Ann Thorac Surg 2008;85:420-423. doi:10.1016/j.athoracsur.2007.09.008
© 2008 The Society of Thoracic Surgeons
Original Articles: General Thoracic
Extending Indications for Radiofrequency Ablation of Lung Tumors Through an Intraoperative Approach
Philip A. Linden, MDa,*,
Jon O. Wee, MDb,
Michael T. Jaklitsch, MDb,
Yolonda L. Colson, MD, PhDb
a Division of Thoracic and Esophageal Surgery, Case Medical Center and Case Western Reserve School of Medicine, Cleveland, Ohio
b Division of Thoracic Surgery, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
Accepted for publication September 6, 2007.
* Address correspondence to Dr Linden, Division of Thoracic and Esophageal Surgery, Case Medical Center, 11100 Euclid Ave, Cleveland, OH 44106 (Email: philip.linden{at}uhhospitals.org).
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Abstract
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Background: Radiofrequency ablation (RFA) is a means of local destruction of lung tumors. The role of this technique in regards to improved survival or quality of life has yet to be well defined. RFA can be performed through an intraoperative or percutaneous route. Percutaneous RFA can be performed without single-lung ventilation under local anesthesia with sedation and is often the preferred route of ablation. We detail instances of RFA in patients who were either not candidates for percutaneous RFA or in whom the tumor was found to be unresectable at operation.
Methods: Ten patients with either primary or secondary lung tumors who underwent operation with consideration of intraoperative RFA were reviewed. Patients were followed up with chest computed tomography scans at least every 6 months. Preoperative characteristics, intraoperative techniques, complications, and tumor response were noted.
Results: The median patient age was 60 years (range, 40 to 85 years). Six patients had lung cancer, 4 had cancer metastatic to the lung, and 5 patients had hilar lesions. Combined lung resection and RFA was done in 4 patients; 6 underwent RFA only. The average size of the ablated lesion was 3.0 cm (range, 1.0 to 5.8 cm). No serious intraoperative or perioperative complications were noted. No immediate or delayed hemorrhage or hemoptysis has been noted. Of patients at least 6 months out from ablation, 4 had no growth of the ablated tumor at an average of 13.5 months (range, 8 to 23 months) after ablation, and 5 have had growth of the tumor first noted at an average of 12.8 months (range, 9 to 14) after ablation.
Conclusions: Intraoperative RFA is useful (1) when the lesion is near vital structures such as the great vessels, hilum, or heart, (2) if resectability can only be determined at the time of operation, and (3) when used in patients with secondary tumors of the lung combined with limited resection to preserve lung parenchyma.
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Introduction
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Surgical resection offers the best chance of local control and cure of primary lung cancer and of other cancers with limited metastases to the lungs. Unfortunately, certain patients are not candidates for resection because of anatomic or physiologic factors. Radiation remains an option for local control of disease but is limited by dose and adjacent organ toxicity.
Radiofrequency ablation (RFA) is a means of local destruction of lung tumors with limited toxicity to adjacent organs. It can be performed intraoperatively or under computed tomography (CT) guidance. Radiofrequency as an ablative tool was first described for hepatic tumors [1] and later applied to malignancies of the lung [2]. The earliest reports of radiofrequency for ablation of lung tumors described a CT-guided percutaneous approach [2, 3]. Percutaneous RFA can be performed without single-lung ventilation, under local anesthesia and sedation, and is often the preferred route of ablation.
In a recent meta-review of RFA for lung malignancies, only two of the 13 publications described open, or intraoperative, RFA [4]. Even in these two open surgical studies, 29 of 36 patients were treated percutaneously [5, 6]. Our institution recently published a series of 30 patients undergoing percutaneous RFA ablation for primary and metastatic cancer of the lung [7]. During that time, 10 patients were selected to receive intraoperative RFA. This report details instances in which open RFA may be useful, namely (1) in the presence of hilar tumors where shielding of adjacent structures (ie, heart, hilar vessels) is necessary, (2) when a combination of resection and destructive therapies are used to conserve lung parenchyma, and (3) when the decision of whether the surgical resection is possible can only be made at time of operation.
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Patients and Methods
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Patient Selection
Patients were evaluated before operation and consented for possible RFA. The criteria for consideration of intraoperative RFA in patients with non-small cell lung cancer included (1) the ability to tolerate general anesthesia, (2) disease localized to the lung as evidenced by a positron emission tomography scan showing no evidence of remote disease and negative result on mediastinoscopy, and (3) inability to tolerate complete excision of all lesions due to anatomic or physiologic limitations but with the need for operation for simultaneous excision of other synchronous lung lesions, determination of resectability, or inability to approach the lesion by percutaneous RFA owing to adjacent vital structures. The criteria for inclusion for patients with metastatic disease to the lungs was identical except that patients did not routinely undergo mediastinoscopy, and any other foci of metastatic disease, if present, were deemed to be controllable by the referring oncologist. Tissue diagnosis was obtained in all patients before or at the time of the procedure. This study was approved by the Institutional Review Board on May 5, 2007. The need for individual consent was waived.
Radiofrequency Ablation Technique
All patients underwent a chest CT with measurement of the size of tumor mass as well as distance from the chest wall. RITA Sunburst XL probes (RITA Medical, Mountain View, CA) were used with the RITA 1500X RF generator, and 10- to 15-cm probes were used, depending on distance from the chest wall to the center of the tumor. The tumor was identified by palpation.
For patients undergoing video-assisted thoracic surgery (VATS), the probes were inserted through the chest wall and into the tumor under thoracoscopic visual guidance. The electrodes were deployed sequentially to 3, 4, and 5, and brought to a temperature of 90°C at each length. Once fully deployed, we provided treatment at 90°C for 15 minutes. Tract ablation was performed as the probe was removed.
Postoperative CT scans were obtained 3 months and then at 6-month intervals.
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Results
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The patients undergoing intraoperative RFA were an average age of 60 years (range, 40 to 85 years). The average size of the ablated lesion was 3.0 cm (range, 1.0 to 5.8 cm). Six patients had non-small cell lung cancer, 4 had cancer metastatic to the lung, and 5 underwent RFA to hilar lesions. Thoracotomy was used in 3 patients, and a VATS approach was used in the rest.
The factors precluding resection included prohibitive lung function in 3 patients, the presence of stable metastatic disease in 1, serious comorbid illness precluding lobectomy or pneumonectomy in 3, desire to avoid lobectomy in 2 sarcoma patients at high risk for recurrence, and severely diseased lung tissue unable to hold staples in 1 patient with idiopathic pulmonary fibrosis.
Average length of stay was 4.2 days (range, 2 to 10 days). Two perioperative complications occurred, a superficial wound infection and a chyle leak in association with concomitant lobectomy that resolved with conservative measures. There were no instances of immediate or delayed hemoptysis or hemorrhage. No patients died in the hospital or within 90 days of operation. The operations and conditions precluding percutaneous RFA as well as perioperative events are listed in Table 1.
Median follow up was 15 months (range, 3 to 32 months). Of patients at least 6 months out from ablation, 4 have had no growth of the ablated tumor an average of 13.5 months (range, 8 to 23) after ablation, and 5 have had growth of the tumor first noted at an average of 12.8 months (range, 9 to 14) after ablation. Three patients died at 12, 13, and 16 months after RFA. Tumor characteristics and follow-up are detailed in Table 2.
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Comment
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Numerous reports have described percutaneous RFA of primary and secondary lung tumors. Some describe RFA under general anesthesia, and others describe the procedure under sedation. In general, these patients have been referred for RFA because they are deemed inoperable, and very few instances of intraoperative RFA have been described. In fact, the risk of percutaneous RFA under general anesthesia is probably similar to that of VATS RFA under general anesthesia. Percutaneous RFA carries a 40% to 50% incidence of pneumothorax, although not every patient requires chest tube placement [4]. Routine placement of a chest drain after VATS RFA mitigates the risk of an enlarging pneumothorax. In our 10 patients, there were no major complications and only two minor complications. One of these complications, a self-limited chyle leak, was related to the concomitant lobectomy. The average length of stay was 4.2 days, including patients who underwent concomitant lung resections.
Less common but more serious complications after percutaneous RFA include hemorrhage and hemoptysis, including a reported instance of fatal hemoptysis after RFA of a hilar lesion. This led a very experienced group to conclude that the risk of RFA for hilar lesions may be prohibitive [5]. The risk of massive hemorrhage or hemoptysis is likely related to direct apposition of tumor with large, vascular structures such as pulmonary veins, arteries, the great vessels, or cardiac chambers. Invasion of these structures by tumor may further increase the risk of hemorrhage. Furthermore, RFA of tumors adjacent to vascular structures may be less efficacious because these vessels may function as heat sinks that prevent achievement of optimal local temperatures.
Surgical RFA allows for the introduction of a pneumothorax and collapse of the lung, allowing for tumors abutting the heart or great vessels to fall away from these structures. Invasion of these structures can be definitively determined at operation. Operative dissection of hilar tumors away from hilar vessels may allow for the safe administration of RFA. Three of the patients in this series underwent intraoperative dissection and RFA to tumors abutting the pulmonary artery or vein without complication.
A second indication for surgical RFA is when the patient is found to be unresectable at operation. In this series, an 84-year-old man with severe chronic obstructive pulmonary disease, cerebrovascular disease, chronic renal insufficiency, and cardiomyopathy was found to have a superior sulcus tumor. No definite chest wall invasion was seen on chest CT. In consultation with his pulmonologist and cardiologist, it was determined that thoracotomy with Pancoast resection would likely put him at high risk of perioperative renal and cardiac failure. At operation, thoracoscopy showed that the lesion was invading the first rib and that simple wedge resection was not possible. Intraoperative core needle biopsy confirmed non-small cell lung cancer, and he underwent RFA with thoracoscopic approach.
A third indication for open RFA is the combined use of resection and RFA for optimal local control and preservation of lung parenchyma in patients with metastatic disease to the lungs. The likelihood of recurrence after resection can be predicted by factors such as disease-free interval, number of metastatic lesions, and tumor histology [8, 9]. In patients with multiple lesions or when recurrence is likely, RFA may be preferable to lobectomy or pneumonectomy. In this series, 4 patients with metastatic disease to the lungs underwent wedge resection of one or multiple lesions and RFA to a solitary lesion that would have otherwise required a large anatomic resection. The 2 patients with metastatic sarcoma have had long disease-free intervals, but the 2 patients with metastatic epithelial tumors have not.
One example of combined limited resection and RFA for lung conservation was in a 39-year-old woman who had undergone five prior operations, including left upper lobectomy and sternal resection for synovial cell sarcoma metastatic to the lungs and sternum. She presented with two peripheral lesions in the right upper lobe and a 1.0-cm hilar lesion adjacent to the right inferior pulmonary vein (Fig 1). She was at high risk for recurrent disease and had reduced lung function. She underwent wedge resection of the peripheral lesions and RFA of the 1.0-cm hilar lesion after dissection of the lesion away from the inferior pulmonary vein. She is disease-free 14 months after the operation (Fig 2).
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Fig 1. A computed tomography scan shows a metastatic sarcoma nodule abutting the right inferior pulmonary vein.
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Fig 2. A computed tomography scan of the patient in Fig 1 taken 14 months after intraoperative radiofrequency ablation shows no evidence of recurrence.
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It remains to be seen whether RFA will provide the same long-term control and survival that is available with complete resection. Even with lesions smaller than 3 cm, the 5-year failure rate of RFA for a single lesion is 53% [10]. If three simultaneous (<3 cm) lesions are ablated, the chance of control at 5 years would be just 15%. Thus, wedge resection of multiple lesions in conjunction with RFA to lesions not amenable to limited resection may offer better long-term control than multiple percutaneous ablations. In this study as with prior studies [3, 10], the risk of tumor progression increased significantly with tumor size. None of our patients with tumors smaller than 3 cm have been noted to have progression by size as judged by follow-up CT scan, whereas patients whose tumors were 3 cm or larger had progression after a period of time.
In summary, our institution has used open RFA in a subgroup of patients whom we believe to be uniquely suited to this approach. These include (1) patients whose lesions are determined to be unresectable at exploration, (2) patients with hilar lesions that are not resectable, and (3) patients with multiple metastases to the lungs treated with a combination of resection and ablation in an effort to achieve local control and conserve lung parenchyma. The long-term benefits of RFA for improved survival, or even quality of life, remain to be determined.
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References
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- Curley SA, Izzo F, Delrio P, et al. Radiofrequency ablation of unresectable primary and metastatic hepatic malignancies: results in 123 patients Ann Surg 1999;230:1-8.[Medline]
- Dupuy DE, Zagoria RJ, Akerley W, Mayo-Smith WW, Kavanagh PV, Safran H. Percutaneous radiofrequency ablation of malignancies in the lung AJR Am J Roentgenol 2000;174:57-59.[Free Full Text]
- Lee JM, Jin GY, Goldberg SN, et al. Percutaneous radiofrequency ablation for inoperable non-small cell lung cancer and metastases: preliminary report Radiology 2004;230:125-134.[Abstract/Free Full Text]
- Nguyen CL, Scott WJ, Young NA, Rader T, Giles LR, Goldberg M. Radiofrequency ablation of lung malignancies Ann Thoracic Surg 2006;82:365-371.[Abstract/Free Full Text]
- Herrera LJ, Fernando HC, Perry Y, et al. Radiofrequency ablation of pulmonary malignant tumors in nonsurgical candidates J Thorac Cardiovasc Surg 2003;125:929-937.[Abstract/Free Full Text]
- Fernando HC, DeHoyos A, Landreneau RJ, et al. Radiofrequency ablation for the treatment of non-small lung cancer in marginal surgical candidates J Thorac Cardiovasc Surg 2005;129:639-644.[Abstract/Free Full Text]
- Van Sonnenberg F, Shankar S, Morrison PR, et al. Radiofrequency ablation of thoracic lesions: part 2, initial clinical experience—technical multidisciplinary considerations in 30 patients AJR Am J Roentgenol 2005;184:381-390.[Abstract/Free Full Text]
- Friedel G, Pastorina U, Buyse M, et al. Resection of lung metastases: long-term results and prognostic analysis based on 5206 cases—the international Registry of Lung Metastases Zentralbl Chir 1999;124:96-103.[Medline]
- Robert JH, Ambrogi V, Mermillod B, Dahabreh D, Goldstraw P. Factors influencing long-term survival after metastasectomy Ann Thorac Surg 1997;63:777-784.[Abstract/Free Full Text]
- Simon CJ, Dupuy DE, DiPetrillo TA, et al. Pulmonary radiofrequency ablation: long-term safety and efficacy in 153 patients Radiology 2007;243:268-275.[Abstract/Free Full Text]
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Abstract
Introduction
