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Department of Surgery, Division of Thoracic and Cardiovascular Surgery, University of Virginia School of Medicine, Charlottesville, Virginia
* Address correspondence to Dr Grogan, Thoracic and Cardiovascular Surgery Outcomes, Heart & Vascular Center, PO Box 800679, University of Virginia Health System, Charlottesville, VA 22908-0679 (Email: elg9q{at}virginia.edu).
Presented at the Minimally Invasive Thoracic Surgery Summit, New York, NY, June 8–9, 2007.
| Abstract |
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Methods: Initial laboratory studies succeeded in selecting a technetium 99m gamma-emitting solution, technetium 99m macro-aggregated albumin, that remained localized in lung parenchyma after percutaneous placement. Subsequently, 84 patients with solitary small nodules underwent computed tomography (CT)–guided percutaneous placement of this technetium solution in or near the nodule. Thoracoscopic localization with a radioprobe and excisional biopsy followed.
Results: In 3 patients, the previous lesion was not present on the CT scan done on the day of surgery. The 81 remaining patients underwent radiotracer placement and operation. No tracer activity was present in the lung in 4 patients, and open thoracotomy was necessary to locate the lesion. The lesion was successfully localized and excised in 77 patients (95.1%), and 71 underwent thoracoscopic excisional biopsy. Four underwent intentional thoracotomy for deep small nodules in which the tracer was used to guide the open biopsy. Two required conversion from thoracoscopy to thoracotomy because the anatomic location of the lesion prevented a thoracoscopic staple excision. Fifty percent of the lesions were benign, 39% were primary lung cancers, and additional 11% were either solitary metastatic lesions or lymphoma. No patients died, and morbidity rate was 16% (arrhythmias or pneumothoraces).
Conclusions: Radiotracer-guided thoracoscopic biopsy was 95% reliable for subsequent surgical successful localization and excision of small nodules. This technique can be expanded to localize deep lesions for open thoracotomy and be used to prevent thoracotomy in 50% of patients with benign disease.
| Introduction |
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Many of the small nodules found with increasing use of improved CT technologies are located in areas of the lung abutting the mediastinum, diaphragm, and apex. These nodules may also lie more than 1 cm deep to the pleura and are frequently not localizable with the routine thoracoscopic techniques. In the past, when dealing with larger nodules, thoracic surgeons have believed that they could always obtain a tissue diagnosis thoracoscopically by visualization, instrumental palpation, or digital palpation, followed by excision. Small nodules in these difficult locations can be challenging to locate without a thoracotomy, however, thereby subjecting patients who ultimately are shown to have a benign diagnosis to unnecessary morbidity. Surgeons may also be more reluctant to be aggressive in obtaining an excisional biopsy if they believe a thoracotomy would be necessary.
The failure of routine thoracoscopy to predictably localize and excise such small nodules has led to many innovative techniques to achieve this goal. These include wire hook and coil markers [3], radiopaque markers using intraoperative fluoroscopy [4, 5], ultrasound guidance [6], and most recently, navigational bronchoscopy [7]. At the University of Virginia School of Medicine, we modified a technique first described by Chella and colleagues [8] that used CT-guided percutaneous placement of a technetium (Tc) radiotracer in or near the small lung nodule to guide subsequent thoracoscopic biopsy. We used Tc 99m macro-aggregated albumin (MAA) that stayed localized in lung parenchyma for up to 18 hours. We designed a long narrow radioprobe (RMD Instruments, LLC, 44 Hunt St, Watertown, MA) with an angled 30° tip to help with the thoracoscopic localization and excision of the nodule. This report describes the results, lessons learned, and expanded applications of the radiotracer guided thoracoscopic nodule excision in 84 patients.
| Materials and Methods |
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Patients
Between November 2002 and August 2006, 84 patients (Fig 1) were selected in the clinic for CT-guided radiotracer placement in the vicinity of their small lung nodule, followed by attempted thoracoscopic localization and excisional biopsy. All patients had been referred to our thoracic surgical service for the evaluation and management of a solitary lung nodule. Patient selection for this procedure by the thoracic surgeons was by the size of the nodule, its ground-glass or solid characteristics, its depth from the pleural surface, and the region of the lung that it lay in. The role of clinical judgment in this decision was difficult to quantify. For example, small and larger ground-glass lesions might not be expected to be apparent, thoracoscopically, as a mass when embedded in an atelectatic lung. Similarly, a small subpleural lesion located in the lateral lung adjacent to the chest wall might be easily palpable digitally or with an endoscopic instrument. This same lesion located in the lung adjacent to the mediastinum would not be palpable and was selected for tracer localization. This procedure has a built-in mechanism to guard against unnecessary operations for those patients whose small nodules disappeared between their office visit and their scheduled procedure in that a repeat CT was always obtained immediately before the operation as part of the localization process. Studies were approved by the University of Virginia Institutional Review Board for Health Sciences Research #12429, and individual consent was waived.
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A 20-guage coaxial needle was positioned in the chest wall along the intended track of the radiotracer placement needle and positioned just proximal to the pleural cavity. A 22-gauge spinal needle was then advanced through this needle into or just deep to the lung nodule under CT fluoroscopy (Fig 2). Care was taken to choose an angle of position to avoid injecting the radiotracer near the pleural surface of a major fissure. Once properly positioned, 0.1 mL of Tc 99m MAA (approximately 0.3 mCi) was injected. An immediate postprocedure nuclear medicine scintigram was obtained to confirm the intraparenchymal location of the radiotracer. The patient then recovered from conscious sedation, reported to the surgical admission suite, and was subsequently taken to the operating room.
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Once the lesion was removed, the radioprobe was used to confirm the absence of strong signal in the remaining lung and also to determine the site of maximum activity in the specimen. This area on the specimen was marked with a suture for immediate frozen-section pathologic examination. Patients found to have primary lung cancers underwent immediate open thoracotomy or video-assisted thoracotomy with lobectomy or segmentectomy, followed by complete nodal staging.
| Results |
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Thoracoscopic excisional biopsies were done in 71 patients (92%), and 4 (5%) underwent intentional thoracotomy for deep nodules that the surgeon believed were not removable by the thoracoscopic stapling technique. These lesions were not palpable at open thoracotomy and required radioprobe guidance for localization and successful excisional biopsy. Two patients (3%) required conversion to open thoracotomy and biopsy after thoracoscopic assessment of the nodules actual location by the operating surgeon judged the nodule was too deep for thoracoscopic wedge excision. All patients found to have primary lung cancers underwent an immediate lobectomy and nodal staging or, if severe emphysema was present, underwent a segmentectomy with nodal staging.
The average length of stay for patients found to have benign lesions, metastatic lesions, or primary pulmonary lymphoma, all of whom had wedge biopsies, was 2.2 days. The average length of stay for patients undergoing lobectomy or segmentectomy was 5 days.
Of the 77 patients (42 men, 35 women) going on to operation after successful lung tracer placement, 83% had a history of current or former smoking. The average age was 61.7 years (range, 33 to 80 years).
Morbidity and Mortality
Minor complications occurred in 16% (12 of 77) of the patients who underwent tracer injection and excisional biopsy. Placement of a pigtail catheter in the radiology suite was required in 8 patients to treat pneumothoraces that developed during CT-guided tracer placement. All patients were taken to the operating room and had successful localization procedures. Intraoperative or postoperative atrial arrhythmias developed in 3 patients, and 1 patient had a prolonged air leak (>6 days) after undergoing a lobectomy for a primary lung cancer. There were no deaths in our series.
Characteristics of Nodules
The mean size of all the 77 nodules that were localized and excised using the radiotracer-guided technique was 9.8 mm (range, 3 to 25 mm). The average distance from the outer edge of the nodule to the nearest pleural surface (apical, diaphragmatic, mediastinal and chest wall) was 11.7 mm (range, 0 mm [subpleural] to 50 mm).
Thirty of the 77 nodules (39%) were primary lung cancers (Fig 4), consisting of 18 adenocarcinomas, nine squamous cell carcinomas, two large cell carcinomas, and one small cell carcinoma. Of these 30 nodules, 28 were stage IA and one 9-mm squamous cancer was stage IIA secondary to an intralobar nodal metastasis. One 6-mm squamous cancer was found to have a 4-mm focus of the same cell type present in the lobe removed at operation, making the pathologic stage IIIB. Eight of the 77 nodules (10%) were solitary metastases from a current or previous known extrathoracic malignancy. One patient had a primary pulmonary lymphoma. Thus, 39 patients (50.7%) had malignant lesions, and the remaining 38 patients (49.3%) had benign lesions.
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One patient had a successful video-assisted thorascopic surgical (VATS) excision the morning after CT-guided radiotracer placement because of an emergency that postponed the planned afternoon case. Experience also taught us that when scheduling difficulties prevented us from being able to perform the operative procedure in the afternoon, we increased the dose to 0.3 to 0.4 mL of Tc 99m MAA (approximately 0.9 to 1.2 mCi). This allowed us to have radiology place the radiotracer late in the afternoon, and then we performed the operation as the first case the next morning. If no pneumothorax occurred requiring a pigtail catheter placement, the patient was allowed to return home and report for surgery the following morning. If a pigtail was necessary, the patient was admitted to the hospital overnight.
As our experience increased with the VATS radiotracer technique, we expanded this to deep lesions for localization for intentional thoracotomy. Four patients had small indeterminate lesions that were deep within the lobe, and VATS excision was felt to be impossible. These lesions were either small or had a ground-glass appearance, and manual palpation during thoracotomy would have been challenging, potentially requiring a lobectomy for a possible benign lesion. Radiotracer was placed in these patients and they underwent planned thoracotomy with radiotracer-guided localization and wedge excision.
| Comment |
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The results of our study add to the growing number of options for the evaluation and management of small lung nodules. We experienced a 95.1% success rate in making a diagnosis of small lung nodules not thought to be accessible by routine thoracoscopic or fine needle aspiration techniques. When the radiotracer was successfully placed in the lung parenchyma, as it was in 95.1% of the patients, we experienced a 100% success rate in localizing and removing the entire nodule for definitive pathologic study and margin assessment.
Compared with other techniques for small nodule localization for biopsy we see the following advantages with this technique:
In addition, this technique can be successfully used for very small nodules (<5 mm) and larger nodules that are deep in the parenchyma that would be difficult to thoracoscopically excise. It is also useful for lesions with ground-glass appearance, which can be difficult to palpate even in open procedures.
There are two major disadvantages:
The treatment algorithm for lung nodule management is now changing rapidly with the introduction of new technology and proteomic knowledge. The ability to predict individual tumor behavior according to gene arrays of tumor tissue is predicated on obtaining adequate tissue sampling. Treatment options other than surgical resection, such as radiofrequency ablation and stereotactic radiosurgery, are also being evaluated. The use of endoscopic bronchial ultrasound imaging to biopsy mediastinal and lobar lymph nodes and the use of the navigational bronchoscope to obtain a tissue diagnosis of small lung nodules without the need for routine hospitalization will undoubtedly change the algorithm for the management of small lung nodules.
The availability and reliability of the radiotracer-guided technique in diagnosing small lung nodules has had a significant influence on our treatment options when making clinical decisions and has given us an additional diagnostic tool. The technique can be used for more than one nodule, but for patients with multiple nodules and metastatic disease, we have preferred open thoracotomy to allow manual palpation of the lung. With these current techniques, our benign diagnosis rate is 49.3%. This has not decreased with our experience and will likely remain high until new imaging techniques that characterize nodules better are clinically available. Most patients and clinicians, however, are willing to accept the risks of thoracoscopy if 50% of the excised lesions are malignant.
In a rapidly changing, technology-driven environment, it is important that thoracic surgeons continue to develop, study, and implement new techniques used to diagnose and treat lung nodules. The thoracic surgeon is often the specialist who sees the patient first, knows the three-dimensional anatomy of the thorax, and can therefore make judgments about nodule accessibility for excisional biopsy using the most effective technique needed for diagnosis and treatment. In addition, thoracic surgeons are experienced in managing the complications such as tension pneumothorax, hemothorax, and massive hemoptysis, and they know the clinical behavior of lung cancer. Used by knowledgeable and thoughtful clinicians, proven diagnostic and therapeutic innovations will ultimately benefit the patient with a lung cancer or a metastatic lesion presenting as a small lung nodule.
| Acknowledgments |
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| References |
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This article has been cited by other articles:
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J. Loscertales, R. Jimenez-Merchan, M. Congregado, F. J. Ayarra, G. Gallardo, and A. Trivino Video-Assisted Surgery for Lung Cancer. State of the Art and Personal Experience Asian Cardiovasc Thorac Ann, June 1, 2009; 17(3): 313 - 326. [Abstract] [Full Text] [PDF] |
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