Laparoscopic Radiofrequency Thermal Ablation of Adrenal Tumors: Technical Details
Eren Berber, MD and Allan Siperstein, MD
Background: Despite reports of percutaneous radiofrequency ablation (RFA), laparoscopic ablative techniques have not been described to treat adrenal tumors. The aim of this study is to describe patient selection criteria and the technique for laparo- scopic adrenal RFA.
Methods: Four patients underwent laparoscopic RFA of adrenal tumors under general anesthesia for adrenal tumors. Procedures were carried out under the guidance of laparoscopic ultrasound. Medical records of these patients were reviewed retrospectively. Ablations were carried out using Angiodynamics Model 30 (n = 1) 2 cm and Model 90 (n = 3) 5-cm ablation catheters.
Results: Pathology included lung metastasis in 2 patients, and renal cell cancer metastasis and cortical adenoma in 1 patient each. Metastatic lesions were not resectable owing to the concomitant liver metastasis in 2 patients and because of local invasion in the third patient. The first 2 patients also underwent concomitant laparoscopic liver RFA. In the fourth patient with adrenocortical adenoma, ablation was carried out owing to the cardiopulmonary instability of the patient during attempted laparoscopic adrena- lectomy. Two patients had right and 2 patients had left sided lesions. Despite normal catecholamine levels preoperatively, 2 patients had a transient hypertensive period during the ablation possibly owing to the release of catecholamines from the normal adrenal medulla. The procedures were carried out using a lateral transabdominal (n = 4) or posterior (n = 1) approaches. There were no perioperative complications or mortality. The ablated lesions showed a nonenhancing hypodense appearance in post- operative CT scans. Patients were followed up for a mean 19 months. One patient died at 3 months from cardiac causes, and 1 other patient died at 51 months.
Conclusions: To our knowledge, this is the first report of laparoscopic adrenal RFA. Laparoscopic RFA is an option for patients with unresectable adrenal tumors owing to the extent of disease or comorbidities. The procedure can be carried out safely using any standard laparoscopic adrenalectomy approaches.
Key Words: radiofrequency ablation, adrenal, laparoscopic, technique
(Surg Laparosc Endosc Percutan Tech 2010;20:58-62)
L aparoscopic adrenalectomy has been the treatment of choice for managing adrenal tumors over the last 2 decades. Nevertheless, some patients might not be candi- dates for surgical removal, either because of unresectability
of adrenal malignancy or patient’s comorbidities precluding a long operation. Percutaneous radiofrequency ablation (RFA) under image guidance has been reported to be an option for these cases in the radiology literature. 1,2
RFA of adrenal tumors could theoretically be carried out with decreased risk of complications and more accuracy using a laparoscopic approach analogous to favoring laparoscopic over percutaneous RFA for the treatment of liver tumors.3
Being a referral center for adrenal tumors and having an established laparoscopic liver RFA program, our group has had the opportunity to treat a number of adrenal tumors with laparoscopic RFA. The aim of this study is to determine the feasibility of laparoscopic RFA for unresect- able adrenal tumors and establish the technique.
PATIENTS AND METHODS
Between 1994 and 2008, among the 164 patients operated upon for adrenal tumors, 4 patients underwent 5 laparoscopic RFA procedures (2.4%). These patients were managed with the same preoperative work-up protocols, including obtaining plasma aldosterone, renin, AM corti- sol, ACTH, catecholamine, and metanephrine levels with 24-hour urine aldosterone, cortisol, catecholamine, and metanephrine levels. All patients reported in this study were nonsecreting in these tests. Imaging included preoperative abdominal CT scans or MRI for those patients with renal insufficiency. The patients were followed up quarterly with abdominal CT or MRI scans.
Data regarding these patients were prospectively collected into an IRB-approved database. Informed con- sent was obtained for the procedures.
Surgical Procedures
The procedures were done under general anesthesia. Patients’ position depended on the surgeon preference. All patients were operated using a lateral transabdominal approach, except for patient no.4, who had a posterior retroperitoneal approach. For the patients, who also had concomitant RFA of liver metastasis (Patients no.1 and no.2), a mobilization of the adrenal gland was not carried out. The decision to ablate the adrenal tumors was made preoperatively in these 2 patients. For the remaining patients, the decision for adrenal RFA was made intra- operatively; hence, the operative steps were identical to laparoscopic adrenalectomy. The procedures were done under the guidance of laparoscopic ultrasound (Aloka Inc.) using a rigid side-viewing 7.5 MHz transducer. The ablations were carried out using the standard algorithms with RITA Medical Systems (currently Angiodynamics, Inc.), Model 30 (Patient 1), and Model 90 (remaining patients) ablation catheters used with Model 500 and 1500 generators.
Presented at the SAGES 2009 Meeting in Phoenix, Arizona in 4/22-25/ 2009.
Reprints: Eren Berber, MD, Division of Endocrine Surgery, Endo- crinology and Metabolism Institute, Cleveland Clinic, 9500 Euclid Avenue/A 80, Cleveland, OH 44195 (e-mail: berbere@ccf.org).
Copyright @ 2010 by Lippincott Williams & Wilkins
CCF · 2009
RESULTS
Patient 1
The patient was a 77-year-old male with a past medical history (PMH) consistent with hypertension, chronic obstructive pulmonary disease (COPD), and atrial fibrilla- tion on Coumadin. He was status post left upper lobectomy for a poorly differentiated lung adenocarcinoma (T2N1M0). A year after his lung surgery, he was found to have a 3.5-cm solitary liver metastasis in segment V and a 1.3-cm right adrenal mass. The adrenal mass had a Hounsfield Unit (HU) density of 34 on noncontrast CT. The percutaneous biopsy of the liver mass showed a poorly differentiated adenocarcinoma consistent with metastasis from his lung primary. In December 1998, he was taken to
the operating room and underwent laparoscopic RFA of his liver and adrenal metastases. His adrenal tumor was treated with a single deployment of the 2-cm ablation catheter. He was discharged from the hospital on POD#1 uneventfully. No recurrence was detected on quarterly CT scans throughout the first year of the follow-up. He died at 51 months.
Patient 2
The patient was an 88-year-old male with a history of COPD and coronary artery disease, s/p stenting. He had undergone right nephrectomy in 2001 for renal cell cancer. In January 2001, he was found to have PET-positive liver and right adrenal metastases. His biochemical work-up was negative for hormonal secretion. He initially had laparo- scopic RFA of his 2.5 cm segment VI liver and 1.5 cm right adrenal metastases in September 2006. This was done through a right lateral transabdominal approach. Using a 5 cm ablation catheter, the right adrenal lesion was ablated with a 4cm deployment after an initial biopsy using an automated 18 G biopsy gun. He was discharged from the hospital on POD#1 uneventfully. He was found to have recurrence involving both lesions on PET scan 7 months later and underwent repeat laparoscopic RFA to both foci in June 2006. At that time, the adrenal recurrence was treated with a 5 cm deployment of the ablation catheter. He developed recurrence of both lesions on MRI at 10 months. He was started on chemotherapy with sunitib and is alive with stable disease at 31 months (Figs. 1, 2).
Patient 3
The patient was a 79-year-old male with a PMH significant for COPD, hypertension, diabetes, arrythmias with a permanent pacemaker, and heparin-induced throm- bocytopenia. He had undergone left upper lobe resection for a T2N1M0 lung adenocarcinoma in October 2005. In September 2006, he was found to have a PET-positive 2.6-cm left adrenal mass. Percutaneous biopsy showed adeno- carcinoma consistent with metastasis from lung primary. In November 2006, he was taken to the operating room for laparoscopic left adrenalectomy. The case was started through a left lateral transabdominal approach, but during the dissection, local invasion into retroperitoneum was identified, which was an indication to convert to open and do en bloc resection. Nevertheless, the patient had refused any open procedure and consented to RFA in case of this finding at the time of his preoperative office visit. Therefore, this adrenal tumor was treated with 2 overlapping cycles of
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ablation with a 3 and 2-cm deployment of the Angiodynamics Model 90 ablation catheter. During the ablation, the patient had elevation of his blood pressure to 200 systolic, which responded to antihypertensives and did not persist beyond ablation. The patient was discharged home uneventfully, a week later owing to social reasons. His postablation 1-week scan showed a successful ablation, but he died free-of-disease in 3 months from cardiac causes (Figs. 3, 4).
Patient 4
The patient was a 69-year-old female nursing home resident with a PMH of obesity, congestive heart failure, hypertension, and stroke, who had developed a progressive polyneuropathy over the last 5 months. During her work- up, an abdominal CT showed a 4.1-cm left adrenal mass with a HU density of 17 on the noncontrast phase. There was a question of whether her neuropathy was part of a paraneoplastic syndrome. A percutaneous biopsy was not possible owing to body habitus. She was taken to the operating room in July 2008 for an attempted left posterior retroperitoneal adrenalectomy. During the procedure, the left adrenal gland was exposed and biopsied using an automated 18-G biopsy gun. Frozen section revealed an adrenocortical neoplasm. During the dissection, the patient developed a progressive hypercapnia (pC02 70 s), preclud- ing further surgical progress. At that time, a decision was made for RFA. The tumor was ablated with 2 overlapping cycles of ablation measuring 3cm each. During the ablation, the patient had elevation of her blood pressure to 200 systolic, which responded to antihypertensives and did not persist beyond ablation. The patient’s preoperative catecholamine and aldosterone levels were normal. The patient was discharged to skilled nursing facility in a month owing to medical issues. The patient’s follow-up scans showed periadrenal inflammatory changes that improved over time. The patient did not have any abdominal symptoms in the follow-up. Lipase and amylase levels were normal at multiple time points. Her polyneuropathy did not improve after adrenal RFA (Figs. 5, 6).
DISCUSSION
Although initially described percutaneously under image-guidance by radiologists, this is the first report of laparoscopic RFA for unresectable adrenal tumors. We showed that the procedure can be done through standard laparoscopic adrenalectomy exposures in a safe fashion in this preliminary report of 5 procedures in 4 patients. With a lateral transabdominal approach, division of the right triangular ligament and cephalad retraction of the right liver lobe seem to be adequate for exposure, whereas on the left, in addition to the division of splenorenal and splenocolic ligaments, the adrenal may need to be dis- sected off the tail of the pancreas for a safe ablation. As the posterior retroperitoneal approach is gaining more
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popularity for laparoscopic adrenalectomy, this study shows that this approach is also appropriate for adrenal RFA.
One technical question is whether the ablation parameters need to be changed for the adrenal gland. Although our experience is limited, we observed an efficient ablation under ultrasound guidance with the standard algorithms used for liver tumors. One difference we noticed was that the target temperatures were reached faster while treating the adrenal than the liver.
There are a number of reports in the literature about radiologic RFA of unresectable adrenal tumors.1,2,4,5 Although these studies, including ours, report the feasibility of RFA for treating adrenal tumors, lessons learned from RFA of liver tumors need to be kept in mind. First of all, the gold-standard option to treat adrenal tumors is
laparoscopic adrenalectomy. Numerous studies have shown good outcomes with minimal morbidity.6,7 Furthermore, an open surgical approach should be considered for more complex malignancy cases. RFA should be reserved only for the unresectable tumors. The criteria for unresectability in our study were accompanying extraadrenal metastasis and patient comorbidities, precluding an open or a longer procedure. Overall, these patients comprised only 2% of the whole series of patients with adrenal tumors undergoing surgery. However, the patients and the surgical team were satisfied to have been able to provide an alternative surgical treatment in these rare situations. We believe that laparo- scopic RFA should be an alternative option in selective cases within a comprehensive adrenal surgery program.
Although technically gratifying, it is important to know how effective RFA is for achieving local tumor control in adrenal malignancies. The success of adrenal RFA is determined by the lack of enhancement and increase in size on imaging in the follow-up. The data in the literature are scant. The success rate of CT-guided RFA was 85% in 12 patients followed for a mean of 11 months in one study (metastases, n = 10, pheochromocytoma, n = 1 and aldosteronoma, n = 1)2 and 83% in 6 patients with adrenal metastases followed for a mean of 21 months in another study.1 Successful ablation was achieved in all the 4 patients in our study, but recurrence was detected in 1 patient in the follow-up. With repeat ablation in this patient, stabilization of disease was achieved.
The mean tumor size in this study was 2.5 cm. This is in accordance with the literature reporting 2.9 to 3.9 cm.1,2 In theory, the size of adrenal tumors to be treated is related to the diameter of the ablation zone achieved with a single deployment of the RFA catheters, which currently range from 4 to 7 cm.
The complication rate in the radiology literature ranges between 8% to 28% and includes severe hyperten- sion, post-RFA syndrome, pneumothorax, and hema- toma.1,2,8 Although no complications were observed in our study, 2 patients had temporary elevations of blood pressure during ablation. Other studies have also described this phenomenon.1,8,9 A likely explanation for the hyper- tensive crisis is the release of catecholamines into the circulation during ablation owing to the lack of adrenal vein ligation.
Most of the reports in the literature, similar to ours, have predominantly involved adrenal malignancies;1,2,4,5 however, RFA has also been described anecdotally for aldosteronoma10 and Cushing syndrome8 with successful outcomes.
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In conclusion, in this first preliminary report, we described the laparoscopic RFA technique for unresectable adrenal tumors. Although the long-term oncologic results need to be further investigated in larger studies, it seems to be promising for achieving local tumor control in selective cases.
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