Hypertensive Crisis during Microwave Ablation of Adrenal Neoplasms: A Retrospective Analysis of Predictive Factors

Hypertension crises and management during radiofrequency ablation of adrenal pheochromocytoma: A case report

This case report describes the radiofrequency (RF) ablation of a pheochromocytoma in a 35-year-old female with multiple endocrine neoplasia (MEN) II syndrome, who previously underwent a right adrenalectomy and thyroidectomy. The patient presented with a new tumor in the left adrenal gland, detected via imaging, without evidence of metastasis. Opting against surgical adrenalectomy due to previous surgeries, she underwent RF ablation after preparatory alpha and beta blockader. During RF ablation, a hypertensive crisis occurred, managed effectively with nitroprusside sodium and supportive measures. Postprocedure recovery was uneventful, with normal metanephrine levels and imaging indicating successful ablation. This report highlights the feasibility and challenges of using RF ablation for adrenal pheochromocytoma, suggesting a potential shift towards less invasive management for select cases.

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.

Safety and efficacy of thermal ablation of adrenal metastases secondary to lung cancer

OBJECTIVES

Assess safety and efficacy of thermal ablation for adrenal metastases (AM) secondary to non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

This retrospective study included patients with NSCLC AM treated with thermal ablation between 2/2010-11/2021. Local tumor progression free survival (LTPFS) and overall survival (OS) were calculated using Kaplan-Meier method. Adverse events were graded using Common Terminology Criteria for Adverse Events v5.

RESULTS

Seven patients (mean age ± SD, 63.9 ± 12.5 years; 6 males) with seven AM were treated in eight sessions. Retreatment was performed in one patient with residual disease. Five sessions were with microwave ablation and 3 with radiofrequency ablation. Mean tumor size was 20.1 ± 7.0 mm. Median number of ablation probes used was 1 (range, 1-5), with a median of 3 activations (range, 1-3), and average ablation time of 14.4 ± 15.0 minutes. Response based on RECIST v 1.1 or PERCIST criteria revealed stable disease in 1 tumor, progression of disease in 3 tumors (one was re-ablated), and partial response in 3 tumors. Median LTPFS was not reached (NR) [95 % CI: 1- NR]. Median OS was 47.97 months (95 % CI: 18.63- NR). Intraprocedural hypertension (blood pressure ≥180 mmHg) occurred during 5/8 (62.5 %) sessions and intraoperative tachycardia occurred during 2/8 (25 %) sessions. Complications within one month of ablation occurred in 3/8 (37.5 %) sessions: grade 2 pneumothorax, grade 1 hematuria, and grade 2 adrenal insufficiency.

CONCLUSIONS

In this small series, thermal ablation for NSCLC AM resulted in prolonged local control and OS with no major complications.

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.

Minimally invasive techniques in benign and malignant adrenal tumors

Minimally invasive adrenalectomy has become the main treatment modality for most adrenal lesions. Both laparoscopic transabdominal and retroperitoneoscopic approaches are safe and feasible options, each with respective advantages, including better surgical outcomes, fewer complications, and faster recovery over open adrenalectomy. While open surgery remains a valid modality in treatment of adrenocortical cancer in the presence of some findings such as invasion, robotic platforms, and minimally invasive surgery have gained popularity as technology continues to evolve. Organ preservation during adrenalectomy is feasible in some conditions to prevent adrenal insufficiency. Ablative technologies are increasingly utilized in benign and malignant tumors, including the adrenal gland, with various outcomes. A multidisciplinary team, an experienced surgeon, and a high-volume center are recommended for any surgical approaches and management of adrenal lesions. This review article evaluated recent findings and current evidence on minimally invasive adrenalectomy.

MWA Performed at 5.8 GHz through 'Side Firing' Approach: An Exploratory Study

Recent studies have shown that ablation techniques have the potential to eradicate adrenal adenomas while preserving the functionalities of the adrenal gland and the surrounding anatomical structures. This study explores a new microwave ablation (MWA) approach operating at 5.8 GHz and using anatomical and dielectric characteristics of the target tissue to create directional heating patterns. Numerical simulations are executed in planar and 3D adrenal models, considering two energy doses. The numerical study is refined accounting for the vaporization of the tissue water content. Ex vivo experimental evaluations on porcine adrenal models complete the study. The numerical and experimental results show that spherical ablation zones are able to cover the target for both energy doses considered. Nonetheless, most of the non-targeted tissues can be preserved from excessive heating when low energy level is used. Numerical models accounting for water vaporization are capable to foresee the experimental temperature values. This study shows that the proposed MWA directional approach operating at 5.8 GHz can be considered for creating effective and selective ablation zones.

Management of adreno-cortical adenomas using microwave ablation: study of the effects of the fat tissue

BACKGROUND AND OBJECTIVES

Adrenocortical neoplasms are the main causes of secondary hypertension and related comorbidities including hypokalemia and cardiovascular diseases. Conventional techniques for the management of this condition are often invasive and not resolutive. Recent studies proposed microwave thermal ablation (MWA) to eradicate adrenocortical adenomas arising in proximity to sensitive structures. This study explores a new MWA approach to selectively direct the electromagnetic energy into the target and shield the surrounding tissues. The new solution relies on the anatomical and dielectric characteristics of the adrenal gland and the surrounding fat capsule.

METHODS

A 3 D model of the adrenal gland is developed, and a cooled microwave applicator is placed parallel to the interface between the fat and adrenal tissue. Numerical simulations are conducted at 2.45 GHz accounting for two energy delivery settings, two orientations of the applicator and blood perfusion of the tissues. Ex vivo and in vivo ablation procedures are conducted on ovine adrenal glands. Histology analysis completes the experimental studies.

RESULTS

Numerical results show asymmetric ablation profiles in ex vivo and in vivo conditions. The asymmetry ratio is influenced by the procedure settings and orientation of the applicator. Ablation zones obtained experimentally agree with those predicted by the numerical simulations. Histology analysis confirms irreversible cellular changes only in the adrenal tissue close to the applicator.

CONCLUSIONS

The outcomes show that the dielectric contrast between the fat layer and tissue target can be a tool in MWA to shape ablation zones to protect the surrounding structures from excessive temperature increases.

Image-based computer modeling assessment of microwave ablation for treatment of adrenal tumors

PURPOSE

To assess the feasibility of delivering microwave ablation for targeted treatment of aldosterone producing adenomas using image-based computational models.

METHODS

We curated an anonymized dataset of diagnostic ¹¹C-metomidate PET/CT images of 14 patients with aldosterone producing adenomas (APA). A semi-automated approach was developed to segment the APA, adrenal gland, and adjacent organs within 2 cm of the APA boundary. The segmented volumes were used to implement patient-specific 3D electromagnetic-bioheat transfer models of microwave ablation with a 2.45 GHz directional microwave ablation applicator. Ablation profiles were quantitatively assessed based on the extent of the APA target encompassed by an ablative thermal dose, while limiting thermal damage to the adjacent normal adrenal tissue and sensitive critical structures.

RESULTS

Across the 14 patients, adrenal tumor volumes ranged between 393 mm³ and 2,395 mm³. On average, 70% of the adrenal tumor volumes received an ablative thermal dose of 240CEM43, while limiting thermal damage to non-target structures, and thermally sparing 83.5-96.4% of normal adrenal gland. Average ablation duration was 293 s (range: 60-600 s). Simulations indicated coverage of the APA with an ablative dose was limited when the axis of the ablation applicator was not well aligned with the major axis of the targeted APA.

CONCLUSIONS

Image-based computational models demonstrate the potential for delivering microwave ablation to APA targets within the adrenal gland, while limiting thermal damage to surrounding non-target structures.

Ablation versus laparoscopic adrenalectomy for the treatment of aldosterone‑producing adenoma: a meta-analysis

PURPOSE

To assess the relative clinical efficacy and safety of ablation and laparoscopic adrenalectomy (LA) for the treatment of adrenal aldosterone-producing adenoma (APA).

MATERIALS AND METHODS

Pubmed, Embase, and Cochrane Library databases were searched for relevant studies, while the meta-analysis was performed with RevMan v5.3.

RESULTS

After initially identifying 496 potentially relevant studies, five were ultimately included in the final meta-analysis. In total, these studies contained 128 patients that underwent LA and 91 patients that underwent ablation to treat APA. Clinical success rates were comparable between these two groups (OR: 0.55, P = 0.20), whereas the pooled decreases of systolic and diastolic blood pressure were significantly larger in the ablation group (P = 0.01 and 0.002, respectively). Pooled changes in the aldosterone-to-renin ratio (ARR), serum potassium levels, and medication use were similar in both groups (P = 0.62, 0.24, and 0.96, respectively). The average operative duration in the ablation group was somewhat shorter, but the difference was not significant (MD: - 57.99; P = 0.05), whereas the average blood loss and postoperative hospital stay duration of patients in the ablation group were decreased for patients in the ablation group compared to the LA group (P < 0.00001 and 0.00001, respectively). Major complication, minor complication, and hypertension crisis rates were comparable between these groups (P = 0.35, 0.69, and 0.09, respectively).

CONCLUSIONS

Ablation offers comparable efficacy to LA when treating patients with APA, but is associated with a reduced operative duration, decreased intraoperative blood loss, and faster postoperative recovery.

Asian Conference on Tumor Ablation Guidelines for Adrenal Tumor Ablation

Thermal ablation is a good alternative treatment in patients who are unable to undergo adrenalectomy. Even though the Asian Conference on Tumor Ablation (ACTA) has been held for many years, adrenal ablation guidelines have not been established. No guidelines for adrenal ablation are established in American and European countries, either. The aim of this review was to introduce the first version of ACTA guidelines for adrenal tumor ablation.

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.

Percutaneous Adrenal Radiofrequency Ablation: A Short Review for Endocrinologists

Image-guided radiofrequency ablation (RFA) has been accepted as a minimally invasive treatment for adrenal tumors in patients who are unable to undergo adrenalectomy. Accordingly, this treatment has become more readily available for treating functioning or non-functioning adrenal masses. Thus, endocrinologists need a better understanding of percutaneous RFA of adrenal tumors. The purpose of this review is to briefly describe the basic mechanism of RFA, indications and contraindications, patient preparation prior to RFA, type of complications, how to avoid complications, RFA procedures, and treatment outcomes.

Microwave Ablation of Adrenal Tumors in Patients With Continuous Intra-Arterial Blood Pressure Monitoring Without Prior Alpha-Adrenergic Blockade: Safety and Efficacy

PURPOSE

Evaluate the safety and efficacy of adrenal microwave ablation performed with continuous intra-arterial blood pressure monitoring (IABPM) and without alpha-adrenergic blockade (AAB) as pretreatment.

MATERIAL AND METHODS

A single-center, retrospective review of all percutaneous adrenal microwave ablation performed between 2011 and 2018. Microwave ablation was completed on 11 patients, with a total of 15 adrenal tumors with a mean size of 3.3 cm (1.4-6.9 cm) treated metastatic RCC, HCC, esophageal carcinoma, adrenal adenoma. Cases were performed without prior AAB, but with continuous IABPM and rapid intervention using short-acting antihypertensive medications.

RESULTS

There were no post-procedural episodes of hypertension, no neurological or cardiovascular complications, and no SIR moderate or worse adverse event complications. Mean intraprocedural maximum systolic blood pressure (SBP) was 211 mmHg (range: 132-288), with an average increase in SBP of 100 mmHg (range: 23-180). A hypertensive crisis (SBP ≥ 180 and/or DBP ≥ 120) occurred in 9 of the 15 procedures (60%) with a mean length of 3.0 min (range: 1-12). The technical success rate was 100% (15/15 procedures). The mean follow-up time was 2.4 years (range: 0.9-7.7 years), with primary and secondary efficacy rates of 77% and 87%, respectively, and an overall survival of 82%.

CONCLUSION

In this single-center retrospective study, microwave ablation of adrenal tumors without AAB was safe and effective when performed with continuous arterial line monitoring of vital signs and the use of short-acting, rapid-onset antihypertensive medications.

LEVEL OF EVIDENCE

Level 4, Case Series.

"How We Do It" - A Practical Approach to Percutaneous Adrenal Ablation Techniques

Incidental adrenal masses are common and are found in 4% of the CT scans.¹ While clinical history, laboratory results, and imaging characteristics are typically sufficient for diagnosis of an adrenal lesion, a biopsy is sometimes warranted. In some cases, adrenal mass ablation is subsequently indicated. This article serves as a brief but comprehensive review of preprocedural work-up and planning before an adrenal mass ablation, as well as a discussion on ablation techniques, associated challenges and solutions, and management of expected and unexpected outcomes.