n = 32) and Control-1 (n=18) revealed a significant difference in LDH (271.93 vs 217.56 U/L; p 0.041) and lactate (1.86 vs 1.34 mmol/L, p = 0.022) and a trend towards significance in glutamate (103.43 vs 73.74 µmol/L, p = 0.07). Comparison between BM group (n=32) and Control-2 (n = 37) revealed a difference in LDH (271.93 vs 210.89 U/L; p < 0.001), lactate (1.86 vs 1.24 mmol/L; p < 0.001), aspartate (16.36 vs 10.22 µmol/L, p 0.006) and glutamate levels (123 vs 103 µmol/L, p = 0.052).

Conclusion

The present study is the first one addressing serum glutamate and scavenger levels in patients with BM. If the hypothesis will be confirmed, new targets in glutamate signalling pathway could be identified to define new therapeutic strategies in this challenging disease.

Resistance to first-generation somatostatin receptor ligands does not impair the results of gamma knife radiosurgery in acromegaly

OBJECTIVE

Gamma knife radiosurgery (GKRS) has proven to be an effective adjuvant treatment for patients with acromegaly. We performed the present study to investigate, which would be the outcome of GKRS, independently on the response to somatostatin receptor ligand (SRL).

DESIGN

Retrospective, observational study.

PATIENTS

Ninety-six patients with active acromegaly were included.

MEASUREMENTS

The cumulative probability of normalisation of insulin-like growth factor 1 (IGF-1) levels after GKRS was assessed by the Kaplan-Meier method. The association of several clinical characteristics with GKRS outcomes was explored with the use of a Cox proportional-hazard model with the relative hazard ratio and 95% confidence interval (CI).

RESULTS

Resistance to SRL occurred in 39 of the 96 patients (40.6%). After GKRS, patients resistant to SRL had a 5- and 10-year probability of remission of 40.7% (95% CI: 23.7%-57.7%) and 75.9% (95% CI: 57.9%-93.9%), respectively. Patients responding to SRL had a 5- and 10-year probability of remission of 46.8% (95% CI: 32.2%-61.4%) and 58.1% (95% CI: 41.5%-74.7%), respectively. The difference was not significant (p = .48 by the log-rank test). Multivariate Cox analysis confirmed that the only independent variables associated with GKRS outcome were basal growth hormone (GH; p = .001) and IGF-1 multiple of the upper limit of normal levels before GKRS (p = .013).

CONCLUSION

We demonstrate for the first time that the responsiveness to SRL has no effect on the probability to obtain remission of acromegaly after GKRS. The remission of disease occurred more frequently in patients who had lower GH and IGF-1 levels before GKRS.

Gamma knife radiosurgery in patients with Nelson's syndrome

PURPOSE

Nelson's syndrome (NS) is a long-term complication of bilateral adrenalectomy in patients with Cushing's disease. The best therapeutic strategy in NS has not been well defined. Gamma knife radiosurgery (GKRS) is very effective to stop the growth of the pituitary adenoma, which is the main goal of the treatment of patients with NS. We report the largest series of patients with NS treated by GKRS at a single center.

METHODS

The study was an observational, retrospective analysis of 28 consecutive patients with NS treated by GKRS in our department between 1995 and 2019. All patients had a growing ACTH-secreting pituitary adenoma. The main outcome of the study was to assess by the Kaplan-Meier method the risk of tumor progression after GKRS.

RESULTS

The median follow-up after GKRS treatment was 98 months (IQR 61-155 months, range 7-250 months). Two patients (7.1%) had a recurrence of disease during follow-up. The 10-year progression-free survival was 91.7% (95% CI 80.5-100%). No patient had deterioration of visual function or oculomotor function after GKRS. New onset of hypogonadism and hypothyroidism occurred in 18.8% and 14.3% of the patients at risk.

CONCLUSION

Our study confirms that GKRS may stop the tumor growth in the majority of patients with NS, even though very aggressive adenomas may ultimately escape this treatment. Safety of GKRS was good in our experience, but due attention must be paid to planning the distribution of radiation to critical structures, especially in patients previously treated by radiation.

Gamma Knife radiosurgery for cluster-tic syndrome unresponsive to medical treatment: illustrative case

BACKGROUND

Cluster-tic syndrome is a disorder characterized by the coexistence of symptoms related to both cluster headache and trigeminal neuralgia. Etiopathogenesis is not yet well defined. Medical treatment, including drugs for both cluster headache and trigeminal neuralgia, is the first therapeutic choice, whereas more invasive treatments are indicated in the case of pharmacological therapy failure or in the presence of drug side effects. To date, no randomized and/or large cohort trials describing Gamma Knife radiosurgery (GKRS) for cluster-tic syndrome are available, probably due to the syndrome’s rarity.

OBSERVATIONS

The authors describe the case of a 76-year-old woman with refractory cluster-tic syndrome who underwent GKRS with double target (the retrogasserian portion of the trigeminal nerve and the sphenopalatine ganglion). The Numerical Rating Scale (NRS) of pain and the Barrow Neurological Institute (BNI) pain intensity score before treatment were 7 (up to 10 during paroxysmal pain attacks) and V, respectively. At last follow-up, 24 months after GKRS, the patient had discontinued her pain medications and NRS and BNI pain scores were 1 and I, respectively. No trigeminal sensory disorders were reported.

LESSONS

The present case shows that GKRS, in selected cases, could be an effective treatment in patients with refractory cluster-tic syndrome.

Endoscope-Assisted Neuroportal Transcerebellar Approach to the Fourth Ventricle: An Anatomical Study

BACKGROUND AND STUDY AIMS

 Minimally invasive approaches to deep-seated lesions still represent a fundamental issue in modern neurosurgery. Tubular retractors allow to enhance the operability of intraventricular lesions, minimizing the risk of damages to brain parenchyma. Increasing interest for portal devices has been mainly focused on supratentorial pathologies, while transportal approaches in the posterior cranial fossa have been rarely described. In the present study, the authors aimed to investigate the surgical exposure and operability obtained with a microsurgical neuroportal transcerebellar approach targeting the fourth ventricle, assisted by endoscopic exploration.

MATERIAL AND METHODS

 Six cadaveric specimens were provided for anatomical microsurgical dissection and Vycor ViewSite Brain Access System was used as tubular retractor. Surgical feasibility of the neuroportal transcerebellar approach was demonstrated through a definable and measurable parameter, the operability score.

RESULTS

 The neuroport provided a surgical corridor away from eloquent structures to target the whole fourth ventricle cavity, preventing injury to cerebellar nuclei and white matter pathways and, potentially, minimizing the risk of surgical morbidity. Maximal operability was reached in the pontomedullary junction and medullary area of the ventricular floor. Transportal endoscopic assistance contributed to a further extension of surgical exposure in blind spots, corresponding to the ipsilateral lateral recess, the uppermost part of the fourth ventricle, and the obex.

CONCLUSION

 The neuroportal transcerebellar approach represents a viable alternative route to the fourth ventricle, avoiding vermian splitting or subarachnoid dissection of the cerebellomedullary cistern. Endoscopic assistance enhances the exposure of the surgical field and accomplishes a valid instrument for intraventricular orientation to ease microsurgical procedures.

Factors affecting long-lasting pain relief after Gamma Knife radiosurgery for trigeminal neuralgia: a single institutional analysis and literature review

Gamma Knife radiosurgery (GKRS) is a well-established safe and effective treatment for trigeminal neuralgia (TN) with high initial success rate (80-90%). Why the pain relief is progressively decreased with time is a matter of considerable debate. To investigate factors related to long-lasting pain relief, the authors conducted a retrospective analysis focusing on anatomical and radiosurgical related parameters, chosen according to literature review. One hundred and twelve patients with classical trigeminal neuralgia and follow-up longer than 12 months were selected from our institutional consecutive series of patients treated by GKRS. Patients were followed for a mean period of 61.5 ± 3.5 months (range, 12-126 months) to evaluate, as endpoints, long-term pain relief and hypoesthesia onset. The median maximum radiation dose was 80 Gy (range 70-90 Gy). Factors related to poor long-term pain relief were prescription dose < 80 Gy (p = 0.038), calibration dose rate < 2.5 Gy/min (p = 0.018), and distance between isocenter and trigeminal nerve emergence > 8 mm (p < 0.001). When analyzing patients who received 80 Gy as maximum dose without any sector blocking, we notice that ID₅₀ < 2.7 mJ was predictive for longer period of pain control (p = 0.043). It was experienced also among patients in which a small volume of the nerve (< 35%) received more than 80% of the maximal dose, compared to those in which a larger volume of the nerve was irradiated with maximal dose (p 0.034). This last result was significant if the shot was 8 mm or less from the pons. Several single-patient anatomical and radiosurgical parameters should be considered to improve GKRS effectiveness.

Primary sellar melanocytoma: pathological, clinical and treatment review

BACKGROUND

Sellar melanocytomas represent a small subgroup of primary melanocytic tumors. They arise from melanocytes located in the meningeal lining of the sellar floor or in the diaphragma sellae and this location is very uncommon. Usually, sellar melanocytomas are benign and slow-growing tumors with a high likelihood of recurrence.

PURPOSE

To our knowledge, due to the rarity of this condition, there are no guidelines regarding their diagnosis and treatment in the medical literature to date. We have developed a narrative review, analyzing the available studies regarding primary sellar melanocytomas reported in the medical literature. We have found ten papers on this topic and all of them are case reports. In all patients, tumor diagnosis was performed after the occurrence of neurological symptoms, in particular progressive visual loss or endocrinological disorders. The diagnosis is difficult, and it requires several preoperative and postoperative investigations, but histological examination is crucial.

CONCLUSIONS

Transsphenoidal surgery is the first-choice treatment. In case of tumor's recurrence or regrowth, the role of radiation therapy and chemotherapy is not entirely clear.

Inverted positioning of Leksell Frame G for very low posterior fossa and brain stem lesions biopsies

BACKGROUND

The specificity of imaging alone in diagnosing posterior fossa lesions is insufficient, hence the importance of biopsy for diagnostic, therapeutic and prognostic purposes. Concerning the operative technique, many studies have demonstrated the superior safety of stereotactic biopsy over craniotomy and superior accuracy of frame-based systems over frameless ones as far as the posterior fossa is concerned; however versatile, frame-based instruments bear some intrinsic limitations in the positioning of frame in lower lesions mainly in short neck and kyphotic patients. For all these reasons, a more proficient technical bioptic approach to the posterior fossa and lower brainstem is sometimes required.

METHODS

In order to obtain a specimen a Leksell System (Elekta®) constituted by the Leksell Coordinate G Frame (Article No: 014611), 4 adjustable posts (Article No: 1006476), 4 reusable screws (Article No: 1006581), an open indicator box (Article No: 1006559), a Leksell Multi-purpose Stereotactic Arc (Article No: 1008174) and a Sedan Needle (Article No: A2430-01) are required.

RESULTS

This is a simple and reliable technique to obtain a brainstem/cerebellar specimen maintaining unchanged the know risks of the procedure, as well the morbidity and mortality. We otherwise recommend this procedure to be performed by a team of neurosurgeons trained in stereotaxy.

CONCLUSIONS

If meticulously planned, our modified procedure provide a direct and precise access to deep seated areas of the posterior fossa and brainstem and is particularly helpful in those patients with short neck and kyphosis in which is crucial obtain an istopathologic diagnosis in lower posterior fossa.

Complications of transsphenoidal surgery in patients with pituitary adenoma: experience at a single centre

OBJECTIVE

This paper reports the complications of transsphenoidal surgery for pituitary adenomas in a series of 1240 consecutive patients operated at our Institute between 1990 and 2004 (first operations) and indicate the clinical characteristics of patients which affected surgical morbidity and mortality.

METHODS

According to tumour type, there were 420 (33.9%) non-functioning pituitary adenomas (NFPA), 349 (28.1%) GH-secreting, 288 (23.2%) ACTH-secreting, 155 (12.5%) prolactin (PRL)-secreting, and 28 (2.3%) TSH-secreting adenomas. The mean age of patients was 43.7 +/- 0.4 yr and 122 patients (9.9%) were 65 yr or older; the female/male ratio was 1.5/1. There were 370 (29.8%) microadenomas and 870 (70.2%) macroadenomas of which 54 (4.4%) were giant adenomas.

RESULTS

The series mortality was 0.2%, the medical morbidity 1.9%, and the surgical morbidity 3.5%. Medical complications were significantly more frequent in patients older than 65 yr (4.9 vs. 1.4%; p = 0.009) and in patients with giant adenomas (5.6 vs. 1.6%; p = 0.03). Multivariate analysis showed that both variables were independently associated with a higher morbidity rate. The surgical morbidity was increased in giant adenomas (15 vs. 3%; p = 0.0001), in NFPA (6.2 vs. 2.1% in secreting adenomas; p = 0.0002) and in patients older than 65 yr (6.6 vs. 3.1%; p = 0.05). Multivariate analysis showed that only giant size was independently associated with an increased surgical morbidity rate.

CONCLUSIONS

In our experience, the size of the adenoma was a risk factor for medical and surgery related complications and age over 65 yr for medical complications alone.