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Year : 2020  |  Volume : 16  |  Issue : 5  |  Page : 1088-1092

Evaluating the efficacy and safety of ultrasound-guided percutaneous microwave ablation for the treatment of adrenal metastasis

Department of Interventional Ultrasound, State Key Laboratory of Kidney Disease, The Chinese PLA General Hospital, Beijing 100853, China

Date of Submission15-Dec-2019
Date of Decision08-Mar-2020
Date of Acceptance03-Jun-2020
Date of Web Publication29-Sep-2020

Correspondence Address:
Xiaoling Yu
Department of Interventional Ultrasound, State Key Laboratory of Kidney Disease, The Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jcrt.JCRT_1119_19

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 > Abstract 

Context: Microwave ablation (MWA) has been proven as a promising method to treat solid tumors.
Aims: This study aims to evaluate the efficacy and safety of ultrasound (US)-guided MWA for treating adrenal metastasis and to explore the factors affecting survival.
Settings and Design: This was a retrospective study performed on patients treated at our department.
Subjects and Methods: A total of 43 patients with adrenal metastasis (22 hepatocellular carcinoma, eight renal cell carcinoma, five non-small cell lung cancer, four colorectal cancer, three liposarcoma, and one malignant fibrous histiocytoma) were enrolled. All patients were treated at our department at least once. The treatment protocol for each patient, the technique used, and the survival details were recorded.
Statistical Analysis Used: Statistical analyses were performed using SPSS 26.0 software.
Results: Technical success was achieved in all cases. MWA was a safe technique for treating all types of metastasis. No major complications were observed. The pathology of adrenal lesions was the significant risk factor contributing to overall survival (OS) (P = 0.040). The 1-year and 3-year OS rates for all patients were 0.828 and 0.389, respectively.
Conclusions: Percutaneous US-guided MWA is safe and effective in terms of local control and survival of adrenal metastasis.

Keywords: Adrenal metastasis, complication, microwave ablation, survival rate, treatment protocol

How to cite this article:
Gao Y, Zheng L, Liang P, Cheng Z, Han Z, Tan SL, Yu X. Evaluating the efficacy and safety of ultrasound-guided percutaneous microwave ablation for the treatment of adrenal metastasis. J Can Res Ther 2020;16:1088-92

How to cite this URL:
Gao Y, Zheng L, Liang P, Cheng Z, Han Z, Tan SL, Yu X. Evaluating the efficacy and safety of ultrasound-guided percutaneous microwave ablation for the treatment of adrenal metastasis. J Can Res Ther [serial online] 2020 [cited 2021 Sep 22];16:1088-92. Available from: https://www.cancerjournal.net/text.asp?2020/16/5/1088/296426

 > Introduction Top

Adrenal tumors are among the most common tumors and are mostly benign, with approximately 2.5% having metastasized to the adrenal gland.[1] Microwave ablation (MWA), a developing heat-based technique, is used to treat many diseases including benign and malignant tumors.[2],[3],[4],[5] Heat-based ablation, which has been shown to augment antitumor immunity,[6] is a promising method for percutaneous treatment of adrenal metastases, but there is little literature documenting experience and reporting survival associated with ultrasound (US)-guided MWA. We evaluated the effectiveness of MWA for treating adrenal metastases and analyzed the characteristics of patients who might benefit from this treatment.

 > Subjects and Methods Top


The study protocol was approved by the ethics committee of our hospital, and the study was conducted in accordance with the principles of the declaration of Helsinki. A detailed verbal and written description of the procedure was provided to all patients, and informed written consent was obtained before treatment.

Selection and description of participants

The inclusion criteria for this study were as follows: (1) nonresectable tumors (i.e., insufficient liver remnant, renal insufficiency, and high risk for complications of resection associated with old age or tumor location) or patient refusing to undergo surgery; (2) clear visualization of the entire tumor on US imaging; (3) no tumor discovered in the liver under contrast-enhanced imaging monitoring; (4) prothrombin time <25 s; (5) prothrombin activity >40%; (6) platelet count >50 × 109/L, (7) pathologically confirmed or clinically diagnosed as hepatocellular carcinoma (HCC). The exclusion criteria for this study were as follows: (1) Child–Pugh class C; (2) severe comorbidities including renal failure or cardiopulmonary disease; (3) severe ascites; and (4) multiple metastases beyond adrenal glands. From April 2006 to September 2017, 43 patients with adrenal metastasis (22 HCC, eight renal cell carcinoma, five non-small cell lung cancer, four colorectal cancer, three liposarcoma, and one malignant fibrous histiocytoma) were included, and they underwent US-guided MWA. Biopsy and positron emission tomography-computed tomography (CT) were the two means for diagnosis. All patients received multidepartment consultation from the urology and endocrinology departments, which evaluated each patient to ensure they were suitable for MWA. The patients' demographics were recorded [Table 1].
Table 1: Summary of patients clinical parameters and tumors characteristics

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Preparation before procedure

All patients received status assessment and routine laboratory examinations when they were admitted. Complete blood count, blood chemistry, viral titers (hepatitis B virus, hepatitis C virus, and human immunodeficiency virus), and coagulation profile were examined for all patients. Adrenal gland function was evaluated (plasma cortisol levels and adrenocorticotropic hormone levels would be tested at 0, 8, and 16 h before treatment). Tumor markers related to specific tumors' progression also needed to be tested. Routine pretreatment imaging scans were indispensable, including contrast-enhanced magnetic resonance imaging (MRI) of abdomen, chest CT scan, and positron emission tomography CT, if necessary. Testing the adrenal glands required patients to take polyethylene glycol electrolyte solution for bowel preparation. Phenoxybenzamine hydrochloride tablets were given to the patients 2 weeks prior to the procedure in case of intraoperative hypertensive crisis.


Every patient underwent US-guided MWA by at least two experienced doctors. The MWA procedure was performed using a 2450 MHz microwave system (KY-2000; Kangyou Medical Instrument Co. Ltd., Nanjing, China). Each patient received intravenous anesthesia (using midazolam to induce anesthesia and propofol and fentanyl to keep patient asleep) and local anesthesia; then, a 5–10-mm skin incision was made using a sterile scalpel blade to insert 15 G antennas under US guidance. Each antenna was about 10 mm apart, within 5 mm of the tumor boundary, with the temperature sensor set in every antenna. The ablation process was monitored by US in real-time to ensure that adjacent tissue was not harmed. In this study, the power ranged from 30 W to 60 W. When the hyperecho overlapped the entire lesion, the ablation process was considered finished and the antennas were withdrawn.

During the procedure, some auxiliary measures were used: (1) a three-dimensional preprocedure planning system was used for patients whose tumor(s) were huge or close to other organs [Figure 1] and (2) the hydrodissection procedure guided by US was implemented with normal saline injection (using a pipe needle, normal saline was injected into the space between tumors and adjacent to vital organs until they were separated).
Figure 1: Three-dimensional visualization treatment platform and preoperative plan for adrenal tumor: This case shows a 8.7 cm × 7.4 cm (ultrasound measured) tumor in a 49-year-old woman, planning six antennas for microwave ablation

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Follow-up included routine physical examinations, laboratory tests (blood count, prothrombin time, and serum total bilirubin, albumin, creatinine, and tumor marker levels), medical imaging examinations (contrast-enhanced US or MRI). All tests and examinations were performed 1 and 3 months' posttreatment. Subsequent follow-ups were performed at 6-month intervals [Figure 2]. Technique success was defined by whether the treatment followed the protocol and completely covered the ablation zone, which was immediately evaluated as soon as the ablation procedure was finished. Technical efficiency was defined as the absence of tumor enhancement in contrast-enhanced images at 1 month posttreatment,[7] which was supposed to be destroyed. Major complications were defined as events that caused morbidity and disability leading to an increased level of care, hospital admission, or substantially prolonged hospital stay.[8] Overall survival (OS) was measured from time of treatment to death. The follow-up was conducted until the last visit or the time of death.
Figure 2: (a) Right adrenal lesion in a 56-year-old male after hepatocellular carcinoma surgery. Contrast-enhanced ultrasound proved abundant blood supply, considered to be hepatocellular carcinoma metastasis. (b) Contrast-enhanced magnetic resonance imaging showing no enhancement 1-year after ablation in the same lesion

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Statistics quantitative data were expressed as mean ± standard deviation, and qualitative data were expressed as frequency. The OS rates were assessed using the Kaplan–Meier method with the log-rank test. Statistical analyses were performed using SPSS 26.0 software (SPSS Inc., Chicago, IL, USA). Univariate and multivariate logistical regression estimates with 95% confidence intervals were also determined. For all tests, P < 0.05 was considered statistically significant.

 > Results Top

The median follow-up period was 28.6 (range, 1.4–117.0) months in 43 patients. All 43 patients received MWA performed using the treatment protocol. The technical success rate was 100%; the technical efficacy was 93.2% (40/43). Hydrodissection technique was used in eight patients' ablation procedure, with the average volume of normal saline injected during the procedure being 1088.33 mL. Adrenal metastasis ablation procedure was well tolerated without the need for blood transfusion. No patient died from ablation, and no severe complications occurred, although 15 patients complained of mild abdominal pain, and four patients had fever. Most of these conditions resolved in 3 days without additional treatment. However, bedside US scan was used for patients with refractory pain in case of bleeding. Seven patients experienced hypertension crises (sharply increased to a very high level) during the ablation procedure, and four of them experienced increased heart rate and ventricular premature beat. Because of narcotism, it was relatively safe for the anesthetist to control blood pressure by intravenous injection of 10–15 mL urapidil hydrochloride. Blood pressure was restored to normal in these patients before they were sent to our ward.

The univariate and multivariate analysis showed in [Table 2] suggested that different types of pathology led to different survival results. Comparing patients in other pathology types, patients with HCC and lung cancer might have higher risks. The 1-year and 3-year OS rates for all patients were 0.828 and 0.389, respectively.
Table 2: Univariate and multivariate analysis of clinical parameters related to overall survival rate after microwave ablation for adrenal metastasis

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 > Discussion Top

To the best of our knowledge, there is no consistent conclusion about which kind of treatment is the best option for adrenal tumors. Laparoscopic surgical resection, the most widely accepted treatment for adrenal metastases, has a local tumor control rate of 77%–84%.[8],[9] Due to the high possibility of complications and limitations by patients' conditions, few patients undergo surgery. Radiotherapy is also regarded as a reasonable choice and might damage the vital organs around adrenal glands, kidneys, liver, vena cava, and aorta.[10] Thus, image-guided percutaneous thermal ablation, such as radiofrequency ablation, MWA, and cryoablation, is safe, well tolerated, and effective.

This retrospective study demonstrated potential survival benefits for patients who undergo adrenal ablation. In our study, patients with adrenal metastasis of different pathologies experienced different risks. Regardless, adrenal metastasis should be treated and managed to avoid adrenal gland dysfunction and other symptoms.

Ultimately, we found that tumor diameter, side of body, and other tumor parameters did not affect survival (P > 0.05). Without evidence from large randomized controlled clinical trials, our experience could serve as a substantiation to support the treatment of patients with adrenal metastasis.

Most of the patients in our study were diagnosed with HCC. Adrenal glands are one of the most common organs wherein extrahepatic metastasis of HCC occurs, after lungs, abdominal lymph nodes, and bones.[11] The main cause of disease-related mortality is tumor recurrence, which is mostly seen in the remnant liver after radical resection.[12] Several studies have reported the rate of adrenal metastasis occurrence for patients with HCC after radical surgery. Popescu et al.[13] reported that it was 0.5% in 174 patients with HCC after liver resection confirmed adrenal metastasis. Ha et al.[14] retrospectively studied 26 patients with HCC who had undergone liver resection or liver transplantation and showed that the rate of metachronous adrenal metastasis was 0.5% and 0.6%, respectively. For patients who are unsuitable for surgery, nonoperative procedures are recommended, such as transcatheter embolization, chemotherapy, ablation, and radiotherapy. Recently, increasing evidence suggests that thermal ablation is a safe and effective method to eliminate adrenal lesion, including primary adrenal adenoma and adrenal metastasis.[14],[15] For all techniques, radiofrequency ablation is the most frequent and earliest reported method of all thermal ablation techniques.[16] However, compared with other forms of thermal ablation, MWA has potential advantages, such as less heat-sink effect, larger ablation zone, and higher intratumoral temperature.[17],[18],[19] Wang et al.,[20] who reported MWA of adrenal lesion for the first time, documented 5 patients with adrenal metastasis (four HCC and one renal cell cancer). The technique effect rate of MWA was 80% (4/5), the median follow-up time was 19 months, and no patient developed local tumor progression. Li et al.[21] documented ten cases of CT-guided percutaneous MWA of adrenal malignant carcinoma. Welch et al.[22] shared their experience in ablation of 37 adrenal gland metastases. The technique effect rate was 97%, the median survival time was 34.5 months, the 3-year progression-free survival rate was 88%, and the OS rate was 52%. As for complications, hypertension crisis was the most concerning symptom during MWA of all kinds of adrenal lesions. The incidence rates varied widely, from 0% to 100%.[21],[22] Intraoperative hypertension is a matter of concern, pheochromocytoma, body mass index, dominant tumor size, and preprocedural systolic blood pressure were significant predictive factors for intraoperative hypertension crisis.[23] Though, it is difficult to evaluate how much functional adrenal tissue left, it seems that local ablation of adrenal metastasis is relatively safe from intraoperative hypertension in our experience (7/43).

The limitations of our study included the small number of patients, retrospective analysis, treatment selective bias, absence of a control group, and lack of tracking time to progress.

MWA is an optional local treatment for adrenal metastasis. In this study, local treatment was shown to be a treatment option in the multimodality management of adrenal metastasis. Further prospective multicenter, randomized, controlled studies are needed.

Financial support and sponsorship

This study was supported by the state key project on infectious diseases of China under Grant number 2018ZX10723204-008; and the National Scientific Foundation Committee of China under Grant Number 81671710.

Conflicts of interest

There are no conflicts of interest.

 > References Top

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Chua TC, Morris DL. Exploring the role of resection of extrahepatic metastases from hepatocellular carcinoma. Surg Oncol 2012;21:95-101.  Back to cited text no. 12
Popescu I, Alexandrescu S, Ciurea S, Brasoveanu V, Hrehoret D, Gangone E, et al. Adrenalectomy for metastases from hepatocellular carcinoma – A single center experience. Langenbecks Arch Surg 2007;392:381-4.  Back to cited text no. 13
Ha TY, Hwang S, Ahn CS, Kim KH, Lee YJ, Moon DB, et al. Resection of metachronous adrenal metastasis after liver resection and transplantation for hepatocellular carcinoma. Dig Surg 2014;31:428-35.  Back to cited text no. 14
Nunes TF, Szejnfeld D, Szejnfeld J, Kater CE, Faintuch S, Castro CH, et al. Assessment of early treatment response with DWI after CT-guided radiofrequency ablation of functioning adrenal adenomas. AJR Am J Roentgenol 2016;207:804-10.  Back to cited text no. 15
Men M, Ye X, Fan W, Zhang K, Bi J, Yang X, et al. Short-term outcomes and safety of computed tomography-guided percutaneous microwave ablation of solitary adrenal metastasis from lung cancer: A multi-center retrospective study. Korean J Radiol 2016;17:864-73.  Back to cited text no. 16
Abraham J, Fojo T, Wood BJ. Radiofrequency ablation of metastatic lesions in adrenocortical cancer. Ann Intern Med 2000;133:312-3.  Back to cited text no. 17
Yu J, Liang P, Yu XL, Cheng ZG, Han ZY, Mu MJ, et al. Local tumour progression after ultrasound-guided microwave ablation of liver malignancies: Risk factors analysis of 2529 tumours. Eur Radiol 2015;25:1119-26.  Back to cited text no. 18
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Welch BT, Callstrom MR, Carpenter PC, Wass CT, Welch TL, Boorjian SA, et al. A single-institution experience in image-guided thermal ablation of adrenal gland metastases. J Vasc Interv Radiol 2014;25:593-8.  Back to cited text no. 22
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  [Figure 1], [Figure 2]

  [Table 1], [Table 2]


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