Imaging-guided percutaneous radiofrequency ablation of adrenal metastases: preliminary results at a single institution with a single device

Radiation Therapy in the Management of Adrenal Metastases

Adrenal glands represent a common site of metastases from several primary tumors, including lung cancer, breast cancer and melanoma. Surgical resection is considered the standard of care, but surgery is not always feasible given the challenges related to anatomical site and/or due to patient and/or disease characteristics. Stereotactic body radiation therapy (SBRT) represents a promising treatment for oligometastases, though the literature on its role for adrenal metastases is still heterogeneous. Herein are summarized the most relevant published studies on the efficacy and safety of SBRT for adrenal gland metastases. The preliminary data suggests that SBRT yields high local control rates and symptom relief with a mild pattern of toxicity. Advanced radiotherapy techniques including IMRT and VMAT, a BED10 > 72 Gy and the use of 4DCT for motion control should be considered for a high quality ablative treatment of adrenal gland metastases.

Comparison between surgery and thermal ablation for adrenal metastases: a retrospective study

PURPOSE

To retrospectively compare the efficacy and safety of surgical resection (SR) and thermal ablation for the treatment of adrenal metastases.

METHODS

From January 2008 to December 2018, 133 patients with adrenal metastases who underwent SR (n = 76) or thermal ablation (n = 57) were enrolled. The mean tumor size was 58.00 ± 10.65 mm (22-80 mm) in the SR group and 58.03 ± 12.76 mm (34-89 mm) in the thermal ablation group. Local progression-free survival (LPFS) and safety were compared between the two groups using the Kaplan-Meier method and log-rank tests. Cox proportional hazard regression models were used to evaluate the prognostic factors of LPFS. Complications, hospitalization days, and blood loss were also assessed.

RESULTS

The median follow-up was 29.0 months (range, 20.4-37.6 months). No treatment-related mortality was observed. The 1-, 3- and 5-year LPFS rates were 74.0%, 62.8%, and 31.4% in the SR group and 72.8%, 68.7%, and 51.5% in the ablation group, with the median LPFS of 41.5 months (95% CI: 9.3-23.4 months) vs. 47.9 months (95% CI 20.6-75.8 months), respectively (p = 0.784). Tumor size ≥3 cm was the only significant risk factor for LPFS (p = 0.031). The ablation group was superior to the SR group with a lower major complication rate (4.1% vs. 14.5%, p = 0.03), less blood loss (1 ml vs. 100 ml, p < 0.001), and a shorter hospital stay (2 d vs. 6 d, p < 0.001).

CONCLUSION

Thermal ablation provided a similar LPFS and less comorbidities than SR, indicating that it is an effective and safe treatment for adrenal metastases.

Percutaneous image-guided radiofrequency ablation for adrenal tumours: a systematic review

AIM

To undertaken a systematic review of the technical success and technique efficacy rates of percutaneous image-guided radiofrequency ablation (RFA) for adrenal tumours.

MATERIALS AND METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the electronic databases MEDLINE, EMBASE, and PubMed were searched for relevant studies from inception to the third week of January 2020. Only studies reporting effectiveness rates of percutaneous RFA for adrenal tumours were included. Data regarding sample size, tumours, effectiveness rates, outcomes, and complications were extracted in duplicate and recorded.

RESULTS

A total of 15 studies evaluating 292 individuals with 305 tumours were included. Patient selection criteria included age ≥18 years, contraindication to surgical intervention, and no uncorrected coagulopathy. Cumulative technical success, primary technique efficacy, and secondary technique efficacy rates were 99%, 95.1% and 100%, respectively, indicating optimal immediate control of adrenal tumours. Technical success and technique efficacy rates of primary adrenal tumours were higher than adrenal metastases; however, formal statistical analyses were precluded due to lack of comparative studies. Local tumour progression rates for adrenal metastases were 20.3% at 3 months, 26.3% at 6 months, and 29.3% at 12 months. Overall survival rates for adrenal metastases were 81.8% at 6 months, 59.6% at 12 months, and 62.9% at 18 months. The intraprocedural complication rate was 30.2%, with the most frequency reported complication being procedural hypertensive crisis.

CONCLUSION

The findings of this study suggest percutaneous image-guided RFA is a safe and efficacious procedure. Further studies are warranted to define patient selection criteria and long-term outcomes.

Comparison of the radiofrequency ablation versus laparoscopic adrenalectomy for aldosterone-producing adenoma: a meta-analysis of perioperative outcomes and safety

Radiofrequency ablation (RFA) has emerged as a new treatment for primary aldosteronism owing to aldosterone-producing adenoma (APA). We aimed to compare the perioperative outcomes and safety of RFA and laparoscopic adrenalectomy (LA) for patients with APA. We searched PubMed, EMBASE, and the Cochrane Library for all literatures published from January 2001 to September 2020 to compare RFA with LA for APA. After data extraction and quality assessments, we used Review Manager 5.4.1 and STATA 14.0 to pool the data. Four retrospective studies consisting of 170 patients were obtained. Patients who underwent RFA were associated with shorter operative time (standard mean difference (SMD): -1.98, 95% confidence interval (CI): -3.86 to 0.11, P = 0.04), less intraoperative blood loss (SMD: -0.61, 95% CI: -0.96 to -0.26, P = 0.0007), and shorter hospital stay (weight mean difference (WMD): -1.40, 95% CI: -1.71 to -1.10, P < 0.00001) than those who underwent LA. No significant differences were found in the complication rate (odds ratio (OR): 0.67, 95% CI: 0.27-1.68, P = 0.39), the incidence of hypertensive crisis (OR: 3.16, 95% CI: 0.36-27.94, P = 0.30), the conversion rate (OR: 0.44, 95% CI: 0.04-4.32, P = 0.48) or the treatment success rate (OR: 0.72, 95% CI: 0.22-2.39, P = 0.59) between the two groups. RFA could achieve clinical outcomes that approach LA for patients with APA but result in shorter operative time, less intraoperative blood loss, and shorter hospital stay. However, RFA does not appear to be able to replace the LA. Future prospective randomized trials are needed to validate these results.

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.

Image-Guided Percutaneous Ablation of Adrenal Metastases: A Meta-Analysis of Efficacy and Safety

PURPOSE

To evaluate the efficacy and safety of percutaneous ablation of adrenal metastases through a meta-analysis of various image-guided percutaneous ablation techniques.

MATERIALS AND METHODS

A comprehensive literature search of PubMed and Embase databases was performed for studies evaluating the efficacy and/or safety of image-guided percutaneous ablation of adrenal metastases. A total of 37 studies published between 2009 and 2020 were analyzed, comprising a sample size of 959 patients. Proportion estimates of overall survival, local control, and toxicity were analyzed in a pooled meta-analysis. The pooled prevalence of adverse events after ablation was calculated based on common terminology criteria for adverse events (CTCAE) grading.

RESULTS

Of the 959 included patients, 320 (33.3%) underwent radiofrequency ablation, 72 (7.5%) microwave ablation, 95 (9.9%) cryoablation, and 46 (4.8%) ethanol injections for treatment of adrenal metastases. The remaining 426 (44.4%) patients were from studies involving a mixture of the 4 listed percutaneous ablation techniques. The pooled 1-year local control rate was 80% (95% confidence interval [CI], 76%-83%). The pooled 1-year overall survival rate was 77% (95% CI, 70%-83%). The overall rate of severe adverse events after ablation (CTCAE grade 3 or higher) was 16.1%. The overall rate of low-grade adverse events after ablation (CTCAE grade 2 or lower) was 32.6%. Approximately 21.9% (n = 203) of patients experienced intraprocedural hypertensive crises, the majority of which were reversed with antihypertensive medications.

CONCLUSIONS

This study demonstrates that image-guided percutaneous ablation can be effective in achieving acceptable short- to mid-term local tumor control and overall survival with a moderate safety profile.

Percutaneous Bilateral Adrenal Radiofrequency Ablation in Severe Adrenocorticotropic Hormone-dependent Cushing Syndrome

Objectives:

The objectives of the study were to evaluate adrenal radiofrequency ablation (RFA) as a method of treatment in patients with severe adrenocorticotropic hormone (ACTH)-dependent Cushing syndrome, among whom bilateral adrenalectomy is not a suitable option.

Material and Methods:

Five patients with ACTH-dependent Cushing syndrome underwent RFA of both adrenal glands. Four of them presented with Cushing disease unsuccessfully treated with pituitary surgery and medical therapy, while one patient had ACTH-dependent Cushing syndrome due to pancreatic endocrine tumor with liver metastases. All patients were disqualified from adrenalectomy due to morbid obesity or lack of consent.

Results:

A technical success was obtained in all cases, with only one re-intervention necessitated by a cooling effect of the inferior vena cava. Despite pre-procedural adrenergic blockade, severe hypertension was noted during the procedure in three cases, this being treated immediately using direct-acting vasodilators. No complications occurred otherwise. In all cases, significant improvement of clinical symptoms was observed, as well as marked decreases in levels of serum cortisol, free urine cortisol, and dehydroepiandrosterone sulfate.

Conclusion:

Bilateral RFA under CT-guidance is technically feasible and clinical improvement can be achieved using the method. In patients disqualified from adrenal surgery, RFA might be considered as an alternative method of ACTH-dependent Cushing syndrome treatment.

[Surgery of adrenal diseases]

Incidentally discovered adrenal alterations should be separated into those without any clinical importance and adrenal diseases that have to be surgically or conservatively treated. Before operative treatment, in addition to the possible different functional activity of tumors, a differentiation must be made between sporadically arising singular or multiple adrenal tumors or nodular adrenal hyperplasia, adrenal tumors as part of a familial syndrome and metastases of other primary malignant tumors into the adrenal glands. Benign hormonally active adrenal tumors as well as questionable malignant tumors of the adrenal cortex are resected by minimally invasive techniques. For large malignant tumors infiltrating into surrounding tissues and tumors with proven lymph node metastases, the primarily open approach is indicated. Patients with adrenal diseases should always undergo an interdisciplinary assessment and in cases with clear indications for surgery, sometimes transferred to a center with experience in surgery and postoperative management of these patients.

Outcomes following minimally invasive imagine-guided percutaneous ablation of adrenal glands

Whilst surgery represents the gold standard for the treatment of adrenal primary malignant tumors, metastatic involvement of the adrenal glands is generally approached conservatively; however, surgery for local control has been controversial, and several reports have described the utility of surgical removal in terms of prolonged survival in selected patients. Different techniques, including radiofrequency ablation (RFA), microwave ablation (MWA), laser induced thermal therapy (LITT), cryoablation (CRA), and chemical ablation, are employed in percutaneous image-guided ablation for primary and metastatic malignancies of the adrenal glands, in case of patients with multiple comorbidities or who refuse surgery. Technical success, clinical success and safety were analysed and discussed in this systematic review. Tumor size was found a significant determinant for local disease control; histology of the primary malignancy and coexistence of tumor elsewhere were correlated with prognosis. These procedures resulted to be feasible and safe, with hypertensive crisis representing the most common complication. Although there is lack of evidence in the literature concerning outcomes compared with surgery, percutaneous ablation may represent a useful therapeutic option for controlling unresectable adrenal metastases, offering patients opportunities for improved survival.

"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.

CT Texture Analysis and Machine Learning Improve Post-ablation Prognostication in Patients with Adrenal Metastases: A Proof of Concept

INTRODUCTION

To assess the performance of pre-ablation computed tomography texture features of adrenal metastases to predict post-treatment local progression and survival in patients who underwent ablation using machine learning as a prediction tool.

MATERIALS AND METHODS

This is a pilot retrospective study of patients with adrenal metastases undergoing ablation. Clinical variables were collected. Thirty-two texture features were extracted from manually segmented adrenal tumors. A univariate cox proportional hazard model was used for prediction of local progression and survival. A linear support vector machine (SVM) learning technique was applied to the texture features and clinical variables, with leave-one-out cross-validation. Receiver operating characteristic analysis and the area under the curve (AUC) were used to assess performance between using clinical variables only versus clinical variables and texture features.

RESULTS

Twenty-one patients (61% male, age 64.1 ± 10.3 years) were included. Mean time to local progression was 29.8 months. Five texture features exhibited association with progression (p < 0.05). The SVM model based on clinical variables alone resulted in an AUC of 0.52, whereas the SVM model that included texture features resulted in an AUC 0.93 (p = 0.01). Mean overall survival was 35 months. Fourteen texture features were associated with survival in the univariate model (p < 0.05). While the trained SVM model based on clinical variables resulted in an AUC of 0.68, the SVM model that included texture features resulted in an AUC of 0.93 (p = 0.024).

DISCUSSION

Pre-ablation texture analysis and machine learning improve local tumor progression and survival prediction in patients with adrenal metastases who undergo ablation.

Percutaneous radiofrequency ablation of adrenal metastases from hepatocellular carcinoma: a single-center experience

Background

The prognosis of adrenal metastases (AM) from hepatocellular carcinoma (HCC) with surgical contraindication was poor. This study evaluated the feasibility, safety and treatment efficacy of percutaneous ultrasound (US)-guided radiofrequency ablation (RFA) for the local treatment of AM originated from HCC.

Methods

A retrospective study was carried out on 22 patients (21 male and 1 female, mean age, 53.0 ± 13.0 years) who had single AM (mean diameter, 4.0 ± 1.8 cm, range, 1.7–8.0 cm) originated from HCC and received US-guided percutaneous RFA at our institution. The diagnosis was established on typical radiologic findings. The primary technical success was defined as the tumour being completely ablated in the first RFA session. The secondary technical success was defined as tumour residual left from the first ablation was completely ablated by a second ablation session. Local tumour progression (LTP) and overall survival (OS) were estimated by using Kaplan-Meier analysis.

Results

A total of 25 ablation sessions were performed. The primary technical success and the secondary technical success were 77.3% (17 of 22) and 86.4% (19 of 22), respectively, with the major complication rate at 4.5% (1 of 22). The median follow-up period after RFA was 10 months (3–55 months). During the follow-up period, five patients were detected LTP. The LTP at 3, 6, and 12 months were 15.8, 26.3, and 26.3%, respectively. Nine patients died of distant extra-adrenal metastases and another five of liver failure due to HCC. The OS at 6, 12, 24 months after RFA for AM were at 79.7, 52.6, and 32.9%, respectively.

Conclusion

Percutaneous US-guided RFA in the treatment of AM originated from HCC is feasible, safe and effective.

Immediate Clinical Success After Percutaneous Ablation of Extra-adrenal Paraganglioma

Paragangliomas (PGLs) are catecholamine-secreting neoplasms of chromaffin cells and represent a rare but curable cause of secondary hypertension. Surgery is the treatment of choice for symptomatic PGLs. A small (7 mm) extra-adrenal PGL was diagnosed in the right retroperitoneal space in a 19-year-old patient affected by symptomatic hypertension unresponsive to medical treatment. Indication to percutaneous radiofrequency ablation (RFA) was given by a multidisciplinary team on the basis of the size of the nodule, the surgical risks, the young age of the patient, and his wish to reduce as much as possible the post-interventional rehabilitation. To our knowledge, the use of percutaneous RFA in the treatment of retroperitoneal extra-adrenal primary paragangliomas has never been described. We describe its feasibility and the patient's clinical outcome.

Interventional radiology of the adrenal glands: current status

As more and more adrenal neoplasms are found incidentally or symptomatically, the need for interventional procedures has being increasing. In recent years these procedures registered continued steady expansion. Interventional radiology of the adrenal glands comprises angiographic and percutaneous procedures. They may be applied both in benign and in malignant pathologies. The present review reports the current status of indications, techniques results and complications of the image-guided procedures.

Effectiveness and safety of CT-guided percutaneous radiofrequency ablation of adrenal metastases

OBJECTIVE

The imaging-guided percutaneous radiofrequency (RF) ablation of adrenal metastases is a relatively new treatment procedure, compared to the more widespread application of the technique for the treatment of liver and renal cancers. The present study aims to evaluate the safety and efficacy of the CT-guided percutaneous RF ablation of adrenal metastases in a cohort of patients.

METHODS

33 patients with 38 adrenal metastases who received percutaneous CT-guided RF ablation between 2012 to 2015 were retrospectively reviewed. The average diameter of the treated adrenal metastases was 3.0 ± 1.6 cm. The treatment outcomes, including presence of residual tumours, technical success rate, recurrence rate, and complications, were evaluated. Patients were followed up for every 3 months to monitor the progression of the disease.

RESULTS

Postoperative CT images showed the lack of tumour enhancement in 30 tumours (30/38 tumours, technical success rate = 78.9%), and residual disease was found in 7 tumours (7/37 tumours, 18.9%). The rate of residual disease was significantly lower in the group with tumour size <3 cm than the group with tumour size ≥3 cm (p = 0.025). The severe complication rate was 4.3%, and the mild complication rate was 48%, with intraoperative hypertensive crisis as the most frequently observed complication (27.3%). The follow-up data showed that 76.3% of patients had recurrence-free survival in 27.4 months.

CONCLUSION

The current study demonstrated that radiofrequency ablation is a relatively safe and effective treatment for controlling adrenal metastases, especially for patients with tumour size <3 cm. Advances in knowledge: Surgical resection of the adrenal metastases was advocated as one of the treatment options for patients. The present study showed that radiofrequency ablation is a relatively safe and effective treatment for controlling adrenal metastases.

Ultrasound-Guided Intratumoral Radiofrequency Ablation Coagulation to Facilitate Meningioma Resection: Preliminary Experience

OBJECTIVES

This study aimed to explore the feasibility and safety of intratumoral radiofrequency ablation (RFA) in meningioma resection.

METHODS

This study was approved by the Xijing Ethics Committee, and informed consent was obtained from all of the patients. Thirteen patients with meningiomas were recruited in the Neurosurgery Department of Xijing Hospital. These patients were treated with intratumoral RFA and surgery. We also chose 13 patients with meningiomas treated with traditional surgery as the control group. Two-dimensional ultrasound, color Doppler flow imaging, contrast-enhanced ultrasound, and magnetic resonance imaging were used to identify the location, border, and blood supply of the meningiomas preoperatively and to assess the therapeutic effect intraoperatively. Finally, the meningiomas were dissected and removed by surgery.

RESULTS

All procedures were technically successful without serious complications. Intraoperative ultrasound was able to provide a clear display of the location, shape, size, and boundary of the tumor and its relationship with other tissues and reveal the vascular distribution in and around the tumors. With intratumoral RFA, coagulative necrosis was induced, and the meningiomas became hard in texture with a decreased blood supply. Blood loss was significantly lower in the RFA group versus control group (320.0 ± 24.8 versus 390.4 ± 36.8 mL; P < .001). The RFA group spent fewer days in the hospital (6.0 ± 0.9 versus 7.0 ± 1.2 days; P = .022). However, the surgical time of the RFA group was relatively longer (3.5 ± 0.5 versus 3.0 ± 0.3 hours, P = .007).

CONCLUSIONS

The application of intratumoral RFA in meningioma resection is effective and safe. It may be a useful adjunct for meningioma treatment.

Comparison of radiofrequency ablation versus laparoscopic adrenalectomy for benign aldosterone-producing adenoma

PURPOSE

To retrospectively compare the safety and efficacy of radiofrequency ablation (RFA) with laparoscopic adrenalectomy (LA) in treating aldosterone-producing adenoma (APA) of the adrenal gland.

MATERIALS AND METHODS

From September 2009 to September 2013, seven patients, diagnosed with unilateral adrenal APA and underwent computed tomography (CT)-guided percutaneous RFA, were recruited in this retrospective study. Eighteen unilateral adrenal APA with the same tumor size (<25 mm) who underwent LA during the same interval were enrolled as control group. Treatment success was defined as complete tumor ablation on follow-up CT scan and normalization of serum aldosterone-to-renin ratio. We also compared "normalization ability" between RFA group and LA group. Normalization ability was defined as reduction in blood pressure, decrease in number of antihypertensive medicine use, reduction in serum aldosterone, and increase in serum potassium level.

RESULTS

There was no statistically significant demographic difference in both groups. The mean tumor size was 18 (8-25) mm in RFA and 19 (11-25) mm in LA groups, respectively. There was only one intra-procedure hypertensive crisis in the RFA group. No other complications needed further management in both groups. During an interval of 3-6 months of follow-up, the treatment success rate reached 100 % in the RFA group versus 94.4 % in the LA group. Normalization ability was statistically equivalent in the RFA and the LA group. Comparing with LA group, RFA group demonstrated with less post-operative pain (visual analog scale, 2.0 ± 1.16 vs. 4.22 ± 1.44, p < 0.001) and shorter operative time (105 ± 34 vs. 194 ± 58 min, p < 0.001).

CONCLUSIONS

CT-guided percutaneous RFA is effective, safe and is a justifiable alternative for patients who are reluctant or unfit for laparoscopic surgery for the treatment of APA.

Catecholamine Surge during Image-Guided Ablation of Adrenal Gland Metastases: Predictors, Consequences, and Recommendations for Management

PURPOSE

To identify retrospectively predictors of catecholamine surge during image-guided ablation of metastases to the adrenal gland.

MATERIALS AND METHODS

Between 2001 and 2014, 57 patients (39 men, 18 women; mean age, 65 y ± 10; age range, 41-81 y) at two academic medical centers underwent ablation of 64 metastatic adrenal tumors from renal cell carcinoma (n = 27), lung cancer (n = 23), melanoma (n = 4), colorectal cancer (n = 3), and other tumors (n = 7). Tumors measured 0.7-11.3 cm (mean, 4 cm ± 2.5). Modalities included cryoablation (n = 38), radiofrequency (RF) ablation (n = 20), RF ablation with injection of dehydrated ethanol (n = 10), and microwave ablation (n = 4). Fisher exact test, univariate, and multivariate logistical regression analysis was used to evaluate factors predicting hypertensive crisis (HC).

RESULTS

HC occurred in 31 sessions (43%). Ventricular tachycardia (n = 1), atrial fibrillation (n = 2), and troponin leak (n = 4) developed during HC episodes. HC was significantly associated with maximum tumor diameter ≤ 4.5 cm (odds ratio [OR], 26.36; 95% confidence interval [CI], 5.26-131.99; P < .0001) and visualization of normal adrenal tissue on CT or MR imaging before the procedure (OR, 8.38; 95% CI, 2.67-25.33; P < .0001). No HC occurred during ablation of metastases in previously irradiated or ablated adrenal glands.

CONCLUSIONS

Patients at high risk of catecholamine surge during ablation of non-hormonally active adrenal metastases can be identified by the presence of normal adrenal tissue and tumor diameter ≤ 4.5 cm on pre-procedure CT or MR imaging.

Unresectable Adrenal Metastases: Clinical Outcomes of Radiofrequency Ablation

PURPOSE

To retrospectively evaluate the clinical outcomes of radiofrequency (RF) ablation for the treatment of unresectable adrenal metastasis.

MATERIALS AND METHODS

The institutional review board approved this retrospective study, and informed consent to perform adrenal RF ablation was obtained from all patients. From February 2005 through May 2014, 35 patients (25 men and 10 women; mean age, 64.7 years ± 9.6; age range, 39-82 years) underwent RF ablation to treat 41 metastatic adrenal tumors from lung cancer (n = 15), renal cell carcinoma (n = 9), colorectal cancer (n = 5), hepatocellular carcinoma (n = 4), and other tumors (n = 2). Tumors ranged in size from 1.2 to 8.2 cm (mean, 3.3 cm ± 1.6). The diagnosis was established mainly on the basis of radiologic findings. Adrenal arterial embolization was combined with RF ablation in 12 of the 35 patients (34%). Technical success, safety, local tumor progression, and survival were evaluated. The Kaplan-Meier method and Cox proportional hazard model were used to evaluate prognostic factors.

RESULTS

There were 48 completed sessions with planned procedures and treatment protocols with no mortality and a major complication rate of 8.3% (four of 48 sessions). Tumor enhancement disappeared after initial adrenal RF ablation in 33 of the 35 patients (94%). Local tumor progression developed in eight of the 35 patients (23%); two patients received repeated RF ablation, resulting in adrenal tumor control in 27 of the 35 patients (77%) at the last follow-up (mean, 30.1 months ± 27.5; range 1.2-96.8 months). The 1-, 3-, and 5-year overall survival rates were 75% (95% confidence interval [CI], 61%, 90%), 34% (95% CI: 17%, 52%), and 30% (95% CI: 13%, 48%), respectively, with a median survival time of 26.0 months. Existence of extra-adrenal tumors (P = .005) and age of 65 years or older (P = .04) were significant indicators of a poor prognosis.

CONCLUSION

Adrenal RF ablation is a feasible and useful method for controlling adrenal metastases and offers patients opportunities for improved survival.

Image-guided ablation of adrenal lesions

Although laparoscopic adrenalectomy has remained the standard of care for the treatment for adrenal tumors, percutaneous image-guided ablation therapy, such as chemical ablation, radiofrequency ablation, cryoablation, and microwave ablation, has been shown to be clinically useful in many nonsurgical candidates. Ablation therapy has been used to treat both functioning adenomas and malignant tumors, including primary adrenal carcinoma and metastasis. For patients with functioning adenomas, biochemical and symptomatic improvement is achieved in 96 to 100% after ablation; for patients with malignant adrenal neoplasms, however, the survival benefit from ablation therapy remains unclear, though good initial results have been reported. This article outlines the current role of ablation therapy for adrenal lesions, as well as identifying some of the technical considerations for this procedure.

Morphologic Change in Computed Tomography of Aldosterone-Producing Adenoma after Radiofrequency Ablation

Objective

To evaluate the morphologic changes of aldosterone-producing adenoma (APA) on computed tomography (CT) before and after radiofrequency ablation (RFA) and to assess the factors that are important in determining successful complete ablation of these tumours.

Method

Between August 2004 and August 2011, 24 consecutive patients with APA undergoing CT-guided percutaneous RFA were identified from our prospective database. The pre-RFA and post-RFA CT appearances of these APAs that showed positive biochemical response were reviewed retrospectively for their 3-dimensional size, tumour volume, and CT attenuation in terms of Hounsfield units (HU). A comparison of these parameters before and after RFA was performed.

Results

In this study, there were 23 APAs in these 24 patients that showed biochemical cure of primary aldosteronism after RFA. When comparing post-RFA to pre-RFA CTs, there was no significant change in tumour size (14.5 mm vs 14.6 mm: P = .83) and tumour volume (1.55 cm3 vs 1.59 cm3; P = .41) after RFA. In nonenhanced CT images, there was no significant reduction in HU from pre-RFA to post-RFA measurements (4.4 HU vs 7.9 HU; P = .52). In contrast-enhanced CTs, there was a significant drop in HU after RFA (from 48.3 HU to 14.7 HU; P = .03). None of the included cases showed a focal region of contrast enhancement to suggest residual tumour.

Conclusion

A change in tumour size, tumour volume, and HU in nonenhanced CT were unreliable in defining radiologic treatment success. Only changes in HU in contrast-enhanced CT was useful in confirming a positive treatment response after RFA for APA.

Percutaneous interstitial brachytherapy for adrenal metastasis: technical report

We developed and evaluated the feasibility of a brachytherapy technique as a safe and effective treatment for adrenal metastasis. Adapting a paravertebral insertion technique in radiofrequency ablation of adrenal tumors, we developed an interstitial brachytherapy for adrenal metastasis achievable on an outpatient basis. Under local anesthesia and under X-ray CT guidance, brachytherapy applicator needles were percutaneously inserted into the target. A treatment plan was created to eradicate the tumor while preserving normal organs including the spinal cord and kidney. We applied this interstitial brachytherapy technique to two patients: one who developed adrenal metastasis as the third recurrence of uterine cervical cancer after reirradiation, and one who developed metachronous multiple metastases from malignant melanoma. The whole procedure was completed in 2.5 hours. There were no procedure-related or radiation-related early/late complications. FDG PET-CT images at two and three months after treatment showed absence of FDG uptake, and no recurrence of the adrenal tumor was observed for over seven months until expiration, and for six months until the present, respectively. This interventional interstitial brachytherapy procedure may be useful as a safe and eradicative treatment for adrenal metastasis.

Ablative therapies in adrenal tumors: primary and metastatic

A large number of adrenal tumors are now identified either incidentally or associated with a metastatic workup for cancer. While the vast majority of these lesions are benign, those that prove to be primary or secondary cancers are traditionally treated with surgical resection. A wide variety of alternative, less invasive therapies exist. One of these, thermal ablation, is examined herein.

Retroperitoneal schwannoma treated with percutaneous computed tomography-guided radiofrequency ablation

Retroperitoneal schwannomas (RSs) are particularly rare tumors, and resection is the first choice for symptomatic patients. However, some RSs with anatomical complexities pose great challenges for surgeons attempting radical resection without sacrificing the nearby critical structures, and subtotal resection leads to local recurrence, especially in refractory malignant RSs. The authors have successfully applied percutaneous CT-guided radiofrequency ablation in 2 cases of RSs, with favorable long-term progression-free survival.

Current role of interventions in metastatic kidney tumors: single center experience

This study on the treatment of kidney tumor metastases aims to expose our experience in different interventional therapies for renal cell carcinomas metastasis in different organs, broaching their complications and comparing our results with the literature. In the last 5 years, after informed consent, 22 patients with metastatic kidney tumors were enrolled in this retrospective observational study. According to lesion sites, different interventional procedures may be performed: RFA for pancreas, lung, adrenal gland and liver lesions; TAE and RFA for bone lesions and IVC filter positioning for thrombosis of renal vein. There were mainly satisfactory results: complete necrosis of pancreas, lung and adrenal gland metastasis with a technical success rate of 100%; after TAE and RFA of bone lesions, an acceptable blood loss was registered during surgical intervention; no recurrences after liver metastasis ablation were observed in a period of 3 months; positioning of IVC filter was technically correct in 100% of patients; few complications, such as diffuse abdominal pain for pancreas, pneumothorax in the lung RCC metastasis and a post-RFA syndrome for the adrenal. There was a nodular recurrence along the ablation margin in one liver RCC metastasis. Inclusion criteria were relatively strict and only 22 patients were included in this study. The follow-up has been relatively short to date, so we are not certain of the long-term results, though these are comparable to those found in literature. It is possible to conclude that Interventional radiology plays an important role in RCC metastasis treatment, if we have few complications and improved outcomes.

Stereotactic body radiation therapy for adrenal metastases: a retrospective review of a noninvasive therapeutic strategy

AIMS

The role of radiation therapy in the treatment of adrenal metastases has traditionally been a palliative one, achieving excellent pain control with very limited toxicity. Recent studies have focused on the potential role of stereotactic body radiation therapy (SBRT) with curative intent in limited metastatic disease, its potential to reduce tumor burden and to prevent symptomatic progression. This study reports the single-institution outcomes of SBRT utilizing both single fraction and hypofractionated regimens in the treatment of adrenal metastases.

METHODS

A total of seven patients with nine adrenal metastases treated with SBRT at the University of Pittsburgh Cancer Institute were retrospectively studied. The primary malignancies consisted of non-small-cell lung cancer (n = 4), small-cell lung cancer (n = 1) and hepatocellular carcinoma (n = 2).

RESULTS

Five lesions were treated in a single fraction to a median prescription dose of 16 Gy (range: 10-22 Gy) to the 80% isodose line. The remaining four lesions were treated over three fractions to a median prescription dose of 27 Gy (range: 24-36 Gy), with a median prescription isodose line of 94% (range: 80-94%). Median follow-up from the primary diagnosis was 38 months (range: 7-88 months) and from SBRT was 14 months (range: 1-60 months). Follow-up imaging for six patients, and eight metastatic lesions, revealed one complete response, two partial responses and five stable lesions. Five of the lesions eventually failed locally, with a median time to failure of 12 months and actuarial local control of 63% at 1 year. The median overall survival was 8 months from SBRT.

CONCLUSION

SBRT can be safely delivered in single fraction, or hypofractionated, regimens for the treatment of adrenal metastases.

Adrenal neoplasms: Effectiveness and safety of CT-guided ablation of 23 tumors in 22 patients

PURPOSE

To retrospectively evaluate the effectiveness and safety of image-guided ablation of adrenal tumors.

MATERIALS AND METHODS

: This HIPAA-compliant study was IRB approved and informed consent was waived. From 5/1999-6/2008, 20 consecutive adrenal metastases (mean diameter 4.2cm; range, 2-8) and 3 hormonally active primary adrenal tumors (mean diameter 2.3cm; range, 1-4), including an aldosteronoma and 2 pheochromocytomas in 22 patients (14 men, 8 women; mean age 61 years; range 40-84) were ablated in 23 sessions. Bilateral metastases were treated in a single patient. Radiofrequency ablation was used to treat 16 adrenal metastases and the 3 hyperfunctioning tumors. Microwave ablation was used to treat 4 metastases. Successful treatment was defined as a lack of both enhancement on follow-up contrast enhanced CT and/or up-take on FDG PET-CT and for functioning tumors, resolution of biochemical abnormalities.

RESULTS

Technical success was achieved in all sessions. Mean follow-up was 45.1 months (range, 1-91) Local tumor progression (focal enhancement at ablation site ≥1cm in short axis) was detected in 4 of 23 tumors, two of which were identified bilaterally in a single patient prompting re-treatment. Of 19 patients with metastatic disease, 16 had fatal extra-adrenal disease progression, and 3 remain alive. Two of the 3 patients who underwent ablation of hyperfunctioning tumors remain alive, including the patient with an aldosteronoma who had recurrent symptoms 91 months post ablation. Intra-ablative hypertension occurred in 9% (2/23) of sessions and was successfully treated pharmacologically.

CONCLUSION

Ablation of metastatic and hyperfunctioning adrenal tumors is safe and may provide local control and treatment of pathologic biochemical activity.

Percutaneous ablation of adrenal tumors

Adrenal tumors comprise a broad spectrum of benign and malignant neoplasms and include functional adrenal adenomas, pheochromocytomas, primary adrenocortical carcinoma, and adrenal metastases. Percutaneous ablative approaches that have been described and used in the treatment of adrenal tumors include percutaneous radiofrequency ablation, cryoablation, microwave ablation, and chemical ablation. Local tumor ablation in the adrenal gland presents unique challenges, secondary to the adrenal gland's unique anatomic and physiological features. The results of clinical series employing percutaneous ablative techniques in the treatment of adrenal tumors are reviewed in this article. Clinical and technical considerations unique to ablation in the adrenal gland are presented, including approaches commonly used in our practices, and risks and potential complications are discussed.

Transhepatic CT-guided radiofrequency ablation of adrenal metastases from hepatocellular carcinoma

The prognosis of patients with adrenal metastases from hepatocellular carcinoma (HCC) has been poor, and aggressive treatment of these tumors is mandatory to improve patients' survival. Since adrenalectomy may be difficult to perform after previous surgery of the right liver lobe, other approaches are required to treat the adrenal mass. This report aims at demonstrating the feasibility of CT-guided transhepatic radiofrequency ablation of right adrenal HCC metastases pretreated with chemoembolization in patients unable to undergo surgical resection.