Inherent Tumor Characteristics That Limit Effective and Safe Resection of Giant Nonfunctioning Pituitary Adenomas

Comparison of Surgical Modalities for Giant Pituitary Adenoma: A Systematic Review and Meta-Analysis of 1413 Patients

BACKGROUND AND OBJECTIVES

Giant pituitary adenomas (GPAs) are a challenging clinical entity, composing 5% to 15% of all pituitary adenomas. While the endoscopic endonasal transsphenoidal (EET) approach has surpassed the microsurgical transsphenoidal (MT) and transcranial (TC) approaches as the first-line surgical modality in most institutions, a systematic review comparing the 3 approaches has not been undertaken since 2012. Given growing adoption of EET and development of novel operative techniques over the past decade, an updated comparison of GPA surgical modalities is warranted.

METHODS

We identified all studies related to the surgical management of GPAs in PubMed, Embase, and Web of Science from inception to December 31, 2021. End points assessed included gross total resection (GTR) rates, postoperative visual improvement, mortality, and perioperative complications.

RESULTS

After screening of 1701 studies, we identified 45 studies on the surgical management of GPAs for meta-analysis. Thirty-one used the EET approach (n = 1413), 11 studies used the MT approach (n = 601), and 10 used the TC approach (n = 416). The cumulative number of patients treated by EET did not exceed that of patients treated by the TC or MT approaches until 2014 and 2015, respectively. Despite patients undergoing EET having the highest average tumor diameter, pooled rates for GTR were significantly higher for EET (42%) than MT (33%, P < .001) and TC (8%, P < .001) and EET similarly exhibited superior rates of visual improvement (85%) than MT (73%, P < .001) and TC (56%, P < .001). Mortality rates were comparable between EET (0.6%) and MT (1.6%), but EET had significantly lower mortality than TC (2.7%, P < .001). Compared with MT, EET had lower rates of hypopituitarism (8.5% vs 14.9%, P = .012) but higher rates of diabetes insipidus (3.1% vs 0.5%, P = .001).

CONCLUSION

In an updated meta-analysis of 1413 patients with GPA, EET resection conferred significantly higher rates of visual improvement and GTR, when compared with the MT and TC approaches.

Combined simultaneous transsphenoidal and transcranial regimen improves surgical outcomes in complex giant pituitary adenomas: a longitudinal retrospective cohort study

BACKGROUND

Surgical treatment of complex giant pituitary adenomas (GPAs) presents significant challenges. The efficacy and safety of combining transsphenoidal and transcranial approaches for these tumors remain controversial. In this largest cohort of patients with complex GPAs, we compared the surgical outcomes between those undergoing a combined regimen and a non-combined regimen. We also examined the differences in risks of complications, costs, and logistics between the two groups, which might offer valuable information for the appropriate management of these patients.

PATIENTS AND METHODS

This was a multicenter retrospective cohort study conducted at 13 neurosurgical centers. Consecutive patients who received a combined or non-combined regimen for complex GPAs were enrolled. The primary outcome was gross total resection, while secondary outcomes included complications, surgical duration, and relapse. A propensity score-based weighting method was used to account for differences between the groups.

RESULTS

Out of 647 patients [298 (46.1%) women, mean age: 48.5 ± 14.0 years] with complex GPAs, 91 were in the combined group and 556 were in the noncombined group. Compared with the noncombined regimen, the combined regimen was associated with a higher probability of gross total resection [50.5% vs. 40.6%, odds ratio (OR): 2.18, 95% confidence interval (CI): 1.30-3.63, P = 0.003]. The proportion of patients with life-threatening complications was lower in the combined group than in the non-combined group (4.4% vs. 11.2%, OR: 0.25, 95% CI: 0.08-0.78, P = 0.017). No marked differences were found between the groups in terms of other surgical or endocrine-related complications. However, the combined regimen exhibited a longer average surgery duration of 1.3 h ( P < 0.001) and higher surgical costs of 22,000 CNY (~ 3,000 USD, P = 0.022) compared with the noncombined approach.

CONCLUSIONS

The combined regimen offered increased rates of total resection and decreased incidence of life-threatening complications, which might be recommended as the first-line choice for these patients.

Management Approaches and Patient Outcomes for Giant Pituitary Neuroendocrine Tumors Classified as Knosp Grade 3 and 4

Background Treatment of patients with a giant pituitary neuroendocrine tumor (GPitNET) is challenging. Here, we present the methods used for the clinical management of patients who underwent GPitNET resection mainly via endoscopic endonasal surgery along with multimodal support to avoid surgical complications, which can affect the outcomes. Methodology The medical records of 25 patients with a GPitNET who underwent endonasal endoscopic surgery were retrospectively reviewed. Complications were analyzed and factors affecting the extent of resection were evaluated. Results Gross total resection was achieved in six (24%), near-total resection (>90%) in nine (36%), and partial resection in 10 (40%) patients. Multivariate analyses revealed that tumors invading the middle fossa had negative effects on the extent of resection (odds ratio = 0.092, p = 0.047). Postoperative vision improved or normalized in 16 (64%), remained stable in eight (32%), and worsened in one (4%), while a new hormonal deficit was noted in seven (28%) patients. Complications included permanent oculomotor nerve palsy in one (4%) and transient oculomotor palsy in one (4%), apoplexy of the residual tumor resulting in ischemic stroke in one (4%), postoperative cerebrospinal fluid leakage in one (4%), and permanent diabetes insipidus in six (24%) patients. Conclusions For GPitNETs that extend into the middle fossa, our study underscored the difficulties in surgical extraction and the necessity for tailored treatment approaches. To ensure the safest and most complete removal possible, the surgical strategy must be specifically adapted to each case. Additionally, employing a comprehensive support approach is essential to reduce the chance of complications in patients impacted by this condition.

Surgical Strategies in the Treatment of Giant Pituitary Adenomas

BACKGROUND AND OBJECTIVES

The management of giant pituitary adenomas (GPAs) is challenging due to associated endocrinopathies and the close proximity of these tumors to critical structures, such as the optic nerves, structures of the cavernous sinus, and hypothalamus. The objective of this review article was to summarize the current management strategies for giant pituitary adenomas, including the role of open and endoscopic surgical approaches and the role of medical and radiation therapy in conjunction with surgery.

METHODS

We conducted a retrospective review of GPAs operated at our institute between January 2010 and March 2023. Surgical approaches, extent of resection, and associated complications were documented. Furthermore, we conducted a thorough literature review to identify relevant studies published in the past decade, which were incorporated along with insights gained from our institutional case series of GPAs to analyze and integrate both the existing knowledge base and our institution's firsthand experience in the management of GPAs.

RESULTS

A total of 46 giant pituitary adenomas (GPAs) were operated on, using various surgical approaches. Transsphenoidal approach was used in 25 cases and a staged approach using transsphenoidal and pterional was used in 15 cases. Other approaches included transcortical-transventricular, transcallosal, pterional/orbitozygomatic, and subfrontal approaches. Complications and technical nuances were reported.

CONCLUSION

The management of giant pituitary adenomas remains complex, often involving several modalities-open or endoscopic resection, radiosurgery, and medical management of both the tumor and associated endocrinopathies. Surgical resections are often challenging procedures that require careful consideration of several factors, including patient characteristics, tumor location, and size, and the experience and skill of the surgical team.

Endoscopic endonasal pituitary surgery: How we do it. Consensus statement on behalf of the EANS skull base section

Introduction and research question

The use of an endoscope in skull base surgery provides a panoramic close-up view over the intracranial structures from multiple angles with excellent illumination, thus permitting greater extent of resection of tumors arising at sellar area, mostly represented by PitNet - Pituitary neuroendocrine tumors, with higher likelihood of preserving vital/intact gland tissue. For this refined specialty of neurosurgery, unique skills need to be acquired along a steep learning curve.

Material and methods

EANS (European Association of Neurosurgical Societies) skull base section panelists were enrolled and 11 completed the survey: the goal was to provide a consensus statement of the endoscopic endonasal approach for pituitary adenoma surgery.

Results

The survey consisted of 44 questions covering demographics data (i.e., academic/non-academic center, case load, years of experience), surgical techniques (i.e., use of neuronavigation, preoperative imaging), and follow-up management.

Discussion and conclusions

In this paper we identified a series of tips and tricks at different phases of an endoscopic endonasal pituitary surgery procedure to underline the crucial steps to perform successful surgery and reduce complications: we took in consideration the principles of the surgical technique, the knowledge of the anatomy and its variations, and finally the importance of adjoining specialties experts.

Two- and three-dimensional endoscopic endonasal surgery of large and giant pituitary adenomas-outcome analysis of a series of 62 patients from a single pituitary center

To analyze the perioperative course and clinical outcome of patients with large (lPA) and giant (gPA) pituitary adenoma who underwent endoscopic endonasal transsphenoidal surgery (EETS) using either two-dimensional (2D-E) or three-dimensional (3D-E) endoscopic systems. Single-center retrospective study of consecutive patients with lPA and gPA who underwent EETS between November 2008 and January 2023. LPA were defined as ≥ 3 cm and < 4 cm in diameter in at least one dimension and a volume of ≥ 10ccm; gPA were defined as larger than 4 cm in diameter and with a greater volume than 10ccm. Patient data (age, sex, endocrinological and ophthalmological status) and tumor data (histology, tumor volume, size, shape, cavernous sinus invasion according to the Knosp classification) were analyzed. 62 patients underwent EETS. 43 patients were treated for lPA (69.4%) and 19 patients for gPA (30.6%). 46 patients (74.2%) underwent surgical resection using 3D-E and 16 patients 2D endoscopy (25.8%). Statistical results are referred to the comparison between 3D-E and 2D-E. Patients' age ranged from 23-88 years (median 57), 16 patients were female (25.8%), 46 male (74.2%). Complete tumor resection was possible in 43.5% (27/62), partial resection in 56.5% (35/62). Resection rates did not differ between 3D-E (27 patients [43.5%]) and 2D-E (7 patients [43.8%], (p = 0.985). Visual acuity improved in 30 of 46 patients with preoperative deficit (65.2%). In the 3D-E group 21 of 32 patients (65.7%) improved, compared to 9 of 14 patients in the 2D-E group (64.3%). Improvement of visual field was achieved in 31 of 50 patients (62.0%; 22 of 37 patients in the 3D-E group [59.4%] and 9 of 13 patients in the 2D-E group [69.2%]). CSF leak was the most frequent complication and occurred in 9 patients (14.5%, [8 patients 17.4% 3D-E]) without statistical significance. Other surgical complications like postoperative bleeding, infection (meningitis) and deterioration of visual acuity and field were detected without statistical difference. New pituitary anterior lobe dysfunction was observed in 30 of 62 patients (48.4%, 8 patients [50.0%] in the 2D-E group and 22 patients [47.8%] in the 3D-E group). A transient deficit of posterior lobe was detected in 22.6% (14/62). No patient died within 30 days of surgery. Although 3D-E may improve surgical dexterity, in this series of lPA and gPA it was not associated with higher resection rates compared to 2D-E. However, 3D-E visualization during resection of large and giant PA is safe and feasible and patient's clinical outcome is not different compared to 2D-E.

Aggressive pituitary tumors (PitNETs)

The majority of anterior pituitary tumors behave benignly, that is, they grow slowly and do not metastasize, and were therefore called adenomas. However, they would frequently invade adjacent structures, leading to recurrence. One of the misleading assumptions in their previous classification was the simplistic distinction made between adenoma and carcinoma. In the upcoming WHO 2022 classification, a new terminology will be introduced: pituitary neuroendocrine tumor (PitNET) which is consistent with that used for other neuroendocrine neoplasms. In general, aggressive PitNETs are invasive and proliferative tumors with frequent recurrences, resistant to conventional treatments, and yet virtually without metastases. At present, no single morphological or histological marker has been shown as yet to reliably predict their aggressive behavior. In terms of treatment, temozolomide (TMZ) had been considered promising and the sole therapeutic option for aggressive and malignant PitNETs following failure of standard therapies. However, recent reports have disclosed that TMZ does not provide long-term control of many aggressive PitNETs. A further multidisciplinary approach is necessary for both reliable prediction and successful management of aggressive PitNETs.

Staged surgery for irregular giant pituitary adenomas: A report of two cases

The resection of giant pituitary adenomas is one of the most challenging brain surgeries, especially when the giant pituitary adenomas have an irregular shape or irregular growth position. The purpose of the present study is to propose staged surgery for irregular giant pituitary adenomas through a retrospective analysis of two cases. The cases of two patients with irregular giant pituitary adenomas who underwent staged surgery are retrospectively analyzed. In one case, a 51-year-old male was hospitalized after 2 months of memory loss. Brain MRI showed that the pituitary adenoma was paginated and located in the sellar and right suprasellar regions, with a size of ~6.15×6.11×5.69 cm. In the second case, a 60-year-old male had a history of intermittent vertigo for 10 years and paroxysmal amaurosis for 1 year. Brain MRI showed that the pituitary adenoma grew laterally and eccentrically, and was located in the sellar region, with a size of ~4.35×3.96×3.07 cm. Both patients underwent staged surgery; more specifically, the tumors were totally removed through two-stage surgery. In the first-stage operation, most of the tumor was removed by the microscopic transcranial approach, while in the second-stage operation, the residual tumor was removed by the endoscopic transsphenoidal approach. Both patients recovered well without obvious postoperative complications after staged surgery. There was no recurrence during the follow-up. Staged surgery is characterized by only treating tumors in the visual field and achieving a total tumor resection, which has the advantages of a high tumor resection rate, high safety and fewer postoperative complications. Staged surgery is especially suitable for irregular giant pituitary adenomas with an irregular shape or irregular growth position.

Predictive model of resection in endoscopic endonasal approach for pituitary adenomas based on anatomical limits

INTRODUCTION

The aim of this project is to study several anatomical-radiological features of pituitary adenomas obtained from preoperative radiological images and to analyze their relationship with the extent of resection achieved through the endoscopic endonasal approach. The second objective was to create a prediction model of the extent of resection.

MATERIAL AND METHODS

We retrospectively evaluated 105 patients. Tumor volume, Knosp grade, suprasellar-diaphragm coefficient and invasion of the posterior compartment have been analyzed. The extent of resection was assessed by analyzing the postoperative magnetic resonance. We created the predictive scale using statistically independent variables.

RESULTS

When each of the variables has been studied individually, a statistically significant value of all of them is appreciated to obtain a complete resection. However, only the Knosp grade and the suprasellar-diaphragm coefficient had a statistically significant value as independent variables. The sum of the Odds Ratio obtained from the Knosp scale, and the suprasellar-diaphragm coefficient gives the probability of complete resection. A new set of cases was employed to validate the scale.

CONCLUSIONS

The cavernous sinus invasion and the newly designed suprasellar diaphragm coefficient are directly related to the extent of resection in pituitary adenoma surgery performed by a transellar endoscopic approach. Moreover, based on both radiologic factors, a predictive scale may predict the probability of complete resection in a series of patients.

Preoperative Magnetic Resonance Imaging Localization of the Normal Pituitary Gland in Nonfunctioning Pituitary Adenoma Patients Using the Radiological Sign of "Internal Carotid Artery Notch"

OBJECTIVE

Asymmetric features of nonfunctioning pituitary adenoma (NFPA) are poorly understood. We investigated the asymmetry in NFPA on magnetic resonance imaging.

METHODS

We reviewed preoperative magnetic resonance imaging findings of patients initially treated for NFPA. The internal carotid artery (ICA) often seemed to cause an indentation in the external shape of the tumor (i.e., the ICA notch).

RESULTS

Two cases with a normal pituitary gland located at the midline were excluded. The remaining 66 cases were examined. The side where the normal gland was located was defined as the normal pituitary side and the opposite side as the cavernous sinus side. The Knosp grade was significantly higher on the cavernous sinus side (P < 0.001), and the vertical distance of the ICA was significantly greater on the cavernous sinus side (P < 0.001). The ICA notch was found in 87.9% of all cases on the normal pituitary side, but in only 45.5% on the cavernous sinus side (P < 0.001). In cases with a single-side ICA notch (34 of 68), the ICA notch was found in 91.2% of cases and on the cavernous sinus side in 8.8% (P < 0.001).

CONCLUSIONS

Magnetic resonance imaging of NFPA frequently shows asymmetry. The tumor does not extend laterally on the normal pituitary side but extends laterally more freely on the cavernous sinus side. The ICA notch is often found on the normal pituitary side where the position of ICA does not move. This may be useful as a preoperative sign to indicate the normal pituitary side.

Effect of facility volume on giant pituitary adenoma neurosurgical outcomes

OBJECTIVE

Giant pituitary adenomas (PAs), defined as 4 cm or greater at their maximum diameter, are commonly treated with neurosurgical intervention as the first-line therapy. However, existing studies are from high-volume institutions whose outcomes may not be representative of many cancer centers. In the present study, the authors use a large cancer registry to evaluate demographics, national treatment trends, and outcomes by facility volume to address knowledge gaps for this uncommon tumor.

METHODS

The National Cancer Database was queried for adult patients with PAs who had undergone resection from 2004 to 2016. Univariate and multivariate logistic regression modeling was used to evaluate the prognostic impact of covariates on short-term outcomes including 30-day readmission (30R), 30-day mortality (30M), 90-day mortality (90M), and prolonged length of inpatient hospital stay (LOS). Propensity score matching was used for validation.

RESULTS

Among the 39,030 patients who met the study inclusion criteria, 3696 giant PAs were identified. These tumors had higher rates of subtotal resection (55% vs 24%, p < 0.001), adjunctive radiotherapy (15% vs 5%, p < 0.001), and hormonal therapy (8% vs 4%, p < 0.001) than nongiant PAs. The giant PAs also had worse 30M (0.6% vs 3.1%, p < 0.001), 90M (1.0% vs 5.0%, p < 0.001), 30R (4.0% vs 6.3%, p < 0.001), and LOS (22.2% vs 42.1%, p < 0.001). On multivariate analysis for giant PA, decreased tumor size, younger age, race other than African American, lower comorbidity score, and high-volume facility (HVF; defined as ≥ 2.5 giant PA cases per year) were statistically significant predictors of favorable outcomes. Specifically, 30M, 90M, 30R, and LOS were decreased by 50%, 43%, 55%, and 32%, respectively, when giant PAs were treated at HVFs (each p < 0.05). HVFs more often used the endoscopic approach (71% vs 46%, p < 0.001) and less adjuvant radiotherapy (11% vs 16%, p < 0.001). Propensity score matching validated 30M, 30R, and LOS outcome differences in a cohort of 1056 patients.

CONCLUSIONS

This study provides evidence of superior outcomes when giant PAs are treated at HVFs. These results likely reflect the relation between physician experience and outcomes for these uncommon tumors, which suggests the need for institutional collaboration as a potential goal in their surgical management.

Microscopic Transsphenoidal Resection of Giant Pituitary Adenomas: Analysis of the Factors Limiting the Degree of Resection in 73 Cases

Purpose

To analyze the risk factors affecting the gross-total resection of giant pituitary adenomas using a transsphenoidal approach under a microscope to provide a reference basis for formulating an appropriate surgical strategy.

Methods

The clinical data of patients who underwent microscopic transsphenoidal resection of giant pituitary adenomas in a single center from January 2011 to December 2020 were retrospectively analyzed. Based on magnetic resonance imaging and surgical records, the predictive factors affecting the gross-total resection of giant pituitary adenomas under microscopy were determined through univariate and multivariate analyses.

Results

A total of 73 patients with giant pituitary adenomas underwent transsphenoidal microsurgery. Gross-total resection was performed in 19 cases (26%), subtotal resection in 31 cases (42%), partial resection in 21 cases (29%), and the degree of resection was <50% in only two cases (3%). After binary logistic analysis, it was found that it was more difficult to completely remove giant pituitary adenomas with a Knosp grade 3–4 [odds ratio (OR) = 0.214, 95% confidence interval (CI): 0.05–0.917; P = 0.038], greater proportion of tumor suprasellar volume (odds ratio = 0.937, 95% confidence interval: 0.898–0.978; P = 0.003), and intraoperative evidence of invasion of the cavernous sinus (odds ratio = 0.187, 95% CI: 0.039–0.898; P = 0.036).

Conclusion

It is difficult to remove a giant pituitary adenoma invading the cavernous sinus completely with a higher degree of invasion of the suprasellar region using microscopic transsphenoidal surgery. The combined application of multiple surgical methods can help to improve the degree of resection during a single operation.

3D Virtual Modeling for Morphological Characterization of Pituitary Tumors: Preliminary Results on Its Predictive Role in Tumor Resection Rate

Among potential factors affecting the surgical resection in pituitary tumors, the role of tumor three-dimensional (3D) features is still unexplored. The aim of this study is to introduce the use of 3D virtual modeling for geometrical and morphological characterization of pituitary tumors and to evaluate its role as a predictor of total tumor removal. A total of 75 patients operated for a pituitary tumor have been retrospectively reviewed. Starting from patient imaging, a 3D tumor model was reconstructed, and 3D characterization based on tumor volume (Vol), area, sphericity (Spher), and convexity (Conv) was provided. The extent of tumor removal was then evaluated at post-operative imaging. Mean values were obtained for Vol (9117 ± 8423 mm3), area (2352 ± 1571 mm2), Spher (0.86 ± 0.08), and Conv (0.88 ± 0.08). Total tumor removal was achieved in 57 (75%) cases. The standard prognostic Knosp grade, Vol, and Conv were found to be independent factors, significantly predicting the extent of tumor removal. Total tumor resection correlated with lower Knosp grades (p = 0.032) and smaller Vol (p = 0.015). Conversely, tumors with a more irregular shape (low Conv) have an increased chance of incomplete tumor removal (p = 0.022). 3D geometrical and morphological features represent significant independent prognostic factors for pituitary tumor resection, and they should be considered in pre-operative planning to allow a more accurate decision-making process.

Transventricular Preforniceal Approach Combined with Endoscopic Transnasal Surgery for a Giant Pituitary Adenoma: A Case Report and Literature Review

Giant pituitary adenomas carry significant surgical risks when treated with transsphenoidal approaches or the transcranial approach alone. Combined transsphenoidal and transcranial approaches have been reported; however, removing adenomas extending into the third ventricle may still be challenging. We report a case of giant pituitary adenoma expanding into the third ventricle, which was removed using a combined transventricular preforniceal approach and an endoscopic endonasal transsphenoidal surgery (ETSS). A 41-year-old man with headache, nausea, and a 1-week history of a visual field defect was transferred to our hospital. He had a disturbed left visual acuity, right homonymous hemianopia, and choked disc in both eyes. Preoperative magnetic resonance imaging revealed a giant pituitary adenoma with a maximum diameter of 55 mm extending from the intrasellar to the suprasellar region, thus occupying the entire third ventricle and causing hydrocephalus. The space between the anterior commissure and the fornix was expanded. The foramen of Monro was shifted backward due to compression by the tumor. He underwent maximum surgical resection using a combined transventricular preforniceal approach and ETSS. Considering technical demands and reliability, the intra- to suprasellar parts were removed by ETSS while the intraventricular part was removed through the preforniceal approach. The residual tumor in the right cavernous sinus and behind the anterior communicating artery was treated with stereotactic radiotherapy. One year after the operation, the patient leads an independent life. The combined technique of the preforniceal approach and ETSS provided a direct view of the entire third ventricle and hemostasis in the present case.

Outcome of giant pituitary tumors requiring surgery

OBJECTIVE

The management of giant pituitary tumors is complex, with few publications and recommendations. Consequently, patient's care mainly relies on clinical experience. We report here a first large series of patients with giant pituitary tumors managed by a multidisciplinary expert team, focusing on treatments and outcome.

METHODS

A retrospective cohort study was conducted. Giant pituitary tumors were defined by a main diameter > 40mm. Macroprolactinomas sensitive to dopamine agonists were excluded. All patients were operated by a single neurosurgical team. After surgery, multimodal management was proposed, including hormone replacement, radiotherapy and anti-tumor medical therapies. Outcome was modeled using Kaplan-Meyer representation. A logistic regression model was built to identify the risk factors associated with surgical complications.

RESULTS

63 consecutive patients presented a giant adenoma, most often with visual defects. Patients were operated once, twice or three times in 59%, 40% and 1% of cases respectively, mainly through endoscopic endonasal approach. Giant adenomas included gonadotroph, corticotroph, somatotroph, lactotroph and mixed GH-PRL subtypes in 67%, 14%, 11%, 6% and 2% of patients respectively. Vision improved in 89% of patients with prior visual defects. Severe surgical complications occurred in 11% of patients, mainly for tumors > 50 mm requiring microscopic transcranial approach. Additional radiotherapy was needed for 29% of patients, 3 to 56 months after first surgery. For 6% of patients, Temozolomide treatment was required, 19 to 66 months after first surgery.

CONCLUSIONS

Giant pituitary tumors require multimodal management, with a central role of surgery. Most often, tumor control can be achieved by expert multidisciplinary teams.

Surgical management of giant pituitary neuroendocrine tumors: Meta-analysis and consensus statement on behalf of the EANS skull base section

Introduction

The optimal surgical treatment for giant pituitary neuroendocrine tumors(GPitNETs) is debated.

Research question

The aim of this paper is to optimize the surgical management of these patients and to provide a consensus statement on behalf of the EANS Skull Base Section.

Material and methods

We constituted a task force belonging to the EANS skull base committee to define some principles for the management of GPitNETs. A systematic review was performed according to PRISMA guidelines to perform a meta-analysis on surgical series of GPitNETs. Weighted summary rates were obtained for the pooled extent of resection and according to the surgical technique. These data were discussed to obtain recommendations after evaluation of the selected articles and discussion among the experts.

Results

20articles were included in our meta-analysis, for a total of 1263 patients. The endoscopic endonasal technique was used in 40.3% of cases, the microscopic endonasal approach in 34% of cases, transcranial approaches in 18.7% and combined approaches in 7% of cases. No difference in terms of gross total resection (GTR) rate was observed among the different techniques. Pooled GTR rate was 36.6%, while a near total resection (NTR) was possible in 45.2% of cases. Cavernous sinus invasion was associated with a lower GTR rate (OR: 0.061). After surgery, 35% of patients had endocrinological improvement and 75.6% had visual improvement. Recurrent tumors were reported in 10% of cases

Discussion and conclusion

After formal discussion in the working group, we recommend the treatment of G-PitNETs tumors with a more complex and multilobular structure in tertiary care centers. The endoscopic endonasal approach is the first option of treatment and extended approaches should be planned according to extension, morphology and consistency of the lesion. Transcranial approaches play a role in selected cases, with a multicompartmental morphology, subarachnoid invasion and extension lateral to the internal carotid artery and in the management of residual tumor apoplexy.

Solid tumor size for prediction of recurrence in large and giant non-functioning pituitary adenomas

A subset of large non-functioning pituitary adenomas (lNFPA) and giant non-functioning pituitary adenomas (gNFPA) undergoes early progression/recurrence (P/R) after surgery. This study revealed the clinical and image predictors of P/R in lNFPA and gNFPA, with emphasis on solid tumor size. This retrospective study investigated the preoperative MR imaging features for the prediction of P/R in lNFPA (> 3 cm) and gNFPA (> 4 cm). Only the patients with a complete preoperative brain MRI and undergone postoperative MRI follow-ups for more than 1 year were included. From November 2010 to December 2020, a total of 34 patients diagnosed with lNFPA and gNFPA were included (median follow-up time 47.6 months) in this study. A total of twenty-three (23/34, 67.6%) patients had P/R, and the median time to P/R is 25.2 months. Solid tumor diameter (STD), solid tumor volume (STV), and extent of resection are associated with P/R (p < 0.05). Multivariate analysis showed large STV is a risk factor for P/R (p < 0.05) with a hazard ratio of 30.79. The cutoff points of STD and STV for prediction of P/R are 26 mm and 7.6 cm³, with AUCs of 0.78 and 0.79 respectively. Kaplan-Meier analysis of tumor P/R trends showed that patients with larger STD and STV exhibited shorter progression-free survival (p < 0.05). For lNFPA and gNFPA, preoperative STD and STV are significant predictors of P/R. The results offer objective and valuable information for treatment planning in this subgroup.

Treatment strategies for giant pituitary adenomas in the era of endoscopic transsphenoidal surgery: a multicenter series

OBJECTIVE

Given the anatomical complexity and frequently invasive growth of giant pituitary adenomas (GPAs), individually tailored approaches are required. The aim of this study was to assess the treatment strategies and outcomes in a large multicenter series of GPAs in the era of endoscopic transsphenoidal surgery (ETS).

METHODS

This was a retrospective case-control series of 64 patients with GPAs treated at two tertiary care centers by surgeons with experience in ETS. GPAs were defined by a maximum diameter of ≥ 4 cm and a volume of ≥ 10 cm3 on preoperative isovoxel contrast-enhanced MRI.

RESULTS

The primary operation was ETS in all cases. Overall gross-total resection rates were 64% in round GPAs, 46% in dumbbell-shaped GPAs, and 8% in multilobular GPAs (p < 0.001). Postoperative outcomes were further stratified into two groups based on extent of resection: group A (gross-total resection or partial resection with intracavernous remnant; 21/64, 33%) and group B (partial resection with intracranial remnant; 43/64, 67%). Growth patterns of GPAs were mostly round (11/14, 79%) in group A and multilobular (33/37, 89%) in group B. In group A, no patients required a second operation, and 2/21 (9%) were treated with adjuvant radiosurgery. In group B, early transcranial reoperation was required in 6/43 (14%) cases due to hemorrhagic transformation of remnants. For the remaining group B patients with remnants, 5/43 (12%) underwent transcranial surgery and 12/43 (28%) underwent delayed second ETS. There were no deaths in this series. Severe complications included stroke (6%), meningitis (6%), hydrocephalus requiring shunting (6%), and loss or distinct worsening of vision (3%). At follow-up (mean 3 years, range 0.5-16 years), stable disease was achieved in 91% of cases.

CONCLUSIONS

ETS as a primary treatment modality to relieve mass effect in GPAs and extent of resection are dependent on GPA morphology. The pattern of residual pituitary adenoma guides further treatment strategies, including early transcranial reoperation, delayed endoscopic transsphenoidal/transcranial reoperation, and adjuvant radiosurgery.

Identification of the Extradural and Intradural Extension of Pituitary Adenomas to the Suprasellar Region: Classification, Surgical Strategies, and Outcomes

Objective

Suprasellar pituitary adenomas (PAs) can be located in either extradural or intradural spaces, which impacts surgical strategies and outcomes. This study determined how to distinguish these two different types of PAs and analyzed their corresponding surgical strategies and outcomes.

Methods

We retrospectively analyzed 389 patients who underwent surgery for PAs with suprasellar extension between 2016 to 2020 at our center. PAs were classified into two main grades according to tumor topography and their relationships to the diaphragm sellae (DS) and DS-attached residual pituitary gland (PG). Grade 1 tumors were located extradurally and further divided into grades 1a and 1b, while grade 2 tumors were located intradurally.

Results

Of 389 PAs, 292 (75.1%) were surrounded by a bilayer structure formed by the DS and the residual PG and classified as grade 1a, 63 (16.2%) had lobulated or daughter tumors resulting from the thinning or absence of the residual PG and subsequently rendering the bilayer weaker were classified as Grade 1b, and the remaining 34 (8.7%) PAs that broke through the DS or traversed the diaphragmic opening and encased suprasellar neurovascular structures were classified as Grade 2. We found that the gross total removal of the suprasellar part of grade 1a, 1b, and 2 PAs decreased with grading (88.4%, 71.4%, and 61.8%, respectively). The rate of major operative complications, including cerebrospinal fluid leakage, hemorrhage, and death, increased with grading.

Conclusions

It is essential to identify whether PAs with suprasellar extension are located extradurally or intradurally, which depends on whether the bilayer structure is intact. PAs with an intact bilayer structure were classified as grade 1. These were extradural and usually had good surgical outcomes and lower complications. PAs with no bilayer structure surrounding them were classified as grade 2. These were intradural, connected to the cranial cavity, and had increased surgical complications and a lower rate of gross total removal. Different surgical strategies should be adopted for extradural and intradural PAs.

Endoscopic Endonasal Transtubercular Approach for Resection of Giant Pituitary Adenomas With Subarachnoid Extension: The "Second Floor" Strategy to Avoid Postoperative Apoplexy

BACKGROUND

Giant pituitary adenomas (GPAs) with subarachnoid extension can be challenging to achieve a gross total resection through a single endonasal or transcranial approach, and any residual tumor is at risk for postoperative apoplexy. Intraoperative venous congestion of the suprasellar tumor can occur following resection of the sellar tumor, limiting tumor descent, and leading to suprasellar residual. We propose a technique for resecting the suprasellar component first, which we call the "second floor" strategy (SFS) for GPA.

METHODS

A retrospective review of cases from 2010-2020 identified 586 endoscopic endonasal approaches (EEAs) for pituitary adenoma resection. We report the rate of postoperative apoplexy and describe the SFS technique used in 2 cases.

RESULTS

Of 586 cases, 2 developed symptomatic postoperative apoplexy (0.3%), and a third transferred to our care after undergoing postoperative apoplexy. All 3 cases had subarachnoid extension of a pituitary adenoma, underwent EEA, and had residual suprasellar tumor. All 3 had permanent morbidity due to the postoperative apoplexy including blindness, stroke, or death, despite undergoing reoperation. The SFS was used for reoperation on 1 of these patients and as a primary strategy in a fourth patient who presented with a GPA with subarachnoid extension. We describe the SFS technique and demonstrate it with a 2-dimensional operative video.

CONCLUSIONS

Postoperative apoplexy of residual adenoma is a rare but serious complication after GPA resection. The proposed SFS allows early access to the suprasellar tumor and may improve the ability to safely achieve a gross total resection without need for additional procedures.

Transcranial approach as surgical treatment for giant pituitary adenoma during COVID 19 pandemic - What can we learn?: A case report

Introduction

In the COVID 19 pandemic, pituitary surgery is one of challenging surgical treatment, especially the involving transsphenoid approach. It was reported that the aerosolisation and mucosal involvement increase the risk of viral transmission during operation. Therefore, transcranial is a safer surgical approach during COVID-19 pandemic. This study aimed to reported transcranial approach to treat giant pituitary adenoma with aggressive visual disturbance which require urgent surgical management.

Case presentation

We reported a 21-year old male, who required urgent surgery because of progressive visual disturbance due to giant pituitary adenoma. On brain MRI with contrast, it was revealed an extraaxial tumor extending anteriorly over plannum sphenoidal with the greatest diameter was 5.34 cm. Transcranial approach was chosen to resect the tumor. Near total removal of the tumor was achieved without damaging vital neurovascular structure. The visual acuity was improved and no significant postoperative complication. Pathology examination revealed pituitary adenoma.

Conclusion

Transcranial surgery for pituitary adenoma is still an armamentarium in neurosurgical practice, especially in the COVID 19 pandemic to provide safer surgical approach.

Extended endonasal approaches for pituitary adenomas

Pituitary adenomas with significant extension beyond the sellar boundary, large size, asymmetrical shape and subarachnoid space invasion, although rare, represent a therapeutic challenge. The invasiveness of the tumor itself often limits the potential for complete tumor resection and increases the likelihood of intraoperative or postoperative complications, regardless of the approach. The extended endoscopic endonasal approach has been proposed as a valid alternative to the transcranial route for the treatment of certain pituitary adenomas not suitable to the standard transsphenoidal approach. Thanks to the wide and close up view provided by the endoscope via the appropriate expanded bone removal at the skull base, this technique offers, in an adequate working space, a safe exposure of the tumor and surrounding anatomical structures, at the supra-, para-, and retro-sellar areas. It stands clear that the primary goal of this approach remains the maximum allowed resection with preservation of neurological and endocrine functions. Herein, we debate the extended endoscopic endonasal technique for the treatment of pituitary adenomas, with the aim of underlying its indications, pitfalls, advantages, and limitations.

Proposal and Validation of a Simple Grading Scale (TRANSSPHER Grade) for Predicting Gross Total Resection of Nonfunctioning Pituitary Macroadenomas After Transsphenoidal Surgery

BACKGROUND

A simple, reliable grading scale to better characterize nonfunctioning pituitary adenomas (NFPAs) preoperatively has potential for research and clinical applications.

OBJECTIVE

To develop a grading scale from a prospective multicenter cohort of patients that accurately and reliably predicts the likelihood of gross total resection (GTR) after transsphenoidal NFPA surgery.

METHODS

Extent-of-resection (EOR) data from a prospective multicenter study in transsphenoidal NFPA surgery were analyzed (TRANSSPHER study; ClinicalTrials.gov NCT02357498). Sixteen preoperative radiographic magnetic resonance imaging (MRI) tumor characteristics (eg, tumor size, invasion measures, tumor signal characteristics, and parameters impacting surgical access) were evaluated to determine EOR predictors, to calculate receiver-operating characteristic curves, and to develop a grading scale. A separate validation cohort (n = 165) was examined to assess the scale's performance and inter-rater reliability.

RESULTS

Data for 222 patients from 7 centers treated by 15 surgeons were analyzed. Approximately one-fifth of patients (18.5%; 41 of 222) underwent subtotal resection (STR). Maximum tumor diameter > 40 mm; nodular tumor extension through the diaphragma into the frontal lobe, temporal lobe, posterior fossa, or ventricle; and Knosp grades 3 to 4 were identified as independent STR predictors. A grading scale (TRANSSPHER grade) based on a combination of these 3 features outperformed individual variables in predicting GTR (AUC, 0.732). In a validation cohort, the scale exhibited high sensitivity and specificity (AUC, 0.779) and strong inter-rater reliability (kappa coefficient, 0.617).

CONCLUSION

This simple, reliable grading scale based on preoperative MRI characteristics can be used to better characterize NFPAs for clinical and research purposes and to predict the likelihood of achieving GTR.

The role of multimodal navigation in endoscopic endonasal surgery for giant pituitary adenomas

Background

Giant pituitary adenoma (GPA) (diameter >40 mm) remains challenging to treat, and the radical resection rate is low. The intraoperative multimodal navigation is sometimes used in endoscopic endonasal surgery (EES). However, the effect of this technique on GPA surgical outcomes is not clear. This study aims to explore the surgical and clinical outcomes of the navigation used in EES for GPA.

Methods

A retrospective review of 60 consecutive patients with GPA who underwent EES was performed. The total resection rate, residual volume, clinical outcomes, and complications were compared. Factors associated with tumor gross total resection (GTR) were analyzed by multinomial logistic regression analysis.

Results

There were 31 patients in the standard group in which intraoperative multimodal navigation was not used, with a mean maximum tumor diameter of 5.21±1.24 cm; meanwhile, there were 29 patients in the navigation group, in which navigation was used, with a mean maximum tumor diameter of 5.32±1.18 cm. GTR was achieved in 10 patients (32.26%) in the standard group, which was significantly lower than that in the navigation group (18/29=62.07%). The residual volume was 7.93±10.78 cm³ in the standard group which was significantly greater than that in the navigation group (2.44±1.26 cm³, P=0.046). There was no significant difference between the two groups in terms of cerebrospinal fluid (CSF) leak, new pituitary deficit, and postoperative diabetes insipidus (DI). The higher Knosp grade of tumor, lobulated configuration and lack of intraoperative multimodal navigation use were relative risk factors associated with the GTR.

Conclusions

The intraoperative multimode navigation appeared to be safe and effective when used in EES for GPA with higher GTR and lower residual tumor volume.

Management of Giant Pituitary Adenomas: Role and Outcome of the Endoscopic Endonasal Surgical Approach

Giant adenomas represent a significant surgical challenge. Although traditionally several transcranial and transsphenoidal microscopic approaches have had a central role in their management, in the last 2 decades here have been increasing reports of the endoscopic endonasal approach for giant adenomas, citing its improved resection rates and lower complication profile. However, its role as the preferred approach has not been fully established and there is currently a paucity of evidence-based recommendations available in the literature. This article reviews the current literature and attempts to define the role and outcomes of the endoscopic endonasal surgical approach for giant pituitary adenomas.

Evaluation of Surgical Resection Goal and Its Relationship to Extent of Resection and Patient Outcomes in a Multicenter Prospective Study of Patients With Surgically Treated, Nonfunctioning Pituitary Adenomas: A Case Series

BACKGROUND

The influence of the surgeon's preoperative goal regarding the extent of tumor resection on patient outcomes has not been carefully studied among patients with nonfunctioning pituitary adenomas.

OBJECTIVE

To analyze the relationship between surgical tumor removal goal and patient outcomes in a prospective multicenter study.

METHODS

Centrally adjudicated extent of tumor resection (gross total resection [GTR] and subtotal resection [STR]) data were analyzed using standard univariate and multivariable analyses.

RESULTS

GTR was accomplished in 148 of 171 (86.5%) patients with planned GTR and 32 of 50 (64.0%) patients with planned STR (P = .001). Sensitivity, specificity, positive predictive value, and negative predictive value of GTR goal were 82.2, 43.9, 86.5, and 36.0%, respectively. Knosp grade 0-2, first surgery, and being an experienced surgeon were associated with surgeons choosing GTR as the goal (P &lt; .01). There was no association between surgical goal and presence of pituitary deficiency at 6 mo (P = .31). Tumor Knosp grade (P = .004) and size (P = .001) were stronger predictors of GTR than was surgical goal (P = .014). The most common site of residual tumor was the cavernous sinus (29 of 41 patients; 70.1%).

CONCLUSION

This is the first pituitary surgery study to examine surgical goal regarding extent of tumor resection and associated patient outcomes. Surgical goal is a poor predictor of actual tumor resection. A more aggressive surgical goal does not correlate with pituitary gland dysfunction. A better understanding of the ability of surgeons to meet their expectations and of the factors associated with surgical result should improve prognostication and preoperative counseling.

Predicting extent of resection in transsphenoidal surgery for pituitary adenoma

BACKGROUND

The extent of resection (EOR) is a crucial outcome parameter in transsphenoidal pituitary surgery (TSS), and is linked to endocrinological outcome, postoperative morbidity, and mortality. We aimed to build a robust, quantitative, and easily reproducible imaging score able to predict EOR in TSS.

METHODS

The ratio (R) between the maximum horizontal adenoma diameter and intercarotid distance at the horizontal C4 segment was used to stratify our patient series in four classes: class I R ≤ 0.75, class II 0.75 < R ≤ 1.25, and class III R ≥ 1.25. Class IV included adenomas which completely encased the internal carotid artery. The resulting score was internally validated for robustness.

RESULTS

One hundred sixteen patients were included in the study, of which 96 (83%) for derivation and 20 (17%) for validation. EOR showed significant differences between grades (grade I, 100%; II, 97.9%; III, 94.2%; IV, 87.2%; all P < 0.05). The same applied to residual volume (RV) (grade I, 0 cm³; II, 0.08 cm³; III, 1.11 cm³; IV, 1.63 cm³; all P < 0.05). Differences in gross total resection (GTR) were statistically significant among classes I, II, and III (P < 0.05). The incidence of residual adenoma in the cavernous sinus increased also constantly from grade I up to grade IV although a significant difference was only found between grades III and II (P = 0.004). The score performed equally well in the validation cohort. Inter-observer agreement was high, with intraclass correlation coefficients > 0.89 for measurement of both the horizontal tumor diameter and the ICD among two independent raters (P < 0.001).

CONCLUSIONS

The proposed score is a simple and reproducible tool which reliably predicts surgical outcome including EOR, RV, and GTR of pituitary adenoma patients undergoing TSS.

Giant pituitary adenoma: histological types, clinical features and therapeutic approaches

Giant pituitary adenomas comprise about 6-10% of all pituitary tumors. They are mostly clinically non-functioning adenomas and occur predominantly in males. The presenting symptoms are usually secondary to compression of neighboring structures, but also due to partial or total hypopituitarism. Functioning adenomas give rise to specific symptoms of hormonal hypersecretion. The use of dopamine agonists is considered a first-line treatment in patients with giant macroprolactinomas. Somatostatin analogs can also be used as primary treatment in cases of growth hormone and thyrotropin producing giant adenomas, although remission of the disease is not achieved in the vast majority of these patients. Neurosurgical treatment, either through transsphenoidal or transcranial surgery, continues to be the treatment of choice in the majority of patients with giant pituitary adenomas. The intrinsic complexity of these tumors requires the use of different therapies in a combined or sequential way. A multimodal approach and a therapeutic strategy involving a multidisciplinary team of expert professionals form the basis of the therapeutic success in these patients.