Radical En Bloc Esophagectomy




Introduction



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Despite improvements in perioperative care, surgical techniques, and neoadjuvant therapy over the last decade, the prognosis of esophageal cancer remains poor. More than 95% of new cases diagnosed annually in the United States succumb to disease. Among the subset of patients resected with curative intent (R0 resection), the 5-year survival after transthoracic esophagectomy or transhiatal esophagectomy rarely exceeds 30% based on reports from large surgical series.14 The principal justification for these poor results is the finding that most patients develop metastatic disease and already may have disseminated disease at the time of diagnosis. A careful analysis of the patterns of failure after surgical resection also implicates inadequate locoregional control. The locoregional failure rates are unacceptably high after conventional surgical resection, ranging from 30% to 60%.58 The addition of preoperative therapy of any kind does not meaningfully reduce the high rate of local failure.68 Thus a meaningful improvement in the survival of patients with esophageal cancer is unlikely without adequate locoregional control.



En bloc resection for tumor of the lower esophagus and cardia was first described by Logan in 1963.9 The reported 5-year survival was unparalleled at the time but was achieved at the cost of high operative mortality. In 1979, Skinner revisited the en bloc approach and extended its use to tumors of the middle and proximal esophagus, publishing his first report in 1983.10 A few years earlier, Orringer and Sloan11 published their first report on the transhiatal approach for esophagectomy without thoracotomy. The controversy continues to the present concerning the efficacy of radical en bloc esophagectomy, and most surgeons favor conventional techniques of esophageal resection through either a transthoracic or a transhiatal approach. However, we and others continue to advocate radical en bloc esophageal resection as the optimal procedure for maximizing locoregional control and improving long-term survival in patients with esophageal cancer.12 The basic concept of en bloc esophagectomy is resection of the tumor-bearing esophagus with a wide margin of surrounding tissues. Thus, for tumors of the middle or lower thoracic esophagus, the en bloc specimen includes the tumor-bearing esophagus, the pericardium anteriorly, both pleural surfaces laterally, and the thoracic duct and all other lymphoareolar tissue wedged posteriorly between the esophagus and the spine. The associated lymphadenectomy includes en bloc resection of all nodal groups in the middle and lower mediastinum as well as the upper abdomen.



For a selected group of patients, the lymphadenectomy is extended to include the superior mediastinal and cervical lymph nodes (three-field lymph node dissection). The three-field concept was first introduced by Japanese surgeons, prompted by their observation that up to 40% of patients resected by radical two-field esophagectomy developed isolated recurrences in the cervical nodes.13 In 1991, Isono et al.14 reported nationwide results of three-field lymph node dissection and found that occult cervical node metastases occurred in one-third of patients. Even for lower-third tumors, up to 20% of patients harbored cervical metastases. Most Western surgeons have been reluctant to adopt the three-field dissection technique for two principal reasons: skepticism that long-term survival can be achieved once nodal disease is present and the reported high morbidity associated with the operation. In particular, injury to one or both recurrent laryngeal nerves has been described in as many as 50% of patients with a consequent high risk for tracheostomy.15,16




Preoperative Assessment



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Preoperative assessment is directed toward establishing, as accurately as possible, the clinical stage of the disease, as well as assessing the patient’s ability to tolerate the planned operation. Our standard diagnostic and staging workup includes an upper endoscopy with biopsy and CT scan of the chest and upper abdomen in all patients. In addition, patients currently undergo endoscopic ultrasonography as well as positron emission tomography. The former is useful in selecting patients for clinical trials of preoperative induction therapy, whereas the latter is a more sensitive test for detecting distant visceral and skeletal metastases. Generally, patients are considered for primary surgical resection if the preoperative evaluation reveals no evidence of distant visceral metastases or clear evidence of direct neoplastic invasion of the airway or major vascular structures. The presence of extensive nodal disease is not considered a contraindication to resection unless it clearly extends beyond the proposed fields of dissection. Finally, all patients are evaluated for pulmonary and cardiac function to determine their ability to withstand the planned procedure.




Operative Technique



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The basic principle underlying en bloc esophagectomy is resection of the tumor-bearing esophagus within a wide envelope of periesophageal tissue, which includes both pleural surfaces laterally, a patch of pericardium anteriorly, and the thoracic duct posteriorly, along with the mediastinal lymph nodes from the tracheal bifurcation to the hiatus (Fig. 19-1).




Figure 19-1


Radical en bloc esophagectomy entails resection of the tumor-bearing esophagus within a wide envelope of periesophageal tissue from the tracheal bifurcation to the hiatus.





An upper abdominal lymphadenectomy is also performed, including the celiac, common hepatic, left gastric, parahiatal, lesser curvature, and retroperitoneal lymph nodes. A “third field” nodal dissection can be incorporated by extending the lymphadenectomy to include the superior mediastinal and cervical lymph nodes (Fig. 19-2). The procedure is almost always carried out through three incisions: a right thoracotomy, followed by a laparotomy and collar neck incision. More recently, the thoracic and abdominal portions of the dissection are accomplished by a minimally invasive approach.




Figure 19-2


A “third field” nodal dissection is performed by extending the lymphadenectomy to include the superior mediastinal and cervical lymph nodes.





The Thorax


A right fifth interspace thoracotomy is performed regardless of the location of the tumor within the esophagus (Fig. 19-3, inset). The “first field” comprises the middle and lower mediastinum and is bound superiorly by the tracheal bifurcation, inferiorly by the esophageal hiatus, anteriorly by the hilum of the lung and pericardium, and posteriorly by the descending thoracic aorta and the spine. Dissection of the middle and lower mediastinum begins by incising the mediastinal pleura over the anterior aspect of the azygos vein from the level of the azygos arch superiorly to the aortic hiatus inferiorly. The dissection proceeds leftward anterior to the aorta and across the mediastinum to the opposite pleura, which is entered along the entire length of the incision. The thoracic duct thus is mobilized anteriorly toward the specimen and is ligated inferiorly at the aortic hiatus and superiorly as it crosses to the left side of the mediastinum (Fig. 19-3). All lymphatic channels are clipped or ligated between the thoracic duct and the spine to minimize the probability of a chylothorax. The arch of the azygos vein, but not its main trunk, is resected en bloc with the specimen. The anterior dissection is commenced by dividing the azygos vein at its caval junction and by carrying the dissection along the right main bronchus and the posterior aspect of the hilum of the right lung. The hilar and subcarinal nodes are cleared, and a patch of pericardium is resected en bloc with the tumor-bearing esophagus for all but submucosal tumors (T1) of the middle and lower thirds of the esophagus. Division of both pulmonary ligaments (left and right) completes the esophageal mobilization (Fig. 19-4). For tumors traversing the hiatus, a 1-in cuff of diaphragm is excised circumferentially en bloc with the specimen using electrocautery. The completed dissection clears all nodal tissue in the middle and lower mediastinum, including the right and left paraesophageal, parahiatal, paraaortic, subcarinal, bilateral hilar, and aortopulmonary lymph nodes.




Figure 19-3


View from a right thoracotomy at the fifth interspace (inset). Specimen is mobilized anteriorly along the descending thoracic aorta, including the thoracic duct.






Figure 19-4


The en bloc specimen is completely mobilized, revealing the left lung, the tracheal bifurcation, and the pericardium.





Dissection of the third field begins during the thoracic portion of the procedure and is later completed through a collar neck incision. Dissection of the nodes in the superior mediastinum includes the nodes along the right and left recurrent laryngeal nerves throughout their mediastinal course. The paratracheal retrocaval compartment is not disturbed. The left recurrent nerve is dissected using a “no touch” technique, and nodes along its anterior aspect are carefully excised. Notably, there is a paucity of nodal tissue along the left nerve in nearly all Caucasians. The right recurrent nerve is carefully exposed near its origin at the base of the right subclavian artery (Fig. 19-5). The right vagus nerve serves as a good guide to locate the right recurrent nerve. The right recurrent nodal chain begins at that level and forms a continuous package that extends through the thoracic inlet to the neck. Again, the nerve is dissected using a strict no touch technique. Through the cervical incision, the remainders of the recurrent nodes are dissected, as are the lower deep cervical nodes located posterior and lateral to the carotid sheath. Thus the third field includes a continuous anatomically inseparable chain of nodes that extends from the superior mediastinum to the lower neck. These nodes should be appropriately labeled cervicothoracic nodes rather than cervical nodes.

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Dec 30, 2018 | Posted by in VASCULAR SURGERY | Comments Off on Radical En Bloc Esophagectomy

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