Bone metastases and skeletal-related events in patients with malignant pheochromocytoma and sympathetic paraganglioma

International consensus statement on the diagnosis and management of phaeochromocytoma and paraganglioma in children and adolescents

Phaeochromocytomas and paragangliomas (PPGL) are rare neuroendocrine tumours that arise not only in adulthood but also in childhood and adolescence. Up to 70-80% of childhood PPGL are hereditary, accounting for a higher incidence of metastatic and/or multifocal PPGL in paediatric patients than in adult patients. Key differences in the tumour biology and management, together with rare disease incidence and therapeutic challenges in paediatric compared with adult patients, mandate close expert cross-disciplinary teamwork. Teams should ideally include adult and paediatric endocrinologists, oncologists, cardiologists, surgeons, geneticists, pathologists, radiologists, clinical psychologists and nuclear medicine physicians. Provision of an international Consensus Statement should improve care and outcomes for children and adolescents with these tumours.

An automated pheochromocytoma and paraganglioma lesion segmentation AI-model at whole-body 68Ga- DOTATATE PET/CT

BACKGROUND

Somatostatin receptor (SSR) targeting radiotracer 68Ga-DOTATATE is used for Positron Emission Tomography (PET)/Computed Tomography (CT) imaging to assess patients with Pheochromocytoma and paraganglioma (PPGL), rare types of Neuroendocrine tumor (NET) which can metastasize thereby becoming difficult to quantify. The goal of this study is to develop an artificial intelligence (AI) model for automated lesion segmentation on whole-body 3D DOTATATE-PET/CT and to automate the tumor burden calculation. 132 68Ga-DOTATATE PET/CT scans from 38 patients with metastatic and inoperable PPGL, were split into 70, and 62 scans, from 20, and 18 patients for training, and test sets, respectively. The training set was further divided into patient-stratified 5 folds for cross-validation. 3D-full resolution nnUNet configuration was trained with 5-fold cross-validation. The model's detection performance was evaluated at both scan and lesion levels for the PPGL test set and two other clinical cohorts with NET (n = 9) and olfactory neuroblastoma (ONB, n = 5). Additionally, quantitative statistical analysis of PET parameters including SUVmax, total lesion uptake (TLU), and total tumor volume (TTV), was conducted.

RESULTS

The nnUNet AI model achieved an average 5-fold validation dice similarity coefficient of 0.84 at the scan level. The model achieved dice similarity coefficients (DSC) of 0.88, 0.6, and 0.67 at the scan level, the sensitivity of 86%, 61.13%, and 61.64%, and a positive predictive value of 89%, 74%, and 86.54% at the lesion level for the PPGL test, NET and ONB cohorts, respectively. For PPGL cohorts, smaller lesions with low uptake were missed by the AI model (p < 0.001). Anatomical region-based failure analysis showed most of the false negative and false positive lesions within the liver for all the cohorts, mainly due to the high physiologic liver background activity and image noise on 68Ga- DOTATATE PET scans.

CONCLUSIONS

The developed deep learning-based AI model showed reliable performance for automated segmentation of metastatic PPGL lesions on whole-body 68Ga-DOTATATE-PET/CT images, which may be beneficial for tumor burden estimation for objective evaluation during therapy follow-up. https://www.

CLINICALTRIALS

gov/study/NCT03206060 , https://www.

CLINICALTRIALS

gov/study/NCT04086485 , https://www.

CLINICALTRIALS

gov/study/NCT05012098 .

Diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body diagnostic CT and MRI in the detection of spinal bone metastases associated with pheochromocytoma and paraganglioma

OBJECTIVE

To compare the diagnostic performance of [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the spine, and whole-body CT and MRI for the detection of pheochromocytoma/paraganglioma (PPGL)-related spinal bone metastases.

MATERIALS AND METHODS

Between 2014 and 2020, PPGL participants with spinal bone metastases prospectively underwent [68Ga]DOTATATE PET/CT, [18F]FDG PET/CT, MRI of the cervical-thoracolumbar spine (MRIspine), contrast-enhanced MRI of the neck and thoraco-abdominopelvic regions (MRIWB), and contrast-enhanced CT of the neck and thoraco-abdominopelvic regions (CTWB). Per-patient and per-lesion detection rates were calculated. Counting of spinal bone metastases was limited to a maximum of one lesion per vertebrae. A composite of all functional and anatomic imaging served as an imaging comparator. The McNemar test compared detection rates between the scans. Two-sided p values were reported.

RESULTS

Forty-three consecutive participants (mean age, 41.7 ± 15.7 years; females, 22) with MRIspine were included who also underwent [68Ga]DOTATATE PET/CT (n = 43), [18F]FDG PET/CT (n = 43), MRIWB (n = 24), and CTWB (n = 33). Forty-one of 43 participants were positive for spinal bone metastases, with 382 lesions on the imaging comparator. [68Ga]DOTATATE PET/CT demonstrated a per-lesion detection rate of 377/382 (98.7%) which was superior compared to [18F]FDG (72.0%, 275/382, p < 0.001), MRIspine (80.6%, 308/382, p < 0.001), MRIWB (55.3%, 136/246, p < 0.001), and CTWB (44.8%, 132/295, p < 0.001). The per-patient detection rate of [68Ga]DOTATATE PET/CT was 41/41 (100%) which was higher compared to [18F]FDG PET/CT (90.2%, 37/41, p = 0.13), MRIspine (97.6%, 40/41, p = 1.00), MRIWB (95.7%, 22/23, p = 1.00), and CTWB (81.8%, 27/33, p = 0.03).

CONCLUSIONS

[68Ga]DOTATATE PET/CT should be the modality of choice in PPGL-related spinal bone metastases due to its superior detection rate.

CLINICAL RELEVANCE STATEMENT

In a prospective study of 43 pheochromocytoma/paraganglioma participants with spinal bone metastases, [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% (377/382), compared to [18F]FDG PET/CT (p < 0.001), MRI of the spine (p < 0.001), whole-body CT (p < 0.001), and whole-body MRI (p < 0.001).

KEY POINTS

• Data regarding head-to-head comparison between functional and anatomic imaging modalities to detect spinal bone metastases in pheochromocytoma/paraganglioma are limited. • [68Ga]DOTATATE PET/CT had a superior per-lesion detection rate of 98.7% in the detection of spinal bone metastases associated with pheochromocytoma/paraganglioma compared to other imaging modalities: [18]F-FDG PET/CT, MRI of the spine, whole-body CT, and whole-body MRI. • [68Ga]DOTATATE PET/CT should be the modality of choice in the evaluation of spinal bone metastases associated with pheochromocytoma/paraganglioma.

Adverse skeletal related events in patients with bone-metastatic pheochromocytoma/paraganglioma

Metastatic pheochromocytomas and paragangliomas (PPGLs) are frequently associated with skeletal complications. Primary objective: to describe the frequency of adverse skeletal related events (SREs) in PPGL patients with bone metastases (BMs). Secondary objectives: to 1) identify predictive and prognostic factors for SREs and 2) obtain information on the effectiveness of bone resorption inhibitors in reducing SRE risk and improving outcomes in term of survival and SREs time onset. In this retrospective multicenter, multinational study, 294 PPGL patients were enrolled. SREs occurred in 90 patients (31 %). Fifty-five patients (19 %) had bone fractures, 47 (16 %) had spinal cord compression, and 11 (4 %) had hypercalcemia. Twenty-two patients (7 %) had more than one SRE. Sixty-four patients (22 %) underwent surgery, and 136 (46 %) underwent radiotherapy. SREs occurred a median of 4.4 months after diagnosis of BM (range, 0-246.6 months). Independent factors associated with reduced risk of SREs in multivariable analysis were I-131-MIBG radionuclide therapy (hazard ratio [HR], 0.536 [95 % CI, 0.309-0.932]; P = .027) and absence of liver metastases (HR, 0.638 [95 % CI, 0.410-0.992]; P = .046). The median overall survival duration was 5.3 year. In multivariable analysis, age younger than 48 years at PPGL diagnosis (HR, 0.558 [95 % CI, 0.3877-0.806]; P = .002), absence of liver metastases (HR, 0.618 [95 % CI, 0.396-0.965]; P = .034), treatment with bisphosphonates or denosumab (HR, 0.598 [95 % CI, 0.405-0.884]; P = .010), and MIBG radionuclide therapy (HR, 0.444 [95 % CI, 0.274-0.718]; P = .001) were associated with a reduced risk of death. SREs occur frequently and early in bone-metastatic PPGL patients but do not negatively impact survival. MIBG radionuclide therapy and treatment with bone resorption inhibitors are associated with favorable outcome.

Approach to the Patient: Concept and Application of Targeted Radiotherapy in the Paraganglioma Patient

Paragangliomas can metastasize, posing potential challenges both in symptomatic management and disease control. Systemic targeted radiotherapies using 131I-MIBG and 177Lu-DOTATATE are a mainstay in the treatment of metastatic paragangliomas. This clinical scenario and discussion aim to enhance physicians' knowledge of the stepwise approach to treat these patients with paraganglioma-targeted radiotherapies. It comprehensively discusses current approaches to selecting paraganglioma patients for targeted radiotherapies and how to choose between the two radiotherapies based on specific patient and tumor characteristics, when either therapy is feasible, or one is superior to another. The safety, efficacy, toxicity profiles, and optimization of these radiotherapies are also discussed, along with other therapeutic options including radiotherapies, available for patients besides these two therapies. Perspectives in radiotherapies of paraganglioma patients are outlined since they hold promising approaches in the near future that can improve patient outcomes.

Management of metastatic pheochromocytomas and paragangliomas: when and what

Recently, the treatment landscape for metastatic pheochromocytomas and paragangliomas (MPPGL) has seen both progress and setbacks. We provide an up-to-date review of the multimodality management of MPPGL and discuss novel opportunities and current challenges in the treatment landscape. Given the unique clinical presentation of MPPGL, we discuss the management of hormone-related clinical sequelae and traditional modalities of therapy. Advances in the understanding of the molecular biology of these diverse tumors have enabled novel strategies such as augmenting DNA damage by targeted delivery of radionuclides such as 131I and 177Lu, abrogating tumor angiogenesis, hypoxia resistance, and DNA damage repair. Despite progress, we address the significant challenges still faced by patients and researchers engaged in efforts to improve outcomes in these rare cancers.

High-Specific-Activity 131 I-MIBG for the Treatment of Advanced Pheochromocytoma and Paraganglioma

PATIENTS AND METHODS

The primary endpoints were objective response rate (ORR) and disease control rate (DCR). Secondary endpoints were duration of response, blood pressure control, safety, overall and progression-free survival rates, MIBG uptake, and correlations with genetic background.

RESULTS

The study included 25 patients. Twenty-four patients had distant metastases, 17 (68%) had hormonally active tumors, and 13 (52%) had previously received antineoplastic treatment. In 24 evaluable patients, the ORR was 38%, including 2 patients with complete response, and the DCR was 83%; median time to response was 12.5 months (95% confidence interval, 4.6-25.1). Twelve patients had sporadic disease, among whom the ORR was 25% and DCR was 83%. Twelve patients had hereditary disease ( SDHB , VHL , RET ); among these, the ORR was 50%, and DCR was 83%. Plasma metanephrines normalized in 30% of patients and improved by greater than 50% in 46%. Sixteen patients had hormonally active tumors and hypertension; in 9 (56%) of these, blood pressure normalized, leading to discontinuation of antihypertensive therapy.The most common adverse events were grades 1-2 nausea/vomiting and transient bone marrow suppression. One patient developed premature ovarian failure. Reversible grades 3-4 myelosuppression were seen in 7 patients (28%). One patient had fatal pneumonitis.

CONCLUSIONS

HSA- 131 I-MIBG is associated with a high DCR in patients with MPPGL, regardless of underlying genetic mutation.

Imaging of Pheochromocytomas and Paragangliomas

Pheochromocytomas/paragangliomas are unique in their highly variable molecular landscape driven by genetic alterations, either germline or somatic. These mutations translate into different clusters with distinct tumor locations, biochemical/metabolomic features, tumor cell characteristics (eg, receptors, transporters), and disease course. Such tumor heterogeneity calls for different imaging strategies in order to provide proper diagnosis and follow-up. This also warrants selection of the most appropriate and locally available imaging modalities tailored to an individual patient based on consideration of many relevant factors including age, (anticipated) tumor location(s), size, and multifocality, underlying genotype, biochemical phenotype, chance of metastases, as well as the patient's personal preference and treatment goals. Anatomical imaging using computed tomography and magnetic resonance imaging and functional imaging using positron emission tomography and single photon emission computed tomography are currently a cornerstone in the evaluation of patients with pheochromocytomas/paragangliomas. In modern nuclear medicine practice, a multitude of radionuclides with relevance to diagnostic work-up and treatment planning (theranostics) is available, including radiolabeled metaiodobenzylguanidine, fluorodeoxyglucose, fluorodihydroxyphenylalanine, and somatostatin analogues. This review amalgamates up-to-date imaging guidelines, expert opinions, and recent discoveries. Based on the rich toolbox for anatomical and functional imaging that is currently available, we aim to define a customized approach in patients with (suspected) pheochromocytomas/paragangliomas from a practical clinical perspective. We provide imaging algorithms for different starting points for initial diagnostic work-up and course of the disease, including adrenal incidentaloma, established biochemical diagnosis, postsurgical follow-up, tumor screening in pathogenic variant carriers, staging and restaging of metastatic disease, theranostics, and response monitoring.

Cabozantinib in patients with unresectable and progressive metastatic phaeochromocytoma or paraganglioma (the Natalie Trial): a single-arm, phase 2 trial

BACKGROUND

Metastatic phaeochromocytomas and paragangliomas (MPPGs) are orphan diseases. Up to 50% of MPPGs are associated with germline pathogenic variants of the SDHB gene. These tumours and many non-familial MPPGs exhibit a phenotype that is characterised by abnormal angiogenesis. We aimed to assess the activity and safety of cabozantinib, an antiangiogenic multi-tyrosine kinase inhibitor, in patients with MPPGs.

METHODS

The Natalie Trial is a single-arm, phase 2 clinical trial being conducted at The University of Texas MD Anderson Cancer Center (Houston, TX, USA). Patients aged 18 years or older with histologically confirmed, progressive, and unresectable MPPGs, with an Eastern Cooperative Oncology Group performance status of 0-2, were treated with oral cabozantinib 60 mg/day. The primary endpoint was the investigator-assessed overall response rate per the Response Evaluation Criteria in Solid Tumours version 1.1 criteria. All outcomes were assessed in all evaluable participants who received any amount of study treatment. The trial is registered with ClinicalTrials.gov (NCT02302833) and is active but not recruiting.

FINDINGS

From March 10, 2015, to May 11, 2021, 17 patients (13 male participants and four female participants) were enrolled. The median follow-up was 25 months (IQR 18-49). The overall response rate was 25·0% (95% CI 7·3-52·4; four of 16 patients). Seven grade 3 adverse events were reported in six patients, including single cases of hand-and-foot syndrome, hypertension, rectal fistula, QT prolongation, and asymptomatic hypomagnesaemia, and two cases of asymptomatic elevations of amylase and lipase. There were no grade 4 adverse events and no patient died on-study.

INTERPRETATION

Cabozantinib shows promising activity in patients with MPPGs.

FUNDING

Team NAT Foundation, Margaret Cazalot, and Clarence P Cazalot.

Management of phaeochromocytoma and paraganglioma in patients with germline SDHB pathogenic variants: an international expert Consensus statement

Adult and paediatric patients with pathogenic variants in the gene encoding succinate dehydrogenase (SDH) subunit B (SDHB) often have locally aggressive, recurrent or metastatic phaeochromocytomas and paragangliomas (PPGLs). Furthermore, SDHB PPGLs have the highest rates of disease-specific morbidity and mortality compared with other hereditary PPGLs. PPGLs with SDHB pathogenic variants are often less differentiated and do not produce substantial amounts of catecholamines (in some patients, they produce only dopamine) compared with other hereditary subtypes, which enables these tumours to grow subclinically for a long time. In addition, SDHB pathogenic variants support tumour growth through high levels of the oncometabolite succinate and other mechanisms related to cancer initiation and progression. As a result, pseudohypoxia and upregulation of genes related to the hypoxia signalling pathway occur, promoting the growth, migration, invasiveness and metastasis of cancer cells. These factors, along with a high rate of metastasis, support early surgical intervention and total resection of PPGLs, regardless of the tumour size. The treatment of metastases is challenging and relies on either local or systemic therapies, or sometimes both. This Consensus statement should help guide clinicians in the diagnosis and management of patients with SDHB PPGLs.

Bone metastasis manifested 52 years after resection of an apparently benign paraganglioma: A case report

Paraganglioma is derived from the paraganglia tissue in the neck, along the sympathetic trunk, and in the pelvis. Paraganglioma has malignant potential and can metastasize to remote organs such as the liver, lungs, and bones. Most metachronous metastases occur within several years after the initial diagnosis of paraganglioma. Here, we report the case of a 71-year-old male patient who developed bony metastasis 52 years after the resection of a large paraganglioma at the aortic bifurcation. The biopsy-proven paraganglioma metastasis to the lesser trochanter of left femur presented as an avulsion fracture. His normetanephrine level was elevated. DOTATATE PET (positron emission tomography) did not find any other metastatic lesions. The bony metastasis was treated with radiation therapy. We believe that the patient had one of the longest gaps ever reported, 52 years, between the initial diagnosis and metastasis of paraganglioma. This case highlights the importance of long-term surveillance of patients with paraganglioma for metastasis.

[French recommendations for malignant pheochromocytomas and paragangliomas by the national ENDOCAN-COMETE network]

Pheochromocytomas and paragangliomas are rare neuroendocrine tumors, developed respectively in the adrenal medulla and in extra-adrenal locations. Their malignancy is defined by the presence of distant metastases. Forty percent of them are inherited and can be part of different hereditary syndromes. Their management is ensured in France by the multidisciplinary expert centers of the ENDOCAN-COMETE national network "Cancers of the Adrenal gland", certified by the National Cancer Institute and discussed within multidisciplinary team meetings. The diagnostic and therapeutic work-up must be standardized, based on an expert analysis of clinical symptoms, hormonal biological secretions, genetics, morphological and specific metabolic imaging. In the context of a heterogeneous survival sometimes beyond seven to ten years, therapeutic intervention must be justified. This is multidisciplinary and relies on surgery, interventional radiology, external or internal radiotherapy and medical treatments such as sunitinib or dacarbazine and temodal chemotherapy. The personalized approach based on functional imaging fixation status and genetics is progressing despite the extreme rarity of this disease.

Surgical Treatment of Spinal Metastatic Pheochromocytoma and Paraganglioma: A Single Institutional Cohort of 18 Patients

STUDY DESIGN

Retrospective Cohort Study.

OBJECTIVES

To describe surgeries and treatment outcomes of metastatic pheochromocytomas and paragangliomas (PPGLs) on the spine.

METHODS

We reviewed a cohort of 18 patients with spinal PPGLs who were consecutively treated in our spinal center. Their clinical data was reviewed. The survival period and its relevant factors was then analyzed.

RESULTS

The cohort included ten cases of pheochromocytomas and eight paragangliomas. The local pain and neurological deficits were the two most common symptoms. One third of the spinal PPGLs were diagnosed as functional tumors, arousing secondary hypertension. The imaging features were consistent with those of osteolytic lesions. The surgical strategies for the cohort included percutaneous vertebroplasty, neurological decompression and partial tumor resection, and total en-bloc resection. The postoperative courses were uneventful except 1 patient developed heart failure. The adjuvant therapies were implemented in 6 patients with 131I-MIBG, five with radiotherapy, two with chemotherapy, and 1 with target therapy. The median survival period was 39 months, and the overall survival rate of 1 year was 77.8% (14/18). The patients' Karnofsky performance scores were positively correlated with the survival period (P < .05).

CONCLUSION

Surgery is indicated for intractable local pain and neurological impairment in the patients with spinal PPGLs. Palliative surgical strategies, including neurological decompression and partial tumor resection, could bring fair outcomes, especially for the patients in poor physical conditions.

Image-Guided Precision Medicine in the Diagnosis and Treatment of Pheochromocytomas and Paragangliomas

In this comprehensive review, we aimed to discuss the current state-of-the-art medical imaging for pheochromocytomas and paragangliomas (PPGLs) diagnosis and treatment. Despite major medical improvements, PPGLs, as with other neuroendocrine tumors (NETs), leave clinicians facing several challenges; their inherent particularities and their diagnosis and treatment pose several challenges for clinicians due to their inherent complexity, and they require management by multidisciplinary teams. The conventional concepts of medical imaging are currently undergoing a paradigm shift, thanks to developments in radiomic and metabolic imaging. However, despite active research, clinical relevance of these new parameters remains unclear, and further multicentric studies are needed in order to validate and increase widespread use and integration in clinical routine. Use of AI in PPGLs may detect changes in tumor phenotype that precede classical medical imaging biomarkers, such as shape, texture, and size. Since PPGLs are rare, slow-growing, and heterogeneous, multicentric collaboration will be necessary to have enough data in order to develop new PPGL biomarkers. In this nonsystematic review, our aim is to present an exhaustive pedagogical tool based on real-world cases, dedicated to physicians dealing with PPGLs, augmented by perspectives of artificial intelligence and big data.

Management of pheochromocytomas and paragangliomas: Review of current diagnosis and treatment options

Pheochromocytomas (PCCs) are rare neuroendocrine tumors derived from the chromaffin cells of the adrenal medulla. When these tumors have an extra-adrenal location, they are called paragangliomas (PGLs) and arise from sympathetic and parasympathetic ganglia, particularly of the para-aortic location. Up to 25% of PCCs/PGLs are associated with inherited genetic disorders. The majority of PCCs/PGLs exhibit indolent behavior. However, according to their affiliation to molecular clusters based on underlying genetic aberrations, their tumorigenesis, location, clinical symptomatology, and potential to metastasize are heterogenous. Thus, PCCs/PGLs are often associated with diagnostic difficulties. In recent years, extensive research revealed a broad genetic background and multiple signaling pathways leading to tumor development. Along with this, the diagnostic and therapeutic options were also expanded. In this review, we focus on the current knowledge and recent advancements in the diagnosis and treatment of PCCs/PGLs with respect to the underlying gene alterations while also discussing future perspectives in this field.

Clinical consensus guideline on the management of phaeochromocytoma and paraganglioma in patients harbouring germline SDHD pathogenic variants

Patients with germline SDHD pathogenic variants (encoding succinate dehydrogenase subunit D; ie, paraganglioma 1 syndrome) are predominantly affected by head and neck paragangliomas, which, in almost 20% of patients, might coexist with paragangliomas arising from other locations (eg, adrenal medulla, para-aortic, cardiac or thoracic, and pelvic). Given the higher risk of tumour multifocality and bilaterality for phaeochromocytomas and paragangliomas (PPGLs) because of SDHD pathogenic variants than for their sporadic and other genotypic counterparts, the management of patients with SDHD PPGLs is clinically complex in terms of imaging, treatment, and management options. Furthermore, locally aggressive disease can be discovered at a young age or late in the disease course, which presents challenges in balancing surgical intervention with various medical and radiotherapeutic approaches. The axiom-first, do no harm-should always be considered and an initial period of observation (ie, watchful waiting) is often appropriate to characterise tumour behaviour in patients with these pathogenic variants. These patients should be referred to specialised high-volume medical centres. This consensus guideline aims to help physicians with the clinical decision-making process when caring for patients with SDHD PPGLs.

Surgical management and outcomes of spinal metastasis of malignant adrenal tumor: A retrospective study of six cases and literature review

Purpose

Spinal metastasis of malignant adrenal tumor (SMMAT) is an extremely rare and poorly understood malignant tumor originating from the adrenal gland. The objective of this study is to elucidate the clinical characteristics and discuss surgical management and outcomes of SMMAT.

Methods

Included in this study were six SMMAT patients who received surgical treatment in our center between February 2013 and May 2022. Their clinical data and outcomes were retrospectively analyzed to gain a better understanding of SMMAT. In addition, ten cases from the literature focusing on SMMAT were also reviewed.

Results

Surgery was performed successfully, and the associated symptoms were relieved significantly in all patients postoperatively. The mean follow-up duration was 26.2 (range 3-55) months. Two patients died of tumor recurrence 12 and 48 months after operation respectively. The other four patients were alive at the last follow-up.

Conclusions

The prognosis of SMMAT is usually poor. Preoperative embolization and early surgical radical resection can offer satisfactory clinical outcomes. The patient's health status, preoperative neurological function, tumor location and the resection mode are potential prognostic factors of SMMAT.

Prognostic value of [18F]FDG-PET prior to [131I]MIBG treatment for pheochromocytoma and paraganglioma (PPGL)

OBJECTIVE

Pheochromocytomas and paragangliomas (PPGLs) are rare tumors arising from the neural crest cells that form the sympathetic and parasympathetic nervous systems. Radiotherapy with [¹³¹I]metaiodobenzylguanidine (MIBG) is recommended for unresectable PPGLs. We investigated the usefulness of the metabolic tumor volume (MTV) and total lesion glycolysis (TLG) derived from [¹⁸F]fluorodeoxyglucose-positron emission tomography (FDG-PET) for predicting the prognosis of patients with unresectable PPGL(s) before receiving [¹³¹I]MIBG therapy.

PATIENTS AND METHODS

We retrospectively analyzed the cases of 25 patients with unresectable PPGLs treated with [¹³¹I]MIBG at our hospital between 2001 and 2020. The MTV and TLG were measured in reference to liver accumulation. We divided the patients into two groups based on median values for the maximum standardized uptake value (SUVmax), MTV, and TLG, and evaluated between-group differences using log-rank tests. Cox proportional hazards models were used to determine whether there were significant differences in prognosis with respect to tumor type (pheochromocytoma vs. paraganglioma), site of metastasis, age, past treatment (chemotherapy, external radiation or [¹³¹I]MIBG treatment before the current [¹³¹I]MIBG treatment), urinary catecholamine, SUVmax, MTV, and TLG.

RESULTS

The median follow-up time was 42 months (range 2-136 months). The median overall survival was 63 months. The overall survival (OS) was significantly shorter in the high-MTV group (log-rank test, p = 0.049) and the high-TLG group (p = 0.049), with no significant difference between the high- and low-SUVmax groups (p = 0.19). Likewise, there was no significant difference in prognosis according to pheochromocytoma or paraganglioma, metastasis location, age, or prior chemotherapy. A history of external radiation before [¹³¹I]MIBG treatment was associated with a significantly worse prognosis (hazard ration [HR] = 7.95, p = 0.0018). Urinary adrenaline and noradrenaline were not significant prognostic factors (p = 0.70, p = 0.25, respectively), but urinary dopamine did predict a worse outcome (p = 0.022). There was no increased risk of death for higher SUVmax or TLG (p = 0.63 and 0.057, respectively), but higher MTV did predict a worse outcome (HR = 7.27, p = 0.029).

CONCLUSION

High MTV and high TLG were significantly associated with a poor prognosis after [¹³¹I]MIBG therapy for PPGLs. Other treatment strategies for such patients may need to be explored.

TNM Staging and Overall Survival in Patients with Pheochromocytoma and Sympathetic Paraganglioma

BACKGROUND

Pheochromocytomas and paragangliomas (PPGL) are rare neuroendocrine tumors. Metastases develop in 15-20%. The American Joint Committee on Cancer (AJCC) established inaugural guidelines for PPGL tumor-node-metastasis (TNM) staging. The objective of this analysis is to investigate the associations between TNM staging and overall survival (OS).

METHODS

We retrospectively applied the TNM staging at the time of diagnosis of the primary tumor. The primary outcome was OS. Unadjusted survival rates were estimated by the Kaplan-Meier method. Cox proportional hazards regression models were used to evaluate the associations between OS and covariates of interest.

RESULTS

The study included 458 patients. Median OS was 18.0 (95% CI: 15.6-not reached) years. At diagnosis, 126 (27.5%) tumors were stage I, 213 (46.5%) were stage II, 47 (10.3%) were stage III, and 72 (15.7%) were stage IV. The 10-year OS probabilities were 0.844 (95% CI: 0.768-0.928) for patients with stage I tumors, 0.792 (95% CI: 0.726-0.865) for stage II, 0.595 (95% CI: 0.435-0.813) for stage III, and 0.221 (95% CI: 0.127-0.384) for stage IV. Compared with stage I, the hazard ratios (HR) for death were 1.50 (0.87-2.57) for stage II, 2.85 (1.45-5.63) for stage III, and 8.88 (5.16-15.29) for stage IV (p < 0.001). Compared with patients with no germline mutations, those with RET 634/918 had better OS (HR: 0.28, 95% CI: 0.12-0.69). Other germline mutations, including SDHB, did not exhibit worse OS than patients with metastasis and sporadic disease.

CONCLUSIONS

OS rates correlated with the recently developed AJCC TNM staging and was not worse in hereditary disease. Stage IV disease exhibited a significantly shorter OS compared with stages I-III. Future staging systems could be adjusted to better separate stages I and II.

Performances of Functional and Anatomic Imaging Modalities in Succinate Dehydrogenase A-Related Metastatic Pheochromocytoma and Paraganglioma

Simple Summary

Pheochromocytoma and paraganglioma (PPGL) are rare neuroendocrine cancers which carry the risk of metastatic disease. Pathogenic variants in the succinate dehydrogenase subunit A gene (SDHA) have been shown to cause metastatic disease, occurring in various regions of the body. Imaging is an early and vital step in the diagnosis and clinical care of these patients. The study here identifies which imaging modality among positron emission tomography (PET), computed tomography (CT), and magnetic resonance imaging (MRI) performs better in localizing metastatic PPGL lesions related to SDHA. The study identified that ⁶⁸Ga-DOTATATE PET/CT performed best at overall lesion detection; however, ¹⁸F-FDG PET/CT performed better in certain anatomic regions of the body. A combined approach with ⁶⁸Ga-DOTATATE and ¹⁸F-FDG would optimize care and guide clinicians in selecting the appropriate interventions and therapies.

Abstract

The study identifies the importance of positron emission tomographic (PET) and anatomic imaging modalities and their individual performances in detecting succinate dehydrogenase A (SDHA)-related metastatic pheochromocytoma and paraganglioma (PPGL). The detection rates of PET modalities—⁶⁸Ga-DOTATATE, ¹⁸F-FDG, and ¹⁸F-FDOPA—along with the combination of computed tomography (CT) and magnetic resonance imaging (MRI) are compared in a cohort of 11 patients with metastatic PPGL in the setting of a germline SDHA mutation. The imaging detection performances were evaluated at three levels: overall lesions, anatomic regions, and a patient-by-patient basis. ⁶⁸Ga-DOTATATE PET demonstrated a lesion-based detection rate of 88.6% [95% confidence interval (CI), 84.3–92.5%], while ¹⁸F-FDG, ¹⁸F-FDOPA, and CT/MRI showed detection rates of 82.9% (CI, 78.0–87.1%), 39.8% (CI, 30.2–50.2%), and 58.2% (CI, 52.0–64.1%), respectively. The study found that ⁶⁸Ga-DOTATATE best detects lesions in a subset of patients with SDHA-related metastatic PPGL. However, ¹⁸F-FDG did detect more lesions in the liver, mediastinum, and abdomen/pelvis anatomic regions, showing the importance of a combined approach using both PET modalities in evaluating SDHA-related PPGL.

Effects of Wnt-β-catenin signaling and sclerostin on the phenotypes of rat pheochromocytoma PC12 cells

Pheochromocytomas and paragangliomas (PPGLs) are classified into 3 major categories with distinct driver genes: pseudohypoxia, kinase signaling, and Wnt-altered subtypes. PPGLs in the Wnt-altered subtype are sporadic and tend to be aggressive with metastasis, where somatic gene fusions affecting mastermind-like 3 (MAML3) and somatic mutations in cold shock domain containing E1 (CSDE1) cause overactivation of Wnt-β-catenin signaling. However, the relation between Wnt-β-catenin signaling and the biological behavior of PPGLs remains unexplored. In rat pheochromocytoma PC12 cells, Wnt3a treatment enhanced cell proliferation and suppressed mRNA expression of tyrosine hydroxylase (TH), i.e. the rate-limiting enzyme of catecholamine biosynthesis, and dopamine secretion. We identified the expression of sclerostin in PC12 cells, which is known as an osteocyte-derived negative regulator for Wnt signaling-driven bone formation. Inhibition of endogenous Wnt pathway by XAV939 or sclerostin resulted in attenuated cell proliferation and increased TH expression. Furthermore, Wnt3a pretreatment suppressed bone morphogenetic protein (BMP)-induced Smad1/5/9 phosphorylation whereas BMPs enhanced sclerostin expression in PC12 cells. In the Wnt-altered subtype, the increased Wnt-β-catenin pathway may contribute the aggressive clinical behavior with reduced catecholamine production. Furthermore, up-regulated expression of sclerostin by BMPs may explain the osteolytic metastatic lesions observed in metastatic PPGLs.

Rare Bone Metastasis of Neuroendocrine Tumors of Unknown Origin: A Case Report and Literature Review

BACKGROUND

The neuroendocrine tumor (NET) is rare, accounting for about 0.5% of all tumors. NETs have the characteristics of metastasis, especially lymph nodes, liver, spleen, and bone.

CASE PRESENTATION

We report a 30-year-old man diagnosed with a NET with bone metastasis and presented with waist and leg pain. The imaging findings of this case showed multiple osteosclerosis and no apparent bone destruction. We collected the patient's previous examinations, including laboratory, imaging, and pathological examination to get a precise diagnosis. Given this case, we carried out symptomatic support treatment to relieve the patients' pain symptoms.

CONCLUSION

Bone metastases from NETs of unknown primary site are rare in both clinical and imaging manifestations. The disease is mainly manifested as multiple osteosclerosis, accompanied by muscle soreness and pain. It is recommended to try chemotherapy for this disorder.

Supportive management of patients with pheochromocytoma/paraganglioma undergoing noninvasive treatment

PURPOSE OF REVIEW

Many publications review perioperative management of pheochromocytomas/paragangliomas (PPGLs); however, a large population, including 10-20% of metastatic PPGL patients, have inoperable disease. This has necessitated the development of noninvasive treatments (e.g., radio/chemotherapy), which, in affording disease-modification, have led to an ever-growing population of surviving patients with inoperable PPGL. These patients experience debilitating symptoms arising from discomforts related to the masses themselves (e.g., pain from osseous metastasis) and symptoms from tumoral catecholamine production and release. Unfortunately, management of these conditions is not yet well-defined. Adding further insult-to-injury, these noninvasive treatments can trigger catecholamine release, worsening catecholamine-induced symptoms. Herein, we detail these ailments and their management, especially while patients receive these noninvasive treatments.

RECENT FINDINGS

Improved diagnostic evaluations have allowed for earlier detection of PPGL, prolonging survival in patients with inoperable PPGLs. Accordingly, noninvasive treatment strategies have rapidly evolved alongside state-of- the-art theranostics and genetic testing, which inform ongoing management and therapeutic response.

SUMMARY

While treatments afford improved survival, there must be a corresponding attention to quality-of-life. This is ensured by employing supportive management, which mitigates debilitating symptoms. This is best accomplished with a multidisciplinary approach and familiarity with genetic and biochemical determinants which guide patient education and management.

Personalized Management of Pheochromocytoma and Paraganglioma

Pheochromocytomas/paragangliomas are characterized by a unique molecular landscape that allows their assignment to clusters based on underlying genetic alterations. With around 30% to 35% of Caucasian patients (a lower percentage in the Chinese population) showing germline mutations in susceptibility genes, pheochromocytomas/paragangliomas have the highest rate of heritability among all tumors. A further 35% to 40% of Caucasian patients (a higher percentage in the Chinese population) are affected by somatic driver mutations. Thus, around 70% of all patients with pheochromocytoma/paraganglioma can be assigned to 1 of 3 main molecular clusters with different phenotypes and clinical behavior. Krebs cycle/VHL/EPAS1-related cluster 1 tumors tend to a noradrenergic biochemical phenotype and require very close follow-up due to the risk of metastasis and recurrence. In contrast, kinase signaling-related cluster 2 tumors are characterized by an adrenergic phenotype and episodic symptoms, with generally a less aggressive course. The clinical correlates of patients with Wnt signaling-related cluster 3 tumors are currently poorly described, but aggressive behavior seems likely. In this review, we explore and explain why cluster-specific (personalized) management of pheochromocytoma/paraganglioma is essential to ascertain clinical behavior and prognosis, guide individual diagnostic procedures (biochemical interpretation, choice of the most sensitive imaging modalities), and provide personalized management and follow-up. Although cluster-specific therapy of inoperable/metastatic disease has not yet entered routine clinical practice, we suggest that informed personalized genetic-driven treatment should be implemented as a logical next step. This review amalgamates published guidelines and expert views within each cluster for a coherent individualized patient management plan.

Overview of the 2022 WHO Classification of Paragangliomas and Pheochromocytomas

This review summarizes the classification of tumors of the adrenal medulla and extra-adrenal paraganglia as outlined in the 5th series of the WHO Classification of Endocrine and Neuroendocrine Tumors. The non-epithelial neuroendocrine neoplasms (NENs) known as paragangliomas produce predominantly catecholamines and secrete them into the bloodstream like hormones, and they represent a group of NENs that have exceptionally high genetic predisposition. This classification discusses the embryologic derivation of the cells that give rise to these lesions and the historical evolution of the terminology used to classify their tumors; paragangliomas can be sympathetic or parasympathetic and the term pheochromocytoma is used specifically for intra-adrenal paragangliomas that represent the classical sympathetic form. In addition to the general neuroendocrine cell biomarkers INSM1, synaptophysin, and chromogranins, these tumors are typically negative for keratins and instead have highly specific biomarkers, including the GATA3 transcription factor and enzymes involved in catecholamine biosynthesis: tyrosine hydroxylase that converts L-tyrosine to L-DOPA as the rate-limiting step in catecholamine biosynthesis, dopamine beta-hydroxylase that is present in cells expressing norepinephrine, and phenylethanolamine N-methyltransferase, which converts norepinephrine to epinephrine and therefore can be used to distinguish tumors that make epinephrine. In addition to these important tools that can be used to confirm the diagnosis of a paraganglioma, new tools are recommended to determine genetic predisposition syndromes; in addition to the identification of precursor lesions, molecular immunohistochemistry can serve to identify associations with SDHx, VHL, FH, MAX, and MEN1 mutations, as well as pseudohypoxia-related pathogenesis. Paragangliomas have a well-formed network of sustentacular cells that express SOX10 and S100, but this is not a distinctive feature, as other epithelial NENs also have sustentacular cells. Indeed, it is the presence of such cells and the association with ganglion cells that led to a misinterpretation of several unusual lesions as paragangliomas; in the 2022 WHO classification, the tumor formerly known as cauda equina paraganglioma is now classified as cauda equina neuroendocrine tumor and the lesion known as gangliocytic paraganglioma has been renamed composite gangliocytoma/neuroma and neuroendocrine tumor (CoGNET). Since the 4th edition of the WHO, paragangliomas have no longer been classified as benign and malignant, as any lesion can have metastatic potential and there are no clear-cut features that can predict metastatic behavior. Moreover, some tumors are lethal without metastatic spread, by nature of local invasion involving critical structures. Nevertheless, there are features that can be used to identify more aggressive lesions; the WHO does not endorse the various scoring systems that are reviewed but also does not discourage their use. The identification of metastases is also complex, particularly in patients with germline predisposition syndromes, since multiple lesions may represent multifocal primary tumors rather than metastatic spread; the identification of paragangliomas in unusual locations such as lung or liver is not diagnostic of metastasis, since these may be primary sites. The value of sustentacular cells and Ki67 labeling as prognostic features is also discussed in this new classification. A staging system for pheochromocytoma and extra-adrenal sympathetic PGLs, introduced in the 8th Edition AJCC Cancer Staging Manual, is now included. This paper also provides a summary of the criteria for the diagnosis of a composite paragangliomas and summarizes the classification of neuroblastic tumors. This review adopts a practical question-answer framework to provide members of the multidisciplinary endocrine oncology team with a most up-to-date approach to tumors of the adrenal medulla and extra-adrenal paraganglia.

Pheochromocytomas and Abdominal Paragangliomas: A Practical Guidance

Simple Summary

Pheochromocytomas and abdominal paragangliomas (PPGLs) are rare. They can be discovered incidentally by imaging with computed tomography or magnetic resonance imaging and during hormonal surveillance in patients with known genetic variants that are associated with PPGLs. As most PPGLs are functioning, a hormonal work-up evaluating for catecholamine excess is recommended. Classical symptoms, such as tachycardia, hypertension and headache, can be present, but when the PPGL is discovered as an incidentaloma, symptoms may be lacking or be more discrete. PPGLs carry malignant potential, and patients should undergo close surveillance, as recurrence of disease or metastasis may develop. Genetic susceptibility for multifocal disease has gained more attention, and germline variants are commonly detected, thus facilitating detection of hereditary cases and afflicted family members. Any patient with a PPGL should be managed by an expert multidisciplinary team consisting of endocrinologists, radiologists, surgeons, pathologists and clinical geneticists.

Abstract

Pheochromocytomas and abdominal paragangliomas (PPGLs) are rare tumors arising from the adrenal medulla or the sympathetic nervous system. This review presents a practical guidance for clinicians dealing with PPGLs. The incidence of PPGLs has risen. Most cases are detected via imaging and less present with symptoms of catecholamine excess. Most PPGLs secrete catecholamines, with diffuse symptoms. Diagnosis is made by imaging and tests of catecholamines. Localized disease can be cured by surgery. PPGLs are the most heritable of all human tumors, and germline variants are found in approximately 30–50% of cases. Such variants can give information regarding the risk of developing recurrence or metastases as well as the risk of developing other tumors and may identify relatives at risk for disease. All PPGLs harbor malignant potential, and current histological and immunohistochemical algorithms can aid in the identification of indolent vs. aggressive tumors. While most patients with metastatic PPGL have slowly progressive disease, a proportion of patients present with an aggressive course, highlighting the need for more effective therapies in these cases. We conclude that PPGLs are rare but increasing in incidence and management should be guided by a multidisciplinary team.

Neuroendocrine neoplasia and bone (Review)

This is a narrative review focusing on neuroendocrine neoplasia (NEN) and bone status, in terms of metastases and osteoporosis/fractures. One fifth of NEN have skeletal dissemination, this affinity being regulated by intrinsic tumor factors such as the C-X-C chemokine receptor 4 (CXCR4). Bone colonization impairs the patient quality of life, representing a surrogate of reduced survival. Patients with NEN without bone metastases may exhibit low bone mineral density, perhaps carcinoid-related osteoporosis, yet not a standardized cause of osteoporosis. Case-finding strategies to address bone health in NEN with a good prognosis are lacking. Contributors to fractures in NEN subjects may include: menopausal status and advanced age, different drugs, induced hypogonadism, malnutrition, malabsorption (due to intestinal resection, carcinoid syndrome), hypovitaminosis D, impaired glucose profile (due to excessive hormones such as glucagon, somatostatinoma or use of somatostatin analogues), various corticoid regimes, and high risk of fall due to sarcopenia. Pheocromocytoma/paraganglioma involve bone through malignant forms (bone is an elective site) and potential secondary osteoporosis due to excessive hormonal content and increased sympathetic activity which is a key player of bone microarchitecture/quality as reflected by low Trabecular Bone Score. Glucocorticoid osteoporosis is related to NEN-associated ectopic Cushing syndrome. Currently, there are a lack of studies to emphasis that excessive gut-derivate serotonin in NENs with carcinoid syndrome is a specific activator of bone loss thus a contributor to carcinoid-related osteoporosis.

Pheochromocytoma: A Clinicopathologic and Molecular Study of 390 Cases From a Single Center

Pheochromocytomas are rare neuroendocrine tumors arising from chromaffin cells in the adrenal medulla. They may occur sporadically or in the context of hereditary syndromes. All pheochromocytomas are considered to have malignant potential (defined as risk of metastasis, not local invasion). The use of grading systems with incorporated clinical and histopathologic parameters can help but not definitively predict the metastatic potential of pheochromocytomas. The recent discovery of susceptibility genes provided new insights into the pathogenesis and introduced additional approaches to estimate the metastatic risk of pheochromocytoma. However, the prevalence of these genetic signatures in pheochromocytomas has yet to be fully addressed. Therefore, in the present study, we retrospectively reviewed cases of pheochromocytoma from 1980 to 2018 in the archives of our institution. Three hundred ninety cases were identified, and their clinicopathologic characteristics and genetic statuses were analyzed. About 25% of the cases had metastases, which were more common in older patients (median, 49 y) than in younger ones. Univariate and multivariate analyses revealed that older age, Hispanic ethnicity, metastasis, and large primary tumor size were markedly associated with poor overall survival. In contrast, family history of pheochromocytoma, lack of symptoms, and bilateral adrenal involvement were associated with better survival. About 37% of the pheochromocytomas were associated with inherited syndromes. About 52% of tested patients had pathogenic mutations of pheochromocytoma susceptibility genes. Of these, succinate dehydrogenase B gene mutation had the strongest association with metastasis. These data support that genetic testing should be offered to all patients with pheochromocytoma.

Malignant pheochromocytoma with cerebral and skull metastasis: A case report and literature review

BACKGROUND

Malignant pheochromocytoma with cerebral and skull metastasis is a very rare disease. Combining our case with 16 previously reported cases identified from a PubMed search, an analysis of 17 cases of malignant cerebral pheochromocytoma was conducted. This literature review aimed to provide information on clinical manifestations, radiographic and histopathological features, and treatment strategies of this condition.

CASE SUMMARY

A 60-year-old man was admitted with a progressive headache and enlarging scalp mass lasting for 3 mo. Radiographic images revealed a left temporal biconvex-shaped epidural mass and multiple lytic lesions. The patient underwent a left temporal craniotomy for resection of the temporal tumor. Histopathological analysis led to identification of the mass as malignant pheochromocytoma. The patient's symptoms were alleviated at the postoperative 3-mo clinical follow-up. However, metastatic pheochromocytoma lesions were found on the right 6th rib and the 6th to 9th thoracic vertebrae on a 1-year clinical follow-up computed tomography scan.

CONCLUSION

Magnetic resonance spectroscopy and histopathological examination are necessary to make an accurate differential diagnosis between malignant cerebral pheochromocytoma and meningioma. Surgery is regarded as the first choice of treatment.

Metastatic Pheochromocytomas and Abdominal Paragangliomas

CONTEXT

Pheochromocytomas and paragangliomas (PPGLs) are believed to harbor malignant potential; about 10% to 15% of pheochromocytomas and up to 50% of abdominal paragangliomas will exhibit metastatic behavior.

EVIDENCE ACQUISITION

Extensive searches in the PubMed database with various combinations of the key words pheochromocytoma, paraganglioma, metastatic, malignant, diagnosis, pathology, genetic, and treatment were the basis for the present review.

DATA SYNTHESIS

To pinpoint metastatic potential in PPGLs is difficult, but nevertheless crucial for the individual patient to receive tailor-made follow-up and adjuvant treatment following primary surgery. A combination of histological workup and molecular predictive markers can possibly aid the clinicians in this aspect. Most patients with PPGLs have localized disease and may be cured by surgery. Plasma metanephrines are the main biochemical tests. Genetic testing is important, both for counseling and prognostic estimation. Apart from computed tomography and magnetic resonance imaging, molecular imaging using 68Ga-DOTATOC/DOTATATE should be performed. 123I-MIBG scintigraphy may be performed to determine whether 131I-MIBG therapy is a possible option. As first-line treatment in patients with metastatic disease, 177Lu-DOTATATE or 131I-MIBG is recommended, depending on which shows best expression. In patients with very low proliferative activity, watch-and-wait or primary treatment with long-acting somatostatin analogues may be considered. As second-line treatment, or first-line in patients with high proliferative rate, chemotherapy with temozolomide or cyclophosphamide + vincristine + dacarbazine is the therapy of choice. Other therapies, including sunitinib, cabozantinib, everolimus, and PD-1/PDL-1 inhibitors, have shown modest effect.

CONCLUSIONS

Metastatic PPGLs need individualized management and should always be discussed in specialized and interdisciplinary tumor boards. Further studies and newer treatment modalities are urgently needed.

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.

The North American Neuroendocrine Tumor Society Consensus Guidelines for Surveillance and Management of Metastatic and/or Unresectable Pheochromocytoma and Paraganglioma

ABSTRACT

This manuscript is the result of the North American Neuroendocrine Tumor Society consensus conference on the medical management and surveillance of metastatic and unresectable pheochromocytoma and paraganglioma held on October 2 and 3, 2019. The panelists consisted of endocrinologists, medical oncologists, surgeons, radiologists/nuclear medicine physicians, nephrologists, pathologists, and radiation oncologists. The panelists performed a literature review on a series of questions regarding the medical management of metastatic and unresectable pheochromocytoma and paraganglioma as well as questions regarding surveillance after resection. The panelists voted on controversial topics, and final recommendations were sent to all panel members for final approval.

Late diagnosis of metastatic pheochromocytoma in multiple endocrine neoplasia 2B with rapid clinical decline

Multiple endocrine neoplasia type 2B (MEN2B) is the rarest and most aggressive of the MEN syndromes. It is characterised by medullary thyroid cancer (MTC), pheochromocytoma, marfanoid body habitus, mucosal neuromas and colonic dysfunction. Patients typically present with chronic constipation and MTC in early childhood. We discuss an atypical late presentation of MEN2B in a 19-year-old man with chronic constipation since childhood admitted with acute spinal cord compression. He underwent emergent neurosurgical intervention followed by postoperative radiotherapy. Bone biopsy revealed metastatic pheochromocytoma. Thyroid nodule biopsy showed MTC. MIBG scan confirmed pheochromocytoma as the dominant malignancy. Germline testing revealed a RET mutation (p.M918T). He received one cycle of cyclophosphamide, vincristine and dacarbazine and subsequently developed a pathological right femur fracture requiring repair. Postoperative course was complicated by hypoxic respiratory failure requiring intubation. Imaging showed lymphangitic spread of disease in the lungs. He unfortunately did not respond to a short trial of sunitinib and transitioned to comfort care.

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.

Management and outcome of metastatic pheochromocytomas/paragangliomas: an overview

BACKGROUND

Metastatic pheochromocytomas and paragangliomas (PPGLs) occur in about 5-26% of cases and are characterized by a heterogeneous prognosis. Metastases can be synchronous at the initial diagnosis, but they can occur also many years after surgery for the primary tumor. To date, the treatment of patients affected by metastatic PPGLs represents a clinical challenge because of the lack of guidelines.

AIM

The aim of this article is to review the available management options and their impact on the outcomes of patients with metastatic PPGLs.

RESULTS

Generally, treatments are not curative. Surgery, when possible, can be used to reduce hormonal symptoms and cardiovascular morbidity. Chemotherapy plays a role in patients with high burden tumor and rapid disease progression. Tyrosine kinases inhibitors (TKIs) might be considered for their ability to block the angiogenesis and cell growth. Radiation therapy and interventional radiology techniques can help in the management of local metastases to control symptoms and avoid tumor progression. On the other hand, peptide receptor radionuclide therapy (PRRT), using ⁹⁰Y or ¹⁷⁷Lu-DOTATATE, could be a promising therapy. In addition, high specific ¹³¹I-MIBG was approved by the Food and Drug Administration (FDA) in the US for the treatment of patients affected by metastatic and unresectable ¹³¹I-MIBG positive PPGLs. Considering the different pathways involved in the pathogenesis of PPGLs, several target therapies have been proposed and are under evaluation in clinical trials.

CONCLUSIONS

The choice of the appropriate treatment should be based on multidisciplinary and personalized approach taking into account the rarity and the variability of these tumors.

131I-MIBG negative progressive symptomatic metastatic paraganglioma: response and outcome with 177Lu-DOTATATE peptide receptor radionuclide therapy

OBJECTIVE

The primary aim of this study was to evaluate the long-term outcome of 177Lu-DOTATATE PRRT in terms of clinical, biochemical and imaging response rates, disease control rate (DCR), progression-free survival (PFS), and overall survival (OS) in 131I-metaiodobenzylguanidine (MIBG) negative progressive/symptomatic locally advanced or metastatic paragangliomas (PGL). The secondary aims of this study were to determine clinical toxicity of 177Lu-DOTATATE and association of PFS with various variables.

MATERIALS AND METHODS

131I-MIBG negative PGL with progressive/symptomatic locally advanced or metastatic disease that underwent 177Lu-DOTATATE PRRT from 2012 to 2019 in our institute were evaluated. Standard dose activity of 5.55-7.4 GBq per cycle of 177Lu-DOTATATE was administered in somatostatin receptor (SSTR) positive PGL. Post-PRRT response was evaluated under three broad categories: (a) symptomatic, (b) biochemical, and (c) imaging (molecular and anatomic imaging). The PFS and OS since first 177Lu-DOTATATE cycle were determined. Associations of PFS with various variables were also investigated. The clinical toxicities of 177Lu-DOTATATE in PGL were determined.

RESULTS

Amongst a total of 9 PGL patients, response to 177Lu-DOTATATE was seen in six patients, two patients, four patients and three patients on symptomatic, biochemical, molecular and anatomical based imaging response evaluation categories respectively with DCR of 67%. The median PFS and OS were not reached at a median follow-up of 40 months. Estimated PFS rate of 63% (95% CI 30-96%) and OS rate of 65% (95% CI 32-97%) were noticed at 40 months. Significant association of PFS was found for site of PGL (non-HNPGL), total cumulative dose of PRRT (> 22.2 GBq), and number of PRRT cycles patient received (≥ 4cycles). 177Lu-DOTATATE was well tolerated without acute catecholamine crisis, nephrotoxicity or bone marrow suppression of any grade or high-grade (grade ≥ 2) hematological toxicities.

CONCLUSION

Our study showed favorable results with minimal low-grade and easily manageable side effects of 177Lu-DOTATATE in patients of PGL. Thus, 177Lu-DOTATATE may be considered as promising therapeutic option in 131I-MIBG negative and SSTR positive subset of PGL cases. However, further prospective study in a large number of patients is required for validation of our study results.

Epidemiology of spinal cord and column tumors

The spine is a frequent location for metastatic disease. As local control of primary tumor pathology continues to improve, survival rates improve and, by extension, the opportunity for metastasis increases. Breast, lung, and prostate cancer are the leading contributors to spinal metastases. Spinal metastases can manifest as bone pain, pathologic fractures, spinal instability, nerve root compression, and, in its most severe form, spinal cord compression. The global extent of disease, the spinal burden, neurologic status, and life expectancy help to categorize patients as to their candidacy for treatment options. Efficient identification and workup of those with spinal metastases will expedite the treatment cascade and improve quality of life.

Autopsy of malignant paraganglioma causing compressive myelopathy due to vertebral metastases

Paraganglioma is a neuroendocrine tumor arising from extra-adrenal sites in the peripheral nervous system. Although malignant paraganglioma is known to metastasize to bones, including vertebral bodies, there is little literature on the compressive myelopathy accompanied by sphincter dysfunction; to our knowledge, only 12 cases have been reported. Moreover, neuropathological investigations of the spinal cord in this state have not been well-documented. This autopsy report describes a 55-year-old man with malignant paraganglioma and compression myelopathy caused by vertebral metastasis. The present case showed a gradual numbness and a sudden onset of irreversible paraplegia with sphincter dysfunction, which were not palliated these neurologic dysfunctions despite radiotherapy. Computed tomography (CT) revealed multiple metastases to the bones, lymph nodes, and lungs when he was diagnosed with malignant paraganglioma. At the same time, he had numbness, and magnetic resonance imaging (MRI) showed multiple diffuse metastatic lesions in the vertebral bodies. Following abrupt onset of paralysis, MRI showed fractured third and sixth thoracic vertebral bodies. An autopsy revealed residual vertebral metastases with fractures of the third and sixth thoracic vertebral bodies, resulting in compressive myelopathy at the fourth thoracic segment, which was characterized by complete spinal cord destruction. Destructive spinal cord lesion-induced secondary degeneration was observed in the gracile fasciculus at the rostral side and in the pyramidal tract at the caudal side, which showed Wallerian degeneration. Such pathology was consistent with the presenting neurological symptoms, including paraplegia and somatic sensory loss below the fourth thoracic spinal cord segment. Although it is difficult to identify the pathognomonic morphological changes responsible for the sphincter dysfunction, the present case suggests a supranuclear dysregulation of the somatosensory and central autonomic nervous systems involved in urination and defecation. Based on a review of the literature and the features of the present case, paraganglioma can metastasize aggressively even with a low pathological grading. This case of vertebral metastasis as a result of malignant paraganglioma may not be extraordinary but the autopsy report is rare. This autopsy revealed transverse myelopathy as a result of malignant vertebral metastasis of malignant paraganglioma.

Phase II Clinical Trial of Pembrolizumab in Patients with Progressive Metastatic Pheochromocytomas and Paragangliomas

Metastatic pheochromocytomas and paragangliomas (MPPGs) are rare endocrine malignancies that are associated with high rates of morbidity and mortality because of their large tumor burden and location, progression, and release of catecholamines. Systemic therapies for MPPGs are limited. MPPGs are characterized by pseudohypoxia that may prevent immune system recognition. We conducted a phase II clinical trial of pembrolizumab in patients with progressive MPPGs. The primary endpoint was the non-progression rate at 27 weeks. The secondary endpoints included the objective response and clinical benefit rates, progression free and overall survival duration, and safety. We also determined whether PDL-1 expression and the presence of infiltrating mononuclear inflammatory cells in the primary tumor were associated with clinical response and hereditary background. Eleven patients were included in this trial, four (36%) with germline mutations and seven (64%) with hormonally active tumors. Four patients (40%, 95% confidence interval (CI) 12–74%) achieved the primary endpoint. The objective response rate was 9% (95% CI: 0–41%). The clinical benefit rate was 73% (95% CI: 39–94%). Four patients had grade 3 adverse events related to pembrolizumab. No patients experienced grade 4 or 5 adverse events or a catecholamine crisis. Progression free survival time was 5.7 months (95% CI: 4.37—not reached). The median survival duration was 19 months (95% CI: 9.9—not reached). PDL-1 expression and the presence of infiltrating mononuclear inflammatory cells in the primary tumor did not seem to be associated with disease response. Single-agent pembrolizumab has modest treatment efficacy in patients with progressive MPPGs. Positive responses seemed to be independent of patients’ hereditary backgrounds, tumor hormonal status, and the presence of infiltrating mononuclear inflammatory cells or PDL-1 expression in the primary tumor.

Recent advances in the management of pheochromocytoma and paraganglioma

Pheochromocytomas and paragangliomas (PPGLs) are rare tumors that cause refractory hypertension and hypertensive crisis. Although metastatic disease accounts for 30% of PPGLs, the diagnosis of malignancy is difficult without the presence of metastatic lesions. Here, we review several advancements in the diagnosis and treatment of PPGL. A nationwide epidemiological survey in Japan revealed that the annual number of patients with PPGL was 3000, which was higher than that reported previously. While plasma and urine fractionated metanephrines are recommended for use in specific biochemical testing for diagnosis, creatinine-corrected fractionated metanephrines in spot urine samples that had been widely used in Japan as a convenient screening test were shown to be as useful as 24-h urine fractionated metanephrines. Regarding imaging studies, a more specific functional imaging for PPGLs, ⁶⁸Ga DOTATATE, was newly developed. ⁶⁸Ga DOTATATE provides a clear image with high sensitivity and specificity. Currently, PASS or GAPP histological scores and SDHB immunostaining are clinically used to attempt to discriminate benign from malignant tumors. However, since this distinguishing process remains difficult, all cases were classified as malignant with the possibility of metastasis in the WHO classification of endocrine tumors updated in 2017. Approximately 60% of PPGLs have germline mutations in PPGL-related genes. Currently, the genes are classified into two clusters based on their mechanism for the etiology of tumorigenesis. Based on the possible mechanisms of tumor development associated with gene mutations, several molecular target drugs are under evaluation to explore more promising treatments for malignant PPGL.

HEREDITARY ENDOCRINE TUMOURS: CURRENT STATE-OF-THE-ART AND RESEARCH OPPORTUNITIES: Metastatic pheochromocytomas and paragangliomas: proceedings of the MEN2019 workshop

Pheochromocytomas and paragangliomas (PPGLs) are adrenal or extra-adrenal autonomous nervous system-derived tumors. Most PPGLs are benign, but approximately 15% progress with metastases (mPPGLs). mPPGLs are more likely to occur in patients with large pheochromocytomas, sympathetic paragangliomas, and norepinephrine-secreting tumors. Older subjects, those with larger tumors and synchronous metastases, advance more rapidly. Germline mutations of SDHB, FH, and possibly SLC25A11, or somatic MAML3 disruptions relate to a higher risk for metastatic disease. However, it is unclear whether these mutations predict outcome. Once diagnosed, there are no well-established predictors of outcome in mPPGLs, and aggressive tumors have few therapeutic options and limited response. High-specific activity (HSA) metaiodine-benzyl-guanidine (MIBG) is the first FDA approved treatment and shows clinical effectiveness for MIBG-avid mPPGLs. Ongoing and future investigations should involve validation of emerging candidate outcome biomarkers, including somatic ATRX, TERT, and microRNA disruptions and identification of novel prognostic indicators. Long-term effect of HSA-MIBG and the role of other radiopharmaceuticals should be investigated. Novel trials targeting molecular events prevalent in SDHB/FH mutant tumors, such as activated hypoxia inducible factor 2 (HIF2), angiogenesis, or other mitochondrial defects that might confer unique vulnerability to these tumors should be developed and initiated. As therapeutic options are anticipated to expand, multi-institutional collaborations and well-defined clinical and molecular endpoints will be critical to achieve higher success rates in improving care for patients with mPPGLs.

Paraganglioma of the Spermatic Cord With Spinal Metastasis: A Case Report

A 40-year-old male with presented to the clinic with the chief complaint of right inguinal pain radiating to his right testicle and right thigh with no history of trauma, fever, chills, dysuria, hematuria, or unprotected sexual activity. Physical exam revealed right testicular tenderness with no palpable abnormality of the bilateral testes or spermatic cords. Scrotal ultrasound was performed and was unremarkable for testicular or other intrascrotal pathology. Concurrently, chronic low back pain had prompted a lumbar CT to be performed, which was indeterminate, but subsequent lumbar MRI performed three months later revealed abnormal signals in the vertebral bodies of T12, L3, and L5, concerning for occult metastatic disease or multiple myeloma. PET-CT was performed revealing hypermetabolic lesions throughout the axial skeleton and, most notably, hypermetabolic lesions in the left inguinal and left upper scrotum. At this time, about 4 months after the original visit, physical exam revealed a palpable mobile mass in the left upper scrotum that was distinct from the left testicle, and another mass palpable near the left inguinal ring.

Pheochromocytoma and Paraganglioma: From Epidemiology to Clinical Findings

Pheochromocytomas (PCC) and paragangliomas (PGL) are rare neuroendocrine tumors. Pheochromocytomas arise from chromaffin cells in the adrenal medulla, and PGLs arise from chromaffin cells in the ganglia of the autonomic nervous system. Paragangliomas originate from sympathetic or parasympathetic ganglia in the abdomen, thorax, and pelvis. The majority of PCC and sympathetic PGL are endocrine active tumors causing clinical symptoms by secreting excess catecholamines (norepinephrine, epinephrine, dopamine) and their metabolites. The incidence of PCC and PGL ranges between 2 and 8 per million, with a prevalence between 1:2500 and 1:6500. It peaks between the 3rd and 5th decades of life, and approximately 20% of cases are pediatric patients. The prevalence among patients with hypertension in outpatient clinic ranges between 0.1-0.6% in adults and between 2-4.5% in the pediatric age group. 10-49% of these tumors is detected incidentally in imaging techniques performed for other reasons. However, 4-8% of adrenal incidentalomas are PCCs. Of these neuroendocrine tumors, 80-85% are PCCs and 15-20% are PGLs. Up to 40% of patients with PCC and PGL has disease-specific germline mutations and the situation is hereditary. Of 60% of the remaining sporadic patients, at least 1/3 has a somatic mutation in predisposing genes. 8% of the sporadic cases, 20-75% of the hereditary cases, 5% of the bilateral, adrenal cases, and 33% of the extra-adrenal cases at first presentation are metastatic. Although PCCs and PGLs have scoring systems for histological evaluation of the primary tumor, it is not possible to diagnose whether the tumor is malignant since there is no histological system approved for the biological aggressiveness of this tumor group. Metastasis is defined as the presence of chromaffin tissue in non-chromaffin organs, such as lymph nodes, liver, lungs and bone. Although most of the PCC and PGL are benign, the metastatic disease may develop in 15-17%. Metastatic disease is reported between 2-25% in PCCs and 2.4-60% in PGLs. The TNM staging system of the American Joint Committee on Cancer (AJCC) was developed to predict the prognosis, based on the specific anatomical features of the primary tumor and the occurrence of metastasis.

Bone tissue and mineral metabolism in hereditary endocrine tumors: clinical manifestations and genetic bases

Inherited endocrine tumors are neoplasms of endocrine cells, transmitted via autosomal dominant germinal mutations. They present in two different forms: non-syndromic (patient has a single affected endocrine organ during his/her lifetime) or syndromic forms (multiple tumors in endocrine and non-endocrine organs during his/her lifetime).In addition to their common tumoral manifestations, many of these diseases present clinical affection of bone tissues and/or mineral metabolism, both as secondary complications of primary tumors and as primary defects due to genetic mutation. To date, few studies have documented these bone complications, and there are no systematic reviews in this area.We present a revision of medical literature about skeletal and mineral metabolism affections in inherited endocrine tumor syndromes, and studies, in cells and animal models, investigating the direct role of some genes, whose mutations are responsible for the development of endocrine tumors, in the regulation of bone and mineral metabolism.

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.