Current perspectives on recurrent pituitary adenoma: The role and timing of surgery vs adjuvant treatment

Patients at Greatest Risk of Missing Initial 1-Year Follow-Up After Pituitary Adenoma Resection

OBJECTIVE

Routine evaluation and surveillance imaging after pituitary adenoma (PA) endoscopic endonasal transsphenoidal resection (EETS) is a neurosurgical practice to identify tumor recurrence. This study aims to identify social and clinical factors that may contribute to patients missing their initial 1-year follow-up appointment and provide guidance for targeted education to improve patient adherence with postoperative treatment plans, ultimately reducing unknown adenoma recurrence.

METHODS

The authors performed a single-center retrospective review of patients who underwent EETS for PAs from 2007 to 2023. Patients were analyzed for sociodemographic factors, presenting symptoms, time to surgery, surgical outcomes, and adherence to postoperative follow-up visits at 1 year after surgery.

RESULTS

A total of 256 patients with PAs treated by EETS met inclusion criteria; 218 (85%) of these patients attended 1-year follow-up, and 38 (15%) missed this visit. Twenty-nine (76%) individuals who missed their 1-year follow up were men (P = 0.006). Divorced/widowed/separated patients were 2 times more likely to miss their follow-up compared with their married counterparts (P = 0.008). Additional significant risk factors included older age, as the mean age for patients who missed their 1-year appointment was 60.1 years compared with 54.7 years (P = 0.028). Patients with visual field deficits at initial presentation were also less likely to follow-up at 1 year (P = 0.03).

CONCLUSIONS

Risk factors of missed 1-year follow-up appointments after PA resection include male sex, divorced/widowed/separated marital status, older age, and the presence of visual deficits at initial presentation. Increased education efforts can be selectively aimed at these at-risk patient cohorts to improve patient compliance and reduce consequences of undetected tumor recurrence.

Development and prospective validation of an artificial intelligence-based smartphone app for rapid intraoperative pituitary adenoma identification

BACKGROUND

Intraoperative pathology consultation plays a crucial role in tumor surgery. The ability to accurately and rapidly distinguish tumor from normal tissue can greatly impact intraoperative surgical oncology management. However, this is dependent on the availability of a specialized pathologist for a reliable diagnosis. We developed and prospectively validated an artificial intelligence-based smartphone app capable of differentiating between pituitary adenoma and normal pituitary gland using stimulated Raman histology, almost instantly.

METHODS

The study consisted of three parts. After data collection (part 1) and development of a deep learning-based smartphone app (part 2), we conducted a prospective study that included 40 consecutive patients with 194 samples to evaluate the app in real-time in a surgical setting (part 3). The smartphone app's sensitivity, specificity, positive predictive value, and negative predictive value were evaluated by comparing the diagnosis rendered by the app to the ground-truth diagnosis set by a neuropathologist.

RESULTS

The app exhibits a sensitivity of 96.1% (95% CI: 89.9-99.0%), specificity of 92.7% (95% CI: 74-99.3%), positive predictive value of 98% (95% CI: 92.2-99.8%), and negative predictive value of 86.4% (95% CI: 66.2-96.8%). An external validation of the smartphone app on 40 different adenoma tumors and a total of 191 scanned SRH specimens from a public database shows a sensitivity of 93.7% (95% CI: 89.3-96.7%).

CONCLUSIONS

The app can be readily expanded and repurposed to work on different types of tumors and optical images. Rapid recognition of normal versus tumor tissue during surgery may contribute to improved intraoperative surgical management and oncologic outcomes. In addition to the accelerated pathological assessments during surgery, this platform can be of great benefit in community hospitals and developing countries, where immediate access to a specialized pathologist during surgery is limited.

Comparison of Cardiac Indices Using Two Different Concentrations of Topical Adrenaline during Endoscopic Transsphenoidal Pituitary Surgery: A Prospective Randomized Observational Study

Introduction  Adrenaline-soaked wicks are often employed to decongest nasal mucosa during transsphenoidal pituitary surgeries to ensure proper hemostasis and visibility of the operating field. Considerable debate exists regarding the optimum concentration of adrenaline that strikes a balance between hemostasis as well as the hemodynamic side effects of adrenaline. This study assessed cardiac indices like cardiac output and cardiac index using a FloTrac Vigileo cardiac output monitor to compare two different concentrations of adrenaline used for topical instillation. Materials and Methods  60 adult patients undergoing transsphenoidal pituitary surgery were randomly assigned to receive cotton wicks soaked in adrenaline solution (either 1:100,000 or 1:200,000) for nasal decongestion. Following a standardized anesthetic regime, a FloTrac Vigileo cardiac output monitor was attached with the invasive arterial line for precise monitoring and recording of cardiac indices (cardiac output and cardiac index). Additionally, quality of surgical field (as reported by the operating surgeon) blood loss, incidences of adverse hemodynamic events, and rescue drug usage were recorded. Results  No difference in cardiac outputs and cardiac indexes of the patients was observed during baseline to 55 minutes and at 80 minutes and onward, whereas difference rose to statistical significance at the time points of 60 minutes and 70 minutes ( p  < 0.05). Other parameters like stroke volume, stroke volume variation, and hemodynamic parameters were similar. Quality of the surgical fields (as reported by the surgeon), intraoperative bleeding, incidences of adverse effects, and frequency of rescue drugs usage were similar. Conclusion  Instillation of 1:100,000 dilution of adrenaline solution compared with 1:200,000 for nasal decongestion is associated with significant rise in cardiac output and cardiac index at 60 and 70 minutes of the surgery with similar blood loss and hemodynamic variables. Therefore, the lower concentration of adrenaline can be recommended for usage during transsphenoidal pituitary surgeries.

Advances in surgical approaches for refractory pituitary adenomas

Refractory pituitary adenomas are difficult to control tumors that progress through optimal surgical, medical, and radiation management. Repeat surgery is a valuable tool to reduce tumor volume for more effective radiation and/or medical therapy, and to decompress critical neurovascular structures. Advances in surgical techniques and technologies, including minimally invasive cranial approaches, intraoperative MRI suites, and cranial nerve monitoring, have improved surgical outcomes and expanded indications. Today, repeat transsphenoidal surgery has similar complications rates to upfront surgery in historical cohorts. The decision to operate on refractory adenomas should be made with multidisciplinary teams, balancing the benefit of tumor reduction with the potential for complications, including cranial nerve injury, carotid injury, and cerebrospinal fluid leak.

Macrophage colony-stimulating factor potentially induces recruitment and maturation of macrophages in recurrent pituitary neuroendocrine tumors

Although pituitary neuroendocrine tumors (PitNETs) are usually benign, some are highly invasive and recurrent. Recurrent PitNETs are often treatment-resistant and there is currently no effective evidence-based treatment. Tumor-associated macrophages (TAMs) promote tumor growth in many cancers, but the effect of TAMs on PitNETs remains unclear. This study investigated the role of TAMs in the incidence of recurrent PitNETs. Immunohistochemical analysis revealed that the densities of CD163- and CD204-positive TAMs tended to increase in recurrent PitNETs. Compared with TAMs in primary lesions, those in recurrent lesions were enlarged. To clarify the cell-cell interactions between TAMs and PitNETs, in vitro experiments were performed using a mouse PitNET cell line AtT20 and the mouse macrophage cell line J774. Several cytokines related to macrophage chemotaxis and differentiation, such as M-CSF, were elevated significantly by stimulation with macrophage conditioned medium. When M-CSF immunohistochemistry analysis was performed using human PitNET samples, M-CSF expression increased significantly in recurrent lesions compared with primary lesions. Although no M-CSF receptor (M-CSFR) expression was observed in tumor cells of primary and recurrent PitNETs, flow cytometric analysis revealed that the mouse PitNET cell line expressed M-CSFR. Cellular proliferation in mouse PitNETs was inhibited by high concentrations of M-CSFR inhibitors, suggesting that cell-to-cell communication between PitNETs and macrophages induces M-CSF expression, which in turn enhances TAM chemotaxis and maturation in the tumor microenvironment. Blocking the M-CSFR signaling pathway might be a novel therapeutic adjuvant in treating recurrent PitNETs.

Pre-Surgery Patient Health Contributes to Aggravated Sino-Nasal Outcome and Quality of Life after Pituitary Adenomectomy

Objectives: The transphenoidal bi-nostril endoscopic resection of pituitary adenomas is regarded as a minimally invasive treatment nowadays. However, sino-nasal outcome and health-related quality of life (HRQoL) might still be impaired after the adenomectomy, depending on patients' prior medical history and health status. A systematic postoperative comparison is required to assess differences in perceived sino-nasal outcome and HRQoL. Methods: In this single-center observational study, we collected data from 81 patients, operated between August 2016 and August 2021, at a 3-6-month follow-up after adenomectomy. We employed the sino-nasal outcome test for neurosurgery (SNOT-NC) and the HRQoL inventory Short Form (SF)-36 to compare sino-nasal and HRQoL outcome in patients with or without allergies, previous nose surgeries, presence of pain, snoring, sleep apnea, usage of continuous positive airway pressure (cpap), and nose drop usage. Results: At the 3-6-month follow-up, patients with previous nasal surgery showed overall reduced subjective sino-nasal health, increased nasal and ear/head discomfort, increased visual impairment, and decreased psychological HRQoL (all p ≤ 0.026) after pituitary adenomectomy. Patients with pain before surgery showed a trend-level aggravated physical HRQoL (p = 0.084). Conclusion: Our data show that patients with previous nasal surgery have an increased risk of an aggravated sino-nasal and HRQoL outcome after pituitary adenomectomy. These patients should be thoroughly informed about potential consequences to induce realistic patient expectations. Moreover, the study shows that patients with moderately severe allergies, snoring, and sleep apnea (± cpap) usually do not have to expect a worsened sino-nasal health and HRQoL outcome.

Radiation Therapy for Recurrent or Residual Pituitary Macroadenoma Invading Extrasellar Structures

PURPOSE

This study aimed to evaluate the efficacy of radiation therapy (RT) for recurrent or residual pituitary macroadenoma (PMA) invading extrasellar regions.

MATERIALS AND METHODS

Patients from 2000 to 2020 who received RT with conventional fractionation for recurrent or residual PMA were included. The patients were divided according to the type of tumor [functioning (fx) or non-fx] and the aim of RT (salvage RT alone, immediate postoperative RT, delayed postoperative RT). Local and biochemical failure-free rates (FFR) were calculated using the Kaplan-Meier method.

RESULTS

With a median follow up of 82 months (IQR; 42-132 months), 36 patients treated with conventional RT (total 45-54 Gy in 1.8 or 2 Gy per fraction) for recurrent or residual PMA were analyzed. The 10-year local FFRs after RT for non-fx and fx tumor were 100% and 74.4%, respectively (p=0.047). In the immediate postoperative RT group, the 10-year local FFR was 100%, which was higher than the 90% FFR for salvage RT alone or 80% FFR for the delayed postoperative RT group (overall p=0.043, immediate vs. salvage; p=0.312, immediate vs. delayed; p=0.072). The local FFR was compared according to size of tumor with a cut-off value of 4 cm, and there was no significant difference (10-year local FFR 100% vs. 84.7% for >4 cm vs. <4 cm, p=0.320). The extents of extrasellar region invasion were not predictive of local failure after RT. We found no grade ≥3 acute toxicities or newly developed visual impairments as a late toxicity of RT.

CONCLUSION

Conventional RT is safe and effective for the local control of recurrent or residual PMA. Our data suggest that immediate postoperative RT can be beneficial in recurrent or residual PMA, although further studies to evaluate risk factors of treatment failure in terms of treatment and disease characteristics are required.

Chemotherapy of Capecitabine plus Temozolomide for Refractory Pituitary Adenoma after Tumor Resection and Its Impact on Serum Prolactin, IGF-1, and Growth Hormone

Objective

To investigate the efficiency of capecitabine (CAP) plus temozolomide (TEM) in refractory pituitary adenoma after tumor resection and its impact on serum prolactin (PRL), insulin-like growth factor 1 (IGF-1), and growth hormone (GH) levels.

Methods

From January 2017 to January 2020, 80 patients assessed for eligibility receiving transsphenoidal tumor resection for refractory pituitary adenoma in the Department of Neurosurgery of our hospital were recruited. They were randomly distributed at a ratio of 1 : 1 via the random number table method to receive either bromocriptine and TEM (control group) or bromocriptine plus combination chemotherapy of TEM and CAP (study group). The two groups were compared in terms of clinical efficacy and serum levels of PRL, IGF-1, and GH.

Results

The objective response rate (ORR) was 87.50% and 67.50% in the study group and the control group, respectively (P=0.032). Before treatment, two groups had similar levels of PRL, IGF-1, and GH. After treatment, PRL levels in the study group were lower than that in the control group (278.35 ± 39.25 versus 326.35 ± 42.45, P < 0.001). Compared with the control group, IGF-1 levels in the study group were also lower (311.78 ± 28.82 versus 364.35 ± 31.35, P < 0.001). The study group presented markedly lower levels of thyroid-stimulating hormone (TSH) and higher serum levels of free thyroxine-4 (FT-4) and adrenocorticotropic hormone (ACTH) versus the control group (P < 0.05). The incidence of adverse events was comparable between the study group (30.0%) and the control group (22.5%) (P > 0.05). All eligible patients had similar progression-free survival (PFS) after chemotherapy.

Conclusion

For patients with refractory pituitary adenoma, the combination chemotherapy of CAP and TEM significantly improves clinical outcomes and corrects hormonal disturbances, with a good safety profile, but its long-term efficacy requires further investigation.

A Preoperative MRI-Based Radiomics-Clinicopathological Classifier to Predict the Recurrence of Pituitary Macroadenoma Within 5 Years

Objective: To investigate the ability of a MRI-based radiomics-clinicopathological model to predict pituitary macroadenoma (PMA) recurrence within 5 years.

Materials and Methods: We recruited 74 recurrent and 94 non-recurrent subjects, following first surgery with 5-year follow-up data. Univariate and multivariate analyses were conducted to identify independent clinicopathological risk factors. Two independent and blinded neuroradiologists used 3D-Slicer software to manually delineate whole tumors using preoperative axial contrast-enhanced T1WI (CE-T1WI) images. 3D-Slicer was then used to extract radiomics features from segmented tumors. Dimensionality reduction was carried out by the least absolute shrinkage and selection operator (LASSO). Two multilayer perceptron (MLP) models were established, including independent clinicopathological risk factors (Model 1) and a combination of screened radiomics features and independent clinicopathological markers (Model 2). The predictive performance of these models was evaluated by receiver operator characteristic (ROC) curve analysis.

Results: In total, 1,130 features were identified, and 4 of these were selected by LASSO. In the test set, the area under the curve (AUC) of Model 2 was superior to Model 1 {0.783, [95% confidence interval (CI): 0.718—.860] vs. 0.739, (95% CI: 0.665–0.818)}. Model 2 also yielded the higher accuracy (0.808 vs. 0.692), sensitivity (0.826 vs. 0.652), and specificity (0.793 vs. 0.724) than Model 1.

Conclusions: The integrated classifier was superior to a clinical classifier and may facilitate the prediction of individualized prognosis and therapy.

Surgical Outcome and Evaluation of Strategies in the Management of Growth Hormone-Secreting Pituitary Adenomas After Initial Transsphenoidal Pituitary Adenectomy Failure

Acromegaly is a systemic disease that requires multidisciplinary treatment to achieve the best clinical outcome. This study aimed to evaluate the outcomes of the endoscopic transsphenoidal approach (TSA) as the primary treatment for somatotroph adenomas and further investigate patients who had suboptimal surgical results. This retrospective study included 83 patients with somatotroph adenomas treated by TSA at our institution from 1999 to 2010. Biochemical remission was defined as hGH <1 and <2.5 ng/ml. Factors associated with failure of TSA and strategy of secondary treatments for refractory and recurrent disease were analyzed. The mean age of patients was 41.1 ± 11.3 years, and the mean follow-up time was 54.2 ± 44.3 months. Approximately 44.5% of patients had residual tumors after TSA. Larger tumor size, higher GH level before the operation, and the existence of residual tumors were associated with TSA failure. Forty-one patients had an inadequate response to TSA or a recurrent lesion, and of these patients, 37 had residual tumor after TSA. Octreotide results in good outcomes in the treatment of DGSA patients, and SRS/EXRT generates good results in treating patients who receive second treatments when remission cannot be reached 6 months after TSA operation.

Predicting Subtype of Growth Hormone Pituitary Adenoma based on Magnetic Resonance Imaging Characteristics

Supplemental digital content is available in the text.

This study aimed to investigate the value of magnetic resonance (MR) characteristics in differentiating the subtypes of growth hormone pituitary adenomas.

Characteristics and overall survival in pediatric versus adult pituitary adenoma: a National Cancer Database analysis

OBJECTIVE

Pituitary adenomas in the pediatric population are extremely rare, resulting in limited information in the literature on these patients. In this study, data from the National Cancer Database (NCDB) to compare pituitary adenoma clinical presentations, treatment management patterns, and overall survival between pediatric and adult patients.

METHODS

The NCDB was queried for all cases of histologically confirmed pituitary adenoma treated between 2004 and 2015. Patients were primarily stratified as either pediatric (< 18 years) or adult (≥ 18 years). Patient demographics/socioeconomics and resulting outcomes were then compared.

RESULTS

1893 pediatric and 77,993 adult patients with pituitary adenomas were evaluated. Average tumor size for pediatric and adult patients was 13.6 ± 13.2 mm and 20.1 ± 13.1 mm, respectively (p < 0.001). Pediatric patients were more likely to undergo gross total resection, less likely to receive adjuvant radiation, more likely to receive medical therapy, more likely to undergo active surveillance, and exhibited improved 5-year and 10-year overall survival (OS) (all p < 0.001). Temporal analysis demonstrated a significant increase in endoscopic approach over time (from 48 to 65%) in the pediatric population (R² = 0.722, p = 0.03). On univariate analysis in the pediatric population, African American race compared to Caucasians (HR: 5.85, 95% CI 1.79-19.2, p < 0.003), patients with government insurance compared to those with private insurance (HR: 5.07, 95% CI 1.31-19.6, p < 0.02) and uninsured patients compared to those with private insurance (HR: 14.4, 95% CI 2.41-86.5, p < 0.003) were associated with decreased OS. Lastly, patients who underwent GTR had improved OS compared to those who underwent subtotal resection (HR: 0.08, 95% CI 0.008-0.93, p < 0.04) in the pediatric population.

CONCLUSIONS

Compared to adults, children with pituitary adenomas more commonly underwent GTR, less frequently underwent adjuvant radiotherapy, more frequently underwent medical management and active surveillance, and had improved survival. Temporal analysis demonstrated increasing utilization of the endoscopic approach for surgical treatment of pediatric and adult pituitary adenoma patients.

LEVEL OF EVIDENCE

Level III.

CircNFIX promotes progression of pituitary adenoma via CCNB1 by sponging miR-34a -5p

Previous studies have shown that CCNB1 affects the invasiveness of pituitary adenomas, and it is of great significance to find the upstream mechanism of regulating CCNB1.In this study, we explored a significantly overexpressed circRNA in invasive pituitary adenomas. Based on bioinformatics analysis and mechanism experiments, we determined that circNFIX (has-circ_0005660) affects cell invasion, migration and proliferation in pituitary adenomas by sponging miR-34a-5p through CCNB1. In pituitary adenoma tissues, the expression of circNFIX and CCNB1 was upregulated, while miR-34a-5p expression was downregulated. The silencing of circNFIX or overexpression of miR-34a-5p inhibited cell invasion, migration and proliferation. Inhibition of miR-34a-5p expression reversed the inhibitory effect of circNFIX silencing on the progression of pituitary adenoma. In conclusion, CircNFIX affects cell invasion, migration, and proliferation in pituitary adenomas by sponging miR-34a-5p through CCNB1. Therefore, circNFIX is expected to serve as a potential target for the treatment of pituitary adenomas.

The impact of endoscopic transsphenoidal pituitary adenoma surgery on endocrine function: a single-centre study

INTRODUCTION

The outcome for pituitary endocrine function following endoscopic transsphenoidal surgery remains unclear. This study aims to evaluate endocrine outcomes following endoscopic surgery in order to provide a benchmark to assist in the counselling of patients perioperatively.

METHODS

A prospectively held pituitary database was retrospectively analysed for all adult pituitary adenoma patients undergoing endoscopic surgery from May 2011 to May 2017. All operations were performed by a single neurosurgeon at a regional centre for pituitary surgery. Functioning and non-functioning adenomas were included. Hormonal status was assessed at most recent follow-up.

RESULTS

One hundred forty-five patients (69 M, 76 F) were included in the study with a median age of 52 years. Median follow-up was 52 months. Eighty-eight patients (61%) were not taking any hormone replacement medications, whilst 57 patients (39%) required hormone replacement therapy (HRT) preoperatively. Preoperatively, 29 patients (20%) had hypothalamo-pituitary-adrenal (HPA) axis dysfunction, 39 patients (27%) had thyroid axis dysfunction, 11 males (16%) and 7 females (9%) had gonadal axis dysfunction, and one patient had preoperative diabetes insipidus. Postoperatively, 26 patients (18%) had a new deficiency in pituitary function, whilst 6 patients (11%) were able to cease HRT. Nineteen patients (13%) had new HPA axis deterioration, 12 (8%) had new thyroid axis dysfunction, 8 males (11%) and 4 females (5%) had gonadal axis deterioration, and 6 patients (4%) had new diabetes insipidus (DI).

CONCLUSIONS

The ability to restore pituitary function following endoscopic surgery remains limited, whilst new deficits still occur. It is essential that patients are counselled accordingly as hormonal replacement therapy can have a significant impact on quality of life. Larger longer-term collaborative studies of endocrine outcome in endoscopic pituitary surgery are needed.

A Preoperative MRI-Based Radiomics-Clinicopathological Classifier to Predict the Recurrence of Pituitary Macroadenoma Within 5 Years

Objective: To investigate the ability of a MRI-based radiomics-clinicopathological model to predict pituitary macroadenoma (PMA) recurrence within 5 years. Materials and Methods: We recruited 74 recurrent and 94 non-recurrent subjects, following first surgery with 5-year follow-up data. Univariate and multivariate analyses were conducted to identify independent clinicopathological risk factors. Two independent and blinded neuroradiologists used 3D-Slicer software to manually delineate whole tumors using preoperative axial contrast-enhanced T1WI (CE-T1WI) images. 3D-Slicer was then used to extract radiomics features from segmented tumors. Dimensionality reduction was carried out by the least absolute shrinkage and selection operator (LASSO). Two multilayer perceptron (MLP) models were established, including independent clinicopathological risk factors (Model 1) and a combination of screened radiomics features and independent clinicopathological markers (Model 2). The predictive performance of these models was evaluated by receiver operator characteristic (ROC) curve analysis. Results: In total, 1,130 features were identified, and 4 of these were selected by LASSO. In the test set, the area under the curve (AUC) of Model 2 was superior to Model 1 {0.783, [95% confidence interval (CI): 0.718-.860] vs. 0.739, (95% CI: 0.665-0.818)}. Model 2 also yielded the higher accuracy (0.808 vs. 0.692), sensitivity (0.826 vs. 0.652), and specificity (0.793 vs. 0.724) than Model 1. Conclusions: The integrated classifier was superior to a clinical classifier and may facilitate the prediction of individualized prognosis and therapy.

Nelson Syndrome: Clival Invasion of Corticotroph Pituitary Adenoma Resulting in Alternating Sixth Nerve Palsies

ABSTRACT

A 44-year-old woman presented with 2 painful and self-limited episodes of binocular horizontal diplopia within 1 year that at the beginning were thought to be secondary to microvascular insult. Her medical history was significant for Cushing syndrome status post transsphenoidal resection with bilateral adrenalectomy 4 years prior, hypertension, and diabetes mellitus. Neuro-ophthalmic evaluation was significant for left abduction deficit and incomitant esotropia consistent with left abducens nerve palsy. Of note, the patient had experienced a similar episode but on the contralateral side a few months prior. Although initially MRI of the brain demonstrated stable residual postoperative finding in the sella, upon review, an heterogenous T-1 hypointense marrow in the clivus was noted. Hypermetabolism of the clivus was also noted on computed tomography positron emission tomography of the skull base. A clival biopsy demonstrated a corticotroph adenoma with elevated proliferation index and scattered mitoses. A corticotroph pituitary adenoma after adrenalectomy, also known as Nelson syndrome, was diagnosed. Radiation therapy was offered to the patient, and resolution of symptoms was gradually observed.

Analysis of Cyclooxygenase 2, Programmed Cell Death Ligand 1, and Arginase 1 Expression in Human Pituitary Adenoma

BACKGROUND

Cyclooxygenase 2 (COX-2) is a key enzyme in the synthesis of prostaglandins. Recent studies have shown that overexpression of COX-2 can reduce the antitumor effect of the immune system by inhibiting the proliferation of B and T lymphocytes. Programmed cell death ligand 1 (PD-L1) was the first functionally characterized ligand of programmed cell death protein 1. It plays an important role in maintaining peripheral and central immune tolerance by combining with programmed cell death protein 1. Arginase 1 (ARG1) can process L-arginine in the local microenvironment and affect the function of T cells, resulting in immune escape. In this study, COX-2, PD-L1, and ARG1 expression in human pituitary adenoma (PA) and their relationship were investigated, which provided an initial theoretic basis for further study of the immune escape mechanism in PA in cellular and animal experiments.

METHODS

The protein expression of COX-2, PD-L1, and ARG1 in 55 PA samples was detected by immunohistochemistry, with 10 normal brain tissues as the control group. The location of COX-2, PD-L1, and ARG1 in PA cells was studied by double immunofluorescence colocalization. The results of immunohistochemistry were further verified by Western blot.

RESULTS

The expression of COX-2, PD-L1, and ARG1 in PA was significantly higher than that in normal brain tissue. In functional PA (FPA) and nonfunctional PA (NFPA), there was no significant difference in the expression of COX-2 and PD-L1, whereas ARG1 was higher in NFPA. Moreover, the protein expression level of COX-2 was positively correlated with that of PD-L1 and ARG1, and the expression of PD-L1 was positively correlated with that of ARG1. Immunofluorescence confocal imaging showed that COX-2, PD-L1, and ARG1 were all expressed in the cytoplasm of PA cells, and the physical positions of COX-2, PD-L1, and ARG1 were partially coincident.

CONCLUSIONS

These findings indicate that overexpression of COX-2, PD-L1, and ARG1 may be involved in the pathogenesis of PA. ARG1 plays a more important role in the development of NFPA. By upregulating the expression of PD-L1, COX-2 may promote the expression of ARG1, forming the COX-2/PD-L1/ARG1 signal pathway in promoting the occurrence and development of PA. Perhaps further study of the pathogenesis of PA can start with the mechanism of immune escape.

Stereotactic reirradiation with temozolomide in patients with recurrent aggressive pituitary tumors and pituitary carcinomas

OBJECTIVES

To evaluate the efficacy of a second course of fractionated stereotactic radiotherapy (re-SRT) and temozolomide (TMZ) as salvage treatment option in patients with aggressive pituitary tumors (APTs) and pituitary carcinomas (PCs).

PATIENTS AND METHODS

Twenty-one patients with recurrent or progressive APTs (n = 17) and PCs (n = 4) who received combined TMZ and re-SRT, 36 Gy/18fractions or 37.5 Gy/15fractions, were retrospectively evaluated. TMZ was given at a dose of 75 mg/m² given concurrently to re-SRT, and then 150-200 mg/m²/day for 5 days every 4 weeks or 50 mg/m² daily for 12 months. Local control (LC) and overall survival (OS) were calculated from the time of re-SRT by Kaplan-Meier method.

RESULTS

With a median follow-up of 27 months (range 12-58 months), 2-year and 4-year LC rates were 73% and 65%, respectively; 2-year and 4-year survival rates were 82% and 66%, respectively. A complete response was achieved in 2 and partial response in 11 patients. Six patients recurred with a median time to progression of 14 months. O(6)-Methylguanine-DNA methyltransferase (MGMT) status and tumor volume emerged as prognostic factors. Grade 3 radiation-related toxicities occurred in 3 (14%) patients. Grade 2 or 3 hematologic toxicities during chemotherapy occurred in 8 (38%) patients.

CONCLUSION

Re-SRT and TMZ is a safe treatment offering high LC in patients with progressive APTs and PCs. The potential advantages of combined chemoradiation as up-front or salvage treatment need to be explored in prospective trials.