© 1999 AlphaMed Press Surgical Management of Esophageal CarcinomaMedical University of South Carolina, Cardiothoracic Surgery, Charleston, South Carolina, USA Correspondence: Carolyn E. Reed, M.D., Medical University of South Carolina, Cardiothoracic Surgery, 96 Jonathan Lucas Street, Suite 409, P. O. Box 250612, Charleston, South Carolina 29425, USA. Telephone: 843-792-3362; Fax: 843-792-8286; e-mail: reedce{at}musc.edu
Surgical management of esophageal carcinoma is reviewed. The anatomy and biology are briefly mentioned, since these factors mitigate against the success of surgery. Staging, the key to proper treatment allocation and prognosis, is discussed, including the use of endoscopic ultrasonography, positron emission tomography, and thoracoscopy/laparoscopy. Patient selection and preparation for surgery are important considerations. Surgical techniques are then discussed, as are the advantages and disadvantages of various approaches, the morbidity of surgical resection, survival, and quality-of-life issues. Adjuvant treatment strategies (preoperative radiation, induction chemotherapy, induction chemoradiotherapy, and postoperative treatment) are summarized. Key Words. Surgery • Cancer • Esophagus
Although the surgical management of esophageal cancer is considered the mainstay of treatment, there are biologic factors that mitigate against its success. The esophagus lacks a serosa, and once tumor penetrates the muscle wall, it can quickly invade surrounding structures. The submucosa is rich in lymphatics that extend longitudinally as well as laterally [1] ( Fig. 1), and therefore submucosal spread of tumor (especially proximally) is common. The longitudinal network of lymphatics allows frequent spread to nodes in the neck, thorax, and abdomen despite tumor location. Once a tumor has breached the muscular layers, the incidence of positive regional lymph nodes exceeds 75% [1]. The submucosal plexus of blood vessels also aids in early systemic dissemination of disease.
Worldwide, squamous cell carcinoma is the most frequent histology, but in the United States, United Kingdom, and Germany, the incidence of adenocarcinoma has risen dramatically. With the rise in adenocarcinoma, there has been a shift in presentation to distal and gastroesophageal junction (GEJ) tumors. The risk factor of Barrett's esophagus and the institution of endoscopic surveillance programs allow the potential to identify esophageal adenocarcinoma in early stages when surgical management can be most effective.
Staging is the key to proper treatment allocation, determination of prognosis, and accurate assessment and communication of the results of clinical trials in the therapy of esophageal cancer. Unfortunately, the staging of esophageal cancer has been imprecise. Computed tomographic (CT) scanning is the most frequently utilized staging tool. CT scanning is excellent for identifying distant metastases in the chest and abdomen. However, CT cannot differentiate the layer of the esophageal wall (T status) or accurately assess regional lymph node disease (N status) [2] ( Table 1). A CT scan underestimates stage in greater than 40% of cases. In two recent studies, the overall accuracy of CT scanning for detecting regional lymph node disease was 55% and 63%, respectively [3, 4].
Endoscopic ultrasonography (EUS) is presently the most accurate noninvasive method for staging the T and N components of esophageal cancer, and EUS should be considered a standard staging tool ( Fig. 2). Using the radial echoendoscope, 360-degree visualization of the layers of esophageal wall is possible, and tumor involvement of adjacent structures, such as aorta and trachea, can be assessed. Comparison of T status from three studies indicated combined accuracy of 90% for EUS and 57% for CT [5-7]. In five comparative studies, EUS accurately predicted positive nodes in 73% of cases and CT in only 54% [5-9]. The ability to combine fine-needle aspiration (FNA) with EUS potentially offers greater precision in staging by histologic verification of identified lymph nodes. Celiac axis lymph nodes are readily accessible to EUS-guided FNA, but until a sheathed needle is developed, peritumoral lymph nodes cannot be biopsied unless they are proximal or distal to the tumor. At the author's institution, dilation prior to EUS is regularly performed when necessary to pass the scope, and successful completion of EUS is >90%.
Thoracoscopic and laparoscopic staging of esophageal cancer have been proposed as a means of increasing the accuracy of esophageal cancer staging. Studies have shown very high accuracy in identifying positive lymph nodes [10, 11]. However, with the requirement of general anesthesia, operative time of up to 3 h, and the need for a two- to three-day hospitalization, this staging tool is obviously more invasive and still investigational. At present, the feasibility and morbidity of thoracoscopic/laparoscopic staging is being evaluated in a cooperative group setting (CALGB 9380). The role of positron emission tomography (PET) in staging esophageal cancer is being investigated. Early studies have shown that unsuspected metastatic disease has been detected in up to 20% of patients considered candidates for esophagectomy [12-13]. Further study is needed to determine the ultimate role of PET in staging. The adequacy of the presently used staging system has been questioned [14] ( Table 1). The current system was developed on retrospective data that focused on patients with squamous cell carcinoma of the cervical and thoracic esophagus and did not fully consider tumors of the GE junction. Although the extent of tumor invasion into the esophageal wall (T descriptor) in the current system is an important prognostic indicator, better descriptors of regional lymph nodal (N1) versus distant nodal (M1) metastases are needed. For example, most surgeons consider celiac axis lymph nodes to be a regional nodal basin for GEJ tumors and would not declare such patients as stage IV (i.e., unresectable). The number of metastatic lymph nodes may be an important predictor of survival and is not considered in the present staging system. Recent clinical trials have employed a lymph node map that provides a number for each lymph node group by anatomic location ( Fig. 3) [15]. Defining regional (N1) versus distant nodal stations (N2) for tumors in different locations and stratifying for number of positive nodes must be considered in a new system. Ultimately, a revised system should more accurately predict patient survival.
Esophageal resection results in a significant physiologic insult to the patient. In the author's opinion, the respiratory and nutritional status of the patient must be of primary concern. If weight loss is greater than 10% and/or the albumin level is abnormal, a manner of nutritional supplementation is needed. If the patient is undergoing neoadjuvant treatment with concurrent chemotherapy and radiation, it is usually the second cycle of chemotherapy that worsens an initial nutritional deficit. About 30% to 50% of patients in the author's series experience radiation-induced esophagitis despite relief of tumor-induced dysphagia. The author favors early placement of a jejunostomy tube (not gastrostomy) when the patient begins the first cycle of chemotherapy. Any nutritional deficit of treatment-related toxicity is more easily corrected prior to planned resection. In most series, respiratory problems are the major postoperative complication. Patients with severe chronic obstructive pulmonary disease (FEV1 and DLCO less than 50% of predicted) should be carefully evaluated. Use of the transhiatal approach in patients identified at increased pulmonary risk will be discussed below. Patients with a history of myocardial infarction and residual reduced ejection fraction or ongoing ischemia are not good candidates for esophagectomy. Although age alone has not been shown by many to be a significant factor in outcome [16-19], reports have documented increased postoperative morbidity in the elderly [16, 20]. Proper surgical management assumes the availability of specialized anesthesia and intensive coordinated postoperative care. It is probably progress in perioperative management that has played the biggest role in the reduction of surgical mortality. It is certainly key to the ability to offer surgical resection to the elderly patient.
The surgical approach used for esophageal resection ( Table 2) depends on tumor characteristics and location, the surgeon's training and experience, and overall surgical philosophy. The most popular approaches ( Fig. 4) in the United States are transthoracic and transhiatal. The right transthoracic approach may result in an anastomosis in the upper thorax for lower-third and GEJ tumors (the Ivor-Lewis technique) or in the neck for higher lesions (three-field). The transhiatal approach avoids thoracotomy and always places the anastomosis in the neck. Resection of the distal esophagus and reconstruction can also be approached via the left chest alone or in a thoracoabdominal approach. En-bloc esophagectomy is a radical resection in which a block of tissue with 10 cm margins proximal and distal to the tumor includes the thoracic esophagus, thoracic duct, azygos vein, posterior pericardium, and soft tissue in the posterior mediastinum. Although this extensive approach minimizes local recurrence, it is performed by selective surgeons.
There are purported advantages and disadvantages to each approach. The transthoracic technique permits direct visualization of the tumor and dissection of more periesophageal and nodal tissue. The disadvantage of this operation is the cardiopulmonary insult imposed by a thoracotomy and the increased morbidity of anastomotic leak in the thorax. The transhiatal approach has the potential to minimize respiratory compromise, and anastomotic complications are usually easily managed. Its disadvantages are the inability to perform a complete node dissection or to always completely visualize the tumor. Despite continuing controversy and the perception by many surgeons, neither retrospective [21] nor prospective [22, 23] series have shown any difference in morbidity or mortality between the Ivor-Lewis and transhiatal esophagectomy. Several series have shown significantly fewer pulmonary complications when the transhiatal approach is used [24, 25]. No contemporary retrospective or prospective study has shown any difference in long-term survival outcome. The author believes the operative technique is best chosen in view of tumor (stage, location, etc.) and patient characteristics. The surgeon's philosophy regarding the radicality of lymphadenectomy will also play a role in surgical approach. For example, the author favors a transhiatal approach for patients with high-grade dysplasia in Barrett's esophagus and in patients with GEJ tumors and poor pulmonary reserve. Surgeons have investigated the use of video-assisted thoracoscopy (VATS) and laparoscopy in the resection of esophageal cancer. VATS potentially avoids the risks of thoracotomy yet allows mobilization of the thoracic esophagus under direct visual control. Feasibility has been confirmed [26]. Radical lymph node dissection requires considerable expertise and decreased postoperative complications have not been proven. At present, this technique is still investigational. The reader can appreciate from Figure 3 that a complete lymph node dissection for esophageal cancer is a formidable task and includes cervical, thoracic, and abdominal dissections (three-field lymphadenectomy). The controversy of whether an extended lymphadenectomy improves survival versus staging is ongoing. Surgeons have demonstrated a 20% to 30% incidence of cervical lymph node metastases in patients undergoing three-field lymphadenectomy. Japanese surgeons have championed this aggressive surgical approach, and some have demonstrated survival benefit [27-29]. Three-field lymphadenectomy is not common in the United States, although surgeons have confirmed Japanese findings even for distal adenocarcinomas [30]. This approach requires considerable surgical skill to avoid postoperative complications. Extended lymphadenectomy has a marked impact on postoperative respiratory function with increased tracheal bronchorrhea and subsequent need for mechanical ventilation and impaired recurrent laryngeal nerve function. Survival benefit must justify the increased postoperative morbidity, and more studies are needed. At present, surgeons performing a transhiatal esophagectomy include abdominal and lower mediastinal lymph nodes in the resection. The transthoracic approach allows a two-field lymphadenectomy. The aggressiveness of the lymph node harvest depends mainly on the surgeon and the pathologist's diligence. Understaging of esophageal cancer is therefore very common. The majority of surgeons use the stomach as the conduit of choice for reconstruction. It is easily mobilized, has excellent vascular supply, and in almost all cases reaches to the neck and base of the tongue. The bed of the resected esophagus is the favored route of reconstruction, although some surgeons use the substernal route. If the stomach cannot be used because of previous gastrectomy or involvement by tumor, most surgeons would elect to use the colon as the replacement conduit. Either the right or left colon can be employed. The author favors the left colon based on the reliable ascending branch of the left colic artery. With its required three anastomoses for gastrointestinal continuity, morbidity is greater; however, functional results are excellent.
Many surgical series in the last decade have demonstrated mortality rates under 10% for esophageal resection, and several document mortality less than 5%. Careful patient selection and preparation, improvements in perioperative management, and experience play a role. Esophageal resection is not an operation for the occasional surgeon. A recent retrospective review confirmed that surgeons who perform six or more esophagectomies per year had significantly lower operative mortality [31]. Despite decreases in mortality, however, esophagectomy remains a highly morbid procedure. It is not uncommon to see surgical series quote a 30% to 50% complication rate. As noted previously, controversy has raged over whether surgical approach (transhiatal versus transthoracic) alters the rate and type of complications. Table 3 compares complications after transthoracic esophagectomy reported in four recent series [24, 32-34] to a collected review of 1,192 patients undergoing transhiatal esophagectomy [35].
A potentially harmful surgical complication is anastomotic leak. It does not appear to be related to technique (one-layer versus two-layer versus stapled anastomosis), but it is more frequently reported when a cervical esophageal anastomosis is performed [24, 34]. However, cervical leaks are easily managed conservatively and seldom result in mortality. Thoracic leaks can also be managed conservatively when they are contained, but overt dehiscence can lead to sepsis and death. Anastomotic technique and occurrences of leak can result in postoperative strictures. Although clearly impacting on quality of life, greater than 90% to 95% of strictures can be managed easily by bougienage. The placement of the anastomosis in the neck and a radical lymphadenectomy with bilateral recurrent nerve dissection puts the patient at risk for recurrent laryngeal nerve palsy and paralysis. The incidence of injury may be as high as 70% for extended lymphadenectomy [29] and has been reported as 11% in a collective review of patients undergoing transhiatal esophagectomy [35]. Chylothorax can occur in both the transhiatal and transthoracic approaches. Aggressive management and early (<7 days) reoperation with thoracic duct ligation are recommended when output is over one liter per day. The author has had excellent success with talc slurry via chest thoracostomy when the output has been one liter or less per day. Two applications are usually necessary. Cardiac complications are quite common but usually minor as manifested by atrial arrhythmias. Pulmonary complications are the leading cause of major complications in most contemporary series. In the author's practice, hospital-acquired pneumonia has been the most frequent precipitating event eventually leading to mortality. This has been reported by others [24, 35]. The patient's baseline pulmonary function, nutritional status, perhaps the performance of thoracotomy, extent of preoperative adjuvant treatment, and extent of lymphadenectomy are factors in the occurrence of respiratory complications. As one of my residents said: "Big operation, big complications!" Esophagectomy is a testament to this observation.
The use of neoadjuvant therapy adds potential morbidity for the patient. Induction chemotherapy with cisplatin and 5-fluorouracil (5-FU) has been fairly well tolerated. Kelsen et al. [36] reported It appears that the addition of three induction chemotherapeutic drugs to hyperfractionated radiotherapy increases toxicity substantially [40, 41]. In the regimen reported by Orringer et al. [40], hematologic toxicity was common (63% febrile neutropenia, 23% thrombocytopenia, 33% requiring blood transfusion). Radiation-induced esophagitis occurred in 86%. Wright et al. [41] added paclitaxel to cisplatin and 5-FU with hyperfractionated radiotherapy, and toxicity was unacceptable.
Survival depends largely on the stage of the tumor. Five-year survival rates by stage from several recent series [32, 42-46] are shown in Table 4. Although the series are not strictly comparable, the unfavorable impact of regional node involvement is clearly evident. Patients who have residual microscopic evidence of tumor at the resection margins (R1 versus R0 resection) or who have gross evidence of residual tumor after resection do not survive five years. Most series demonstrate no difference in stage-specific survival between adenocarcinoma and squamous carcinoma. There is evidence that the number of positive lymph nodes has a significant impact on overall survival ( Fig. 5) [14, 47].
It is now accepted that Barrett's esophagus is a premalignant condition. The enrollment of such patients in endoscopic surveillance programs has led to the detection of early adenocarcinomas (tumors confined to the mucosa or submucosa) and subsequent improved survival [48-51] ( Fig. 6). Although the author believes esophagectomy should be considered for patients once high-grade dysplasia is identified, some investigators feel that continued rigorous endoscopic surveillance can differentiate high-grade dysplasia from early malignant change.
Because esophagectomy is so often palliative, quality of life is an important issue. Valid measures must come from patient self-assessment. Studies have indicated that quality of life after esophageal resection is primarily impaired by physical limitations (ability to do strenuous activities) and disease symptoms (fatigue, swallowing difficulties) [52]. Patients with anastomotic strictures have a lower global quality of life and high rate of disease symptoms. Self-rating of functional scale and disease symptoms deteriorates after surgery and may take six to nine months to improve. The most significant factor in determining postoperative quality of life is tumor recurrence. Delayed gastric emptying and delayed gastroesophageal reflux have been shown to be more common after transthoracic esophagectomy compared to the transhiatal approach. Erythromycin may be useful in improving emptying of the denervated stomach. The reflux is difficult to treat, as the major component is bile. Diarrhea has been ascribed to truncal vagotomy, but usually resolves over time. Postprandial nausea, fullness, etc., usually respond to dietary manipulation.
The lack of desired success in surgical management of esophageal cancer has led to the investigation of preoperative and postoperative adjuvant therapies. As discussed, the biology of esophageal cancer and the anatomy of the esophagus make an R0 resection difficult to achieve. Although many phase II adjuvant studies have been completed, this discussion will focus upon phase III studies. The rationale for neoadjuvant (preoperative or induction) therapy has been to A) improve local control and enhance resectability of the tumor; B) assess response directly in the primary tumor; C) treat micrometastases when chemotherapy is used, and D) treat the patient when potential toxic reactions can be tolerated. Postoperative adjuvant therapy allows treatment to be based on precise pathologic findings. Postoperative radiation therapy (RT) has been added in order to improve local control, and chemotherapy has been given to avoid or delay systemic metastases.
Preoperative RT
Induction Chemotherapy
Induction Chemoradiotherapy The low rate of complete pathologic responses with preoperative chemotherapy alone has led to the investigation of combining RT with chemotherapy to increase local tumor control. Phase II studies have shown a much higher rate of pCRs, in the range of 20% to 40%. Recent phase II studies utilizing taxol have shown particularly high response rates. The most common chemotherapy regimen has been 5-FU and cisplatin with concurrent RT in the range of 40 to 45 Gy. In terms of survival, the best results again correlate with tumor response. Control of locoregional disease does appear to be enhanced in these studies. Phase III studies are summarized in Table 6 [38, 39, 63-65]. Despite great enthusiasm for this approach, the results indicate that it cannot yet be considered standard and needs to be done in the setting of controlled trials. Obviously, any investigation that would identify responders would greatly benefit these patients.
Postoperative Adjuvant Therapy The rationale for postoperative RT in surgery is to improve locoregional control and hopefully impact survival. Three recent controlled studies [66-68] have shown no benefit in terms of survival to patients who receive postoperative radiotherapy. Quality of life was measured in one trial, and adjuvant radiotherapy delayed return of overall function and increased the incidence of fibrotic anastomotic strictures [66]. However, a lower rate of local recurrences has been noted in some studies [68, 69], although limited to patients with palliative resections in one trial [68]. The use of postoperative chemotherapy holds great appeal since the prevalence of occult micrometastases at the time of surgical resection is high, and results continue to be unfavorable even after radical resection (i.e., en bloc esophagectomy and three-field lymphadenectomy). The extent of lymph node disease is an indicator of the risk of distant micrometastases and is the strongest prognostic factor in most surgical series. The utilization of chemotherapy in the postoperative setting has been systemically studied by the Japanese. It should be noted that these trials are restricted to squamous cell carcinoma of the esophagus. In the latest reported prospective randomized trial, 100 patients undergoing radical surgery alone were compared with 105 patients who underwent two courses of postoperative chemotherapy consisting of cisplatin and vindesine [70]. There were no differences in five-year survival between the two groups, even with lymph node stratification. The use of postoperative adjuvant chemotherapy after preoperative therapy in patients who are demonstrated responders needs further investigation. Such studies are hampered by the inability of patients to complete chemotherapy after induction therapy and major resection.
Surgery for esophageal cancer remains the gold standard of treatment. It offers excellent relief of dysphagia, and although morbidity is high, mortality of surgical resection is now under 10%. Attention to staging, patient selection, technical detail, and careful perioperative management optimize surgical results. It remains to be seen whether more radical resection offers improved survival and for what cost. With the exception of monitoring patients with Barrett's esophagus, the basic biology of esophageal cancer dictates a late presentation and advanced stage in most cases. It is not surprising that physicians have embraced adjuvant treatment strategies since survival is poor. However, at present enthusiasm must be tempered by the results of well-constructed phase III studies. We need to improve staging, develop techniques to identify patients who are potential responders to adjuvant treatment, and continue to test strategies in a rigorous scientific manner. There are those who consider esophageal cancer a nonsurgical disease. Although open-minded to this concept, I would argue that surgery now plays a pivotal role in determining future treatment allocation to subsets of patients with esophageal cancer. Much work remains to be done!
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