Metastatic pheochromocytoma and paraganglioma: focus on therapeutics

CT-based radiomics research for discriminating the risk stratification of pheochromocytoma using different machine learning models: a multi-center study

OBJECTIVES

The purpose of this study was to explore and verify the value of various machine learning models in preoperative risk stratification of pheochromocytoma.

METHODS

A total of 155 patients diagnosed with pheochromocytoma through surgical pathology were included in this research (training cohort: n = 105; test cohort: n = 50); the risk stratification scoring system classified a PASS score of < 4 as low risk and a PASS score of ≥ 4 as high risk. From CT images captured during the non-enhanced, arterial, and portal venous phase, radiomic features were extracted. After reducing dimensions and selecting features, Logistic Regression (LR), Extra Trees, and K-Nearest Neighbor (KNN) were utilized to construct the radiomics models. By adopting ROC curve analysis, the optimal radiomics model was selected. Univariate and multivariate logistic regression analyses of clinical radiological features were used to determine the variables and establish a clinical model. The integration of radiomics and clinical features resulted in the creation of a combined model. ROC curve analysis was used to evaluate the performance of the model, while decision curve analysis (DCA) was employed to assess its clinical value.

RESULTS

3591 radiomics features were extracted from the region of interest in unenhanced and dual-phase (arterial and portal venous phase) CT images. 13 radiomics features were deemed to be valuable. The LR model demonstrated the highest prediction efficiency and robustness among the tested radiomics models, with an AUC of 0.877 in the training cohort and 0.857 in the test cohort. Ultimately, the composite of clinical features was utilized to formulate the clinical model. The combined model demonstrated the best discriminative ability (AUC, training cohort: 0.887; test cohort: 0.874). The DCA of the combined model showed the best clinical efficacy.

CONCLUSION

The combined model integrating radiomics and clinical features had an outstanding performance in differentiating the risk of pheochromocytoma and could offer a non-intrusive and effective approach for making clinical decisions.

Malignant carotid body tumors: What we know, what we do, and what we need to achieve. A systematic review of the literature

Malignant carotid body tumors (MCBT) are rare and diagnosed after detection of nodal or distant metastases. This systematic review (SR) focuses on MCBT initially approached by surgery. Preferred Reporting Items for SR and Meta-Analysis (MA) guided the articles search from 2000 to 2023 on PubMed, Scopus, and Web of Science. Among 3548 papers, 132 (337 patients) were considered for SR; of these, 20 (158 patients) for MA. Malignancy rate was 7.3%, succinate dehydrogenase (SDH) mutation 17%, age at diagnosis between 4th and 6th decades, with a higher prevalence of females. MCBTs were mostly Shamblin III, with nodal and distant metastasis in 79.7% and 44.7%, respectively. Malignancy should be suspected if CBT >4 cm, Shamblin III, painful or otherwise symptomatic, at the extremes of age, bilateral, with multifocal disease, and SDHx mutations. Levels II-III clearance should be performed to exclude nodal metastases and adjuvant treatments considered on a case-by-case basis.

[18F]FDOPA PET/CT is superior to [68Ga]DOTATOC PET/CT in diagnostic imaging of pheochromocytoma

BACKGROUND

Both [18F]FDOPA (FDOPA) and [68Ga]DOTATOC PET/CT (DOTATOC) are widely used for detection of pheochromocytomas/paraganglioma (PPGL). However, direct comparisons of the performance of the two tracers are only available in small series. We conducted a retrospective comparative analysis of FDOPA and DOTATOC to assess their sensitivity and accuracy in detecting PPGL when administered based on suspicion of PPGL. We consecutively included patients referred on suspicion of PPGL or PPGL recurrence who were scanned with both FDOPA and DOTATOC. Both scans were reviewed retrospectively by two experienced observers, who were blinded to the final diagnosis. The assessment was made both visually and quantitatively. The final diagnosis was primarily based on pathology.

RESULTS

In total, 113 patients were included (97 suspected of primary PPGL and 16 suspected of recurrence). Of the 97 patients, 51 had pheochromocytomas (PCC) (in total 55 lesions) and 6 had paragangliomas (PGL) (in total 7 lesions). FDOPA detected and correctly localized all 55 PCC, while DOTATOC only detected 25 (sensitivity 100% vs. 49%, p < 0.0001; specificity 95% vs. 98%, p = 1.00). The negative predictive value (100% vs. 63%, p < 0.001) and diagnostic accuracy (98% vs. 70%, p < 0.01) were higher for FDOPA compared to DOTATOC. FDOPA identified 6 of 6 patients with hormone producing PGL, of which one was negative on DOTATOC. Diagnostic performances of FDOPA and DOTATOC were similar in the 16 patients with previous PPGL suspected of recurrence.

CONCLUSIONS

FDOPA is superior to DOTATOC for localization of PCC. In contrast to DOTATOC, FDOPA also identified all PGL but with a limited number of patient cases.

Expression of endocan and vascular endothelial growth factor and their correlation with histopathological prognostic parameters in pheochromocytoma

OBJECTIVE

Endocan and vascular endothelial growth factor (VEGF) are markers expressed in various cancer types that are highly vascular, and they have prognostic significance for these cancers. In this study, we aimed to show the expression of endocan and VEGF in pheochromocytoma tumor tissues and to evaluate their correlations with histopathological parameters.

MATERIAL AND METHODS

Thirty-eight patients who had been operated for pheochromocytoma were included in the study. As the control group, 28 subjects whose specimens contained normal adrenal medulla tissue were included. The formalin-fixed paraffin-embedded specimens of pheochromocytoma patients were evaluated for Pheochromocytoma of the Adrenal gland Scaled Score (PASS). Sections were then stained for immunohistochemical analysis. The degree of endocan and VEGF positivity was determined by the proportion of stained cells on a negative to strong scale.

RESULTS

Endocan (p < 0.001) and VEGF (p = 0.004) expressions were found to be significantly higher in the pheochromocytoma group than in the control group. In the pheochromocytoma group, total PASS score (r = 0.714; p < 0.001) and most of the PASS score components were positively correlated with the level of endocan expression. Median Ki-67 index (p = 0.010), total PASS score (p < 0.001), tumor cell spindling (p = 0.048), and nuclear pleomorphism (p = 0.030) were higher in pheochromocytoma with VEGF expression than in those without.

CONCLUSION

If our findings are supported by studies with a larger sample size, we think that endocan has the potential to be used both as a tumor marker and in predicting malignancy potential in patients with pheochromocytoma, and that the detection of VEGF expression in these tumors is also associated with an increase in malignancy potential.

Multimodality Imaging Appearance of Intrapericardial Paragangliomas

Paragangliomas are neuroendocrine tumors of the sympathetic and parasympathetic nervous system that originate from neural crest cells. Less than 1% of paragangliomas are found in the heart, originating from intrinsic cardiac ganglia cells in the posterior wall the atria, atrioventricular groove, and along the root of the great vessels. A 10-year review of our institution's database identified nine patients who had documented intrapericardial paragangliomas. We describe the multimodality imaging appearance of these tumors. The most common findings include embedment and wrapping around the great vessels and atrioventricular groove within the confines of the pericardium, markedly avid heterogeneous enhancement, distinct engorged neovascularization, and in large lesions, central low attenuation areas compatible with hemorrhage, necrosis, or cystic degeneration.

Disease biomarker identification based on sample network optimization

A large amount of evidence shows that biomarkers are discriminant features related to disease development. Thus, the identification of disease biomarkers has become a basic problem in the analysis of complex diseases in the medical fields, such as disease stage judgment, disease diagnosis and treatment. Research based on networks have become one of the most popular methods. Several algorithms based on networks have been proposed to identify biomarkers, however the networks of genes or molecules ignored the similarities and associations among the samples. It is essential to further understand how to construct and optimize the networks to make the identified biomarkers more accurate. On this basis, more effective strategies can be developed to improve the performance of biomarkers identification. In this study, a multi-objective evolution algorithm based on sample similarity networks has been proposed for disease biomarker identification. Specifically, we design the sample similarity networks to extract the structural characteristic information among samples, which used to calculate the influence of the sample to each class. Besides, based on the networks and the group of biomarkers we choose in every iteration, we can divide samples into different classes by the importance for each class. Then, in the process of evolution algorithm population iteration, we develop the elite guidance strategy and fusion selection strategy to select the biomarkers which make the sample classification more accurate. The experiment results on the five gene expression datasets suggests that the algorithm we proposed is superior over some state-of-the-art disease biomarker identification methods.

Biomarker response to high-specific-activity I-131 meta-iodobenzylguanidine in pheochromocytoma/paraganglioma

The objective of this study is to present the complete biomarker response dataset from a pivotal trial evaluating the efficacy and safety of high-specific-activity I-131 meta-iodobenzylguanidine in patients with advanced pheochromocytoma or paraganglioma. Biomarker status was assessed and post-treatment responses were analyzed for catecholamines, metanephrines, and serum chromogranin A. Complete biomarker response (normalization) or partial response, defined as at least 50% reduction from baseline if above the normal range, was evaluated at specified time points over a 12-month period. These results were correlated with two other study objectives: blood pressure control and objective tumor response as per RECIST 1.0. In this open-label, single-arm study, 68 patients received at least one therapeutic dose (~18.5 GBq (~500 mCi)) of high-specific-activity I-131 meta-iodobenzylguanidine. Of the patients, 79% and 72% had tumors associated with elevated total plasma free metanephrines and serum chromogranin A levels, respectively. Best overall biomarker responses (complete or partial response) for total plasma free metanephrines and chromogranin A were observed in 69% (37/54) and 80% (39/49) of patients, respectively. The best response for individual biomarkers was observed 6-12 months following the first administration of high-specific-activity I-131 meta-iodobenzylguanidine. Biochemical tumor marker response was significantly associated with both reduction in antihypertensive medication use (correlation coefficient 0.35; P = 0.006) as well as objective tumor response (correlation coefficient 0.36; P = 0.007). Treatment with high-specific-activity I-131 meta-iodobenzylguanidine resulted in long-lasting biomarker responses in patients with advanced pheochromocytoma or paraganglioma that correlated with blood pressure control and objective response rate. ClinicalTrials.gov number: NCT00874614.

Role of imaging test with radionuclides in the diagnosis and treatment of pheochromocytomas and paragangliomas

Radionuclide imaging tests with [¹²³I] Metaiodobenzylguanidine (MIBG), [¹⁸F] -fluorodeoxyglucose, [¹⁸F]-fluorodopa, or ⁶⁸Ga-DOTA(0)-Tyr(3)-octreotate are useful for the diagnosis, staging and follow-up of pheochromocytomas (PHEOs) and paragangliomas (PGLs) (PPGLs). In addition to their ability to detect and localize the disease, they allow a better molecular characterization of the tumours, which is useful for planning targeted therapy with iodine-131 (¹³¹I) -labelled MIBG or with peptide receptor radionuclide therapy (PRRT) with [¹⁷⁷Lu]-labelled DOTATATE or other related agents in patients with metastatic disease. In this review we detail the main characteristics of the radiopharmaceuticals used in the functional study of PPGLs and the role of nuclear medicine tests for initial evaluation, staging, selection of patients for targeted molecular therapy, and radiation therapy planning. It also offers a series of practical recommendations regarding the functional imaging according to the different clinical and genetic scenarios in which PPGLs occur, and on the indications and efficacy of therapy with [¹³¹I]-MIBG and ¹⁷⁷Lu-DOTATATE.

Lim E, Challis BG, Park S, Izatt L, Carroll PV, Velusamy A, Hulse T, Whitelaw BC, Martin E, Rodger F, Maranian M, Clark GR, A. Akker S, Maher ER, Casey RT. Investigating the role of somatic sequencing platforms for phaeochromocytoma and paraganglioma in a large UK cohort

OBJECTIVES

Phaeochromocytomas and paragangliomas (PPGL) are rare neuroendocrine tumours with malignant potential and a hereditary basis in almost 40% of patients. Germline genetic testing has transformed the management of PPGL enabling stratification of surveillance approaches, earlier diagnosis and predictive testing of at-risk family members. Recent studies have identified somatic mutations in a further subset of patients, indicating that molecular drivers at either a germline or tumour level can be identified in up to 80% of PPGL cases. The aim of this study was to investigate the clinical utility of somatic sequencing in a large cohort of patients with PPGL in the United Kingdom.

DESIGN AND PATIENTS

Prospectively collected matched germline and tumour samples (development cohort) and retrospectively collected tumour samples (validation cohort) of patients with PPGL were investigated.

MEASUREMENTS

Clinical characteristics of patients were assessed and tumour and germline DNA was analysed using a next-generation sequencing strategy. A screen for variants within 'mutation hotspots' in 68 human cancer genes was performed.

RESULTS

Of 141 included patients, 45 (32%) had a germline mutation. In 37 (26%) patients one or more driver somatic variants were identified including 26 likely pathogenic or pathogenic variants and 19 variants of uncertain significance. Pathogenic somatic variants, observed in 25 (18%) patients, were most commonly identified in the VHL, NF1, HRAS and RET genes. Pathogenic somatic variants were almost exclusively identified in patients without a germline mutation (all but one), suggesting that somatic sequencing is likely to be most informative for those patients with negative germline genetic test results.

CONCLUSIONS

Somatic sequencing may further stratify surveillance approaches for patients without a germline genetic driver and may also inform targeted therapeutic strategies for patients with metastatic disease.

Multimodality imaging appearance of intrapericardial paragangliomas

Paragangliomas are neuroendocrine tumours of the sympathetic and parasympathetic nervous systems originating from neural crest cells. Less than 1% of paragangliomas in the heart originate from intrinsic cardiac ganglia cells in the posterior wall of the atria, atrioventricular groove, and along the root of the great vessels. We describe the tumour characteristics, patient demographics, presentation, means of diagnosis, pathology correlation, management, and outcome in 11 patients with intrapericardial paragangliomas. To the authors' knowledge, this is the largest case series reported, with emphasis on multimodality imaging findings.

Postoperative Recurrences in Patients Operated for Pheochromocytomas and Paragangliomas: New Data Supporting Lifelong Surveillance

Simple Summary

At least 10% of pheochromocytomas (PHEOs) and paragangliomas (PPGLs) may recur after the initial surgery. The optimal follow-up time for these tumors remains unknown. We present a cohort of recurrent PPGLs in a clinical care setting of a quaternary center. In this paper, we describe recurrence patterns based on tumor location (head and neck paragangliomas, thoracoabdominal paragangliomas, and pheochromocytomas). We report that the overall mean delay of recurrence was 9.7 years and that one-third of the cohort had a recurrence more than 10 years after the initial surgery. Additionally, 17.6% of recurrent PHEOs were smaller than the predicted cutoff for recurrence (5 cm). Finally, more than 50% of recurrent PPGLs harbored a germline mutation in a susceptibility gene. In sum, this paper supports that overall, the safest option remains a lifelong follow-up.

Abstract

At least 10% of pheochromocytomas (PHEOs) and paragangliomas (PGLs) (PPGLs) may recur after the initial surgery. Guidelines recommend annual screening for recurrence in non-metastatic tumors for at least 10 years after the initial surgical resection and lifelong screening in high-risk patients. However, recent data suggest that a shorter follow-up might be appropriate. We performed a retrospective analysis on patients with PPGLs who had local and/or metastatic recurrences between 1995 and 2020 in our center. Data were available for 39 cases of recurrence (69.2% female) including 20 PHEOs (51.3%) and 19 PGLs (48.7%) (13 head and neck (HNPGL) and 6 thoracoabdominal (TAPGL)). The overall average delay of recurrence was 116.6 months (14–584 months) or 9.7 years and the median was 71 months or 5.9 years. One-third of the cohort had a recurrence more than 10 years after the initial surgery (10–48.7 years). The average tumor size at initial diagnosis was 8.2 cm for PHEOs, 2.7 cm for HNPGLs, and 9.6 cm for TAPGLs. Interestingly, 17.6% of PHEOs were under 5 cm at the initial diagnosis. Metastatic recurrence was identified in 75% of PHEOs, 15.4% of HNPGLs, and 66.7% of TAPGLs. Finally, 12/23 (52.2%) patients with recurrence who underwent genetic testing carried a germline mutation. Overall, the safest option remains a lifelong follow-up.

Metastatic pheochromocytomas and paragangliomas: where are we?

Pheochromocytomas and paragangliomas (PPGLs) can metastasize in approximately 15-20% of cases. This review discusses the available evidence on the biology and treatment of metastatic PPGLs. Chemotherapy is the first-line treatment option for this evolving and symptomatic disease. In patients with high MIBG uptake and positive PETGa-68, radiometabolic treatment may be considered. The efficacy of sunitinib has been shown in observational studies, and pembrolizumab has been evaluated in phase II clinical studies, while other agents investigated in this setting are anti-angiogenic drugs cabozantinib, dovitinib, axitinib and lenvatinib. As these agents' efficacy and safety data, alone or in combination, are scant and based on few treated patients, enrollment in clinical trials is mandatory. Future therapeutic options may be represented by DNA repair system inhibitors (such as olaparib), HIF2 inhibitors and immunotherapy.

Spinal paraganglioma presenting with raised intracranial pressure: a note on the diagnosis and post-operative management

BACKGROUND

Spinal paragangliomas are tumors of neuroendocrine origin that present with symptoms of mass effect or neurosecretion but rarely involve the central nervous system. Raised intracranial pressure and papilledema are therefore unusual presentations of a spinal paraganglioma.

METHODS

We review the case of a 54-year-old man who presented with headache and visual disturbance. Fundoscopy confirmed papilledema with normal intracranial imaging. Neuraxis imaging revealed a lumbar intradural extramedullary tumor and pathological analysis confirmed a WHO Grade I spinal paraganglioma. The tumor was resected and post operatively his vison improved with resolution of optic disc swelling.

CONCLUSIONS

Raised intracranial pressure and papilledema are unusual clinical manifestations of spinal tumors and imaging the entire neuraxis can be valuable.

Analysis of Telomere Maintenance Related Genes Reveals NOP10 as a New Metastatic-Risk Marker in Pheochromocytoma/Paraganglioma

Simple Summary

Telomere maintenance involving TERT and ATRX genes has been recently described in metastatic pheochromocytoma and paraganglioma, reinforcing the importance of immortalization mechanisms in the progression of these tumors. Thus, the aim of this study was to analyze additional telomere-related genes to uncover potential new markers capable of identifying metastatic-risk patients more accurately. After analyzing 29 telomere-related genes, we were able to validate the predictive value of TERT and ATRX in mPPGL progression. In addition, we were able to identify NOP10 as a novel prognostic risk marker of mPPGLs, which also facilitates telomerase-dependent telomere length maintenance in these tumors. Interestingly, NOP10 overexpression assessment by IHC could be easily included within the current battery of markers for stratifying PPGL patients to fine-tune their clinical diagnoses.

Abstract

One of the main problems we face with PPGL is the lack of molecular markers capable of predicting the development of metastases in patients. Telomere-related genes, such as TERT and ATRX, have been recently described in PPGL, supporting the association between the activation of immortalization mechanisms and disease progression. However, the contribution of other genes involving telomere preservation machinery has not been previously investigated. In this work, we aimed to analyze the prognostic value of a comprehensive set of genes involved in telomere maintenance. For this study, we collected 165 PPGL samples (97 non-metastatic/63 metastatic), genetically characterized, in which the expression of 29 genes of interest was studied by NGS. Three of the 29 genes studied, TERT, ATRX and NOP10, showed differential expression between metastatic and non-metastatic cases, and alterations in these genes were associated with a shorter time to progression, independent of SDHB-status. We studied telomere length by Q-FISH in patient samples and in an in vitro model. NOP10 overexpressing tumors displayed an intermediate-length telomere phenotype without ALT, and in vitro results suggest that NOP10 has a role in telomerase-dependent telomere maintenance. We also propose the implementation of NOP10 IHC to better stratify PPGL patients.

Peptide receptor radionuclide therapy in patients with metastatic progressive pheochromocytoma and paraganglioma: long-term toxicity, efficacy and prognostic biomarker data of phase II clinical trials

BACKGROUND

Pheochromocytoma and paraganglioma (PPGL) have currently only limited treatment options available for patients in the metastatic phase (mPPGL) in either post-surgery or inoperable settings. However, these rare tumors overexpress somatostatin receptors and can thus be treated with peptide receptor radionuclide therapy (PRRT). We present data about our 10-year experience treating 46 consecutive mPPGL patients with 90Y-DOTATOC or 177Lu-DOTATATE.

PATIENTS AND METHODS

All patients (20 men and 26 women, median age 52 years) showed positive scintigraphic imaging at 111In-octreotide or 68Ga-DOTATOC positron emission tomography/computed tomography (PET/CT). 90Y-DOTATOC was administered in 12 patients, with cumulative dosages ranging from 7.4 to 11 GBq, while 34 patients received 18.5 or 27.5GBq of 177Lu-DOTATATE. We used Southwest Oncology Group Response Evaluation Criteria in Solid Tumors criteria to evaluate treatment efficacy and Common Terminology Criteria for Adverse Events criteria to assess toxicity. The prognostic role of primary tumor site, hormone secretion, succinate dehydrogenase (SDHx) mutation, and metastatic involvement was also evaluated.

RESULTS

Both 90Y-DOTATOC and 177Lu-DOTATATE PRRT were well tolerated by patients without significant renal or bone marrow toxicity. The median follow-up was 73 months (range 5-146 months). The overall disease control rate (DCR) was 80% [95% confidence interval (CI) 68.9% to 91.9%] with a mean five cycles of therapy. However, 177Lu-DOTATATE patients showed a longer median overall survival (mOS) than those receiving 90Y-Dotatoc and a better DCR when higher dosages were administered, even if a direct comparison was not carried out. Syndromic patients had a poorer mOS. SDHx mutations did not interfere with treatment efficacy.

CONCLUSIONS

PRRT is safe and effective for the treatment of patients with progressive mPPGL, especially at higher dosages. The longer mOS of 177Lu-DOTATATE-treated patients in our protocols indicates the former radiopharmaceutical as the better candidate for further clinical application.

Virtual or real: lifelike cinematic rendering of adrenal tumors

The adrenal gland is small in size and hidden in location. Adrenal tumors are relatively difficult to diagnose due to the wide variety of tumors and partial overlap of image features. Cinematic rendering (CR) is a novel, three-dimensional post-processing technology that simulates how light propagates in the real world, providing high-resolution visualizations that truly present subtle anatomical details. We retrospectively collected a series of pathologically confirmed adrenal tumor cases, raw data was introduced into the post-processing workstation, and different tools and templates of CR software were used for reconstruction and rendering. Compared with traditional black and white two-dimensional images and three-dimensional volume rendering (VR) images, CR images were more colorful, layered, and closer to the truth. CR has potential in diagnosing and preoperative planning of adrenal tumors, allowing vivid and realistic visualization of tumor location, morphology, different components (solid, cystic, fat, calcification, etc.), the pattern of enhancement, and the relationship with surrounding tissues and organs.

A Critical Appraisal of Contemporary and Novel Biomarkers in Pheochromocytomas and Adrenocortical Tumors

Simple Summary

Pheochromocytomas/paragangliomas (PPGLs) and adrenocortical tumors are neoplasms that originate from different regions of the adrenal gland and display significant heterogeneity with respect to their biological and clinical behavior. They may be sporadic or develop in the context of hereditary syndromes. Adrenocortical tumors are mostly benign but less than 2% are carcinomas associated with a poor outcome when diagnosed in advanced disease. The majority of PPGLS are benign, but a subset may develop metastatic disease. In particular, for PPGLs, it is mandatory to identify biomarkers of high sensitivity and specificity that lead to accurate diagnosis and predict patients with a malignant potential that would benefit from aggressive surveillance and administration of early treatment. Current biomarkers include mostly histopathological and genetic parameters but none of them can be considered independent predictive factors. Recent genomic studies have implemented new molecular biomarkers of high accuracy for the diagnosis and management of PPGLs and adrenocortical tumors. In this review, we summarize the current and novel biomarkers that may be considered valuable tools for diagnosis and prediction of malignancy in patients with PPGLs and adrenocortical tumors.

Abstract

Pheochromocytomas/Paragangliomas (PPGLs) and adrenocortical tumors are rare neoplasms with significant heterogeneity in their biologic and clinical behavior. Current diagnostic and predictive biomarkers include hormone secretion, as well as histopathological and genetic features. PPGL diagnosis is based on biochemical measurement of catecholamines/metanephrines, while histopathological scoring systems have been proposed to predict the risk of malignancy. Adrenocortical tumors are mostly benign, but some can be malignant. Currently, the stage of disease at diagnosis and tumor grade, appear to be the most powerful prognostic factors. However, recent genomic and proteomic studies have identified new genetic and circulating biomarkers, including genes, immunohistochemical markers and micro-RNAs that display high specificity and sensitivity as diagnostic or prognostic tools. In addition, new molecular classifications have been proposed that divide adrenal tumors in distinct subgroups with different clinical outcomes.

Diagnosis for Pheochromocytoma and Paraganglioma: A Joint Position Statement of the Korean Pheochromocytoma and Paraganglioma Task Force

Pheochromocytoma and paraganglioma (PPGLs) are rare catecholamine-secreting neuroendocrine tumors but can be life-threatening. Although most PPGLs are benign, approximately 10% have metastatic potential. Approximately 40% cases are reported as harboring germline mutations. Therefore, timely and accurate diagnosis of PPGLs is crucial. For more than 130 years, clinical, molecular, biochemical, radiological, and pathological investigations have been rapidly advanced in the field of PPGLs. However, performing diagnostic studies to localize lesions and detect metastatic potential can be still challenging and complicated. Furthermore, great progress on genetics has shifted the paradigm of genetic testing of PPGLs. The Korean PPGL task force team consisting of the Korean Endocrine Society, the Korean Surgical Society, the Korean Society of Nuclear Medicine, the Korean Society of Pathologists, and the Korean Society of Laboratory Medicine has developed this position statement focusing on the comprehensive and updated diagnosis for PPGLs.

Metastatic Paraganglioma of the Spine With SDHB Mutation: Case Report and Review of the Literature

BACKGROUND

Paragangliomas (PGLs) are rare neuroendocrine tumors that can arise from any autonomic ganglion of the body. Most PGLs do not metastasize. Here, we present a rare case of metastatic PGL of the spine in a patient with a germline pathogenic succinate dehydrogenase subunit B (SDHB) mutation.

METHODS

In addition to a case report we provide a literature review of metastatic spinal PGL to highlight the importance of genetic testing and long-term surveillance of these patients.

RESULTS

A 45-year-old woman with history of spinal nerve root PGL, 17 years prior, presented with back pain of several months' duration. Imaging revealed multilevel lytic lesions throughout the cervical, thoracic, and lumbar spine as well as involvement of the right mandibular condyle and clavicle. Percutaneous biopsy of the L1 spinal lesion confirmed metastatic PGL and the patient underwent posterior tumor resection and instrumented fusion of T7-T11. Postoperatively the patient was found to have a pathogenic SDHB deletion.

CONCLUSIONS

Patients with SDHx mutation, particularly SDHB, have increased risk of developing metastatic PGLs. Consequently, these individuals require long-term surveillance given the risk for developing new tumors or disease recurrence, even years to decades after primary tumor resection. Surgical management of spinal metastatic PGL involves correcting spinal instability, minimizing tumor burden, and alleviating epidural cord compression. In patients with metastatic PGL of the spine, genetic testing should be considered.

Pheochromocytoma: A three-decade clinical experience in a multicenter study

OBJECTIVE

To analyze the clinical and analytical features, diagnostic tests, therapies, and outcomes of pheochromocytoma (PCC).

DESIGN AND METHODS

A multicenter retrospective study in surgically treated patients with PCC followed in 3 Spanish tertiary referral hospitals.

RESULTS

A total of 106 patients (61 [57.5%] women, mean age 52.3 ± 14.8 years) were evaluated. At diagnosis, PCC was symptomatic in 62% and sporadic in 83%. Patients with familial PCC were significantly younger than those with sporadic disease (40.8 ± 14.2 years vs. 54.5 ± 13.9 years, p<.001). Familial PCCs were more frequently associated with MEN2A (n=8). Levels of 24-h urinary fractionated metanephrines were positively related to tumor size. The maximum tumor diameter was 4.3cm (3-6cm); 27.7% of the patients had tumors ≥6cm. Incidental PCCs were significantly smaller than symptomatic PCCs (3.4cm [2.4-5.0cm] vs. 5.6cm [4.0-7.0cm], p<.001). Scintigraphy by 123I-metaiodobenzylguanidine showed a high sensitivity (81.9%). Preoperative alpha blockade with phenoxybenzamine was used in 93.6% and doxazosin in the rest. Laparoscopic surgery was used in 2/3 of the patients, with a low conversion (1.9%) to open surgery. Perioperative complications appeared in approximately 20% of patients, mainly hypertensive crisis (9.4%). Recurrent disease appeared in 10%, and malignant PCC was uncommon (6.3%).

CONCLUSIONS

PCCs surgically treated in Spain are usually large, symptomatic, and sporadic tumors diagnosed around the sixth decade of life. Hereditary PCC is usually associated with MEN2A. The main type of surgical technique used is laparoscopic surgery, and the prevalence of metastatic PCC is low.

131I-metaiodobenzylguanidine and peptide receptor radionuclide therapy in pheochromocytoma and paraganglioma

PURPOSE OF REVIEW

Pheochromocytomas and paragangliomas are rare tumors arising, respectively, from the adrenal medulla and extra-adrenal sympathetic or parasympathetic paraganglia. The main therapeutic objectives in case of metastatic disease are the reduction of tumor burden and the control of symptoms resulting from excessive catecholamine secretion. Treatment choices constitute not only a wait and see attitude, locoregional approaches, chemotherapy regiments but also radiopharmaceutical agents, and they should be discussed in a specialized multidisciplinary board. This review will briefly discuss the radiopharmaceutical modalities in patients with pheochromocytomas and paragangliomas (I-MIBG and PRRT).

RECENT FINDINGS

I-MIBG (Azedra) has received FDA approval for patients with iobenguane-scan-positive, unresectable, locally advanced or metastatic pheochromocytomas and paragangliomas who require systemic anticancer therapy, whereas peptide receptor radionuclide therapy using radiolabelled somatostatin analogues is currently performed in compassionate use, with very promising results. No prospective head-to-head comparison between the modalities has been conducted to date.

SUMMARY

Promising results have been reported for both radiopharmaceutical agents, mostly in the setting of retrospective series. No prospective head-to-head comparison between the modalities is yet available.

Predicting Metastatic Potential in Pheochromocytoma and Paraganglioma: A Comparison of PASS and GAPP Scoring Systems

PURPOSE

The Pheochromocytoma of the Adrenal Gland Scaled Score (PASS) and the Grading System for Adrenal Pheochromocytoma and Paraganglioma (GAPP) are scoring systems to predict metastatic potential in pheochromocytomas (PCC) and paragangliomas (PGLs). The goal of this study is to assess PASS and GAPP as metastatic predictors and to correlate with survival outcomes.

METHODS

The cohort included PCC/PGL with ≥5 years of follow-up or known metastases. Surgical pathology slides were rereviewed. PASS and GAPP scores were assigned. Univariable and multivariable logistic regression, Kaplan-Meier survival analysis, and Cox proportional hazards were performed to assess recurrence-free survival (RFS) and disease-specific survival (DSS).

RESULTS

From 143 subjects, 106 tumors were PCC and 37 were PGL. Metastases developed in 24%. The median PASS score was 6.5 (interquartile range [IQR]: 4.0-8.0) and median GAPP score was 3.0 (IQR: 2.0-4.0). Interrater reliability was low-moderate for PASS (intraclass correlation coefficient [ICC]: 0.6082) and good for GAPP (ICC 0.7921). Older age (OR: 0.969, P = .0170) was associated with longer RFS. SDHB germline pathogenic variant (OR: 8.205, P = .0049), extra-adrenal tumor (OR: 6.357, P < .0001), Ki-67 index 1% to 3% (OR: 4.810, P = .0477), and higher GAPP score (OR: 1.537, P = .0047) were associated with shorter RFS. PASS score was not associated with RFS (P = .1779). On Cox regression, a GAPP score in the moderately differentiated range was significantly associated with disease recurrence (HR: 3.367, P = .0184) compared with well-differentiated score.

CONCLUSION

Higher GAPP scores were associated with aggressive PCC/PGL. PASS score was not associated with metastases and demonstrated significant interobserver variability. Scoring systems for predicting metastatic PCC/PGL may be improved by incorporation of histopathology, clinical data, and germline and somatic tumor markers.

Pheochromocytoma: A three-decade clinical experience in a multicenter study

OBJECTIVE

To analyze the clinical and analytical features, diagnostic tests, therapies, and outcomes of pheochromocytoma (PCC).

DESIGN AND METHODS

A multicenter retrospective study in surgically treated patients with PCC followed in 3 Spanish tertiary referral hospitals.

RESULTS

A total of 106 patients (61 [57.5%] women, mean age 52.3 ± 14.8 years) were evaluated. At diagnosis, PCC was symptomatic in 62% and sporadic in 83%. Patients with familial PCC were significantly younger than those with sporadic disease (40.8 ± 14.2 years vs 54.5 ± 13.9 years, p < .001). Familial PCCs were more frequently associated with MEN2A (n = 8). Levels of 24-h urinary fractionated metanephrines were positively related to tumor size. The maximum tumor diameter was 4.3 cm (3-6 cm); 27.7% of the patients had tumors ≥6 cm. Incidental PCCs were significantly smaller than symptomatic PCCs (3.4 cm [2.4-5.0 cm] vs 5.6 cm [4.0-7.0 cm], p < .001). Scintigraphy by ¹²³I-metaiodobenzylguanidine showed a high sensitivity (81.9%). Preoperative alpha blockade with phenoxybenzamine was used in 93.6% and doxazosin in the rest. Laparoscopic surgery was used in 2/3 of the patients, with a low conversion (1.9%) to open surgery. Perioperative complications appeared in approximately 20% of patients, mainly hypertensive crisis (9.4%). Recurrent disease appeared in 10%, and malignant PCC was uncommon (6.3%).

CONCLUSIONS

PCCs surgically treated in Spain are usually large, symptomatic, and sporadic tumors diagnosed around the sixth decade of life. Hereditary PCC is usually associated with MEN2A. The main type of surgical technique used is laparoscopic surgery, and the prevalence of metastatic PCC is low.

Current trend in the diagnosis and management of malignant pheochromocytoma: Clinical and prognostic factors

Pheochromocytomas are tumors arising from the chromaffin cell of the adrenal gland and paragangliomas as tumors from extra-adrenal sympathetic chromaffin cells. The combined yearly incidence of pheochromocytoma and paraganglioma (PPGL) is approximately 0.8 per 100000 person/year. Malignant pheochro-mocytoma is defined only by the presence of metastasis, as there is no confirmatory histology or biomarkers. The most common metastatic sites of these chromaffin tumors are the lymph node, bone, lungs, and liver. This review focuses on relevant clinical and immunohistological factors that are predictive of malignant PPGL or metastasis and determinants of prognosis. Findings showed that the risk of malignant PPGL, along with disease survival, is closely associated with age, primary tumor size, gender, synchronous metastasis, and absence of surgical excision. Other essential biomarkers or immunohistology investigated were galectin-3, COX-2, nm-23, microRNA-210, ERBB-2 overexpression and succinate dehydrogenase subunit mutation, which were predictive of malignancy as well as disease prognosis. Curative resection is possible but most metastatic diseases are amenable to radiopharmaceuticals and chemotherapy due to late presentation. Other therapeutic options, like molecular-targeted therapy, are still undergoing clinical trials.

Malignant pheochromocytoma and paraganglioma: management options

PURPOSE OF REVIEW

Although the majority of pheochromocytoma and paraganglioma are benign, 15-17% develop metastatic disease, being present at the initial diagnosis in about 11-31% of cases. The natural course of metastasized disease is highly heterogeneous, with an overall 5-year survival rate varying between 40% and 85%. For individual patients, overall survival, progression-free survival, and clinical outcome are difficult to predict. Management of metastasized pheochromocytoma and paraganglioma is challenging. Currently available therapeutic options are surgical debulking, treatment with radiopharmaceuticals (I-MIBG, Y and Lu-DOTATATE), chemotherapy and targeted therapy.

RECENT FINDINGS

The pathogenesis of pheochromocytoma and paraganglioma (PPGL) is largely driven by genomic alterations in PPGL susceptibility genes related to three different clusters: altered pseudo-hypoxic signaling (cluster-1), altered MAP-kinase signaling (cluster-2) and altered Wnt signaling (cluster-3). Novel targeted therapies (tyrosine kinase inhibitors) and potential future therapeutic options, guided by improved knowledge about the oncogenic cluster 1-3 signaling pathways, will be discussed.

SUMMARY

Treatment of metastasized pheochromocytoma and paraganglioma remains challenging. Profiling of gene expression and methylation can serve as a powerful tool for characterizing disease clusters and for guiding targeted therapy to improve selectivity and efficacy. Current knowledge of signatures involved in molecular signaling, metabolism, and resistance mechanisms of PPGLs suggests that therapeutic regimens can be optimized to each molecular subtype.

Emerging Treatments for Advanced/Metastatic Pheochromocytoma and Paraganglioma

OPINION STATEMENT

The incidence of metastatic pheochromocytoma (PHEO) and paraganglioma (PGL) may occur in as many as 35% of patients particularly with PGL and even more frequently in those with specific mutations. Biochemical, morphological, and molecular markers have been investigated for use in the distinction of benign from malignant PHEO/PGL. PHEO/PGL metastasizes via hematogenous or lymphatic routes and shows differences based on mutational status. The most common sites of involvement in patients that have an SDHB mutation are the bone (78%), lungs (45%), lymph nodes (36%), and liver (35%). In patients with sporadic PHEO/PGL, the most common sites of metastasis are the bones (64%), lungs (47%), lymph nodes (36%), and liver (32%). Metastases may be present at presentation or may occur later. Metastases to the liver and lungs are associated with a shorter survival. Overall, the estimated 5-year survival rates are between 34 and 74%. Currently, treatments for metastatic PHEO/PGL are essentially palliative. Surgery is potentially curative; however, tumor dissemination limits the chance for a curative resection. When surgical intervention is not amenable, the therapeutic options include radiolabeled MIBG (Azedra®-iobenguane 131 was recently FDA-approved for patients > 12 years and older with iobenguane scan positive) or systemic chemotherapy with cyclophosphamide, vincristine, and dacarbazine (CVD) with an overall objective response rate (ORR) of less than 40%; however, it is not clear if the administration of CVD impacts overall survival, as nearly all patients develop progressive and ultimately fatal disease. Other treatment modalities under investigation include cytoreductive techniques, novel radiopharmaceuticals, chemotherapy, radiotherapy, immunotherapy, and experimental therapies. Here we are discussing emerging treatment for advanced/metastatic PHEO/PGL.

Clinical features and prognosis analysis of metastatic spinal pheochromocytoma: A single center retrospective study

•

It is difficult for clinicians to determine appropriate treatment strategies and predict the prognosis of metastatic spinal pheochromocytoma.

•

Surgical treatment is an effective option in treating MSP and plays an important role in improving patients’ quality of life.

•

Extraosseous metastasis, Tomita score, and number of spinal metastases are all potential prognostic factors for OS and PFS.

•

Individualized treatment plans should be developed based on the actual situation of each patient.

•

Through a multi-disciplinary collaboration and reasonable perioperative management, patients with MSP can be treated more effectively.

Purpose

Metastatic spinal pheochromocytoma (MSP) is very rare in clinical practice, with only a few case reports in the literature. Its low incidence makes it profoundly difficult for clinicians to determine appropriate treatment strategies and predict the prognosis. In this study, we analyzed the clinical characteristics, surgical procedure and prognosis of patients with MSP in one of the largest clinical investigations of this entity to date.

Methods

In this study, we conducted a retrospective analysis of the clinical data of 10 patients with MSP who were treated in our department from 2012 to 2020. We performed a total of 14 operations using two types of surgery: open surgery and percutaneous vertebroplasty.

Results

Among them, nine patients underwent 14 spinal operations with satisfactory effect and without any perioperative complications. The mean time from the initial operation to detection of spinal metastasis was 85.3 (12–132) months. The average follow-up time was 27.3 months. Disease progression was detected in nine patients, and eight patients (80%) died during the follow-up period. Univariate analysis showed that extraosseous visceral metastasis (P = 0.022), Tomita score (P = 0.027), and number of spinal metastases (P = 0.024) were associated with overall survival (OS). In addition, extraosseous visceral metastasis (P = 0.030), Tomita score (P = 0.013), and number of spinal metastases (P = 0.026) were associated with progression-free survival (PFS).

Conclusions

Surgical treatment is an effective option in treating MSP and plays an important role in improving patients’ quality of life, due to its efficacy in relieving pain, reconstruction of stability, and restoration of function. Extraosseous metastasis, Tomita score, and number of spinal metastases are all potential prognostic factors for OS and PFS.

Pheochromocytoma and Paraganglioma in Children and Adolescents: Experience of the French Society of Pediatric Oncology (SFCE)

Purpose

The purpose of this work is to assess the clinical outcome of pediatric patients diagnosed with pheochromocytoma and paraganglioma (PPGL) detected in France since 2000.

Methods

A retrospective multicenter study was conducted that included all patients younger than 18 years with PPGL diagnosed in France between 2000 and 2016. Patients were identified from 4 different sources: the National Registry of Childhood Solid Tumors, the French Pediatric Rare Tumors Database, the French registry of succinate dehydrogenase (SDH)-related hereditary paraganglioma, and the nationwide TenGen network.

Results

Among 113 eligible patients, 81 children with available data were enrolled (41 with adrenal and 40 with extra-adrenal PPGL). At diagnosis, 11 had synchronous metastases. After a median follow-up of 53 months, 27 patients experienced a new event (n = 7 second PPGL, n = 1 second paraganglioma [PGL], n = 8 local recurrences, n = 10 metastatic relapses, n = 1 new tumor) and 2 patients died of their disease. The 3- and 10-year event-free survival rates were 80% (71%-90%) and 39% (20%-57%),respectively, whereas the overall survival rate was 97% (93%-100%)at 3 and 10 years. A germline mutation in one PPGL-susceptibility gene was identified in 53 of the 68 (77%) patients who underwent genetic testing (SDHB [n = 25], VHL [n = 21], RET [n = 2], HIF2A [n = 2], SDHC [n = 1], SDHD [n = 1], NF1 [n = 1]). Incomplete resection and synchronous metastases were associated with higher risk of events (P = .011, P = .004), but presence of a germline mutation was not (P = .11).

Conclusions

Most pediatric PPGLs are associated with germline mutations and require specific follow-up because of the high risk of tumor recurrence.

Disease monitoring of patients with pheochromocytoma or paraganglioma by biomarkers and imaging studies

Pheochromocytoma and paraganglioma (PPGL) are rare neuroendocrine tumors, a large proportion of which secrete catecholamines. PPGL are associated with a high cardiovascular morbidity and come with a risk of malignancy. The therapy of choice is surgical resection. Nevertheless, PPGL are associated with a lifelong risk of tumor persistence or recurrence. Currently, there are no clinical, biochemical, histopathological or imaging characteristics, which can predict or exclude malignant behavior or tumor recurrence. Therefore, long-term follow-up is recommended even after apparent complete surgical removal. Early detection of recurrence is essential to reduce cardiovascular morbidity and mortality due to catecholamine secretion, to prevent morbidity by mass effects of paraganglioma (PGL) or by metastatic spread of disease. Due to the rarity of these tumors, no prospective data on long-term surveillance exist. In fact, current recommendations are based on retrospective analyses, expert opinions and case studies. The aim of this review is to provide an overview on the current state of knowledge with regard to known factors that increase the risk of recurrence and might impact disease monitoring as well as the available possibilities for biochemical and imaging follow-up. Based on this overview, we aim to propose a practical approach for a patient-oriented follow-up after surgical removal of a PPGL.

Metastatic pheochromocytoma and paraganglioma: Management of endocrine manifestations, surgery and ablative procedures, and systemic therapies

Metastatic pheochromocytomas and paragangliomas (MPPGs) are rare neuroendocrine tumors. Most patients present with advanced disease that is associated with manifestations of catecholamine release. Surgical resection of the primary tumor and ablative therapies of metastases-whenever possible-may improve clinical outcomes and, perhaps, lengthen the patient's overall survival. Significant steps in understanding the genetic alterations linked to MPPGs and scientific progress made on cancers that share a similar pathogenesis are leading to the recognition of potential systemic therapeutic options. Data derived from clinical trials evaluating targeted therapies such as tyrosine kinase inhibitors, radiopharmaceuticals, immunotherapy, and combinations of these will likely improve the outcomes of patients with advanced and progressive MPPGs. Exemplary of this success is the recent approval in the United States of the high-specific-activity iodine¹³¹ meta-iodine-benzylguanidine (MIBG) for patients with unresectable and progressive MPPGs that express the noradrenaline transporter. This review will discuss the therapeutic approaches for patients with MPPGs.

Pheochromocytoma: An approach to diagnosis

Pheochromocytomas are rare neuroendocrine chromaffin-derived tumors that arise within the adrenal medulla. They are usually benign, but if not diagnosed or if left untreated, they can have devastating consequences. Clinical consideration of the diagnosis is paramount, as they may have protean manifestations, and a high index of suspicion is essential if serious consequences are to be avoided. An accurate biochemical diagnosis is crucial for the management of these patients: either plasma or urinary metanephrines are both highly sensitive and specific if correctly employed, but knowledge of pre- and post-analytic interference is essential. Diagnostic imaging with cross-sectional CT and/or MRI offers high sensitivity in their detection, but lack specificity. The introduction of PET/CT/MR has led to a dramatic improvement in the localization of both pheochromocytomas and paragangliomas, together with the increasing availability of new functional imaging radionuclides. Optimal investigation and accurate diagnosis is best achieved at 'centers of excellence' with expert multidisciplinary teams.

Epidemiology and Prognosis of Pheochromocytoma/Paraganglioma in Korea: A Nationwide Study Based on the National Health Insurance Service

BACKGROUND

Pheochromocytomas and paragangliomas (PPGLs) are rare endocrine tumors originating from chromaffin cells. PPGLs are associated with a high mortality rate and several complications. To date, no epidemiological studies have been conducted on PPGLs in Asia. This study aimed to investigate the epidemiology and prognosis of PPGLs in Korea using nationwide data.

METHODS

Using the National Health Insurance Service Database, subjects with a principal diagnosis of PPGLs on two or more occasions between 2003 and 2014 who satisfied the operational definition of PPGLs were included. Incidence, prevalence, complications, metastasis, and mortality were investigated.

RESULTS

In total, 1048 subjects with a mean age of 47.6±16.1 years were included. There was no sex preponderance. The overall prevalence of PPGLs was 2.13 per 100,000 persons, and the overall age-standardized incidence rate was 0.18 per 100,000 person-years. Malignant PPGLs accounted for 17.7% (185 of 1,048) of cases, and 94 subjects exhibited metastasis at the time of diagnosis. Among initially non-metastatic PPGLs, 9.5% (nine of 954) eventually metastasized after a mean duration of 78.1±41.4 months. The 5-year survival rates for non-metastatic and metastatic PPGLs at diagnosis were 97% and 84%, respectively. Multivariable Cox regression models adjusted for covariates showed that metastatic PPGLs were associated with a 2.40-fold higher risk of mortality than non-metastatic PPGLs (95% confidence interval, 1.38 to 4.17; P=0.002).

CONCLUSION

PPGLs are rare in Korea, and the prognosis of these endocrine tumors varies depending on whether they are benign or malignant. This epidemiological study paves the way for further research on PPGLs.

Pheochromocytomas and Paragangliomas

Pheochromocytomas are rare neuroendocrine tumors. Extra-adrenal lesions arising from the autonomic neural ganglia are termed paraganglioma. Clinical symptoms are common between the adrenal and extra-adrenal forms and are determined by excess secretion of catecholamines. Hypertension is a critical and often dramatic feature of pheochromocytoma/paraganglioma, and its most prevalent reported symptom. However, given the rare occurrence of this cancer, in patients undergoing screening for hypertension, the prevalence ranges from 0.1% to 0.6%. Still, patients frequently come to the attention of endocrinologist when pheochromocytoma/paraganglioma is suspected as a secondary cause of hypertension. This article summarizes current clinical approaches in patients with pheochromocytoma/paraganglioma.

Metastatic pheochromocytoma to the pancreas diagnosed by endoscopic ultrasound-guided fine needle aspiration: A case report and review of literature

Pancreatic pheochromocytomas are rare and typically diagnosed by local resection. We present the first reported case of metastatic pheochromocytoma to the pancreas diagnosed by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) and cytology. A 67-year-old female presented with 2 to 3 months of abdominal pain. A CT scan showed a large mass in the head of the pancreas engulfing the superior mesentery artery and vein, along with a large mass in the left adrenal gland. An EUS-FNA was performed on the pancreatic mass with a 22-gauge needle, yielding an adequate sample. Papanicolaou stain, Diff-Quik, and cell block showed loosely cohesive clustered tumor cells and singly dispersed pleomorphic naked tumor nuclei with anisonucleosis and cytoplasmic vacuolization. Tumor cells stained positive for synaptophysin, chromogranin A, and CD56 and negative for CK AE1/3 and CK AE1/3-CAM5.2 cytokeratin cocktail. Because of cytokeratin negativity, diffusely positive neuroendocrine markers, and the presence of an adrenal mass, a metastatic malignant pheochromocytoma was suspected. Additional testing showed elevations in plasma metanephrines and normetanephrines, urine metanephrine-to-creatinine and normetanephrine-to-creatinine ratios, and serum chromogranin A. An iodine¹²³ -metaiodobenzylguanidine (MIBG) scan was obtained, which showed significantly increased MIBG uptake in the left adrenal lesion. A diagnosis of metastatic malignant pheochromocytoma was made. Surgical oncology was consulted, who recommended against resection of the adrenal mass in favor of outpatient management. Metastatic pheochromocytoma to the pancreas are rare tumors that may yield diagnostic material by EUS-FNA with a 22-gauge needle.

Targeted Radionuclide Therapy for Patients with Metastatic Pheochromocytoma and Paraganglioma: From Low-Specific-Activity to High-Specific-Activity Iodine-131 Metaiodobenzylguanidine

Low-specific-activity iodine-131–radiolabeled metaiodobenzylguanidine (I-131-MIBG) was introduced last century as a potential systemic therapy for patients with malignant pheochromocytomas and paragangliomas. Collective information derived from mainly retrospective studies has suggested that 30–40% of patients with these tumors benefit from this treatment. A low index of radioactivity, lack of therapeutic standardization, and toxicity associated with intermediate to high activities (absorbed radiation doses) has prevented the implementation of I-131-MIBG’s in clinical practice. High-specific-activity, carrier-free I-131-MIBG has been developed over the past two decades as a novel therapy for patients with metastatic pheochromocytomas and paragangliomas that express the norepinephrine transporter. This drug allows for a high level of radioactivity, and as yet is not associated with cardiovascular toxicity. In a pivotal phase two clinical trial, more than 90% of patients achieved partial responses and disease stabilization with the improvement of hypertension. Furthermore, many patients exhibited long-term persistent antineoplastic effects. Currently, the high-specific-activity I-131-MIBG is the only approved therapy in the US for patients with metastatic pheochromocytomas and paragangliomas. This review will discuss the historical development of high-specific-activity I-131-MIBG, its benefits and adverse events, and future directions for clinical practice applicability and trial development.

Integrative multi-omics analysis identifies a prognostic miRNA signature and a targetable miR-21-3p/TSC2/mTOR axis in metastatic pheochromocytoma/paraganglioma

Rationale: Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors that present variable outcomes. To date, no effective therapies or reliable prognostic markers are available for patients who develop metastatic PPGL (mPPGL). Our aim was to discover robust prognostic markers validated through in vitro models, and define specific therapeutic options according to tumor genomic features.

Methods: We analyzed three PPGL miRNome datasets (n=443), validated candidate markers and assessed them in serum samples (n=36) to find a metastatic miRNA signature. An integrative study of miRNome, transcriptome and proteome was performed to find miRNA targets, which were further characterized in vitro.

Results: A signature of six miRNAs (miR-21-3p, miR-183-5p, miR-182-5p, miR-96-5p, miR-551b-3p, and miR-202-5p) was associated with metastatic risk and time to progression. A higher expression of five of these miRNAs was also detected in PPGL patients' liquid biopsies compared with controls. The combined expression of miR-21-3p/miR-183-5p showed the best power to predict metastasis (AUC=0.804, P=4.67·10^-18), and was found associated in vitro with pro-metastatic features, such as neuroendocrine-mesenchymal transition phenotype, and increased cell migration rate. A pan-cancer multi-omic integrative study correlated miR-21-3p levels with TSC2 expression, mTOR pathway activation, and a predictive signature for mTOR inhibitor-sensitivity in PPGLs and other cancers. Likewise, we demonstrated in vitro a TSC2 repression and an enhanced rapamycin sensitivity upon miR-21-3p expression.

Conclusions: Our findings support the assessment of miR-21-3p/miR-183-5p, in tumors and liquid biopsies, as biomarkers for risk stratification to improve the PPGL patients' management. We propose miR-21-3p to select mPPGL patients who may benefit from mTOR inhibitors.

Retrospective application of the pathologic tumor-node-metastasis classification system for pheochromocytoma and abdominal paraganglioma in a well characterized cohort with long-term follow-up

BACKGROUND

A pathologic tumor-node-metastasis staging algorithm for pheochromocytoma and sympathetic paraganglioma was introduced recently in the 8th Edition of the cancer staging manual of the American Joint Committee on Cancer. There is no information, however, as to how this staging correlates to well-established clinical cohorts of pheochromocytoma and sympathetic paraganglioma with extensive follow-up.

METHODS

We applied the pathologic tumor-node-metastasis staging retrospectively to a cohort of 118 patients with pheochromocytoma and sympathetic paraganglioma, in which the majority has been characterized for susceptibility gene mutations and global mRNA expressional patterns as well as histologic risk criteria using the pheochromocytoma of the adrenal gland scaled score (PASS).

RESULTS

The overall tumor stage correlated with the presence of metastases, disease-related death, and PASS scores as well as established mutational and expressional clusters.

CONCLUSION

Stage III to IV pheochromocytomas and sympathetic paragangliomas are associated with increased mortality, increased PASS scores, and mutational and expressional aberrancies in the pseudo-hypoxia pathway cluster. These findings validate the stratification proposed by the American Joint Committee on Cancer staging manual by linking malignancy-associated pheno- and genotypes to more advanced stages. Moreover, because few pheochromocytomas and sympathetic paragangliomas are metastatic at the time of the original presentation, the staging relies heavily on identifying histologic signs of extra-adrenal invasion.

Efficacy and Safety of High-Specific-Activity 131I-MIBG Therapy in Patients with Advanced Pheochromocytoma or Paraganglioma

Patients with metastatic or unresectable (advanced) pheochromocytoma and paraganglioma (PPGL) have poor prognoses and few treatment options. This multicenter, phase 2 trial evaluated the efficacy and safety of high-specific-activity ¹³¹I-meta-iodobenzylguanidine (HSA ¹³¹I-MIBG) in patients with advanced PPGL. Methods: In this open-label, single-arm study, 81 PPGL patients were screened for enrollment, and 74 received a treatment-planning dose of HSA ¹³¹I-MIBG. Of these patients, 68 received at least 1 therapeutic dose (∼18.5 GBq) of HSA ¹³¹I-MIBG intravenously. The primary endpoint was the proportion of patients with at least a 50% reduction in baseline antihypertensive medication use lasting at least 6 mo. Secondary endpoints included objective tumor response as assessed by Response Evaluation Criteria in Solid Tumors version 1.0, biochemical tumor marker response, overall survival, and safety. Results: Of the 68 patients who received at least 1 therapeutic dose of HSA ¹³¹I-MIBG, 17 (25%; 95% confidence interval, 16%–37%) had a durable reduction in baseline antihypertensive medication use. Among 64 patients with evaluable disease, 59 (92%) had a partial response or stable disease as the best objective response within 12 mo. Decreases in elevated (≥1.5 times the upper limit of normal at baseline) serum chromogranin levels were observed, with confirmed complete and partial responses 12 mo after treatment in 19 of 28 patients (68%). The median overall survival was 36.7 mo (95% confidence interval, 29.9–49.1 mo). The most common treatment-emergent adverse events were nausea, myelosuppression, and fatigue. No patients had drug-related acute hypertensive events during or after the administration of HSA ¹³¹I-MIBG. Conclusion: HSA ¹³¹I-MIBG offers multiple benefits, including sustained blood pressure control and tumor response in PPGL patients.

Metastatic Phaeochromocytoma: Spinning Towards More Promising Treatment Options

Phaeochromocytomas (PCC) and paragangliomas (PGL) are rare tumours arising from the chromaffin cells of the adrenal medulla (PCC) or the paraganglia located outside the adrenal gland (PGL). However, their incidence is likely to be underestimated; around 10% of all PCC/PGL are metastatic, with higher metastatic potential of PGLs compared to PCCs. If benign, surgery is the treatment of choice, but if metastatic, therapy is challenging. Here we review the currently existing therapy options for metastatic PCCs/PGLs including conventional chemotherapy (the original Averbuch scheme, but updated), radiopharmaceutical treatments (¹³¹I-MIBG, ⁹⁰Y- and ¹⁷⁷Lu-DOTATATE) and novel targeted therapies (anti-angiogenic tyrosine kinase inhibitors and mTORC1 inhibitors), emphasising future therapeutic approaches (HIF-2α and PARP inhibitors, temozolomide alone, metronomic temozolomide, somatostatin analogues) based on the oncogenic signalling pathways related to three different clusters comprising more than 20 well-characterised PCC/PGL susceptibility genes. We suggest that targeted combination therapies including repurposed agents may offer more effective future options worthy of exploration.

MIBG (metaiodobenzylguanidine) theranostics in pediatric and adult malignancies

Metaiodobenzylguanidine, a guanithidine analog, labeled with ¹²³I and ¹³¹I, is used for imaging and therapy of neuroblastomas and various neural crest tumors like paragangliomas, pheochromocytomas, medullary cancer of thyroid and carcinoids since the past three to four decades. In this review article, we shall revisit metaiodobenzylguanidine as a radiopharmaceutical and its various applications in neural crest tumors.

Recent advances in the management of malignant pheochromocytoma and paraganglioma: focus on tyrosine kinase and hypoxia-inducible factor inhibitors

Inactivating mutations of the succinate dehydrogenase subunit B ( SDHB) gene and the subsequent stabilization and activation of the hypoxia-inducible factor 2-alpha (HIF2α) unit are recognized hallmarks associated with the development of metastatic pheochromocytomas and paragangliomas (MPPG). Despite this discovery, the development of systemic therapies for patients with MPPG has been very slow. The rarity of the disease, the lack of preclinical animal models, and the impracticable development of large clinical trials has hindered the therapeutic progress for MPPG. Chemotherapy and low-specific activity ¹³¹meta-iodo-benzyl-guanidine (MIBG) (manufactured by simple isotope exchange methodology) led to positive clinical responses in about a third of patients. Molecular targeted therapies were introduced into oncological clinical practice at the beginning of the 21st century. These therapies have been demonstrated to be effective for patients with cancers that previously exhibited limited responses to systemic chemotherapy, such as kidney and thyroid carcinomas and pancreatic neuroendocrine tumors. The pathogenesis of MPPG overlaps in some way with the pathogenesis of kidney, medullary thyroid, and pancreatic neuroendocrine carcinomas, providing scientific support to explore molecular targeted therapies such as tyrosine kinase and HIF inhibitors.

A clinical prediction model to estimate the metastatic potential of pheochromocytoma/paraganglioma: ASES score

BACKGROUND

Malignant pheochromocytoma and paraganglioma can be defined only after the development of metastases in nonchromaffin tissues. There is no single clinical parameter that is sufficiently reliable to predict metastatic potential, so our goal was to develop a prediction model based on multiple clinical parameters.

METHODS

The baseline age, size, extra-adrenal location, secretory type score was calculated in a retrospective cohort study comprising 333 patients with pheochromocytoma and paraganglioma. In each patient, each variable for age ≤35 years, tumor size ≥ 6.0 cm, extra-adrenal, and norepinephrine-secretory type was coded as 1 point (otherwise 0 point); these points were summed to yield age, size, extra-adrenal location, secretory type score.

RESULTS

Metastases occurred in 23 of 333 patients (6.9%). Metastatic pheochromocytoma and paraganglioma was associated with age ≤35 years (hazard ratio [HR] 2.74, 95% confidence interval [95% CI] 1.19-6.35), tumor size ≥6.0 cm (HR 2.43, 95% CI 1.06-5.56), extra-adrenal location (HR 2.73, 95% confidence interval 1.10-7.40), and tumor producing only norepinephrine (HR 2.96, 95% CI 1.30-6.76). The area under the curve of the age, size, extra-adrenal location, secretory type score was 0.735. There was a significant difference in metastasis-free survival between participants with age, size, extra-adrenal location, secretory type score ≥2 and score <2 (P < .0001 by the log rank test). The negative predictive value of this system was 96.5% for a cutoff point of 2.

CONCLUSION

We developed a new prediction model, the age, size, extra-adrenal location, secretory type score, based on multiple clinical parameters to assess the metastatic potential of pheochromocytoma and paraganglioma.

Unusual presentation of pheochromocytoma: thirteen years of anxiety requiring psychiatric treatment

Pheochromocytoma is a rare tumor of the adrenal gland. It often presents with the classic triad of headache, palpitations and generalized sweating. Although not described as a typical symptom of pheochromocytoma, anxiety is the fourth most common symptom reported by patients suffering of pheochromocytoma. We report the case of a 64 year old man who had severe anxiety and panic disorder as presenting symptoms of pheochromocytoma. After 13 years of psychiatric follow-up, the patient was diagnosed with malignant pheochromocytoma. After surgical resection of his pheochromocytoma and his hepatic metastases, the major panic attacks completely disappeared, the anxiety symptoms improved significantly and the psychiatric medications were stopped except for a very low maintenance dose of venlafaxine. We found in our cohort of 160 patients with pheochromocytoma 2 others cases of apparently benign tumors with severe anxiety that resolved after pheochromocytoma resection. These cases highlight that pheochromocytoma should be included in the differential diagnosis of refractory anxiety disorder.

Learning points

Anxiety and panic disorder may be the main presenting symptoms of pheochromocytoma.The diagnosis of pheochromocytoma should be excluded in cases of long-term panic disorder refractory to medications since the anxiety may be secondary to a catecholamine-secreting tumor.Surgical treatment of pheochromocytoma leads to significant improvement of anxiety disorders.

Phase 1 Study of High-Specific-Activity I-131 MIBG for Metastatic and/or Recurrent Pheochromocytoma or Paraganglioma

CONTEXT

No therapies are approved for the treatment of metastatic and/or recurrent pheochromocytoma or paraganglioma (PPGL) in the United States.

OBJECTIVE

To determine the maximum tolerated dose (MTD) of high-specific-activity I-131 meta-iodobenzylguanidine (MIBG) for the treatment of metastatic and/or recurrent PPGL.

DESIGN

Phase 1, dose-escalating study to determine the MTD via a standard 3 + 3 design, escalating by 37 MBq/kg starting at 222 MBq/kg.

SETTING

Three centers.

PATIENTS

Twenty-one patients were eligible, received study drug, and were evaluable for MTD, response, and toxicity.

INTERVENTION

Open-label use of high-specific-activity I-131 MIBG therapy.

MAIN OUTCOME MEASURES

Dose-limiting toxicities, adverse events, radiation absorbed dose estimates, radiographic tumor response, biochemical response, and survival.

RESULTS

The MTD was determined to be 296 MBq/kg on the basis of two observed dose-limiting toxicities at the next dose level. The highest mean radiation absorbed dose estimates were in the thyroid and lower large intestinal wall (each 1.2 mGy/MBq). Response was evaluated by total administered activity: four patients (19%), all of whom received >18.5 GBq of study drug, had radiographic tumor responses of partial response by Response Evaluation Criteria in Solid Tumors. Best biochemical responses (complete or partial response) for serum chromogranin A and total metanephrines were observed in 80% and 64% of patients, respectively. Overall survival was 85.7% at 1 year and 61.9% at 2 years after treatment. The majority (84%) of adverse events were considered mild or moderate in severity.

CONCLUSIONS

These findings support further development of high-specific-activity I-131 MIBG for the treatment of metastatic and/or recurrent PPGL at an MTD of 296 MBq/kg.